give the selection cards their own parts instead of label blobs

The cards were assembled from plain labels carrying whole blocks of text.
Replace those with the widget vocabulary the requirements describe, so a part
means the same thing wherever it appears and a card is a list of parts rather
than a string builder.

The parts, all free of Simulation and GameConfig -- they take prepared values,
and the contents work out what those are:
- StatRow, BarRow, SectionBox: label/value line, captioned fill bar, captioned
  group. The bar is one part for three things: construction progress,
  production progress, and HP.
- ItemChip / ItemChipRow: buffered items as icon, count and sub-line
  (REQ-UI-SINGLE-SELECTION). An input chip carries its per-cycle amount, an
  output chip its count against the buffer capacity. The chips are rebuilt only
  when the set of items changes, so a 30 Hz refresh moves numbers rather than
  widgets.
- RecipeSummaryRow: inputs, arrow, outputs, cycle time (REQ-UI-RECIPE-SUMMARY),
  which is now the panel's only display of the cycle time.
- CountRow, StatusPill, EmptyNote.

Behaviour that changed with them:
- The station card shows damage, range and fire rate as the requirement asks
  (REQ-UI-STATION-STATS-PANEL) rather than the combined DPS it showed before.
- A ship's behaviour moves from a stats row into the card header
  (REQ-UI-SHIP-BEHAVIOR). ShipStatsPanel keeps setBehavior for the balancing
  tool's inspect window, which has no header to put it in.
- A construction site's card shows a progress bar and the "no buffers until
  built" note (REQ-UI-SELECTION-CARD), and now also its recipe summary, since
  that is configuration and a site carries it (REQ-BLD-SITE-CONFIG). Costing a
  shipyard site's schematic needed computeShipyardRequiredMaterials to take a
  stored configuration as well as a live building -- one overload, so the
  module sum still exists once.

ShipStatsPanel is rebuilt on StatRow, BarRow and SectionBox, so the selection
card, the layout dialog's design preview and the balancing tool read alike.
Those three parts are compiled into the balancing target, which does not link
the ui library; keeping them sim-free is what makes that possible, and the
build enforces it.

Build clean, 541 tests pass, app and balancing tool both run with no Qt
warnings. Visual check pending.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JcReq7hVk4KUPhTDKWAG7K

docs/architecture.md

@@ -125,6 +125,7 @@ Three product targets plus tests:
 
 - `lib/` — simulation + config. Depends on Qt Core + Qt Gui, toml++, tinyexpr. No QtWidgets.
 - `ui/` — QtWidgets + `QOpenGLWidget` code: header bar, game world view, selection panel, build button bar. Depends on `lib` and on Qt's OpenGL widgets module.
+  - `ui/selection/` — the selection panel's contents. `SelectionPanel` itself only arbitrates between the two selection categories, picks a card from the catalog (`SelectionContentFactory`), and hosts one at a time; each kind of selection has its own `SelectionContent` subclass assembled from shared parts (REQ-UI-SELECTION-CARD, REQ-UI-SELECTION-CONTENT).
 - `app/` — thin `main()` that creates the simulation, the UI, and wires them together. Depends on `ui`.
 - `tests/` — Catch2 tests. Links only against `lib`.
 

src/CMakeLists.txt

@@ -10,7 +10,12 @@ set(TARGET_LIB_INCLUDE_DIRS
     "${CMAKE_CURRENT_SOURCE_DIR}/lib"
     "${CMAKE_CURRENT_SOURCE_DIR}/external"
 )
-set(TARGET_UI_INCLUDE_DIRS "${CMAKE_CURRENT_SOURCE_DIR}/ui")
+set(TARGET_UI_INCLUDE_DIRS
+    "${CMAKE_CURRENT_SOURCE_DIR}/ui"
+    # The balancing target compiles a few ui files into itself rather than linking the
+    # ui library, and the ship stats panel is built from the selection card's parts.
+    "${CMAKE_CURRENT_SOURCE_DIR}/ui/selection"
+)
 set(TARGET_TEST_INCLUDE_DIRS "${CMAKE_CURRENT_SOURCE_DIR}/test")
 set(TARGET_BALANCING_INCLUDE_DIRS "${CMAKE_CURRENT_SOURCE_DIR}/balancing")
 
@@ -78,6 +83,7 @@ unset(SRCS)
 
 set(HDRS)
 set(SRCS)
+set(UI_INCLUDE_PATH)
 
 add_subdirectory(ui)
 
@@ -106,6 +112,7 @@ set_target_properties(${TARGET_UI_NAME} PROPERTIES
 )
 target_include_directories(${TARGET_UI_NAME} PUBLIC
     "${TARGET_UI_INCLUDE_DIRS}"
+    "${UI_INCLUDE_PATH}"
     "${TARGET_LIB_INCLUDE_DIRS}"
     "${LIB_INCLUDE_PATH}"
 )

src/balancing/CMakeLists.txt

@@ -7,6 +7,12 @@ SET(HDRS
 	${CMAKE_CURRENT_SOURCE_DIR}/BalancingWindow.h
 	${CMAKE_CURRENT_SOURCE_DIR}/InspectWindow.h
 	${CMAKE_CURRENT_SOURCE_DIR}/../ui/ShipStatsPanel.h
+	# The card parts the ship stats panel is built from. They are deliberately free of
+	# Simulation and GameConfig, which is what lets them come along here.
+	${CMAKE_CURRENT_SOURCE_DIR}/../ui/selection/StatRow.h
+	${CMAKE_CURRENT_SOURCE_DIR}/../ui/selection/BarRow.h
+	${CMAKE_CURRENT_SOURCE_DIR}/../ui/selection/SectionBox.h
+	${CMAKE_CURRENT_SOURCE_DIR}/../ui/selection/SelectionNames.h
 	${CMAKE_CURRENT_SOURCE_DIR}/../ui/VisualsConfig.h
 	${CMAKE_CURRENT_SOURCE_DIR}/../ui/VisualsLoader.h
 	# Shared world-space shapes so the arena keeps looking like the game
@@ -26,6 +32,10 @@ SET(SRCS
 	${CMAKE_CURRENT_SOURCE_DIR}/BalancingWindow.cpp
 	${CMAKE_CURRENT_SOURCE_DIR}/InspectWindow.cpp
 	${CMAKE_CURRENT_SOURCE_DIR}/../ui/ShipStatsPanel.cpp
+	${CMAKE_CURRENT_SOURCE_DIR}/../ui/selection/StatRow.cpp
+	${CMAKE_CURRENT_SOURCE_DIR}/../ui/selection/BarRow.cpp
+	${CMAKE_CURRENT_SOURCE_DIR}/../ui/selection/SectionBox.cpp
+	${CMAKE_CURRENT_SOURCE_DIR}/../ui/selection/SelectionNames.cpp
 	${CMAKE_CURRENT_SOURCE_DIR}/../ui/VisualsLoader.cpp
 	${CMAKE_CURRENT_SOURCE_DIR}/../ui/WorldPrimitives.cpp
 	PARENT_SCOPE

src/lib/sim/ProductionRules.cpp

@@ -45,9 +45,17 @@ bool recipeInputsAvailable(const Building& b, const RecipeDef& recipe)
 }
 std::map<std::string, int>
 computeShipyardRequiredMaterials(const GameConfig& config, const Building& b)
+{
+    return computeShipyardRequiredMaterials(config, b.recipeId, b.shipLayout);
+}
+
+std::map<std::string, int>
+computeShipyardRequiredMaterials(const GameConfig& config,
+                                 const std::string& recipeId,
+                                 const std::optional<ShipLayoutConfig>& shipLayout)
 {
     std::map<std::string, int> requiredMaterials;
-    const ShipDef* shipDef = config.ships.findShipDef(b.recipeId);
+    const ShipDef* shipDef = config.ships.findShipDef(recipeId);
     if (!shipDef)
     {
         return requiredMaterials;
@@ -56,9 +64,9 @@ computeShipyardRequiredMaterials(const GameConfig& config, const Building& b)
     {
         requiredMaterials[ing.item] += ing.amount;
     }
-    if (b.shipLayout.has_value())
+    if (shipLayout.has_value())
     {
-        for (const PlacedModule& pm : b.shipLayout->placedModules)
+        for (const PlacedModule& pm : shipLayout->placedModules)
         {
             const ModuleDef* modDef = config.modules.findModuleDef(pm.moduleId);
             if (!modDef)

src/lib/sim/ProductionRules.h

@@ -38,6 +38,12 @@ bool recipeInputsAvailable(const Building& b, const RecipeDef& recipe);
 std::map<std::string, int> computeShipyardRequiredMaterials(const GameConfig& config,
                                                             const Building& b);
 
+// The same sum over a stored configuration rather than an operational building, so a
+// construction site's schematic can be costed before it is built (REQ-BLD-SITE-CONFIG).
+std::map<std::string, int> computeShipyardRequiredMaterials(
+    const GameConfig& config, const std::string& recipeId,
+    const std::optional<ShipLayoutConfig>& shipLayout);
+
 // True when a production cycle could start right now, ignoring output-buffer space.
 bool hasInputsToStart(const GameConfig& config, const Building& b);
 

src/ui/BuildButtonBar.cpp

@@ -2,9 +2,7 @@
 
 #include <string>
 
-#include <QByteArray>
 #include <QColor>
-#include <QFile>
 #include <QFont>
 #include <QFontMetrics>
 #include <QGuiApplication>
@@ -15,12 +13,11 @@
 #include <QPixmap>
 #include <QPushButton>
 #include <QRect>
-#include <QRegularExpression>
 #include <QSignalMapper>
 #include <QSize>
 #include <QString>
-#include <QSvgRenderer>
 
+#include "BuildingIconCache.h"
 #include "BuildingType.h"
 #include "BuildingTypeSelectedEvent.h"
 #include "DeconstructModeToggleRequestedEvent.h"
@@ -54,45 +51,15 @@ namespace
     // Gap between the chip icon and the cost line on a button face.
     const int kFaceGapPx = 2;
 
-    // Rasterizes a chip SVG straight at its on-screen size times the device pixel
-    // ratio, so it stays crisp without a downscale step.
-    QPixmap renderChip(const QByteArray& svg)
-    {
-        const qreal dpr = qApp ? qApp->devicePixelRatio() : 1.0;
-        QSvgRenderer renderer(svg);
-        QPixmap pixmap(static_cast<int>(kIconSize.width()  * dpr),
-                       static_cast<int>(kIconSize.height() * dpr));
-        pixmap.setDevicePixelRatio(dpr);
-        pixmap.fill(Qt::transparent);
-        QPainter painter(&pixmap);
-        renderer.render(&painter);
-        return pixmap;
-    }
-
-    // Normal and grey-background chip pixmaps for a "<id>.svg" file. Empty pixmaps if
-    // the file cannot be read; the caller then falls back to a name caption
+    // Normal and grey-background chip pixmaps for one icon name. Empty pixmaps if the
+    // file cannot be read; the caller then falls back to a name caption
     // (REQ-UI-BUILD-ICON).
     struct ChipPixmaps { QPixmap normal; QPixmap grey; };
-    ChipPixmaps loadChipPixmaps(const QString& path)
+    ChipPixmaps loadChipPixmaps(BuildingIconCache& icons, const std::string& iconName)
     {
-        QFile file(path);
-        if (!file.open(QIODevice::ReadOnly)) { return {}; }
-        const QByteArray svg = file.readAll();
-
         ChipPixmaps result;
-        result.normal = renderChip(svg);
-
-        // Recolor only the chip background: the first "#rrggbb" fill in the file is the
-        // rounded background rect; the white glyph uses fill="none" and is left alone.
-        QString greyed = QString::fromUtf8(svg);
-        static const QRegularExpression fillPattern(QStringLiteral("fill=\"#[0-9a-fA-F]{6}\""));
-        const QRegularExpressionMatch match = fillPattern.match(greyed);
-        if (match.hasMatch())
-        {
-            greyed.replace(match.capturedStart(), match.capturedLength(),
-                           QStringLiteral("fill=\"#5f636e\""));
-        }
-        result.grey = renderChip(greyed.toUtf8());
+        result.normal = icons.getChip(iconName, kIconSize.width());
+        result.grey   = icons.getGreyChip(iconName, kIconSize.width());
         return result;
     }
 
@@ -181,12 +148,12 @@ namespace
 
 
 BuildButtonBar::BuildButtonBar(Simulation* sim, const GameConfig* config,
-                               const std::string& iconDir,
+                               BuildingIconCache* buildingIcons,
                                ItemIconCache* itemIcons, QWidget* parent)
     : QWidget(parent)
     , m_sim(sim)
     , m_config(config)
-    , m_iconDir(iconDir)
+    , m_buildingIcons(buildingIcons)
     , m_itemIcons(itemIcons)
 {
     // The bar floats over the rendered world rather than sitting in a panel, so it
@@ -231,13 +198,12 @@ BuildButtonBar::BuildButtonBar(Simulation* sim, const GameConfig* config,
         const QString name = (def.type == BuildingType::TunnelEntry)
             ? tr("Tunnel")
             : QString::fromStdString(toDisplayName(def.id));
+
         // Icon file name matches the building id (REQ-UI-BUILD-ICON); Tunnel Entry's
         // "tunnel_entry.svg" serves the shared Tunnel button.
-        const QString iconPath = QString::fromStdString(m_iconDir) + "/"
-            + QString::fromStdString(def.id) + ".svg";
-
         const ButtonFace face = buildButtonFace(
-            loadChipPixmaps(iconPath), InputMapper::getBuildHotkeyLabel(def.type), name,
+            loadChipPixmaps(*m_buildingIcons, def.id),
+            InputMapper::getBuildHotkeyLabel(def.type), name,
             QString::number(def.cost), blockIcon, font(), palette());
 
         QPushButton* btn = new QPushButton(this);
@@ -268,7 +234,7 @@ BuildButtonBar::BuildButtonBar(Simulation* sim, const GameConfig* config,
     // Having no cost, it shows its name where the building buttons show theirs
     // (REQ-UI-DECONSTRUCT-BUTTON), and its Q toggle as the badge (REQ-UI-HOTKEYS).
     const ButtonFace deconstructFace = buildButtonFace(
-        loadChipPixmaps(QString::fromStdString(m_iconDir) + "/deconstruct.svg"),
+        loadChipPixmaps(*m_buildingIcons, "deconstruct"),
         QStringLiteral("Q"), tr("Deconstruct"), tr("Deconstruct"), QPixmap(),
         font(), palette());
 

src/ui/BuildButtonBar.h

@@ -20,6 +20,7 @@
 
 class QPushButton;
 class Simulation;
+class BuildingIconCache;
 class ItemIconCache;
 
 // The build menu: one horizontal row of build buttons floating over the game world
@@ -36,13 +37,11 @@ class BuildButtonBar : public QWidget,
     Q_OBJECT
 
 public:
-    // iconDir is the directory holding the per-building "<id>.svg" chip icons
-    // (REQ-UI-BUILD-ICON), read from disk at runtime like the config files.
-    // itemIcons is the window-wide per-item icon cache and supplies the
-    // building_block icon shown in each button's cost (REQ-UI-BUILD-COST). Not
-    // owned; must outlive this widget.
+    // buildingIcons supplies each button's chip icon (REQ-UI-BUILD-ICON) and itemIcons
+    // the building_block icon shown in each button's cost (REQ-UI-BUILD-COST). Both are
+    // window-wide caches; neither is owned, and both must outlive this widget.
     BuildButtonBar(Simulation* sim, const GameConfig* config,
-                   const std::string& iconDir, ItemIconCache* itemIcons,
+                   BuildingIconCache* buildingIcons, ItemIconCache* itemIcons,
                    QWidget* parent = nullptr);
     ~BuildButtonBar() override;
 
@@ -85,8 +84,8 @@ private slots:
 private:
     Simulation*                      m_sim;
     const GameConfig*                m_config;
-    std::string                      m_iconDir;
-    ItemIconCache*                   m_itemIcons;  // Not owned; lives in MainWindow.
+    BuildingIconCache*               m_buildingIcons;  // Not owned; lives in MainWindow.
+    ItemIconCache*                   m_itemIcons;      // Not owned; lives in MainWindow.
     std::vector<BuildingType>        m_types;
     std::vector<QPushButton*>        m_buttons;
     std::map<BuildingType, int>      m_costs;

src/ui/BuildingIconCache.cpp

@@ -0,0 +1,120 @@
+#include "BuildingIconCache.h"
+
+#include <QFile>
+#include <QGuiApplication>
+#include <QPainter>
+#include <QRegularExpression>
+#include <QSvgRenderer>
+
+namespace
+{
+
+// Chip background color for a build button the player cannot afford
+// (REQ-UI-BUILD-DISABLED). Part of the icon rather than of any widget's palette, so it
+// lives with the recoloring step.
+const char* const kGreyFill = "fill=\"#5f636e\"";
+
+}  // namespace
+
+
+BuildingIconCache::BuildingIconCache(const QString& iconDir)
+    : m_iconDir(iconDir)
+{
+}
+
+const QByteArray& BuildingIconCache::getSvg(const std::string& iconName)
+{
+    const std::map<std::string, QByteArray>::const_iterator cached =
+        m_svgByName.find(iconName);
+    if (cached != m_svgByName.end())
+    {
+        return cached->second;
+    }
+
+    // An absent or unreadable file caches an empty byte array so it is not retried;
+    // a missing icon is not an error (REQ-UI-BUILD-ICON).
+    QByteArray svg;
+    QFile file(m_iconDir + "/" + QString::fromStdString(iconName) + ".svg");
+    if (file.open(QIODevice::ReadOnly))
+    {
+        svg = file.readAll();
+    }
+    return m_svgByName.emplace(iconName, std::move(svg)).first->second;
+}
+
+const QByteArray& BuildingIconCache::getGreySvg(const std::string& iconName)
+{
+    const std::map<std::string, QByteArray>::const_iterator cached =
+        m_greySvgByName.find(iconName);
+    if (cached != m_greySvgByName.end())
+    {
+        return cached->second;
+    }
+
+    // Recolor only the chip background: the first "#rrggbb" fill in the file is the
+    // rounded background rect; the white glyph uses fill="none" and is left alone.
+    const QByteArray& svg = getSvg(iconName);
+    QByteArray greyed = svg;
+    if (!svg.isEmpty())
+    {
+        QString text = QString::fromUtf8(svg);
+        static const QRegularExpression fillPattern(
+            QStringLiteral("fill=\"#[0-9a-fA-F]{6}\""));
+        const QRegularExpressionMatch match = fillPattern.match(text);
+        if (match.hasMatch())
+        {
+            text.replace(match.capturedStart(), match.capturedLength(),
+                         QLatin1String(kGreyFill));
+        }
+        greyed = text.toUtf8();
+    }
+    return m_greySvgByName.emplace(iconName, std::move(greyed)).first->second;
+}
+
+bool BuildingIconCache::hasIcon(const std::string& iconName)
+{
+    return !getSvg(iconName).isEmpty();
+}
+
+QPixmap BuildingIconCache::getChip(const std::string& iconName, int sizePx)
+{
+    return getPixmap(iconName, getSvg(iconName), sizePx);
+}
+
+QPixmap BuildingIconCache::getGreyChip(const std::string& iconName, int sizePx)
+{
+    return getPixmap("grey:" + iconName, getGreySvg(iconName), sizePx);
+}
+
+QPixmap BuildingIconCache::getPixmap(const std::string& cacheKey,
+                                     const QByteArray& svg, int sizePx)
+{
+    if (sizePx <= 0)
+    {
+        return QPixmap();
+    }
+
+    const std::pair<std::string, int> key(cacheKey, sizePx);
+    const std::map<std::pair<std::string, int>, QPixmap>::const_iterator cached =
+        m_pixmapCache.find(key);
+    if (cached != m_pixmapCache.end())
+    {
+        return cached->second;
+    }
+
+    QPixmap pixmap;
+    if (!svg.isEmpty())
+    {
+        // Rasterized straight at its on-screen size times the device pixel ratio, so it
+        // stays crisp without a downscale step.
+        const qreal dpr = qApp ? qApp->devicePixelRatio() : 1.0;
+        QSvgRenderer renderer(svg);
+        pixmap = QPixmap(static_cast<int>(sizePx * dpr), static_cast<int>(sizePx * dpr));
+        pixmap.setDevicePixelRatio(dpr);
+        pixmap.fill(Qt::transparent);
+        QPainter painter(&pixmap);
+        painter.setRenderHint(QPainter::Antialiasing, true);
+        renderer.render(&painter);
+    }
+    return m_pixmapCache.emplace(key, std::move(pixmap)).first->second;
+}

src/ui/BuildingIconCache.h

@@ -0,0 +1,55 @@
+#pragma once
+
+#include <map>
+#include <string>
+#include <utility>
+
+#include <QByteArray>
+#include <QPixmap>
+#include <QString>
+
+// Rasterizes and caches the per-building chip SVGs (REQ-UI-BUILD-ICON). A chip is a
+// rounded colored background bearing a white line glyph, loaded from a directory with
+// one file per building named after the building's id (e.g. "belt.svg"). Shared by the
+// build button bar and the selection panel's card header (REQ-UI-SELECTION-CARD) so the
+// rasterization is not duplicated.
+//
+// A missing icon file is not an error: hasIcon() returns false for it and the caller
+// falls back (a name caption on a build button, a bare title in the panel header).
+class BuildingIconCache
+{
+public:
+    // iconDir is the directory holding the "<id>.svg" chip files (typically
+    // "<configDir>/../icons/buildings").
+    explicit BuildingIconCache(const QString& iconDir);
+
+    // True if a chip SVG file exists for the given icon name. Loads the file's bytes on
+    // first query and remembers the result (including absence) so repeated calls are
+    // cheap. The name is a building id for the building buttons, but need not be one --
+    // the Deconstruct button's "deconstruct" chip goes through the same path.
+    bool hasIcon(const std::string& iconName);
+
+    // The chip rasterized to a transparent sizePx*sizePx pixmap at the device pixel
+    // ratio, cached per (name, size). Returns a null pixmap when the file is missing.
+    QPixmap getChip(const std::string& iconName, int sizePx);
+
+    // As getChip(), but with the chip background recolored grey and the glyph left
+    // alone, for a build button the player cannot currently afford
+    // (REQ-UI-BUILD-DISABLED).
+    QPixmap getGreyChip(const std::string& iconName, int sizePx);
+
+private:
+    // Raw SVG bytes for an icon name, loading and caching them on first access. An
+    // absent file caches an empty QByteArray so it is not retried.
+    const QByteArray& getSvg(const std::string& iconName);
+    // The same SVG with its background fill replaced by grey, cached alongside.
+    const QByteArray& getGreySvg(const std::string& iconName);
+    // Shared rasterize-and-cache step. cacheKey distinguishes the normal and grey
+    // variants of one icon name within the single pixmap cache.
+    QPixmap getPixmap(const std::string& cacheKey, const QByteArray& svg, int sizePx);
+
+    QString                           m_iconDir;
+    std::map<std::string, QByteArray> m_svgByName;
+    std::map<std::string, QByteArray> m_greySvgByName;
+    std::map<std::pair<std::string, int>, QPixmap> m_pixmapCache;
+};

src/ui/CMakeLists.txt

@@ -1,3 +1,5 @@
+add_subdirectory(selection)
+
 SET(HDRS
     ${HDRS}
     ${CMAKE_CURRENT_SOURCE_DIR}/VisualsConfig.h
@@ -12,7 +14,6 @@ SET(HDRS
     ${CMAKE_CURRENT_SOURCE_DIR}/HeaderBar.h
     ${CMAKE_CURRENT_SOURCE_DIR}/BuildButtonBar.h
     ${CMAKE_CURRENT_SOURCE_DIR}/SelectionPanel.h
-    ${CMAKE_CURRENT_SOURCE_DIR}/FieldSelectionPanel.h
     ${CMAKE_CURRENT_SOURCE_DIR}/BlueprintLibrary.h
     ${CMAKE_CURRENT_SOURCE_DIR}/BlueprintSelectionDialog.h
     ${CMAKE_CURRENT_SOURCE_DIR}/ShipLayoutDialog.h
@@ -22,10 +23,16 @@ SET(HDRS
     ${CMAKE_CURRENT_SOURCE_DIR}/RecipeSelectionDialog.h
     ${CMAKE_CURRENT_SOURCE_DIR}/RecipeTooltip.h
     ${CMAKE_CURRENT_SOURCE_DIR}/ItemIconCache.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/BuildingIconCache.h
     ${CMAKE_CURRENT_SOURCE_DIR}/IconCaption.h
     PARENT_SCOPE
 )
 
+set(UI_INCLUDE_PATH
+    ${UI_INCLUDE_PATH}
+    PARENT_SCOPE
+)
+
 SET(SRCS
     ${SRCS}
     ${CMAKE_CURRENT_SOURCE_DIR}/VisualsLoader.cpp
@@ -38,7 +45,6 @@ SET(SRCS
     ${CMAKE_CURRENT_SOURCE_DIR}/HeaderBar.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/BuildButtonBar.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/SelectionPanel.cpp
-    ${CMAKE_CURRENT_SOURCE_DIR}/FieldSelectionPanel.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/BlueprintLibrary.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/BlueprintSelectionDialog.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/ShipLayoutDialog.cpp
@@ -48,6 +54,7 @@ SET(SRCS
     ${CMAKE_CURRENT_SOURCE_DIR}/RecipeSelectionDialog.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/RecipeTooltip.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/ItemIconCache.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/BuildingIconCache.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/IconCaption.cpp
     PARENT_SCOPE
 )

src/ui/FieldSelectionPanel.cpp

@@ -1,403 +0,0 @@
-#include "FieldSelectionPanel.h"
-
-#include <algorithm>
-#include <map>
-#include <string>
-
-#include <QFont>
-#include <QLabel>
-#include <QStringList>
-#include <QVBoxLayout>
-
-#include "DebrisSystem.h"
-#include "DisplayName.h"
-#include "EntityAdmin.h"
-#include "FactionComponent.h"
-#include "GameConfig.h"
-#include "HealthComponent.h"
-#include "ModuleOwnerComponent.h"
-#include "SelectedBehaviorComponent.h"
-#include "ShipIdentityComponent.h"
-#include "ShipStatsCalculator.h"
-#include "ShipStatsPanel.h"
-#include "Simulation.h"
-#include "StationBodyComponent.h"
-#include "ThreatCostCalculator.h"
-#include "WeaponComponent.h"
-
-
-FieldSelectionPanel::FieldSelectionPanel(Simulation* sim,
-                                         const GameConfig* config,
-                                         QWidget* parent)
-    : QWidget(parent)
-    , m_sim(sim)
-    , m_config(config)
-{
-    // Zero margins and the same spacing as the enclosing SelectionPanel layout, so
-    // nesting the field widgets in this panel leaves their geometry unchanged.
-    m_layout = new QVBoxLayout(this);
-    m_layout->setContentsMargins(0, 0, 0, 0);
-    m_layout->setSpacing(4);
-    m_layout->setAlignment(Qt::AlignTop);
-
-    m_entityTitleLabel = new QLabel(this);
-    QFont titleFont = m_entityTitleLabel->font();
-    titleFont.setBold(true);
-    m_entityTitleLabel->setFont(titleFont);
-    m_layout->addWidget(m_entityTitleLabel);
-    m_entityTitleLabel->hide();
-
-    m_entityStatsPanel = new ShipStatsPanel(config, this);
-    m_layout->addWidget(m_entityStatsPanel);
-    m_entityStatsPanel->hide();
-
-    m_stationStatsLabel = new QLabel(this);
-    m_stationStatsLabel->setWordWrap(true);
-    m_layout->addWidget(m_stationStatsLabel);
-    m_stationStatsLabel->hide();
-
-    m_entitySummaryLabel = new QLabel(this);
-    m_entitySummaryLabel->setWordWrap(true);
-    m_layout->addWidget(m_entitySummaryLabel);
-    m_entitySummaryLabel->hide();
-
-    m_scrapLabel = new QLabel(this);
-    m_layout->addWidget(m_scrapLabel);
-    m_scrapLabel->hide();
-
-    hide();
-
-    registerForEvents();
-}
-
-FieldSelectionPanel::~FieldSelectionPanel()
-{
-    unregisterForEvents();
-}
-
-void FieldSelectionPanel::setSelectedEntities(const std::vector<entt::entity>& entities)
-{
-    m_selectedEntities = entities;
-    rebuild();
-}
-
-void FieldSelectionPanel::setSelectedDebris(const std::vector<entt::entity>& debris)
-{
-    m_selectedDebris = debris;
-    rebuild();
-}
-
-void FieldSelectionPanel::clearSelection()
-{
-    m_selectedEntities.clear();
-    m_selectedDebris.clear();
-    rebuild();
-}
-
-bool FieldSelectionPanel::hasSelection() const
-{
-    return !m_selectedEntities.empty() || !m_selectedDebris.empty();
-}
-
-void FieldSelectionPanel::hideAllWidgets()
-{
-    m_entityTitleLabel->hide();
-    m_entityStatsPanel->hide();
-    m_stationStatsLabel->hide();
-    m_entitySummaryLabel->hide();
-    m_scrapLabel->hide();
-}
-
-void FieldSelectionPanel::rebuild()
-{
-    if (!hasSelection())
-    {
-        // Nothing in the field category: take no space, leaving the panel to whatever
-        // the building category shows (REQ-UI-SELECTION-CATEGORIES).
-        hideAllWidgets();
-        hide();
-        return;
-    }
-
-    show();
-
-    EntityAdmin& admin = m_sim->getAdmin();
-
-    // A full single-object stats panel is shown only for a lone field object: one actor
-    // with no debris, or one piece of debris with no actors. As soon as the selection holds
-    // more than one object (multiple actors, multiple debris, or actors plus debris), the
-    // panel switches to the compact count summary (REQ-UI-FIELD-MULTI-SELECTION).
-    if (m_selectedEntities.size() == 1 && m_selectedDebris.empty())
-    {
-        m_entitySummaryLabel->hide();
-        m_scrapLabel->hide();
-        const entt::entity entity = m_selectedEntities.front();
-        if (admin.isValid(entity) && admin.hasAll<ShipIdentityComponent>(entity))
-        {
-            buildEntityShip(entity);
-        }
-        else if (admin.isValid(entity) && admin.hasAll<StationBodyComponent>(entity))
-        {
-            buildEntityStation(entity);
-        }
-        else
-        {
-            m_entityTitleLabel->hide();
-            m_entityStatsPanel->hide();
-            m_stationStatsLabel->hide();
-        }
-        return;
-    }
-
-    if (m_selectedEntities.empty() && m_selectedDebris.size() == 1)
-    {
-        // Single piece of debris: a "Debris" heading plus a "Scrap" stat row, styled like
-        // the ship/station stats panels (REQ-UI-DEBRIS-PANEL).
-        m_entitySummaryLabel->hide();
-        m_entityStatsPanel->hide();
-        m_stationStatsLabel->hide();
-        buildDebrisSingle();
-        return;
-    }
-
-    // More than one field object: a compact count summary. buildEntitySummary() appends the
-    // "Debris x N" and "Scrap x N" lines when debris is part of the selection.
-    m_entityTitleLabel->hide();
-    m_entityStatsPanel->hide();
-    m_stationStatsLabel->hide();
-    m_scrapLabel->hide();
-    buildEntitySummary();
-}
-
-void FieldSelectionPanel::refreshDisplay()
-{
-    if (!hasSelection()) { return; }
-
-    // Keep the live values current: the single-actor stats panel, the single-debris stats
-    // panel (whose Scrap row shrinks as it is collected), or the count summary (whose Scrap
-    // line shrinks likewise) — matching the layout chosen by rebuild()
-    // (REQ-UI-SHIP-STATS-PANEL, REQ-UI-DEBRIS-PANEL).
-    if (m_selectedEntities.size() == 1 && m_selectedDebris.empty())
-    {
-        refreshEntityStats();
-    }
-    else if (m_selectedEntities.empty() && m_selectedDebris.size() == 1)
-    {
-        buildDebrisSingle();
-    }
-    else
-    {
-        buildEntitySummary();
-    }
-}
-
-void FieldSelectionPanel::buildDebrisSingle()
-{
-    // "Debris" heading + a single "Scrap" stat row for the piece's remaining amount,
-    // mirroring the single-actor stats panels (REQ-UI-DEBRIS-PANEL).
-    m_entityTitleLabel->setText(tr("Debris"));
-    m_entityTitleLabel->show();
-    m_scrapLabel->setText(tr("Scrap: %1").arg(selectedDebrisScrapTotal()));
-    m_scrapLabel->show();
-}
-
-void FieldSelectionPanel::buildEntitySummary()
-{
-    EntityAdmin& admin = m_sim->getAdmin();
-
-    // Group actors by faction + kind + ship schematic, preserving first-seen order
-    // (REQ-UI-FIELD-MULTI-SELECTION).
-    std::vector<QString> keys;
-    std::map<QString, int> counts;
-    std::map<QString, QString> labels;
-
-    for (entt::entity entity : m_selectedEntities)
-    {
-        if (!admin.isValid(entity)) { continue; }
-        const bool isEnemy = admin.hasAll<FactionComponent>(entity)
-            && admin.get<FactionComponent>(entity).isEnemy;
-
-        QString key;
-        QString label;
-        if (admin.hasAll<ShipIdentityComponent>(entity))
-        {
-            const std::string& id = admin.get<ShipIdentityComponent>(entity).schematicId;
-            const QString name = QString::fromStdString(toDisplayName(id));
-            key = (isEnemy ? QStringLiteral("ship:enemy:") : QStringLiteral("ship:player:"))
-                + QString::fromStdString(id);
-            label = isEnemy ? tr("Enemy %1").arg(name) : name;
-        }
-        else if (admin.hasAll<StationBodyComponent>(entity))
-        {
-            key = isEnemy ? QStringLiteral("station:enemy") : QStringLiteral("station:player");
-            label = isEnemy ? tr("Enemy Defence Station") : tr("Player Defence Station");
-        }
-        else
-        {
-            continue;
-        }
-
-        if (counts.find(key) == counts.end())
-        {
-            keys.push_back(key);
-            labels[key] = label;
-        }
-        counts[key] += 1;
-    }
-
-    // One "<type> x <count>" line per group (matching the recipe tooltip and the building
-    // multi-selection). No total-count header, consistent with the building panel. When
-    // debris is part of the selection, a "Debris x <count>" line followed by a
-    // "Scrap x <total>" line are appended into the same label so the line spacing is
-    // uniform (REQ-UI-FIELD-MULTI-SELECTION, REQ-UI-DEBRIS-PANEL).
-    QStringList lines;
-    for (const QString& key : keys)
-    {
-        lines << tr("%1 x %2").arg(labels[key]).arg(counts[key]);
-    }
-    if (!m_selectedDebris.empty())
-    {
-        lines << tr("Debris x %1").arg(static_cast<int>(m_selectedDebris.size()));
-        lines << scrapTotalText();
-    }
-    m_entitySummaryLabel->setText(lines.join('\n'));
-    m_entitySummaryLabel->show();
-}
-
-void FieldSelectionPanel::buildEntityShip(entt::entity entity)
-{
-    EntityAdmin& admin = m_sim->getAdmin();
-    const ShipIdentityComponent& identity = admin.get<ShipIdentityComponent>(entity);
-    const HealthComponent& health = admin.get<HealthComponent>(entity);
-
-    m_entityTitleLabel->setText(tr("Ship: %1")
-        .arg(QString::fromStdString(identity.schematicId)));
-    m_entityTitleLabel->show();
-
-    const ShipStats stats = buildShipStatsFromEntity(admin, entity);
-    m_entityStatsPanel->refreshFromLive(stats, health.hp);
-    m_entityStatsPanel->setBehavior(
-        admin.get<SelectedBehaviorComponent>(entity).winner);
-    m_entityStatsPanel->setDebugDrawEnabled(m_debugDraw);
-
-    const ShipDef* schematicDef =
-        m_config->ships.findShipDef(identity.schematicId);
-    if (schematicDef)
-    {
-        const double threat = calculateShipThreatCost(
-            m_config->threatCosts, *m_config, schematicDef->id,
-            schematicDef->defaultModules);
-        m_entityStatsPanel->setThreatCost(threat);
-    }
-
-    m_entityStatsPanel->show();
-
-    m_stationStatsLabel->hide();
-}
-
-void FieldSelectionPanel::buildEntityStation(entt::entity entity)
-{
-    EntityAdmin& admin = m_sim->getAdmin();
-    const HealthComponent& health = admin.get<HealthComponent>(entity);
-
-    const bool isEnemy = admin.hasAll<FactionComponent>(entity)
-        && admin.get<FactionComponent>(entity).isEnemy;
-    m_entityTitleLabel->setText(isEnemy
-        ? tr("Enemy Defence Station")
-        : tr("Player Defence Station"));
-    m_entityTitleLabel->show();
-
-    float totalDps = 0.0f;
-    float maxRange = 0.0f;
-    bool hasWeapons = false;
-
-    admin.forEach<ModuleOwnerComponent, WeaponComponent>(
-        [&](entt::entity /*child*/, const ModuleOwnerComponent& owner, const WeaponComponent& w)
-        {
-            if (owner.owner != entity) { return; }
-            hasWeapons = true;
-            totalDps += w.damage * w.fireRateHz;
-            if (w.range_tiles > maxRange) { maxRange = w.range_tiles; }
-        });
-
-    QString statsText = tr("HP: %1 / %2")
-        .arg(static_cast<int>(health.hp + 0.5f))
-        .arg(static_cast<int>(health.maxHp + 0.5f));
-
-    if (hasWeapons)
-    {
-        statsText += tr("\nDPS: %1").arg(QString::number(static_cast<double>(totalDps), 'f', 1));
-        statsText += tr("\nRange: %1 tiles").arg(QString::number(static_cast<double>(maxRange), 'f', 1));
-    }
-
-    m_stationStatsLabel->setText(statsText);
-    m_stationStatsLabel->show();
-
-    m_entityStatsPanel->hide();
-}
-
-void FieldSelectionPanel::refreshEntityStats()
-{
-    // Only the single-actor stats panel needs a live refresh; the multi-actor summary is
-    // static counts, and GameWorldView prunes dead/despawned actors and re-emits the
-    // selection (REQ-UI-ENTITY-CLICK-SELECT), so the panel does not mutate it here.
-    if (m_selectedEntities.size() != 1) { return; }
-
-    EntityAdmin& admin = m_sim->getAdmin();
-    const entt::entity entity = m_selectedEntities.front();
-
-    if (!admin.isValid(entity) || !admin.hasAll<HealthComponent>(entity)) { return; }
-    const HealthComponent& health = admin.get<HealthComponent>(entity);
-    if (health.hp <= 0.0f) { return; }
-
-    if (admin.hasAll<ShipIdentityComponent>(entity))
-    {
-        const ShipStats stats = buildShipStatsFromEntity(admin, entity);
-        m_entityStatsPanel->refreshFromLive(stats, health.hp);
-        m_entityStatsPanel->setBehavior(
-            admin.get<SelectedBehaviorComponent>(entity).winner);
-    }
-    else if (admin.hasAll<StationBodyComponent>(entity))
-    {
-        buildEntityStation(entity);
-    }
-}
-
-int FieldSelectionPanel::selectedDebrisScrapTotal() const
-{
-    // Sum the remaining scrap across the still-living selected debris (REQ-UI-DEBRIS-PANEL).
-    int total = 0;
-    for (const DebrisInfo& info : getAllDebrisInfo(m_sim->getAdmin()))
-    {
-        if (std::find(m_selectedDebris.begin(), m_selectedDebris.end(), info.entity)
-            != m_selectedDebris.end())
-        {
-            total += info.amount;
-        }
-    }
-    return total;
-}
-
-QString FieldSelectionPanel::scrapTotalText() const
-{
-    return tr("Scrap x %1").arg(selectedDebrisScrapTotal());
-}
-
-void FieldSelectionPanel::handleEvent(std::shared_ptr<const TickAdvancedEvent> /*event*/)
-{
-    refreshDisplay();
-}
-
-void FieldSelectionPanel::handleEvent(
-    std::shared_ptr<const PlayerCommandsAppliedEvent> /*event*/)
-{
-    // Player commands are applied by a queued drain, not synchronously. When the game is
-    // paused no tick advances, so TickAdvancedEvent never fires; refresh here too.
-    refreshDisplay();
-}
-
-void FieldSelectionPanel::handleEvent(std::shared_ptr<const DebugDrawToggledEvent> event)
-{
-    m_debugDraw = event->active;
-    m_entityStatsPanel->setDebugDrawEnabled(event->active);
-}

src/ui/FieldSelectionPanel.h

@@ -1,91 +0,0 @@
-#pragma once
-
-#include <vector>
-
-#include <QString>
-#include <QWidget>
-
-#include "entt/entity/entity.hpp"
-
-#include "DebugDrawToggledEvent.h"
-#include "EventHandler.h"
-#include "PlayerCommandsAppliedEvent.h"
-#include "TickAdvancedEvent.h"
-
-struct GameConfig;
-class Simulation;
-class ShipStatsPanel;
-class QLabel;
-class QVBoxLayout;
-
-// Renders the "field" selection category — ships, defence stations and debris — as either
-// a single-object stats panel (ship, station, or debris) or a compact multi-object count
-// summary (REQ-UI-SELECTION-CATEGORIES, REQ-UI-FIELD-MULTI-SELECTION, REQ-UI-DEBRIS-PANEL).
-//
-// The panel owns its own selection state and its own widgets, and nothing else. Which of
-// the two selection categories owns the selection panel is arbitrated by the parent
-// SelectionPanel: it feeds this panel through setSelectedEntities() /
-// setSelectedDebris() / clearSelection() and asks it via hasSelection(). This panel hides
-// itself whenever its selection is empty, so an inactive field category takes no space.
-class FieldSelectionPanel : public QWidget,
-                            public CombinedEventHandler<TickAdvancedEvent,
-                                                        PlayerCommandsAppliedEvent,
-                                                        DebugDrawToggledEvent>
-{
-    Q_OBJECT
-
-public:
-    FieldSelectionPanel(Simulation* sim, const GameConfig* config,
-                        QWidget* parent = nullptr);
-    ~FieldSelectionPanel() override;
-
-    // Replaces the selected actors (ships and defence stations); debris is left alone,
-    // the two coexist within the field category (REQ-UI-SELECTION-CATEGORIES).
-    void setSelectedEntities(const std::vector<entt::entity>& entities);
-    // Replaces the selected debris; the selected actors are left alone.
-    void setSelectedDebris(const std::vector<entt::entity>& debris);
-    // Drops the whole field selection — used when the building category takes over.
-    void clearSelection();
-    // True while the field category has anything selected, i.e. while this panel owns
-    // the selection panel's content.
-    bool hasSelection() const;
-
-private:
-    void handleEvent(std::shared_ptr<const TickAdvancedEvent> event) override;
-    void handleEvent(std::shared_ptr<const PlayerCommandsAppliedEvent> event) override;
-    void handleEvent(std::shared_ptr<const DebugDrawToggledEvent> event) override;
-
-    // Picks the layout for the current selection and shows/hides this panel accordingly.
-    void rebuild();
-    // Keeps the live values of the layout chosen by rebuild() current.
-    void refreshDisplay();
-    void buildEntityShip(entt::entity entity);
-    void buildEntityStation(entt::entity entity);
-    void buildEntitySummary();
-    void buildDebrisSingle();
-    void refreshEntityStats();
-    void hideAllWidgets();
-    // Summed remaining scrap across the selected debris (REQ-UI-DEBRIS-PANEL).
-    int selectedDebrisScrapTotal() const;
-    // "Scrap x N" line for the multi-object summary (REQ-UI-FIELD-MULTI-SELECTION).
-    QString scrapTotalText() const;
-
-    Simulation*       m_sim;
-    const GameConfig* m_config;
-
-    bool m_debugDraw = false;
-
-    // The selected ships/defence stations. Shares the "field" selection category with
-    // debris (m_selectedDebris): both can be non-empty at once (REQ-UI-SELECTION-CATEGORIES).
-    std::vector<entt::entity> m_selectedEntities;
-    std::vector<entt::entity> m_selectedDebris;
-
-    QVBoxLayout*    m_layout;
-    QLabel*         m_entityTitleLabel;
-    ShipStatsPanel* m_entityStatsPanel;
-    QLabel*         m_stationStatsLabel;
-    QLabel*         m_entitySummaryLabel;
-    // Shows the debris "Scrap" stat row (single selection) — the scrap total for the
-    // multi-object summary lives in m_entitySummaryLabel instead.
-    QLabel*         m_scrapLabel;
-};

src/ui/MainWindow.cpp

@@ -31,6 +31,7 @@
 #include "SelectionPanel.h"
 #include "ShipLayoutBlueprintSerializer.h"
 #include "ShipLayoutDialog.h"
+#include "BuildingIconCache.h"
 #include "ItemIconCache.h"
 #include "ModalPauseScope.h"
 #include "Simulation.h"
@@ -48,31 +49,28 @@ MainWindow::MainWindow(Simulation* sim, const std::string& configDir,
     setWindowTitle(tr("Dota Factory"));
     resize(1280, 768);
 
-    // Item icons live alongside the config (a sibling of the config dir), read from
-    // disk at runtime like the building icons and visuals.toml (REQ-UI-ITEM-ICON).
-    const std::string itemsIconDir = QDir::cleanPath(
-        QString::fromStdString(m_configDir) + "/../icons/items").toStdString();
-
+    // Item and building icons live alongside the config (siblings of the config dir),
+    // read from disk at runtime the same way visuals.toml is (REQ-UI-ITEM-ICON,
+    // REQ-UI-BUILD-ICON).
+    const QString configDirPath = QString::fromStdString(m_configDir);
     m_itemIcons = std::make_unique<ItemIconCache>(
-        QString::fromStdString(itemsIconDir));
+        QDir::cleanPath(configDirPath + "/../icons/items"));
+    m_buildingIcons = std::make_unique<BuildingIconCache>(
+        QDir::cleanPath(configDirPath + "/../icons/buildings"));
 
     m_headerBar = new HeaderBar(sim, &sim->getConfig(), m_itemIcons.get(), this);
 
     m_gameWorldView = new GameWorldView(sim, &sim->getConfig(), &m_visuals, m_configDir,
                                         m_itemIcons.get(), m_replay.get(), this);
 
-    // Building icons live alongside the config (a sibling of the config dir), read
-    // from disk at runtime the same way visuals.toml is.
-    const std::string iconDir = QDir::cleanPath(
-        QString::fromStdString(m_configDir) + "/../icons/buildings").toStdString();
-
     // Floats over the game world at its bottom center, sized to its buttons
     // (REQ-UI-BUILD-BAR). Creation order is the stacking order for siblings, so
     // building it after the world view puts it above the world and its vignettes,
     // and before the dim overlay keeps modals dimming it too (REQ-UI-MODAL-DIM).
     // Its geometry comes from layoutPanels().
-    m_buildButtonBar = new BuildButtonBar(sim, &sim->getConfig(), iconDir,
-                                          m_itemIcons.get(), this);
+    m_buildButtonBar = new BuildButtonBar(sim, &sim->getConfig(),
+                                          m_buildingIcons.get(), m_itemIcons.get(),
+                                          this);
 
     // The blueprints have no widget of their own: they are saved with Ctrl+C and picked
     // from a modal dialog (REQ-UI-BLUEPRINT-DIALOG), both driven from this window
@@ -85,7 +83,9 @@ MainWindow::MainWindow(Simulation* sim, const std::string& configDir,
     // the build button bar it is a sibling of the world view built after it, which is
     // what puts it above the world and its vignettes and below the dim overlay. It
     // brings its own chrome; its geometry comes from layoutPanels().
-    m_selectionPanel = new SelectionPanel(sim, &sim->getConfig(), this);
+    m_selectionPanel = new SelectionPanel(sim, &sim->getConfig(), &m_visuals,
+                                          m_itemIcons.get(), m_buildingIcons.get(),
+                                          this);
 
     // Created last so it stacks above the other children; covers the whole window and
     // dims the game behind modal dialogs/menus (REQ-UI-MODAL-DIM).

src/ui/MainWindow.h

@@ -31,6 +31,7 @@ class HeaderBar;
 class SelectionPanel;
 class BuildButtonBar;
 class BlueprintLibrary;
+class BuildingIconCache;
 class ItemIconCache;
 class QCloseEvent;
 class QResizeEvent;
@@ -92,6 +93,9 @@ private:
     // One per-item icon cache for the whole window (REQ-UI-ITEM-ICON): the header,
     // build bar, world view, and recipe dialog all rasterize the same SVGs.
     std::unique_ptr<ItemIconCache> m_itemIcons;
+    // Likewise one per-building chip cache (REQ-UI-BUILD-ICON), shared by the build bar
+    // and the selection panel's card headers (REQ-UI-SELECTION-CARD).
+    std::unique_ptr<BuildingIconCache> m_buildingIcons;
     GameWorldView*         m_gameWorldView;
     HeaderBar*             m_headerBar;
     SelectionPanel*        m_selectionPanel;

src/ui/SelectionPanel.h

@@ -1,48 +1,34 @@
 #pragma once
 
-#include <optional>
-#include <string>
-#include <vector>
-
-#include <QPoint>
 #include <QRect>
 #include <QWidget>
 
-#include "BeltSystem.h"
-#include "Building.h"
-#include "BuildingId.h"
+#include "DebrisSelectionChangedEvent.h"
+#include "DebugDrawToggledEvent.h"
 #include "EntitySelectionChangedEvent.h"
 #include "EventHandler.h"
-#include "GameConfig.h"
 #include "PlayerCommandsAppliedEvent.h"
-#include "RecipesConfig.h"
-#include "DebrisSelectionChangedEvent.h"
 #include "SelectionChangedEvent.h"
-#include "ShipLayout.h"
-#include "ShipsConfig.h"
-#include "Tick.h"
 #include "TickAdvancedEvent.h"
+#include "selection/SelectionContentFactory.h"
+#include "selection/SelectionContext.h"
 
+struct GameConfig;
+struct VisualsConfig;
+class BuildingIconCache;
+class ItemIconCache;
+class SelectionContent;
 class Simulation;
-class FieldSelectionPanel;
-class ShipLayoutPreview;
-class QLabel;
-class QListWidget;
-class QPushButton;
 class QScrollArea;
 class QVBoxLayout;
 
-// Shows the current selection. The building category (buildings and construction sites)
-// is rendered by this panel itself; the field category (ships, defence stations, debris)
-// is rendered by the embedded FieldSelectionPanel.
-//
-// The two categories are mutually exclusive (REQ-UI-SELECTION-CATEGORIES) and this panel
-// is the sole arbiter of which one owns the content: it listens to all three selection
-// events, forwards the field ones to the child panel, and drops the losing category's
-// content. Neither panel touches the other's widgets.
+// Shows the current selection. The panel itself renders nothing: it arbitrates between
+// the two selection categories (REQ-UI-SELECTION-CATEGORIES), picks the card that fits
+// what is selected (REQ-UI-SELECTION-CONTENT), and hosts exactly one of them at a time.
+// What each card looks like lives in src/ui/selection/.
 //
 // The panel floats over the game world view rather than occupying a column of its own
-// (REQ-UI-SELECTION-PANEL): it sizes itself to its content, anchors to the right edge of
+// (REQ-UI-SELECTION-PANEL): it sizes itself to its card, anchors to the right edge of
 // the band its owner hands it, and hides itself entirely while nothing is selected
 // (REQ-UI-EMPTY-SELECTION).
 class SelectionPanel : public QWidget,
@@ -50,13 +36,17 @@ class SelectionPanel : public QWidget,
                                                    PlayerCommandsAppliedEvent,
                                                    EntitySelectionChangedEvent,
                                                    SelectionChangedEvent,
-                                                   DebrisSelectionChangedEvent>
+                                                   DebrisSelectionChangedEvent,
+                                                   DebugDrawToggledEvent>
 {
     Q_OBJECT
 
 public:
+    // visuals, itemIcons and buildingIcons are window-wide rendering resources the cards
+    // draw from; none is owned and all must outlive this widget.
     SelectionPanel(Simulation* sim, const GameConfig* config,
-                   QWidget* parent = nullptr);
+                   const VisualsConfig* visuals, ItemIconCache* itemIcons,
+                   BuildingIconCache* buildingIcons, QWidget* parent = nullptr);
     ~SelectionPanel() override;
 
     // Confines the panel to the given band of the game world view: it right-aligns
@@ -66,86 +56,41 @@ public:
     void anchorTo(const QRect& bandRect);
 
 private:
+    void handleEvent(std::shared_ptr<const SelectionChangedEvent> event) override;
+    void handleEvent(std::shared_ptr<const EntitySelectionChangedEvent> event) override;
+    void handleEvent(std::shared_ptr<const DebrisSelectionChangedEvent> event) override;
     void handleEvent(std::shared_ptr<const TickAdvancedEvent> event) override;
     void handleEvent(std::shared_ptr<const PlayerCommandsAppliedEvent> event) override;
-    void handleEvent(std::shared_ptr<const EntitySelectionChangedEvent> event) override;
-    void handleEvent(std::shared_ptr<const SelectionChangedEvent> event) override;
-    void handleEvent(std::shared_ptr<const DebrisSelectionChangedEvent> event) override;
+    void handleEvent(std::shared_ptr<const DebugDrawToggledEvent> event) override;
 
-private slots:
-    void onSelectRecipeClicked();
-    void onClearBelt();
-    void onSplitterFilterChanged();
-
-private:
-    // Why the selection display is being refreshed. A periodic tick only needs a
-    // lightweight content update (e.g. a construction site's progress label),
-    // whereas an applied player command may have changed the configuration and
-    // needs a full structural rebuild.
-    enum class RefreshReason
-    {
-        PeriodicTick,
-        CommandApplied
-    };
-
-    void onSelectionChanged(const std::vector<BuildingId>& ids);
-    // Gives the panel to the field category once it has anything selected.
-    void yieldToFieldSelection();
-    // Shows the panel while either category has a selection and hides it otherwise
-    // (REQ-UI-EMPTY-SELECTION), re-fitting it to its current content while it is shown.
-    // Every path that changes the content ends here, because the content is what sizes
-    // the panel.
+    // Re-reads the live values of the card on screen. When the selection now calls for a
+    // different card -- a construction site finishing is the case that matters -- it
+    // rebuilds instead, because a card never changes its own shape.
+    void refreshContent();
+    // Replaces the card with the one the current selection calls for.
+    void rebuildContent();
+    // Shows the panel while a card exists and hides it otherwise
+    // (REQ-UI-EMPTY-SELECTION), re-fitting it to the card while it is shown.
     void updateVisibility();
-    // Re-fits the panel to its content within the anchored band.
+    // Re-fits the panel to its card within the anchored band.
     void refit();
-    void refreshSelectionDisplay(RefreshReason reason);
-    void rebuild();
-    void hideAllWidgets();
-    void buildEmpty();
-    void buildSingle(BuildingId id);
-    void buildMulti(const std::vector<BuildingId>& ids);
-    void refreshBuffers(const Building* b);
-    void refreshSiteProgress(const ConstructionSite* s);
-    void updateShipyardLayoutWidgets(BuildingType type,
-                                     const std::string& recipeId,
-                                     const std::optional<ShipLayoutConfig>& shipLayout);
-    void buildSplitterFilters(const std::optional<BeltSystem::SplitterInfo>& info);
-    const RecipeDef* findRecipe(const Building* b) const;
-    const ShipDef*   findShipDef(const std::string& id) const;
-    std::vector<std::string> getAllItemIds() const;
 
-    Simulation*        m_sim;
-    const GameConfig*  m_config;
-    std::vector<BuildingId> m_selectedBuildingIds;
+    SelectionContext m_context;
+    // Read through m_context by the cards that need it, so a toggle reaches the card on
+    // screen without it having to subscribe to the event itself.
+    bool m_debugDrawEnabled = false;
+
+    SelectionRequest  m_request;
+    ContentKey        m_contentKey;
+    SelectionContent* m_content = nullptr;
 
     // The band the panel confines itself to, in the coordinates of its parent; null
     // until the owner has anchored it for the first time.
     QRect m_bandRect;
 
-    // Scrolls the content once it outgrows the band (REQ-UI-SELECTION-PANEL). All the
-    // content widgets below are children of m_content, not of the panel itself.
+    // Scrolls the card once it outgrows the band (REQ-UI-SELECTION-PANEL). The card is a
+    // child of m_body, not of the panel itself.
     QScrollArea* m_scrollArea;
-    QWidget*     m_content;
-
-    QVBoxLayout* m_layout;
-    QLabel*      m_titleLabel;
-    QPushButton* m_recipeSelectButton;
-    QPushButton* m_clearBeltBtn;
-    QLabel*      m_filterALabel;
-    QListWidget* m_filterAList;
-    QLabel*      m_filterBLabel;
-    QListWidget* m_filterBList;
-    QLabel*      m_buffersLabel;
-
-    ShipLayoutPreview* m_layoutPreview;
-    QPushButton*       m_configureLayoutBtn;
-
-    std::optional<BuildingId> m_singleBuildingId;
-    bool         m_singleIsSite = false;  // selected single entity is a construction site
-    QPoint       m_splitterTile;
-    std::string  m_currentRecipeId;
-
-    // Renders the field selection (actors + debris) below the building content
-    // (REQ-UI-FIELD-MULTI-SELECTION). Hides itself while nothing field-side is selected.
-    FieldSelectionPanel* m_fieldSelectionPanel;
+    QWidget*     m_body;
+    QVBoxLayout* m_bodyLayout;
 };

src/ui/ShipStatsPanel.cpp

@@ -1,11 +1,14 @@
 #include "ShipStatsPanel.h"
 
-#include <QLabel>
 #include <QString>
 #include <QVBoxLayout>
 
+#include "BarRow.h"
 #include "GameConfig.h"
+#include "SectionBox.h"
+#include "SelectionNames.h"
 #include "ShipStatsCalculator.h"
+#include "StatRow.h"
 #include "ThreatCostCalculator.h"
 
 namespace
@@ -16,20 +19,6 @@ QString fmt(float value)
     return QString::number(static_cast<double>(value), 'f', 1);
 }
 
-QLabel* makeSectionHeader(const QString& text, QWidget* parent)
-{
-    QLabel* label = new QLabel(text, parent);
-    QFont f = label->font();
-    f.setBold(true);
-    label->setFont(f);
-    return label;
-}
-
-QLabel* makeStatLabel(QWidget* parent)
-{
-    return new QLabel(parent);
-}
-
 }  // namespace
 
 
@@ -38,215 +27,150 @@ ShipStatsPanel::ShipStatsPanel(const GameConfig* config, QWidget* parent)
     , m_config(config)
 {
     QVBoxLayout* layout = new QVBoxLayout(this);
-    layout->setContentsMargins(4, 4, 4, 4);
+    layout->setContentsMargins(0, 0, 0, 0);
     layout->setSpacing(2);
     layout->setAlignment(Qt::AlignTop);
 
-    // Hull stats — always visible.
-    m_hpLabel               = makeStatLabel(this);
-    m_speedLabel            = makeStatLabel(this);
-    m_sensorRangeLabel      = makeStatLabel(this);
-    m_mainAccelLabel        = makeStatLabel(this);
-    m_maneuveringAccelLabel = makeStatLabel(this);
-    m_angularAccelLabel     = makeStatLabel(this);
-    m_maxRotSpeedLabel      = makeStatLabel(this);
-    m_cargoCapacityLabel    = makeStatLabel(this);
-    m_cargoCapacityLabel->setVisible(false);
+    // Hull stats -- always visible, except cargo capacity, which only a ship that can
+    // carry anything shows (REQ-MOD-UI-STATS-PANEL).
+    m_hpBar               = new BarRow(tr("HP"), this);
+    m_speedRow            = new StatRow(tr("Max speed"), this);
+    m_sensorRangeRow      = new StatRow(tr("Sensor range"), this);
+    m_mainAccelRow        = new StatRow(tr("Main accel"), this);
+    m_maneuveringAccelRow = new StatRow(tr("Maneuvering accel"), this);
+    m_angularAccelRow     = new StatRow(tr("Angular accel"), this);
+    m_maxRotSpeedRow      = new StatRow(tr("Max rotation"), this);
+    m_cargoCapacityRow    = new StatRow(tr("Cargo capacity"), this);
+    m_cargoCapacityRow->hide();
 
-    layout->addWidget(m_hpLabel);
-    layout->addWidget(m_speedLabel);
-    layout->addWidget(m_sensorRangeLabel);
-    layout->addWidget(m_mainAccelLabel);
-    layout->addWidget(m_maneuveringAccelLabel);
-    layout->addWidget(m_angularAccelLabel);
-    layout->addWidget(m_maxRotSpeedLabel);
-    layout->addWidget(m_cargoCapacityLabel);
+    layout->addWidget(m_hpBar);
+    layout->addWidget(m_speedRow);
+    layout->addWidget(m_sensorRangeRow);
+    layout->addWidget(m_mainAccelRow);
+    layout->addWidget(m_maneuveringAccelRow);
+    layout->addWidget(m_angularAccelRow);
+    layout->addWidget(m_maxRotSpeedRow);
+    layout->addWidget(m_cargoCapacityRow);
 
-    // Weapon capability section.
-    m_weaponSection = new QWidget(this);
-    {
-        QVBoxLayout* sl = new QVBoxLayout(m_weaponSection);
-        sl->setContentsMargins(0, 4, 0, 0);
-        sl->setSpacing(2);
-        sl->addWidget(makeSectionHeader(tr("Weapons"), m_weaponSection));
-        m_weaponDpsLabel   = makeStatLabel(m_weaponSection);
-        m_weaponRangeLabel = makeStatLabel(m_weaponSection);
-        sl->addWidget(m_weaponDpsLabel);
-        sl->addWidget(m_weaponRangeLabel);
-    }
-    m_weaponSection->setVisible(false);
+    // One section per capability module type, each shown only while at least one such
+    // module is installed (REQ-MOD-UI-STATS-PANEL).
+    m_weaponSection  = new SectionBox(tr("Weapons"), this);
+    m_weaponDpsRow   = new StatRow(tr("DPS"), m_weaponSection);
+    m_weaponRangeRow = new StatRow(tr("Range"), m_weaponSection);
+    m_weaponSection->getContentLayout()->addWidget(m_weaponDpsRow);
+    m_weaponSection->getContentLayout()->addWidget(m_weaponRangeRow);
+    m_weaponSection->hide();
     layout->addWidget(m_weaponSection);
 
-    // Salvage capability section.
-    m_salvageSection = new QWidget(this);
-    {
-        QVBoxLayout* sl = new QVBoxLayout(m_salvageSection);
-        sl->setContentsMargins(0, 4, 0, 0);
-        sl->setSpacing(2);
-        sl->addWidget(makeSectionHeader(tr("Salvage"), m_salvageSection));
-        m_salvageRateLabel  = makeStatLabel(m_salvageSection);
-        m_salvageRangeLabel = makeStatLabel(m_salvageSection);
-        sl->addWidget(m_salvageRateLabel);
-        sl->addWidget(m_salvageRangeLabel);
-    }
-    m_salvageSection->setVisible(false);
+    m_salvageSection  = new SectionBox(tr("Salvage"), this);
+    m_salvageRateRow  = new StatRow(tr("Collection rate"), m_salvageSection);
+    m_salvageRangeRow = new StatRow(tr("Range"), m_salvageSection);
+    m_salvageSection->getContentLayout()->addWidget(m_salvageRateRow);
+    m_salvageSection->getContentLayout()->addWidget(m_salvageRangeRow);
+    m_salvageSection->hide();
     layout->addWidget(m_salvageSection);
 
-    // Repair capability section.
-    m_repairSection = new QWidget(this);
-    {
-        QVBoxLayout* sl = new QVBoxLayout(m_repairSection);
-        sl->setContentsMargins(0, 4, 0, 0);
-        sl->setSpacing(2);
-        sl->addWidget(makeSectionHeader(tr("Repair"), m_repairSection));
-        m_repairRateLabel  = makeStatLabel(m_repairSection);
-        m_repairRangeLabel = makeStatLabel(m_repairSection);
-        sl->addWidget(m_repairRateLabel);
-        sl->addWidget(m_repairRangeLabel);
-    }
-    m_repairSection->setVisible(false);
+    m_repairSection  = new SectionBox(tr("Repair"), this);
+    m_repairRateRow  = new StatRow(tr("Repair rate"), m_repairSection);
+    m_repairRangeRow = new StatRow(tr("Range"), m_repairSection);
+    m_repairSection->getContentLayout()->addWidget(m_repairRateRow);
+    m_repairSection->getContentLayout()->addWidget(m_repairRangeRow);
+    m_repairSection->hide();
     layout->addWidget(m_repairSection);
 
-	// Current behavior — live entities only; hidden in the static design
-	// preview (REQ-UI-SHIP-BEHAVIOR).
-	m_behaviorLabel = makeSectionHeader(QString(), this);
-	m_behaviorLabel->setVisible(false);
-	layout->addWidget(m_behaviorLabel);
+    // Live entities only; the design preview has no behavior to show
+    // (REQ-UI-SHIP-BEHAVIOR).
+    m_behaviorRow = new StatRow(tr("Behavior"), this);
+    m_behaviorRow->hide();
+    layout->addWidget(m_behaviorRow);
 
-    // Threat cost — debug-only, initially hidden.
-    m_threatCostLabel = makeStatLabel(this);
-    m_threatCostLabel->setVisible(false);
-    layout->addWidget(m_threatCostLabel);
-
-    layout->addStretch();
-}
-
-void ShipStatsPanel::refresh(const std::string& shipId,
-                              const std::vector<PlacedModule>& modules)
-{
-    const ShipStats stats = calculateShipStats(*m_config, shipId, modules);
-    const QString hpText = tr("HP: %1").arg(static_cast<int>(stats.hp + 0.5f));
-    applyStats(stats, hpText);
-
-    const double threat = calculateShipThreatCost(m_config->threatCosts, *m_config,
-                                                  shipId, modules);
-    setThreatCost(threat);
-
-    // The static design preview has no live behavior to show.
-    m_behaviorLabel->setVisible(false);
-}
-
-void ShipStatsPanel::refreshFromLive(const ShipStats& stats, float currentHp)
-{
-    const QString hpText = tr("HP: %1 / %2")
-        .arg(static_cast<int>(currentHp + 0.5f))
-        .arg(static_cast<int>(stats.hp + 0.5f));
-    applyStats(stats, hpText);
-}
-
-void ShipStatsPanel::applyStats(const ShipStats& stats, const QString& hpText)
-{
-    m_hpLabel->setText(hpText);
-    m_speedLabel->setText(
-        tr("Max Speed: %1 tiles/s").arg(fmt(stats.maxSpeed_tps)));
-    m_sensorRangeLabel->setText(
-        tr("Sensor Range: %1 tiles").arg(fmt(stats.sensorRange_tiles)));
-    m_mainAccelLabel->setText(
-        tr("Main Accel: %1 tiles/s\xc2\xb2").arg(fmt(stats.mainAcceleration_tpss)));
-    m_maneuveringAccelLabel->setText(
-        tr("Maneuvering Accel: %1 tiles/s\xc2\xb2").arg(fmt(stats.maneuveringAcceleration_tpss)));
-    m_angularAccelLabel->setText(
-        tr("Angular Accel: %1 rad/s\xc2\xb2").arg(fmt(stats.angularAcceleration_radpss)));
-    m_maxRotSpeedLabel->setText(
-        tr("Max Rotation: %1 rad/s").arg(fmt(stats.maxRotationSpeed_radps)));
-
-    // Cargo capacity is shown only when the ship can actually hold cargo
-    // (REQ-MOD-UI-STATS-PANEL).
-    if (stats.cargoCapacity > 0)
-    {
-        m_cargoCapacityLabel->setText(
-            tr("Cargo Capacity: %1").arg(stats.cargoCapacity));
-        m_cargoCapacityLabel->setVisible(true);
-    }
-    else
-    {
-        m_cargoCapacityLabel->setVisible(false);
-    }
-
-    if (stats.weapons.has_value())
-    {
-        m_weaponDpsLabel->setText(
-            tr("DPS: %1").arg(fmt(stats.weapons->combinedDps)));
-        m_weaponRangeLabel->setText(
-            tr("Range: %1 tiles").arg(fmt(stats.weapons->maxRange_tiles)));
-        m_weaponSection->setVisible(true);
-    }
-    else
-    {
-        m_weaponSection->setVisible(false);
-    }
-
-    if (stats.salvage.has_value())
-    {
-        m_salvageRateLabel->setText(
-            tr("Collection Rate: %1/s").arg(fmt(stats.salvage->combinedCollectionRate)));
-        m_salvageRangeLabel->setText(
-            tr("Range: %1 tiles").arg(fmt(stats.salvage->maxRange_tiles)));
-        m_salvageSection->setVisible(true);
-    }
-    else
-    {
-        m_salvageSection->setVisible(false);
-    }
-
-    if (stats.repair.has_value())
-    {
-        m_repairRateLabel->setText(
-            tr("Repair Rate: %1 HP/s").arg(fmt(stats.repair->combinedRepairRate_hps)));
-        m_repairRangeLabel->setText(
-            tr("Range: %1 tiles").arg(fmt(stats.repair->maxRange_tiles)));
-        m_repairSection->setVisible(true);
-    }
-    else
-    {
-        m_repairSection->setVisible(false);
-    }
+    // Threat cost -- shown only while debug draw is active (REQ-UI-SHIP-STATS-PANEL).
+    m_threatCostRow = new StatRow(tr("Threat cost"), this);
+    m_threatCostRow->hide();
+    layout->addWidget(m_threatCostRow);
 }
 
 void ShipStatsPanel::setBehavior(BehaviorKind kind)
 {
-    QString label;
-    switch (kind)
+    const QString label = getBehaviorLabel(kind);
+    m_behaviorRow->setValue(label);
+    m_behaviorRow->setVisible(!label.isEmpty());
+}
+
+void ShipStatsPanel::refresh(const std::string& shipId,
+                             const std::vector<PlacedModule>& modules)
+{
+    const ShipStats stats = calculateShipStats(*m_config, shipId, modules);
+    applyStats(stats, 1.0, QString::number(static_cast<int>(stats.hp + 0.5f)));
+
+    setThreatCost(calculateShipThreatCost(m_config->threatCosts, *m_config,
+                                          shipId, modules));
+}
+
+void ShipStatsPanel::refreshFromLive(const ShipStats& stats, float currentHp)
+{
+    const double fraction = (stats.hp > 0.0f)
+        ? static_cast<double>(currentHp) / stats.hp
+        : 0.0;
+    applyStats(stats, fraction, tr("%1 / %2")
+        .arg(static_cast<int>(currentHp + 0.5f))
+        .arg(static_cast<int>(stats.hp + 0.5f)));
+}
+
+void ShipStatsPanel::applyStats(const ShipStats& stats, double hpFraction,
+                                const QString& hpText)
+{
+    m_hpBar->setValue(hpFraction, hpText);
+    m_speedRow->setValue(tr("%1 tiles/s").arg(fmt(stats.maxSpeed_tps)));
+    m_sensorRangeRow->setValue(tr("%1 tiles").arg(fmt(stats.sensorRange_tiles)));
+    m_mainAccelRow->setValue(
+        tr("%1 tiles/s\xc2\xb2").arg(fmt(stats.mainAcceleration_tpss)));
+    m_maneuveringAccelRow->setValue(
+        tr("%1 tiles/s\xc2\xb2").arg(fmt(stats.maneuveringAcceleration_tpss)));
+    m_angularAccelRow->setValue(
+        tr("%1 rad/s\xc2\xb2").arg(fmt(stats.angularAcceleration_radpss)));
+    m_maxRotSpeedRow->setValue(tr("%1 rad/s").arg(fmt(stats.maxRotationSpeed_radps)));
+
+    // Cargo capacity is shown only when the ship can actually hold cargo
+    // (REQ-MOD-UI-STATS-PANEL).
+    m_cargoCapacityRow->setVisible(stats.cargoCapacity > 0);
+    if (stats.cargoCapacity > 0)
     {
-        case BehaviorKind::Retreat:      label = tr("Retreating"); break;
-        case BehaviorKind::Attack:       label = tr("Engaging");   break;
-        case BehaviorKind::SalvageScrap:
-        case BehaviorKind::DeliverScrap: label = tr("Salvaging");  break;
-        case BehaviorKind::Repair:       label = tr("Repairing");  break;
-        case BehaviorKind::Rally:        label = tr("Rallying");   break;
-        case BehaviorKind::Standby:      label = tr("Standby");    break;
-        case BehaviorKind::Advance:      label = tr("Advancing");  break;
-        case BehaviorKind::None:         break;
+        m_cargoCapacityRow->setValue(QString::number(stats.cargoCapacity));
     }
 
-    if (label.isEmpty())
+    m_weaponSection->setVisible(stats.weapons.has_value());
+    if (stats.weapons.has_value())
     {
-        m_behaviorLabel->setVisible(false);
-        return;
+        m_weaponDpsRow->setValue(fmt(stats.weapons->combinedDps));
+        m_weaponRangeRow->setValue(tr("%1 tiles").arg(fmt(stats.weapons->maxRange_tiles)));
     }
 
-    m_behaviorLabel->setText(tr("Behavior: %1").arg(label));
-    m_behaviorLabel->setVisible(true);
+    m_salvageSection->setVisible(stats.salvage.has_value());
+    if (stats.salvage.has_value())
+    {
+        m_salvageRateRow->setValue(
+            tr("%1 /s").arg(fmt(stats.salvage->combinedCollectionRate)));
+        m_salvageRangeRow->setValue(tr("%1 tiles").arg(fmt(stats.salvage->maxRange_tiles)));
+    }
+
+    m_repairSection->setVisible(stats.repair.has_value());
+    if (stats.repair.has_value())
+    {
+        m_repairRateRow->setValue(
+            tr("%1 HP/s").arg(fmt(stats.repair->combinedRepairRate_hps)));
+        m_repairRangeRow->setValue(tr("%1 tiles").arg(fmt(stats.repair->maxRange_tiles)));
+    }
 }
 
 void ShipStatsPanel::setThreatCost(double cost)
 {
-    m_threatCostLabel->setText(tr("Threat Cost: %1").arg(cost, 0, 'f', 1));
-    m_threatCostLabel->setVisible(m_debugDraw);
+    m_threatCostRow->setValue(QString::number(cost, 'f', 1));
+    m_threatCostRow->setVisible(m_debugDraw);
 }
 
 void ShipStatsPanel::setDebugDrawEnabled(bool enabled)
 {
     m_debugDraw = enabled;
-    m_threatCostLabel->setVisible(m_debugDraw);
+    m_threatCostRow->setVisible(m_debugDraw);
 }

src/ui/ShipStatsPanel.h

@@ -1,18 +1,28 @@
 #pragma once
 
-#include <map>
 #include <string>
 #include <vector>
 
 #include <QWidget>
 
-#include "BehaviorKind.h"
 #include "ShipLayout.h"
 #include "ShipStatsCalculator.h"
 
-struct GameConfig;
-class QLabel;
+#include "BehaviorKind.h"
 
+struct GameConfig;
+class BarRow;
+class SectionBox;
+class StatRow;
+
+// The hull stats and capability module summaries of one ship, as a bar for HP and a
+// label/value row for everything else. Shared by the live selection card
+// (REQ-UI-SHIP-STATS-PANEL), the layout configuration dialog's design preview
+// (REQ-MOD-UI-STATS-PANEL) and the balancing tool, so all three read alike.
+//
+// The behavior row is for consumers with no header to put it in. The selection card
+// shows the behavior in its header instead (REQ-UI-SHIP-BEHAVIOR) and leaves the row
+// unset; the design preview has no live ship to have a behavior at all.
 class ShipStatsPanel : public QWidget
 {
     Q_OBJECT
@@ -20,44 +30,47 @@ class ShipStatsPanel : public QWidget
 public:
     explicit ShipStatsPanel(const GameConfig* config, QWidget* parent = nullptr);
 
+    // Stats of a design rather than of a live ship: the HP bar reads full, because the
+    // number shown is the maximum the design would have.
     void refresh(const std::string& shipId,
                  const std::vector<PlacedModule>& modules);
 
     void refreshFromLive(const ShipStats& stats, float currentHp);
 
-    // Displays the ship's current top-priority behavior (REQ-UI-SHIP-BEHAVIOR).
+    // Shows the ship's top-priority behavior as a row of its own. Never called by the
+    // selection card, which has a header slot for it.
     void setBehavior(BehaviorKind kind);
 
     void setThreatCost(double cost);
     void setDebugDrawEnabled(bool enabled);
 
 private:
-    void applyStats(const ShipStats& stats, const QString& hpText);
+    void applyStats(const ShipStats& stats, double hpFraction, const QString& hpText);
 
     const GameConfig* m_config;
     bool m_debugDraw = false;
 
-    QLabel* m_behaviorLabel;
-    QLabel* m_hpLabel;
-    QLabel* m_speedLabel;
-    QLabel* m_sensorRangeLabel;
-    QLabel* m_mainAccelLabel;
-    QLabel* m_maneuveringAccelLabel;
-    QLabel* m_angularAccelLabel;
-    QLabel* m_maxRotSpeedLabel;
-    QLabel* m_cargoCapacityLabel;
+    BarRow*  m_hpBar;
+    StatRow* m_speedRow;
+    StatRow* m_sensorRangeRow;
+    StatRow* m_mainAccelRow;
+    StatRow* m_maneuveringAccelRow;
+    StatRow* m_angularAccelRow;
+    StatRow* m_maxRotSpeedRow;
+    StatRow* m_cargoCapacityRow;
 
-    QWidget* m_weaponSection;
-    QLabel*  m_weaponDpsLabel;
-    QLabel*  m_weaponRangeLabel;
+    SectionBox* m_weaponSection;
+    StatRow*    m_weaponDpsRow;
+    StatRow*    m_weaponRangeRow;
 
-    QWidget* m_salvageSection;
-    QLabel*  m_salvageRateLabel;
-    QLabel*  m_salvageRangeLabel;
+    SectionBox* m_salvageSection;
+    StatRow*    m_salvageRateRow;
+    StatRow*    m_salvageRangeRow;
 
-    QWidget* m_repairSection;
-    QLabel*  m_repairRateLabel;
-    QLabel*  m_repairRangeLabel;
+    SectionBox* m_repairSection;
+    StatRow*    m_repairRateRow;
+    StatRow*    m_repairRangeRow;
 
-    QLabel* m_threatCostLabel;
+    StatRow* m_behaviorRow;
+    StatRow* m_threatCostRow;
 };

src/ui/selection/AutoProductionContent.cpp

@@ -0,0 +1,44 @@
+#include "AutoProductionContent.h"
+
+#include "Building.h"
+#include "BuildingTarget.h"
+#include "GameConfig.h"
+
+AutoProductionContent::AutoProductionContent(const SelectionContext& context,
+                                             const SelectionRequest& request,
+                                             QWidget* parent)
+    : BufferedBuildingContent(context, request.buildings.front(), parent)
+{
+}
+
+BufferedBuildingContent::CycleInfo AutoProductionContent::getCycleInfo(
+    const BuildingTarget& target) const
+{
+    CycleInfo info;
+    // An auto-recipe building always runs an implicit recipe (REQ-BLD-SMELTER,
+    // REQ-BLD-REPROCESSING), so its production section is always shown -- but only a
+    // running cycle names a recipe, so while it is idle there is no cycle to describe.
+    info.runsProduction = true;
+    if (!target.building || !target.building->production.has_value())
+    {
+        return info;
+    }
+
+    const RecipeDef* recipe = getContext().config->recipes.findRecipeDef(
+        target.building->production->recipeId, target.type);
+    if (!recipe)
+    {
+        return info;
+    }
+
+    for (const RecipeIngredient& ingredient : recipe->inputs)
+    {
+        info.perCycleInputs[ingredient.item] = ingredient.amount;
+    }
+    for (const RecipeOutput& output : recipe->outputs)
+    {
+        info.perCycleOutputs[output.item] = output.amount;
+    }
+    info.durationSeconds = recipe->durationSeconds;
+    return info;
+}

src/ui/selection/AutoProductionContent.h

@@ -0,0 +1,20 @@
+#pragma once
+
+#include "BufferedBuildingContent.h"
+#include "SelectionContentFactory.h"
+
+// The card for a Smelter or a Reprocessing Plant (REQ-UI-SELECTION-CONTENT). Both
+// auto-process whatever they receive and have no player-facing recipe selection
+// (REQ-BLD-SMELTER, REQ-BLD-REPROCESSING), so the card has no configuration group at
+// all; its cycle is whichever recipe is currently in production.
+class AutoProductionContent : public BufferedBuildingContent
+{
+    Q_OBJECT
+
+public:
+    AutoProductionContent(const SelectionContext& context,
+                          const SelectionRequest& request, QWidget* parent = nullptr);
+
+protected:
+    CycleInfo getCycleInfo(const BuildingTarget& target) const override;
+};

src/ui/selection/BarRow.cpp

@@ -0,0 +1,118 @@
+#include "BarRow.h"
+
+#include <algorithm>
+
+#include <QHBoxLayout>
+#include <QLabel>
+#include <QPainter>
+#include <QPaintEvent>
+#include <QVBoxLayout>
+
+namespace
+{
+
+// Height and corner radius of the fill bar, in device-independent pixels.
+const int   kBarHeightPx   = 6;
+const qreal kBarRadiusPx   = 3.0;
+
+// Opacity of the unfilled track, over the card's background.
+const int kTrackAlpha = 60;
+
+}  // namespace
+
+
+// The bar itself. Painted rather than assembled from a QProgressBar, because all it
+// needs is a rounded track with a rounded fill and a style sheet cannot be relied on to
+// leave a progress bar's groove and chunk alone across styles.
+class BarRow::Bar : public QWidget
+{
+public:
+    explicit Bar(QWidget* parent)
+        : QWidget(parent)
+        , m_fraction(0.0)
+    {
+        setFixedHeight(kBarHeightPx);
+        setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Fixed);
+    }
+
+    void setFraction(double fraction)
+    {
+        m_fraction = std::max(0.0, std::min(1.0, fraction));
+        update();
+    }
+
+    void setFillColor(const QColor& color)
+    {
+        m_fillColor = color;
+        update();
+    }
+
+protected:
+    void paintEvent(QPaintEvent* /*event*/) override
+    {
+        const QColor fill = m_fillColor.isValid()
+            ? m_fillColor
+            : palette().color(QPalette::Highlight);
+
+        QColor track = fill;
+        track.setAlpha(kTrackAlpha);
+
+        QPainter painter(this);
+        painter.setRenderHint(QPainter::Antialiasing, true);
+        painter.setPen(Qt::NoPen);
+
+        painter.setBrush(track);
+        painter.drawRoundedRect(rect(), kBarRadiusPx, kBarRadiusPx);
+
+        if (m_fraction > 0.0)
+        {
+            QRect filled = rect();
+            filled.setWidth(static_cast<int>(filled.width() * m_fraction));
+            painter.setBrush(fill);
+            painter.drawRoundedRect(filled, kBarRadiusPx, kBarRadiusPx);
+        }
+    }
+
+private:
+    double m_fraction;
+    QColor m_fillColor;
+};
+
+
+BarRow::BarRow(const QString& caption, QWidget* parent)
+    : QWidget(parent)
+{
+    QVBoxLayout* layout = new QVBoxLayout(this);
+    layout->setContentsMargins(0, 0, 0, 0);
+    layout->setSpacing(2);
+
+    QWidget* captionRow = new QWidget(this);
+    QHBoxLayout* captionLayout = new QHBoxLayout(captionRow);
+    captionLayout->setContentsMargins(0, 0, 0, 0);
+    captionLayout->setSpacing(8);
+
+    m_captionLabel = new QLabel(caption, captionRow);
+    m_captionLabel->setVisible(!caption.isEmpty());
+    m_valueLabel = new QLabel(captionRow);
+    m_valueLabel->setAlignment(Qt::AlignRight | Qt::AlignVCenter);
+
+    captionLayout->addWidget(m_captionLabel);
+    captionLayout->addStretch(1);
+    captionLayout->addWidget(m_valueLabel);
+
+    m_bar = new Bar(this);
+
+    layout->addWidget(captionRow);
+    layout->addWidget(m_bar);
+}
+
+void BarRow::setValue(double fraction, const QString& valueText)
+{
+    m_bar->setFraction(fraction);
+    m_valueLabel->setText(valueText);
+}
+
+void BarRow::setFillColor(const QColor& color)
+{
+    m_bar->setFillColor(color);
+}

src/ui/selection/BarRow.h

@@ -0,0 +1,36 @@
+#pragma once
+
+#include <QColor>
+#include <QString>
+#include <QWidget>
+
+class QLabel;
+
+// A caption with its value hard right and a horizontal fill bar beneath it. One part for
+// the three things the panel shows as a proportion: a construction site's progress, a
+// building's production cycle, and the HP of a ship, a station or the HQ
+// (REQ-UI-PRODUCTION-PROGRESS, REQ-UI-SHIP-STATS-PANEL, REQ-UI-STATION-STATS-PANEL,
+// REQ-UI-HQ-PANEL).
+//
+// The caption may be left empty, for a bar whose meaning is already given by the section
+// it sits in.
+class BarRow : public QWidget
+{
+    Q_OBJECT
+
+public:
+    explicit BarRow(const QString& caption, QWidget* parent = nullptr);
+
+    // fraction is clamped to [0, 1]; valueText is shown beside the caption as-is, so a
+    // bar can read "72%" or "340 / 500" as its meaning requires.
+    void setValue(double fraction, const QString& valueText);
+    // Overrides the fill color, which defaults to the palette's highlight.
+    void setFillColor(const QColor& color);
+
+private:
+    class Bar;
+
+    QLabel* m_captionLabel;
+    QLabel* m_valueLabel;
+    Bar*    m_bar;
+};

src/ui/selection/BeltContent.cpp

@@ -0,0 +1,38 @@
+#include "BeltContent.h"
+
+#include <QVBoxLayout>
+
+#include "BuildingTarget.h"
+#include "ClearBeltControl.h"
+#include "SelectionNames.h"
+
+BeltContent::BeltContent(const SelectionContext& context,
+                         const SelectionRequest& request, QWidget* parent)
+    // Only an operational tile aggregates, so a card showing several is never a site;
+    // a single selected tile still can be one.
+    : SelectionContent(context,
+                       request.buildings.size() == 1
+                           ? asConstructionSite(context, request.buildings.front())
+                           : std::nullopt,
+                       parent)
+    , m_ids(request.buildings)
+{
+    getRuntimeLayout()->addWidget(new ClearBeltControl(context, m_ids, this));
+}
+
+void BeltContent::refreshConfiguration()
+{
+    const BuildingTarget target = resolveBuildingTarget(getContext(), m_ids.front());
+    if (!target.isValid())
+    {
+        return;
+    }
+
+    // An aggregated selection may mix belts with tunnel ends, so it is named after the
+    // first tile; the count says how many are held (REQ-UI-SELECTION-AGGREGATE).
+    setBuildingIdentity(target.type, getBuildingTypeName(target.type));
+    if (m_ids.size() > 1)
+    {
+        setCountSlot(static_cast<int>(m_ids.size()));
+    }
+}

src/ui/selection/BeltContent.h

@@ -0,0 +1,30 @@
+#pragma once
+
+#include <vector>
+
+#include "BuildingId.h"
+#include "SelectionContent.h"
+#include "SelectionContentFactory.h"
+
+// The card for a belt, a tunnel entry or a tunnel exit
+// (REQ-UI-SELECTION-CONTENT). These carry no configuration and no buffers of their own;
+// their card is the clear action alone (REQ-UI-BELT-CLEAR).
+//
+// Because that action already operates on the whole selection, several of them aggregate
+// into this one card with the count in the header (REQ-UI-SELECTION-AGGREGATE) -- the
+// splitter is not among them, as its output filters are per-object.
+class BeltContent : public SelectionContent
+{
+    Q_OBJECT
+
+public:
+    BeltContent(const SelectionContext& context, const SelectionRequest& request,
+                QWidget* parent = nullptr);
+
+protected:
+    void refreshConfiguration() override;
+    void refreshRuntime() override {}
+
+private:
+    std::vector<BuildingId> m_ids;
+};

src/ui/selection/BufferSection.cpp

@@ -0,0 +1,103 @@
+#include "BufferSection.h"
+
+#include <vector>
+
+#include <QVBoxLayout>
+
+#include "Building.h"
+#include "DisplayName.h"
+#include "ItemChipRow.h"
+#include "SectionBox.h"
+
+namespace
+{
+
+int findPerCycle(const std::map<std::string, int>& perCycle, const std::string& itemId)
+{
+    const std::map<std::string, int>::const_iterator it = perCycle.find(itemId);
+    return (it != perCycle.end()) ? it->second : 0;
+}
+
+}  // namespace
+
+
+BufferSection::BufferSection(const SelectionContext& context, QWidget* parent)
+    : QWidget(parent)
+{
+    QVBoxLayout* layout = new QVBoxLayout(this);
+    layout->setContentsMargins(0, 0, 0, 0);
+    layout->setSpacing(6);
+
+    m_inputSection = new SectionBox(tr("Input buffers"), this);
+    m_inputChips   = new ItemChipRow(context.itemIcons, m_inputSection);
+    m_inputSection->getContentLayout()->addWidget(m_inputChips);
+
+    m_outputSection = new SectionBox(tr("Output buffer"), this);
+    m_outputChips   = new ItemChipRow(context.itemIcons, m_outputSection);
+    m_outputSection->getContentLayout()->addWidget(m_outputChips);
+
+    layout->addWidget(m_inputSection);
+    layout->addWidget(m_outputSection);
+}
+
+void BufferSection::setBuffers(const Building& building,
+                               const std::map<std::string, int>& perCycleInputs,
+                               const std::map<std::string, int>& perCycleOutputs)
+{
+    std::vector<ItemChipRow::Entry> inputs;
+    for (const std::pair<const ItemType, int>& entry : building.inputBuffer.counts)
+    {
+        ItemChipRow::Entry chip;
+        chip.itemId    = entry.first.id;
+        chip.countText = QString::number(entry.second);
+
+        const int perCycle = findPerCycle(perCycleInputs, entry.first.id);
+        if (perCycle > 0)
+        {
+            chip.subLine = tr("/ %1 per cycle").arg(perCycle);
+        }
+        inputs.push_back(chip);
+    }
+
+    // Output-side items are the buffered ones plus those still emerging onto the output
+    // belts: an emerging item still belongs to the output buffer (REQ-MAT-OUTPUT-EMERGE),
+    // so leaving it out would make it vanish from the panel while it animates.
+    std::map<std::string, int> outputCounts;
+    for (const Item& item : building.outputBuffer.items)
+    {
+        outputCounts[item.type.id]++;
+    }
+    for (const std::vector<BeltItemSlot>& lane : building.emergingItems)
+    {
+        for (const BeltItemSlot& slot : lane)
+        {
+            outputCounts[slot.item.type.id]++;
+        }
+    }
+    // A configured building lists everything its cycle produces, so an output the player
+    // is waiting for reads as 0 rather than being absent.
+    for (const std::pair<const std::string, int>& entry : perCycleOutputs)
+    {
+        outputCounts.emplace(entry.first, 0);
+    }
+
+    std::vector<ItemChipRow::Entry> outputs;
+    for (const std::pair<const std::string, int>& entry : outputCounts)
+    {
+        ItemChipRow::Entry chip;
+        chip.itemId = entry.first;
+        // Counted against the buffer's capacity, which is what production stops at
+        // (REQ-MAT-OUTPUT-BUFFER).
+        chip.countText = building.outputBuffer.capacity > 0
+            ? tr("%1 / %2").arg(entry.second).arg(building.outputBuffer.capacity)
+            : QString::number(entry.second);
+        chip.subLine = QString::fromStdString(toDisplayName(entry.first));
+        outputs.push_back(chip);
+    }
+
+    m_inputChips->setEntries(inputs);
+    m_outputChips->setEntries(outputs);
+    m_inputSection->setVisible(!inputs.empty());
+    m_outputSection->setVisible(!outputs.empty());
+    setVisible(!inputs.empty() || !outputs.empty());
+}

src/ui/selection/BufferSection.h

@@ -0,0 +1,39 @@
+#pragma once
+
+#include <map>
+#include <string>
+
+#include <QWidget>
+
+#include "SelectionContext.h"
+
+struct Building;
+class ItemChipRow;
+class SectionBox;
+
+// The input and output buffer contents of one building, each a captioned section of item
+// chips (REQ-UI-SINGLE-SELECTION).
+//
+// Counting what is in the buffers is the same for every building type, so it happens
+// here; what a cycle consumes and produces is not, so the owning content supplies those
+// per-cycle amounts. An item with no entry in the maps is shown without a denominator,
+// and a section holding nothing is not shown at all.
+class BufferSection : public QWidget
+{
+    Q_OBJECT
+
+public:
+    explicit BufferSection(const SelectionContext& context, QWidget* parent = nullptr);
+
+    // perCycleInputs and perCycleOutputs map an item id to the amount one production
+    // cycle consumes or produces. Both may be empty, for a building that runs no cycle.
+    void setBuffers(const Building& building,
+                    const std::map<std::string, int>& perCycleInputs,
+                    const std::map<std::string, int>& perCycleOutputs);
+
+private:
+    SectionBox*  m_inputSection;
+    ItemChipRow* m_inputChips;
+    SectionBox*  m_outputSection;
+    ItemChipRow* m_outputChips;
+};

src/ui/selection/BufferedBuildingContent.cpp

@@ -0,0 +1,84 @@
+#include "BufferedBuildingContent.h"
+
+#include <vector>
+
+#include <QVBoxLayout>
+
+#include "Building.h"
+#include "BufferSection.h"
+#include "BuildingTarget.h"
+#include "FactoryQueries.h"
+#include "ProductionSection.h"
+#include "RecipeSummaryRow.h"
+#include "SelectionNames.h"
+#include "Simulation.h"
+
+namespace
+{
+
+std::vector<RecipeSummaryRow::Amount> toAmounts(const std::map<std::string, int>& map)
+{
+    std::vector<RecipeSummaryRow::Amount> amounts;
+    amounts.reserve(map.size());
+    for (const std::pair<const std::string, int>& entry : map)
+    {
+        amounts.push_back(RecipeSummaryRow::Amount{ entry.first, entry.second });
+    }
+    return amounts;
+}
+
+}  // namespace
+
+
+BufferedBuildingContent::BufferedBuildingContent(const SelectionContext& context,
+                                                 BuildingId id, QWidget* parent)
+    : SelectionContent(context, asConstructionSite(context, id), parent)
+    , m_id(id)
+{
+    // The summary is configuration -- what the building will do -- so it sits with the
+    // selection control and is shown for a construction site too (REQ-UI-RECIPE-SUMMARY).
+    m_recipeSummary = new RecipeSummaryRow(context.itemIcons, this);
+    getConfigurationLayout()->addWidget(m_recipeSummary);
+
+    m_buffers = new BufferSection(context, this);
+    m_production = new ProductionSection(this);
+    getRuntimeLayout()->addWidget(m_buffers);
+    getRuntimeLayout()->addWidget(m_production);
+}
+
+void BufferedBuildingContent::refreshConfiguration()
+{
+    const BuildingTarget target = resolveBuildingTarget(getContext(), m_id);
+    if (!target.isValid())
+    {
+        // Gone under the card. SelectionPanel rebuilds on the same refresh; this only
+        // has to avoid reading it.
+        return;
+    }
+
+    setBuildingIdentity(target.type, getBuildingTypeName(target.type));
+
+    const CycleInfo cycle = getCycleInfo(target);
+    m_recipeSummary->setSummary(toAmounts(cycle.perCycleInputs),
+                                toAmounts(cycle.perCycleOutputs),
+                                cycle.durationSeconds);
+
+    refreshControls(target);
+}
+
+void BufferedBuildingContent::refreshRuntime()
+{
+    const BuildingTarget target = resolveBuildingTarget(getContext(), m_id);
+    if (!target.building)
+    {
+        return;
+    }
+
+    setProductionStatusSlot(*target.building);
+
+    const CycleInfo cycle = getCycleInfo(target);
+    m_buffers->setBuffers(*target.building, cycle.perCycleInputs, cycle.perCycleOutputs);
+    m_production->setProduction(cycle.runsProduction, *target.building,
+                                cycle.durationSeconds,
+                                getContext().sim->getCurrentTick());
+}

src/ui/selection/BufferedBuildingContent.h

@@ -0,0 +1,62 @@
+#pragma once
+
+#include <map>
+#include <string>
+
+#include "BuildingId.h"
+#include "SelectionContent.h"
+
+struct BuildingTarget;
+class BufferSection;
+class ProductionSection;
+class RecipeSummaryRow;
+
+// Shared body of the four cards that show one building with buffers -- the Miner and
+// Assembler, the Smelter and Reprocessing Plant, the Shipyard, and the Salvage Bay
+// (REQ-UI-SELECTION-CONTENT). All four show the same header identity and status, recipe
+// summary, buffer contents and production progress; they differ only in what one
+// production cycle costs and how long it takes, which is what the subclass supplies.
+//
+// This is implementation sharing, not a catalog entry: every concrete subclass is one
+// row of the content catalog.
+class BufferedBuildingContent : public SelectionContent
+{
+    Q_OBJECT
+
+protected:
+    // What one production cycle of this building consumes, produces, and takes.
+    struct CycleInfo
+    {
+        std::map<std::string, int> perCycleInputs;
+        std::map<std::string, int> perCycleOutputs;
+        // False when the building produces nothing at all (the Salvage Bay,
+        // REQ-BLD-SALVAGE-BAY) or has no recipe or schematic selected yet: the
+        // production section is then not shown (REQ-UI-PRODUCTION-PROGRESS).
+        bool runsProduction = false;
+        // 0 while an auto-recipe building sits between cycles, when no single recipe
+        // names a cycle time; the progress line then reads "idle".
+        double durationSeconds = 0.0;
+    };
+
+    BufferedBuildingContent(const SelectionContext& context, BuildingId id,
+                            QWidget* parent);
+
+    // Called with a construction site's stored configuration too, so the summary of what
+    // the building will produce is shown before it is built (REQ-BLD-SITE-CONFIG).
+    virtual CycleInfo getCycleInfo(const BuildingTarget& target) const = 0;
+
+    // The subclass's own configuration controls. The identity, the recipe summary, the
+    // buffers and the production progress are handled here.
+    virtual void refreshControls(const BuildingTarget& /*target*/) {}
+
+    BuildingId getBuildingId() const { return m_id; }
+
+private:
+    void refreshConfiguration() override;
+    void refreshRuntime() override;
+
+    BuildingId         m_id;
+    RecipeSummaryRow*  m_recipeSummary;
+    BufferSection*     m_buffers;
+    ProductionSection* m_production;
+};

src/ui/selection/BuildingTarget.cpp

@@ -0,0 +1,34 @@
+#include "BuildingTarget.h"
+
+#include "FactoryQueries.h"
+#include "SelectionContext.h"
+#include "Simulation.h"
+
+BuildingTarget resolveBuildingTarget(const SelectionContext& context, BuildingId id)
+{
+    BuildingTarget target;
+    target.building = findBuilding(context.sim->getFactoryState(), id);
+    target.site     = target.building
+        ? nullptr
+        : findSite(context.sim->getFactoryState(), id);
+    if (!target.isValid())
+    {
+        return target;
+    }
+
+    target.type       = target.building ? target.building->type       : target.site->type;
+    target.recipeId   = target.building ? target.building->recipeId   : target.site->recipeId;
+    target.shipLayout = target.building ? target.building->shipLayout : target.site->shipLayout;
+    target.anchor     = target.building ? target.building->anchor     : target.site->anchor;
+    return target;
+}
+
+std::optional<BuildingId> asConstructionSite(const SelectionContext& context,
+                                             BuildingId id)
+{
+    if (findSite(context.sim->getFactoryState(), id) != nullptr)
+    {
+        return id;
+    }
+    return std::nullopt;
+}

src/ui/selection/BuildingTarget.h

@@ -0,0 +1,45 @@
+#pragma once
+
+#include <optional>
+#include <string>
+
+#include <QPoint>
+
+#include "BuildingId.h"
+#include "BuildingType.h"
+#include "ShipLayout.h"
+
+struct Building;
+struct ConstructionSite;
+struct SelectionContext;
+
+// One selected building id resolved to whichever of the two things it names: an
+// operational building or a construction site still queued or under construction. A
+// site carries the same configuration as the building it will become
+// (REQ-BLD-SITE-CONFIG), so the fields both have are read out here once instead of in
+// every content that shows a single building.
+struct BuildingTarget
+{
+    const Building*         building = nullptr;  // null while it is still a site
+    const ConstructionSite* site     = nullptr;  // null once it is built
+
+    BuildingType type = BuildingType::Miner;
+    std::string  recipeId;
+    std::optional<ShipLayoutConfig> shipLayout;
+    QPoint       anchor;
+
+    // False when the id names neither -- the object went away under the panel (it was
+    // deconstructed, or its site finished and its id was reused).
+    bool isValid() const { return building != nullptr || site != nullptr; }
+};
+
+// Resolves the id against the current factory state. The returned pointers are only
+// valid until the simulation next mutates, so this is called per refresh rather than
+// cached.
+BuildingTarget resolveBuildingTarget(const SelectionContext& context, BuildingId id);
+
+// The id wrapped as a construction site id when it names one, nullopt when it names an
+// operational building. Every content showing a single building hands this to
+// SelectionContent so the base can apply the site rule (REQ-UI-SELECTION-CARD).
+std::optional<BuildingId> asConstructionSite(const SelectionContext& context,
+                                            BuildingId id);

src/ui/selection/CMakeLists.txt

@@ -0,0 +1,78 @@
+SET(HDRS
+    ${HDRS}
+    ${CMAKE_CURRENT_SOURCE_DIR}/SelectionContext.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/SelectionContent.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/SelectionContentFactory.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/SelectionNames.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/BuildingTarget.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/DebrisScrap.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/StatRow.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/BarRow.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/SectionBox.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/CountRow.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/StatusPill.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/EmptyNote.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/ItemChip.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/ItemChipRow.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/RecipeSummaryRow.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/BufferSection.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/ProductionSection.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/RecipeSelectionControl.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/ClearBeltControl.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/BufferedBuildingContent.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/RecipeProductionContent.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/AutoProductionContent.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/ShipyardContent.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/StorageContent.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/HqContent.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/BeltContent.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/SplitterContent.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/MultiBuildingContent.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/ShipContent.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/StationContent.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/DebrisContent.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/FieldMultiContent.h
+    PARENT_SCOPE
+)
+
+SET(SRCS
+    ${SRCS}
+    ${CMAKE_CURRENT_SOURCE_DIR}/SelectionContent.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/SelectionContentFactory.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/SelectionNames.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/BuildingTarget.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/DebrisScrap.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/StatRow.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/BarRow.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/SectionBox.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/CountRow.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/StatusPill.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/EmptyNote.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/ItemChip.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/ItemChipRow.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/RecipeSummaryRow.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/BufferSection.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/ProductionSection.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/RecipeSelectionControl.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/ClearBeltControl.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/BufferedBuildingContent.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/RecipeProductionContent.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/AutoProductionContent.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/ShipyardContent.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/StorageContent.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/HqContent.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/BeltContent.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/SplitterContent.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/MultiBuildingContent.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/ShipContent.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/StationContent.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/DebrisContent.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/FieldMultiContent.cpp
+    PARENT_SCOPE
+)
+
+set(UI_INCLUDE_PATH
+    ${UI_INCLUDE_PATH}
+    ${CMAKE_CURRENT_SOURCE_DIR}
+    PARENT_SCOPE
+)

src/ui/selection/ClearBeltControl.cpp

@@ -0,0 +1,54 @@
+#include "ClearBeltControl.h"
+
+#include <QPoint>
+#include <QPushButton>
+#include <QVBoxLayout>
+
+#include "Building.h"
+#include "Command.h"
+#include "CommandRequestedEvent.h"
+#include "EventManager.h"
+#include "FactoryQueries.h"
+#include "Simulation.h"
+
+ClearBeltControl::ClearBeltControl(const SelectionContext& context,
+                                   const std::vector<BuildingId>& ids, QWidget* parent)
+    : QWidget(parent)
+    , m_context(context)
+    , m_ids(ids)
+{
+    QVBoxLayout* layout = new QVBoxLayout(this);
+    layout->setContentsMargins(0, 0, 0, 0);
+    layout->setSpacing(0);
+
+    QPushButton* button = new QPushButton(tr("Clear stuck items"), this);
+    layout->addWidget(button);
+
+    connect(button, &QPushButton::clicked, this, [this]() { clearSelectedTiles(); });
+}
+
+void ClearBeltControl::clearSelectedTiles() const
+{
+    std::vector<QPoint> tiles;
+    for (BuildingId id : m_ids)
+    {
+        const Building* building = findBuilding(m_context.sim->getFactoryState(), id);
+        if (building && isBeltSubsystemType(building->type))
+        {
+            for (const QPoint& cell : building->bodyCells)
+            {
+                tiles.push_back(cell);
+            }
+        }
+    }
+    if (tiles.empty())
+    {
+        return;
+    }
+
+    std::shared_ptr<ClearBeltTilesCommand> command =
+        std::make_shared<ClearBeltTilesCommand>();
+    command->tiles = std::move(tiles);
+    EventManager::getInstance()->sendEventImmediately(
+        std::make_shared<CommandRequestedEvent>(command));
+}

src/ui/selection/ClearBeltControl.h

@@ -0,0 +1,31 @@
+#pragma once
+
+#include <vector>
+
+#include <QWidget>
+
+#include "BuildingId.h"
+#include "SelectionContext.h"
+
+// The "Clear stuck items" action of the card's runtime group (REQ-UI-BELT-CLEAR): it
+// removes every item from the selected belt, splitter and tunnel tiles, which is how a
+// stalled line is resolved.
+//
+// It acts on the whole selection rather than on one tile, which is why a selection of
+// belts and tunnel ends aggregates into a single card instead of a count summary
+// (REQ-UI-SELECTION-AGGREGATE), and why the count summary shows the action too when a
+// belt is among the selected buildings.
+class ClearBeltControl : public QWidget
+{
+    Q_OBJECT
+
+public:
+    ClearBeltControl(const SelectionContext& context,
+                     const std::vector<BuildingId>& ids, QWidget* parent = nullptr);
+
+private:
+    void clearSelectedTiles() const;
+
+    SelectionContext        m_context;
+    std::vector<BuildingId> m_ids;
+};

src/ui/selection/CountRow.cpp

@@ -0,0 +1,29 @@
+#include "CountRow.h"
+
+#include <QHBoxLayout>
+#include <QLabel>
+
+CountRow::CountRow(const QPixmap& symbol, const QString& name, int count,
+                   QWidget* parent)
+    : QWidget(parent)
+{
+    QHBoxLayout* layout = new QHBoxLayout(this);
+    layout->setContentsMargins(0, 0, 0, 0);
+    layout->setSpacing(6);
+
+    m_symbolLabel = new QLabel(this);
+    m_symbolLabel->setPixmap(symbol);
+    m_symbolLabel->setVisible(!symbol.isNull());
+
+    m_nameLabel = new QLabel(name, this);
+
+    // The same "x<count>" notation the recipe tooltip and the header's aggregate count
+    // use (REQ-UI-MULTI-SELECTION).
+    m_countLabel = new QLabel(tr("x%1").arg(count), this);
+    m_countLabel->setAlignment(Qt::AlignRight | Qt::AlignVCenter);
+
+    layout->addWidget(m_symbolLabel);
+    layout->addWidget(m_nameLabel);
+    layout->addStretch(1);
+    layout->addWidget(m_countLabel);
+}

src/ui/selection/CountRow.h

@@ -0,0 +1,25 @@
+#pragma once
+
+#include <QPixmap>
+#include <QString>
+#include <QWidget>
+
+class QLabel;
+
+// One "<symbol> <name>  x<count>" line of a count summary. The same part serves the
+// building summary and the field summary, which count different things the same way
+// (REQ-UI-MULTI-SELECTION, REQ-UI-FIELD-MULTI-SELECTION).
+class CountRow : public QWidget
+{
+    Q_OBJECT
+
+public:
+    // An empty symbol leaves the icon off, for the kinds of object that have none.
+    CountRow(const QPixmap& symbol, const QString& name, int count,
+             QWidget* parent = nullptr);
+
+private:
+    QLabel* m_symbolLabel;
+    QLabel* m_nameLabel;
+    QLabel* m_countLabel;
+};

src/ui/selection/DebrisContent.cpp

@@ -0,0 +1,32 @@
+#include "DebrisContent.h"
+
+#include <QVBoxLayout>
+
+#include "DebrisScrap.h"
+#include "Simulation.h"
+#include "StatRow.h"
+
+DebrisContent::DebrisContent(const SelectionContext& context,
+                             const SelectionRequest& request, QWidget* parent)
+    : SelectionContent(context, std::nullopt, parent)
+    , m_debris(request.debris)
+{
+    m_scrapRow = new StatRow(tr("Scrap remaining"), this);
+    m_scrapRow->setValueEmphasized(true);
+    getRuntimeLayout()->addWidget(m_scrapRow);
+
+    setIdentity(QPixmap(), tr("Debris"));
+    if (m_debris.size() > 1)
+    {
+        setCountSlot(static_cast<int>(m_debris.size()));
+    }
+}
+
+void DebrisContent::refreshRuntime()
+{
+    // The value falls as the debris is collected and as pieces despawn
+    // (REQ-UI-DEBRIS-CLICK-SELECT), so it is re-summed rather than remembered. With
+    // several pieces selected it is their sum (REQ-UI-SELECTION-AGGREGATE).
+    m_scrapRow->setValue(QString::number(
+        sumDebrisScrap(getContext().sim->getAdmin(), m_debris)));
+}

src/ui/selection/DebrisContent.h

@@ -0,0 +1,31 @@
+#pragma once
+
+#include <vector>
+
+#include "entt/entity/entity.hpp"
+
+#include "SelectionContent.h"
+#include "SelectionContentFactory.h"
+
+class StatRow;
+
+// The card for selected debris (REQ-UI-DEBRIS-PANEL): the scrap still left in it.
+//
+// It is the field category's aggregating content (REQ-UI-SELECTION-AGGREGATE): several
+// pieces of debris show this same card with the count in the header and their scrap
+// summed, because that is the one value the card holds and it adds up.
+class DebrisContent : public SelectionContent
+{
+    Q_OBJECT
+
+public:
+    DebrisContent(const SelectionContext& context, const SelectionRequest& request,
+                  QWidget* parent = nullptr);
+
+protected:
+    void refreshRuntime() override;
+
+private:
+    std::vector<entt::entity> m_debris;
+    StatRow*                  m_scrapRow;
+};

src/ui/selection/DebrisScrap.cpp

@@ -0,0 +1,18 @@
+#include "DebrisScrap.h"
+
+#include <algorithm>
+
+#include "DebrisSystem.h"
+
+int sumDebrisScrap(const EntityAdmin& admin, const std::vector<entt::entity>& debris)
+{
+    int total = 0;
+    for (const DebrisInfo& info : getAllDebrisInfo(admin))
+    {
+        if (std::find(debris.begin(), debris.end(), info.entity) != debris.end())
+        {
+            total += info.amount;
+        }
+    }
+    return total;
+}

src/ui/selection/DebrisScrap.h

@@ -0,0 +1,13 @@
+#pragma once
+
+#include <vector>
+
+#include "entt/entity/entity.hpp"
+
+class EntityAdmin;
+
+// Remaining scrap summed over the given debris, skipping pieces that have already been
+// collected or despawned (REQ-RES-DEBRIS-DROP). Shared by the debris card and the field
+// count summary, which show the same total in two shapes (REQ-UI-DEBRIS-PANEL,
+// REQ-UI-FIELD-MULTI-SELECTION).
+int sumDebrisScrap(const EntityAdmin& admin, const std::vector<entt::entity>& debris);

src/ui/selection/EmptyNote.cpp

@@ -0,0 +1,19 @@
+#include "EmptyNote.h"
+
+#include <QFont>
+#include <QPalette>
+
+EmptyNote::EmptyNote(const QString& text, QWidget* parent)
+    : QLabel(text, parent)
+{
+    setWordWrap(true);
+
+    QFont noteFont = font();
+    noteFont.setItalic(true);
+    setFont(noteFont);
+
+    QPalette notePalette = palette();
+    notePalette.setColor(QPalette::WindowText,
+                         palette().color(QPalette::Disabled, QPalette::WindowText));
+    setPalette(notePalette);
+}

src/ui/selection/EmptyNote.h

@@ -0,0 +1,15 @@
+#pragma once
+
+#include <QString>
+#include <QLabel>
+
+// A dimmed aside explaining why a part of the card is not there yet -- a construction
+// site's "no buffers until built" (REQ-UI-SELECTION-CARD). Styled apart from the card's
+// values so it reads as an explanation rather than as data.
+class EmptyNote : public QLabel
+{
+    Q_OBJECT
+
+public:
+    explicit EmptyNote(const QString& text, QWidget* parent = nullptr);
+};

src/ui/selection/FieldMultiContent.cpp

@@ -0,0 +1,105 @@
+#include "FieldMultiContent.h"
+
+#include <map>
+#include <string>
+
+#include <QVBoxLayout>
+
+#include "CountRow.h"
+#include "DebrisScrap.h"
+#include "DisplayName.h"
+#include "EntityAdmin.h"
+#include "FactionComponent.h"
+#include "ShipIdentityComponent.h"
+#include "Simulation.h"
+#include "StatRow.h"
+#include "StationBodyComponent.h"
+
+FieldMultiContent::FieldMultiContent(const SelectionContext& context,
+                                     const SelectionRequest& request, QWidget* parent)
+    : SelectionContent(context, std::nullopt, parent)
+    , m_debris(request.debris)
+    , m_scrapRow(nullptr)
+{
+    setIdentity(QPixmap(), tr("Mixed selection"));
+    setCountSlot(static_cast<int>(request.actors.size() + request.debris.size()));
+
+    buildSummary(request.actors);
+}
+
+void FieldMultiContent::buildSummary(const std::vector<entt::entity>& actors)
+{
+    EntityAdmin& admin = getContext().sim->getAdmin();
+
+    // Grouped by faction, kind and ship schematic, in the order the groups are first
+    // seen (REQ-UI-FIELD-MULTI-SELECTION).
+    std::vector<QString> keys;
+    std::map<QString, int>     counts;
+    std::map<QString, QString> labels;
+
+    for (entt::entity actor : actors)
+    {
+        if (!admin.isValid(actor)) { continue; }
+        const bool isEnemy = admin.hasAll<FactionComponent>(actor)
+            && admin.get<FactionComponent>(actor).isEnemy;
+
+        QString key;
+        QString label;
+        if (admin.hasAll<ShipIdentityComponent>(actor))
+        {
+            const std::string& id = admin.get<ShipIdentityComponent>(actor).schematicId;
+            const QString name = QString::fromStdString(toDisplayName(id));
+            key = (isEnemy ? QStringLiteral("ship:enemy:")
+                           : QStringLiteral("ship:player:"))
+                + QString::fromStdString(id);
+            label = isEnemy ? tr("Enemy %1").arg(name) : name;
+        }
+        else if (admin.hasAll<StationBodyComponent>(actor))
+        {
+            key = isEnemy ? QStringLiteral("station:enemy")
+                          : QStringLiteral("station:player");
+            label = isEnemy ? tr("Enemy Defence Station") : tr("Player Defence Station");
+        }
+        else
+        {
+            continue;
+        }
+
+        if (counts.find(key) == counts.end())
+        {
+            keys.push_back(key);
+            labels[key] = label;
+        }
+        counts[key] += 1;
+    }
+
+    for (const QString& key : keys)
+    {
+        getRuntimeLayout()->addWidget(
+            new CountRow(QPixmap(), labels[key], counts[key], this));
+    }
+
+    if (!m_debris.empty())
+    {
+        getRuntimeLayout()->addWidget(new CountRow(
+            QPixmap(), tr("Debris"), static_cast<int>(m_debris.size()), this));
+
+        // Indented under the debris row, so the total reads as belonging to it
+        // (REQ-UI-DEBRIS-PANEL).
+        m_scrapRow = new StatRow(tr("holding"), this);
+        m_scrapRow->setIndented(true);
+        m_scrapRow->setValueEmphasized(true);
+        getRuntimeLayout()->addWidget(m_scrapRow);
+    }
+}
+
+void FieldMultiContent::refreshRuntime()
+{
+    // The counts are fixed for a given selection -- an actor leaving it re-publishes the
+    // selection and rebuilds this card -- but the scrap falls as the debris is collected.
+    if (m_scrapRow)
+    {
+        m_scrapRow->setValue(tr("%1 scrap")
+            .arg(sumDebrisScrap(getContext().sim->getAdmin(), m_debris)));
+    }
+}

src/ui/selection/FieldMultiContent.h

@@ -0,0 +1,33 @@
+#pragma once
+
+#include <vector>
+
+#include "entt/entity/entity.hpp"
+
+#include "SelectionContent.h"
+#include "SelectionContentFactory.h"
+
+class StatRow;
+
+// The count summary for a field selection holding more than one object that does not
+// aggregate (REQ-UI-FIELD-MULTI-SELECTION): several actors, or actors together with
+// debris. A count per type, and the debris' summed scrap when debris is part of it.
+class FieldMultiContent : public SelectionContent
+{
+    Q_OBJECT
+
+public:
+    FieldMultiContent(const SelectionContext& context, const SelectionRequest& request,
+                      QWidget* parent = nullptr);
+
+protected:
+    void refreshRuntime() override;
+
+private:
+    void buildSummary(const std::vector<entt::entity>& actors);
+
+    std::vector<entt::entity> m_debris;
+    // Null unless debris is part of the selection; the only value here that changes
+    // while the selection stands.
+    StatRow*                  m_scrapRow;
+};

src/ui/selection/HqContent.cpp

@@ -0,0 +1,60 @@
+#include "HqContent.h"
+
+#include <vector>
+
+#include <QVBoxLayout>
+
+#include "BarRow.h"
+#include "EntityAdmin.h"
+#include "HealthComponent.h"
+#include "HqProxyComponent.h"
+#include "IconCaption.h"
+#include "ItemChipRow.h"
+#include "SectionBox.h"
+#include "SelectionNames.h"
+#include "Simulation.h"
+
+HqContent::HqContent(const SelectionContext& context, const SelectionRequest& request,
+                     QWidget* parent)
+    // The HQ is placed before the game starts and can never be deconstructed
+    // (REQ-BLD-DECONSTRUCT), so it is never a construction site.
+    : SelectionContent(context, std::nullopt, parent)
+{
+    m_stockSection = new SectionBox(tr("Building blocks"), this);
+    m_stockChips   = new ItemChipRow(context.itemIcons, m_stockSection);
+    m_stockSection->getContentLayout()->addWidget(m_stockChips);
+
+    m_hpBar = new BarRow(tr("HP"), this);
+
+    getRuntimeLayout()->addWidget(m_stockSection);
+    getRuntimeLayout()->addWidget(m_hpBar);
+
+    setBuildingIdentity(BuildingType::Hq, getBuildingTypeName(BuildingType::Hq));
+}
+
+void HqContent::refreshRuntime()
+{
+    // Not a buffer: blocks delivered by belt go straight into the global stock
+    // (REQ-HQ-BELT-INPUT). Showing it here is what tells the player to route them here
+    // (REQ-UI-HQ-PANEL).
+    ItemChipRow::Entry stock;
+    stock.itemId    = kBlockItemId;
+    stock.countText = QString::number(getContext().sim->getBuildingBlocksStock());
+    stock.subLine   = tr("in stock");
+    m_stockChips->setEntries(std::vector<ItemChipRow::Entry>{ stock });
+
+    // The HQ's health lives on its proxy entity, not on the building
+    // (REQ-HQ-STATS, REQ-UI-HP-BARS).
+    EntityAdmin& admin = getContext().sim->getAdmin();
+    admin.forEach<HqProxyComponent, HealthComponent>(
+        [this](entt::entity /*entity*/, const HqProxyComponent& /*proxy*/,
+               const HealthComponent& health)
+        {
+            const double fraction = (health.maxHp > 0.0f)
+                ? static_cast<double>(health.hp) / health.maxHp
+                : 0.0;
+            m_hpBar->setValue(fraction, tr("%1 / %2")
+                .arg(static_cast<int>(health.hp + 0.5f))
+                .arg(static_cast<int>(health.maxHp + 0.5f)));
+        });
+}

src/ui/selection/HqContent.h

@@ -0,0 +1,32 @@
+#pragma once
+
+#include "SelectionContent.h"
+#include "SelectionContentFactory.h"
+
+class BarRow;
+class ItemChipRow;
+class SectionBox;
+
+// The card for the HQ (REQ-UI-HQ-PANEL): the global building blocks stock and the HQ's
+// HP. It has no configuration group and no status indicator.
+//
+// The stock is not a buffer: blocks delivered by belt go straight into the global stock
+// (REQ-HQ-BELT-INPUT), which is exactly why the card shows it -- it is what tells the
+// player to route blocks here. The HP comes from the HQ's proxy entity rather than from
+// the building, since that is where its health lives.
+class HqContent : public SelectionContent
+{
+    Q_OBJECT
+
+public:
+    HqContent(const SelectionContext& context, const SelectionRequest& request,
+              QWidget* parent = nullptr);
+
+protected:
+    void refreshRuntime() override;
+
+private:
+    SectionBox*  m_stockSection;
+    ItemChipRow* m_stockChips;
+    BarRow*      m_hpBar;
+};

src/ui/selection/ItemChip.cpp

@@ -0,0 +1,72 @@
+#include "ItemChip.h"
+
+#include <QFont>
+#include <QHBoxLayout>
+#include <QLabel>
+#include <QPalette>
+#include <QVBoxLayout>
+
+namespace
+{
+
+// Point-size rise of the count and drop of the sub-line, relative to the card's text.
+const int kCountSizeRisePt   = 2;
+const int kSubLineSizeDropPt = 1;
+
+}  // namespace
+
+
+ItemChip::ItemChip(const QPixmap& icon, QWidget* parent)
+    : QWidget(parent)
+{
+    // Its own boxed chrome, drawn with palette colors like the rest of the panel's
+    // furniture rather than from visuals.toml, which is for world rendering.
+    setAttribute(Qt::WA_StyledBackground, true);
+    setStyleSheet(QStringLiteral(
+        "ItemChip { border: 1px solid palette(mid); border-radius: 3px; }"));
+
+    QHBoxLayout* layout = new QHBoxLayout(this);
+    layout->setContentsMargins(4, 3, 4, 3);
+    layout->setSpacing(6);
+
+    m_iconLabel = new QLabel(this);
+    m_iconLabel->setPixmap(icon);
+    m_iconLabel->setVisible(!icon.isNull());
+
+    QWidget* text = new QWidget(this);
+    QVBoxLayout* textLayout = new QVBoxLayout(text);
+    textLayout->setContentsMargins(0, 0, 0, 0);
+    textLayout->setSpacing(0);
+
+    m_countLabel = new QLabel(text);
+    QFont countFont = m_countLabel->font();
+    countFont.setPointSize(countFont.pointSize() + kCountSizeRisePt);
+    m_countLabel->setFont(countFont);
+
+    m_subLineLabel = new QLabel(text);
+    QFont subLineFont = m_subLineLabel->font();
+    subLineFont.setPointSize(qMax(1, subLineFont.pointSize() - kSubLineSizeDropPt));
+    m_subLineLabel->setFont(subLineFont);
+    QPalette subLinePalette = m_subLineLabel->palette();
+    subLinePalette.setColor(QPalette::WindowText,
+                            palette().color(QPalette::Disabled, QPalette::WindowText));
+    m_subLineLabel->setPalette(subLinePalette);
+    m_subLineLabel->hide();
+
+    textLayout->addWidget(m_countLabel);
+    textLayout->addWidget(m_subLineLabel);
+
+    layout->addWidget(m_iconLabel);
+    layout->addWidget(text);
+}
+
+void ItemChip::setCount(const QString& count)
+{
+    m_countLabel->setText(count);
+}
+
+void ItemChip::setSubLine(const QString& subLine)
+{
+    m_subLineLabel->setText(subLine);
+    m_subLineLabel->setVisible(!subLine.isEmpty());
+}

src/ui/selection/ItemChip.h

@@ -0,0 +1,28 @@
+#pragma once
+
+#include <QPixmap>
+#include <QString>
+#include <QWidget>
+
+class QLabel;
+
+// One buffered item: its icon, its count in a larger type, and a sub-line beneath the
+// count (REQ-UI-SINGLE-SELECTION). Boxed so a row of them reads as separate quantities
+// rather than as a run of text.
+class ItemChip : public QWidget
+{
+    Q_OBJECT
+
+public:
+    // An empty icon leaves the icon off and the chip laid out around the text alone.
+    ItemChip(const QPixmap& icon, QWidget* parent = nullptr);
+
+    void setCount(const QString& count);
+    // Left empty for an item with nothing to say beneath its count.
+    void setSubLine(const QString& subLine);
+
+private:
+    QLabel* m_iconLabel;
+    QLabel* m_countLabel;
+    QLabel* m_subLineLabel;
+};

src/ui/selection/ItemChipRow.cpp

@@ -0,0 +1,78 @@
+#include "ItemChipRow.h"
+
+#include <QGridLayout>
+
+#include "ItemChip.h"
+#include "ItemIconCache.h"
+
+namespace
+{
+
+// Size the item icon is drawn at inside a chip, in device-independent pixels.
+const int kChipIconSizePx = 18;
+
+// Chips per row. Two fit the panel's capped width side by side; a third would force the
+// counts to shrink.
+const int kChipsPerRow = 2;
+
+}  // namespace
+
+
+ItemChipRow::ItemChipRow(ItemIconCache* itemIcons, QWidget* parent)
+    : QWidget(parent)
+    , m_itemIcons(itemIcons)
+{
+    m_layout = new QGridLayout(this);
+    m_layout->setContentsMargins(0, 0, 0, 0);
+    m_layout->setSpacing(4);
+}
+
+void ItemChipRow::setEntries(const std::vector<Entry>& entries)
+{
+    std::vector<std::string> itemIds;
+    itemIds.reserve(entries.size());
+    for (const Entry& entry : entries)
+    {
+        itemIds.push_back(entry.itemId);
+    }
+
+    // Only the set of items changing is a structural change; the counts change every
+    // tick and must not cost a widget rebuild.
+    if (itemIds != m_itemIds)
+    {
+        m_itemIds = std::move(itemIds);
+        rebuildChips(entries);
+    }
+
+    for (std::size_t index = 0; index < entries.size(); ++index)
+    {
+        m_chips[index]->setCount(entries[index].countText);
+        m_chips[index]->setSubLine(entries[index].subLine);
+    }
+    setVisible(!entries.empty());
+}
+
+void ItemChipRow::rebuildChips(const std::vector<Entry>& entries)
+{
+    for (ItemChip* chip : m_chips)
+    {
+        m_layout->removeWidget(chip);
+        chip->deleteLater();
+    }
+    m_chips.clear();
+
+    for (std::size_t index = 0; index < entries.size(); ++index)
+    {
+        const std::string& itemId = entries[index].itemId;
+        // A missing icon file is not an error (REQ-UI-ITEM-ICON): the chip is then laid
+        // out around its count alone.
+        const QPixmap icon = m_itemIcons->hasIcon(itemId)
+            ? m_itemIcons->getPixmap(itemId, kChipIconSizePx)
+            : QPixmap();
+
+        ItemChip* chip = new ItemChip(icon, this);
+        m_layout->addWidget(chip, static_cast<int>(index) / kChipsPerRow,
+                            static_cast<int>(index) % kChipsPerRow);
+        m_chips.push_back(chip);
+    }
+}

src/ui/selection/ItemChipRow.h

@@ -0,0 +1,44 @@
+#pragma once
+
+#include <string>
+#include <vector>
+
+#include <QString>
+#include <QWidget>
+
+class ItemChip;
+class ItemIconCache;
+class QGridLayout;
+
+// The buffered items of one building, each as a chip carrying the item's icon, its
+// current count and a sub-line (REQ-UI-SINGLE-SELECTION): the per-cycle amount for an
+// input, the item's name for an output.
+//
+// The chips are rebuilt only when the set of items changes, not when their counts do, so
+// a refresh at tick rate updates numbers instead of churning widgets.
+class ItemChipRow : public QWidget
+{
+    Q_OBJECT
+
+public:
+    struct Entry
+    {
+        std::string itemId;
+        QString     countText;
+        QString     subLine;
+    };
+
+    // itemIcons is the window-wide per-item icon cache (REQ-UI-ITEM-ICON); an item with
+    // no icon file simply shows no icon, which is not an error. Not owned.
+    explicit ItemChipRow(ItemIconCache* itemIcons, QWidget* parent = nullptr);
+
+    void setEntries(const std::vector<Entry>& entries);
+
+private:
+    void rebuildChips(const std::vector<Entry>& entries);
+
+    ItemIconCache*           m_itemIcons;
+    QGridLayout*             m_layout;
+    std::vector<std::string> m_itemIds;  // what the chips currently stand for
+    std::vector<ItemChip*>   m_chips;
+};

src/ui/selection/MultiBuildingContent.cpp

@@ -0,0 +1,99 @@
+#include "MultiBuildingContent.h"
+
+#include <map>
+
+#include <QVBoxLayout>
+
+#include "Building.h"
+#include "BuildingIconCache.h"
+#include "ClearBeltControl.h"
+#include "CountRow.h"
+#include "FactoryQueries.h"
+#include "GameConfig.h"
+#include "SelectionNames.h"
+#include "Simulation.h"
+#include "StatRow.h"
+
+namespace
+{
+
+// Size the type symbol is drawn at on a count row, matching the card header's chip.
+const int kCountSymbolSizePx = 20;
+
+}  // namespace
+
+
+MultiBuildingContent::MultiBuildingContent(const SelectionContext& context,
+                                           const SelectionRequest& request,
+                                           QWidget* parent)
+    : SelectionContent(context, std::nullopt, parent)
+    , m_ids(request.buildings)
+{
+    // The header names the size of the selection instead of an object
+    // (REQ-UI-MULTI-SELECTION).
+    setIdentity(QPixmap(), tr("%1 buildings").arg(static_cast<int>(m_ids.size())));
+
+    buildSummary();
+
+    // A selection holding any belt-subsystem tile can still be cleared as a whole
+    // (REQ-UI-BELT-CLEAR), even though the mixture is what kept it from aggregating.
+    bool hasBeltTile = false;
+    for (BuildingId id : m_ids)
+    {
+        const Building* building = findBuilding(context.sim->getFactoryState(), id);
+        if (building && isBeltSubsystemType(building->type))
+        {
+            hasBeltTile = true;
+            break;
+        }
+    }
+    if (hasBeltTile)
+    {
+        getRuntimeLayout()->addWidget(new ClearBeltControl(context, m_ids, this));
+    }
+}
+
+void MultiBuildingContent::buildSummary()
+{
+    std::map<BuildingType, int> counts;
+    for (BuildingId id : m_ids)
+    {
+        const Building* building =
+            findBuilding(getContext().sim->getFactoryState(), id);
+        if (building)
+        {
+            counts[building->type]++;
+            continue;
+        }
+        const ConstructionSite* site =
+            findSite(getContext().sim->getFactoryState(), id);
+        if (site)
+        {
+            counts[site->type]++;
+        }
+    }
+
+    int totalCost = 0;
+    for (const std::pair<const BuildingType, int>& entry : counts)
+    {
+        getRuntimeLayout()->addWidget(new CountRow(
+            getContext().buildingIcons->getChip(buildingTypeId(entry.first),
+                                                kCountSymbolSizePx),
+            getBuildingTypeName(entry.first), entry.second, this));
+
+        // Only player-placeable buildings count toward the total; the HQ and defence
+        // stations are excluded (REQ-UI-MULTI-SELECTION). A construction site counts at
+        // its type's full placement cost regardless of progress.
+        const BuildingDef* def =
+            getContext().config->buildings.findBuildingDef(entry.first);
+        if (def && def->playerPlaceable)
+        {
+            totalCost += def->cost * entry.second;
+        }
+    }
+
+    StatRow* totalRow = new StatRow(tr("Total cost"), this);
+    totalRow->setValue(QString::number(totalCost));
+    totalRow->setValueEmphasized(true);
+    getRuntimeLayout()->addWidget(totalRow);
+}

src/ui/selection/MultiBuildingContent.h

@@ -0,0 +1,31 @@
+#pragma once
+
+#include <vector>
+
+#include "BuildingId.h"
+#include "SelectionContent.h"
+#include "SelectionContentFactory.h"
+
+
+// The count summary for several selected buildings that do not aggregate
+// (REQ-UI-MULTI-SELECTION, REQ-UI-SELECTION-AGGREGATE): how many of each type, and the
+// total building block cost of the selection. No per-building detail is shown.
+class MultiBuildingContent : public SelectionContent
+{
+    Q_OBJECT
+
+public:
+    MultiBuildingContent(const SelectionContext& context,
+                         const SelectionRequest& request, QWidget* parent = nullptr);
+
+protected:
+    // The summary is fixed for a given selection -- how many of each type were selected,
+    // and what they cost -- so it is built once and has nothing to keep current. A
+    // building leaving the selection re-publishes it and rebuilds this card.
+    void refreshRuntime() override {}
+
+private:
+    void buildSummary();
+
+    std::vector<BuildingId> m_ids;
+};

src/ui/selection/ProductionSection.cpp

@@ -0,0 +1,48 @@
+#include "ProductionSection.h"
+
+#include <algorithm>
+
+#include <QVBoxLayout>
+
+#include "BarRow.h"
+#include "Building.h"
+#include "SectionBox.h"
+
+ProductionSection::ProductionSection(QWidget* parent)
+    : QWidget(parent)
+{
+    QVBoxLayout* layout = new QVBoxLayout(this);
+    layout->setContentsMargins(0, 0, 0, 0);
+    layout->setSpacing(0);
+
+    m_section = new SectionBox(tr("Production"), this);
+    m_bar     = new BarRow(QString(), m_section);
+    m_section->getContentLayout()->addWidget(m_bar);
+    layout->addWidget(m_section);
+}
+
+void ProductionSection::setProduction(bool runsProduction, const Building& building,
+                                      double durationSeconds, Tick currentTick)
+{
+    // Nothing selected to produce means no progress indicator at all
+    // (REQ-UI-PRODUCTION-PROGRESS).
+    if (!runsProduction)
+    {
+        hide();
+        return;
+    }
+    show();
+
+    // No running cycle, or none whose length is known: the bar is empty and reads idle.
+    if (durationSeconds <= 0.0 || !building.production.has_value())
+    {
+        m_bar->setValue(0.0, tr("idle"));
+        return;
+    }
+
+    const Tick cycleTicks = secondsToTicks(durationSeconds);
+    const Tick elapsed = currentTick - (building.production->completesAt - cycleTicks);
+    const Tick clamped = std::max(Tick(0), std::min(cycleTicks, elapsed));
+    const int percent = static_cast<int>(clamped * 100 / cycleTicks);
+    m_bar->setValue(static_cast<double>(clamped) / cycleTicks, tr("%1%").arg(percent));
+}

src/ui/selection/ProductionSection.h

@@ -0,0 +1,35 @@
+#pragma once
+
+#include <QWidget>
+
+#include "Tick.h"
+
+struct Building;
+class BarRow;
+class SectionBox;
+
+// The cycle time and production progress of one building (REQ-UI-PRODUCTION-PROGRESS).
+//
+// Reading the progress off an active cycle is the same for every building type, so it
+// happens here; working out how long that cycle is differs per type (a recipe's
+// duration, a schematic's production time plus its modules'), so the owning content
+// supplies it.
+class ProductionSection : public QWidget
+{
+    Q_OBJECT
+
+public:
+    explicit ProductionSection(QWidget* parent = nullptr);
+
+    // runsProduction false hides the section entirely -- the building produces nothing
+    // (a Salvage Bay) or has no recipe or schematic selected yet. When it is true but
+    // durationSeconds is 0 or less, the building is between cycles with no single recipe
+    // to name a cycle time for (an idle auto-recipe building), so the progress line
+    // reads "idle" and the cycle time is left out.
+    void setProduction(bool runsProduction, const Building& building,
+                       double durationSeconds, Tick currentTick);
+
+private:
+    SectionBox* m_section;
+    BarRow*     m_bar;
+};

src/ui/selection/RecipeProductionContent.cpp

@@ -0,0 +1,51 @@
+#include "RecipeProductionContent.h"
+
+#include <QVBoxLayout>
+
+#include "BuildingTarget.h"
+#include "GameConfig.h"
+#include "RecipeSelectionControl.h"
+
+RecipeProductionContent::RecipeProductionContent(const SelectionContext& context,
+                                                 const SelectionRequest& request,
+                                                 QWidget* parent)
+    : BufferedBuildingContent(context, request.buildings.front(), parent)
+{
+    const BuildingTarget target = resolveBuildingTarget(context, getBuildingId());
+
+    // Shown for a construction site too: a site is configured exactly like the building
+    // it will become (REQ-BLD-SITE-CONFIG).
+    m_recipeControl = new RecipeSelectionControl(context, getBuildingId(), target.type,
+                                                 this);
+    getConfigurationLayout()->insertWidget(0, m_recipeControl);
+}
+
+void RecipeProductionContent::refreshControls(const BuildingTarget& target)
+{
+    m_recipeControl->setRecipeId(target.recipeId);
+}
+
+BufferedBuildingContent::CycleInfo RecipeProductionContent::getCycleInfo(
+    const BuildingTarget& target) const
+{
+    CycleInfo info;
+    const RecipeDef* recipe = target.recipeId.empty()
+        ? nullptr
+        : getContext().config->recipes.findRecipeDef(target.recipeId, target.type);
+    if (!recipe)
+    {
+        return info;
+    }
+
+    for (const RecipeIngredient& ingredient : recipe->inputs)
+    {
+        info.perCycleInputs[ingredient.item] = ingredient.amount;
+    }
+    for (const RecipeOutput& output : recipe->outputs)
+    {
+        info.perCycleOutputs[output.item] = output.amount;
+    }
+    info.runsProduction  = true;
+    info.durationSeconds = recipe->durationSeconds;
+    return info;
+}

src/ui/selection/RecipeProductionContent.h

@@ -0,0 +1,26 @@
+#pragma once
+
+#include "BufferedBuildingContent.h"
+#include "SelectionContentFactory.h"
+
+class RecipeSelectionControl;
+
+// The card for a Miner or an Assembler (REQ-UI-SELECTION-CONTENT): a player-selected
+// recipe, plus the buffers and production progress every buffered building shows. The
+// two share a card because both run one selected recipe; a Miner simply has no inputs,
+// so its input buffer section shows nothing of its own accord.
+class RecipeProductionContent : public BufferedBuildingContent
+{
+    Q_OBJECT
+
+public:
+    RecipeProductionContent(const SelectionContext& context,
+                            const SelectionRequest& request, QWidget* parent = nullptr);
+
+protected:
+    void refreshControls(const BuildingTarget& target) override;
+    CycleInfo getCycleInfo(const BuildingTarget& target) const override;
+
+private:
+    RecipeSelectionControl* m_recipeControl;
+};

src/ui/selection/RecipeSelectionControl.cpp

@@ -0,0 +1,57 @@
+#include "RecipeSelectionControl.h"
+
+#include <vector>
+
+#include <QPushButton>
+#include <QVBoxLayout>
+
+#include "EventManager.h"
+#include "RecipeSelectionDialog.h"
+#include "RecipeSelectionRequestedEvent.h"
+#include "Simulation.h"
+
+RecipeSelectionControl::RecipeSelectionControl(const SelectionContext& context,
+                                               BuildingId id, BuildingType type,
+                                               QWidget* parent)
+    : QWidget(parent)
+    , m_context(context)
+    , m_id(id)
+    , m_type(type)
+{
+    QVBoxLayout* layout = new QVBoxLayout(this);
+    layout->setContentsMargins(0, 0, 0, 0);
+    layout->setSpacing(0);
+
+    m_button = new QPushButton(this);
+    layout->addWidget(m_button);
+
+    connect(m_button, &QPushButton::clicked, this, [this]() {
+        // Sent synchronously: MainWindow pauses the game, runs the modal dialog, and
+        // restores the speed before this returns. The chosen recipe is only enqueued as
+        // a command though, and drains on a later frame -- so the caption follows from
+        // the next refresh, not from here.
+        EventManager::getInstance()->sendEventImmediately(
+            std::make_shared<RecipeSelectionRequestedEvent>(m_id));
+    });
+}
+
+void RecipeSelectionControl::setRecipeId(const std::string& recipeId)
+{
+    const std::vector<RecipeSelectionOption> options =
+        buildRecipeSelectionOptions(m_type, *m_context.sim, *m_context.config);
+
+    for (const RecipeSelectionOption& option : options)
+    {
+        if (option.id == recipeId && !option.id.empty())
+        {
+            m_button->setText(option.caption);
+            m_button->setToolTip(option.tooltip);
+            return;
+        }
+    }
+
+    m_button->setText(m_type == BuildingType::Shipyard
+        ? tr("Select schematic")
+        : tr("Select recipe"));
+    m_button->setToolTip(QString());
+}

src/ui/selection/RecipeSelectionControl.h

@@ -0,0 +1,38 @@
+#pragma once
+
+#include <string>
+
+#include <QWidget>
+
+#include "BuildingId.h"
+#include "BuildingType.h"
+#include "SelectionContext.h"
+
+class QPushButton;
+
+// The recipe/schematic selection control of the card's configuration group: one button
+// captioned with the current selection that opens the modal selection dialog
+// (REQ-UI-SELECT-BUTTON, REQ-UI-CONFIG-INLINE). Used by the Miner and Assembler for
+// their recipe and by the Shipyard for its schematic; the placeholder caption is the
+// only difference between the two.
+//
+// The control does not apply the choice itself: it asks for the dialog and the choice
+// arrives back as a command, so the caption follows from the next refresh rather than
+// from the click.
+class RecipeSelectionControl : public QWidget
+{
+    Q_OBJECT
+
+public:
+    RecipeSelectionControl(const SelectionContext& context, BuildingId id,
+                           BuildingType type, QWidget* parent = nullptr);
+
+    // Re-reads the caption and tooltip for the currently configured recipe id.
+    void setRecipeId(const std::string& recipeId);
+
+private:
+    SelectionContext m_context;
+    BuildingId       m_id;
+    BuildingType     m_type;
+    QPushButton*     m_button;
+};

src/ui/selection/RecipeSummaryRow.cpp

@@ -0,0 +1,108 @@
+#include "RecipeSummaryRow.h"
+
+#include <QHBoxLayout>
+#include <QLabel>
+#include <QLayoutItem>
+#include <QPixmap>
+
+#include "ItemIconCache.h"
+
+namespace
+{
+
+// Size the item icons are drawn at on the summary line, in device-independent pixels.
+const int kSummaryIconSizePx = 14;
+
+}  // namespace
+
+
+RecipeSummaryRow::RecipeSummaryRow(ItemIconCache* itemIcons, QWidget* parent)
+    : QWidget(parent)
+    , m_itemIcons(itemIcons)
+{
+    m_layout = new QHBoxLayout(this);
+    m_layout->setContentsMargins(0, 0, 0, 0);
+    m_layout->setSpacing(4);
+
+    hide();
+}
+
+void RecipeSummaryRow::setSummary(const std::vector<Amount>& inputs,
+                                  const std::vector<Amount>& outputs,
+                                  double durationSeconds)
+{
+    if (outputs.empty() && inputs.empty())
+    {
+        // Forgotten as well as hidden, so re-selecting the same recipe later is seen as
+        // a change and shows the row again.
+        m_inputs.clear();
+        m_outputs.clear();
+        m_durationSeconds = -1.0;
+        hide();
+        return;
+    }
+    if (inputs == m_inputs && outputs == m_outputs
+        && durationSeconds == m_durationSeconds)
+    {
+        return;
+    }
+
+    m_inputs          = inputs;
+    m_outputs         = outputs;
+    m_durationSeconds = durationSeconds;
+    rebuild(inputs, outputs, durationSeconds);
+    show();
+}
+
+void RecipeSummaryRow::rebuild(const std::vector<Amount>& inputs,
+                               const std::vector<Amount>& outputs,
+                               double durationSeconds)
+{
+    while (QLayoutItem* item = m_layout->takeAt(0))
+    {
+        if (item->widget())
+        {
+            item->widget()->deleteLater();
+        }
+        delete item;
+    }
+
+    addAmounts(inputs);
+    if (!inputs.empty())
+    {
+        const QChar rightArrow(0x2192);  // U+2192 RIGHTWARDS ARROW
+        m_layout->addWidget(new QLabel(QString(rightArrow), this));
+    }
+    addAmounts(outputs);
+
+    if (durationSeconds > 0.0)
+    {
+        const QChar middleDot(0x00B7);  // U+00B7 MIDDLE DOT
+        m_layout->addWidget(new QLabel(
+            QStringLiteral("%1 %2").arg(middleDot).arg(
+                tr("%1 s").arg(durationSeconds, 0, 'f', 1)), this));
+    }
+    m_layout->addStretch(1);
+}
+
+void RecipeSummaryRow::addAmounts(const std::vector<Amount>& amounts)
+{
+    for (const Amount& entry : amounts)
+    {
+        // A missing icon file is not an error (REQ-UI-ITEM-ICON): the item's id then
+        // stands in for its icon.
+        if (m_itemIcons->hasIcon(entry.itemId))
+        {
+            QLabel* iconLabel = new QLabel(this);
+            iconLabel->setPixmap(
+                m_itemIcons->getPixmap(entry.itemId, kSummaryIconSizePx));
+            m_layout->addWidget(iconLabel);
+        }
+        else
+        {
+            m_layout->addWidget(
+                new QLabel(QString::fromStdString(entry.itemId), this));
+        }
+        m_layout->addWidget(new QLabel(QString::number(entry.amount), this));
+    }
+}

src/ui/selection/RecipeSummaryRow.h

@@ -0,0 +1,52 @@
+#pragma once
+
+#include <string>
+#include <vector>
+
+#include <QWidget>
+
+class ItemIconCache;
+class QHBoxLayout;
+
+// What one production cycle does, on a line: each input item with its per-cycle amount,
+// an arrow, each output with its amount, and the cycle time
+// (REQ-UI-RECIPE-SUMMARY). It restates the selected recipe without the player having to
+// open the selection dialog, and it is the panel's only display of the cycle time.
+class RecipeSummaryRow : public QWidget
+{
+    Q_OBJECT
+
+public:
+    struct Amount
+    {
+        std::string itemId;
+        int         amount = 0;
+
+        bool operator==(const Amount& other) const
+        {
+            return itemId == other.itemId && amount == other.amount;
+        }
+    };
+
+    // itemIcons is the window-wide per-item icon cache (REQ-UI-ITEM-ICON); an item with
+    // no icon file falls back to its id. Not owned.
+    explicit RecipeSummaryRow(ItemIconCache* itemIcons, QWidget* parent = nullptr);
+
+    // Hides the row when there is nothing selected to produce, which is how a building
+    // with no recipe shows no summary at all.
+    void setSummary(const std::vector<Amount>& inputs,
+                    const std::vector<Amount>& outputs, double durationSeconds);
+
+private:
+    void rebuild(const std::vector<Amount>& inputs, const std::vector<Amount>& outputs,
+                 double durationSeconds);
+    void addAmounts(const std::vector<Amount>& amounts);
+
+    ItemIconCache*      m_itemIcons;
+    QHBoxLayout*        m_layout;
+    // What the row currently shows, so a refresh at tick rate rebuilds it only when the
+    // recipe actually changed.
+    std::vector<Amount> m_inputs;
+    std::vector<Amount> m_outputs;
+    double              m_durationSeconds = -1.0;
+};

src/ui/selection/SectionBox.cpp

@@ -0,0 +1,50 @@
+#include "SectionBox.h"
+
+#include <QFont>
+#include <QLabel>
+#include <QPalette>
+#include <QVBoxLayout>
+
+namespace
+{
+
+// Point-size drop of the caption relative to the card's text, so it reads as a heading
+// without competing with the values beneath it.
+const int kCaptionSizeDropPt = 1;
+
+}  // namespace
+
+
+SectionBox::SectionBox(const QString& caption, QWidget* parent)
+    : QWidget(parent)
+{
+    QVBoxLayout* layout = new QVBoxLayout(this);
+    layout->setContentsMargins(0, 0, 0, 0);
+    layout->setSpacing(2);
+
+    m_captionLabel = new QLabel(caption.toUpper(), this);
+    QFont captionFont = m_captionLabel->font();
+    captionFont.setPointSize(qMax(1, captionFont.pointSize() - kCaptionSizeDropPt));
+    captionFont.setBold(true);
+    m_captionLabel->setFont(captionFont);
+
+    // Dimmed to the palette's disabled text, so the caption sits behind its content.
+    QPalette captionPalette = m_captionLabel->palette();
+    captionPalette.setColor(QPalette::WindowText,
+                            palette().color(QPalette::Disabled, QPalette::WindowText));
+    m_captionLabel->setPalette(captionPalette);
+    m_captionLabel->setVisible(!caption.isEmpty());
+
+    QWidget* content = new QWidget(this);
+    m_contentLayout = new QVBoxLayout(content);
+    m_contentLayout->setContentsMargins(0, 0, 0, 0);
+    m_contentLayout->setSpacing(2);
+
+    layout->addWidget(m_captionLabel);
+    layout->addWidget(content);
+}
+
+QVBoxLayout* SectionBox::getContentLayout()
+{
+    return m_contentLayout;
+}

src/ui/selection/SectionBox.h

@@ -0,0 +1,28 @@
+#pragma once
+
+#include <QString>
+#include <QWidget>
+
+class QLabel;
+class QVBoxLayout;
+
+// A captioned group of parts within a card's configuration or runtime group
+// (REQ-UI-SELECTION-CARD): a small heading over whatever the owner puts inside it.
+//
+// A section and its caption are shown or hidden as one, which is what lets a card list
+// its sections unconditionally and simply hide the ones with nothing in them -- a Miner
+// consumes nothing, so its input buffer section is never shown.
+class SectionBox : public QWidget
+{
+    Q_OBJECT
+
+public:
+    explicit SectionBox(const QString& caption, QWidget* parent = nullptr);
+
+    // The layout to add this section's parts to.
+    QVBoxLayout* getContentLayout();
+
+private:
+    QLabel*      m_captionLabel;
+    QVBoxLayout* m_contentLayout;
+};

src/ui/selection/SelectionContent.cpp

@@ -0,0 +1,222 @@
+#include "SelectionContent.h"
+
+#include <algorithm>
+#include <string>
+
+#include <QFont>
+#include <QHBoxLayout>
+#include <QLabel>
+#include <QVBoxLayout>
+
+#include "BarRow.h"
+#include "BuildingIconCache.h"
+#include "EmptyNote.h"
+#include "FactoryQueries.h"
+#include "GameConfig.h"
+#include "ProductionRules.h"
+#include "SectionBox.h"
+#include "Simulation.h"
+#include "StatusPill.h"
+#include "Tick.h"
+#include "VisualsConfig.h"
+
+namespace
+{
+
+// Size of the identity chip in the card header, in device-independent pixels. Smaller
+// than the build button's 32 px chip: here it labels a line of text rather than being
+// the whole button face.
+const int kSymbolSizePx = 20;
+
+// Spacing inside the card and between the header's elements.
+const int kCardSpacingPx   = 6;
+const int kHeaderSpacingPx = 6;
+
+}  // namespace
+
+
+SelectionContent::SelectionContent(const SelectionContext& context,
+                                   std::optional<BuildingId> constructionSiteId,
+                                   QWidget* parent)
+    : QWidget(parent)
+    , m_context(context)
+    , m_siteId(constructionSiteId)
+    , m_constructionSection(nullptr)
+    , m_constructionBar(nullptr)
+{
+    QVBoxLayout* cardLayout = new QVBoxLayout(this);
+    cardLayout->setContentsMargins(0, 0, 0, 0);
+    cardLayout->setSpacing(kCardSpacingPx);
+
+    // Header: identity symbol, name, and the right slot pushed to the far edge
+    // (REQ-UI-SELECTION-CARD).
+    QWidget* header = new QWidget(this);
+    QHBoxLayout* headerLayout = new QHBoxLayout(header);
+    headerLayout->setContentsMargins(0, 0, 0, 0);
+    headerLayout->setSpacing(kHeaderSpacingPx);
+
+    m_symbolLabel = new QLabel(header);
+    m_symbolLabel->hide();
+
+    m_nameLabel = new QLabel(header);
+    QFont nameFont = m_nameLabel->font();
+    nameFont.setBold(true);
+    m_nameLabel->setFont(nameFont);
+
+    m_statusPill = new StatusPill(header);
+
+    headerLayout->addWidget(m_symbolLabel);
+    headerLayout->addWidget(m_nameLabel);
+    headerLayout->addStretch(1);
+    headerLayout->addWidget(m_statusPill);
+    cardLayout->addWidget(header);
+
+    m_configurationGroup = new QWidget(this);
+    QVBoxLayout* configurationLayout = new QVBoxLayout(m_configurationGroup);
+    configurationLayout->setContentsMargins(0, 0, 0, 0);
+    configurationLayout->setSpacing(kCardSpacingPx);
+    cardLayout->addWidget(m_configurationGroup);
+
+    m_runtimeGroup = new QWidget(this);
+    QVBoxLayout* runtimeLayout = new QVBoxLayout(m_runtimeGroup);
+    runtimeLayout->setContentsMargins(0, 0, 0, 0);
+    runtimeLayout->setSpacing(kCardSpacingPx);
+    cardLayout->addWidget(m_runtimeGroup);
+
+    if (m_siteId.has_value())
+    {
+        // A site has no buffers and runs no production cycle, so whatever the subclass
+        // puts into the runtime group is not shown at all; the construction section
+        // takes its place (REQ-BLD-SITE-CONFIG, REQ-UI-SELECTION-CARD). The subclass
+        // still fills the group -- it just never becomes visible.
+        m_runtimeGroup->hide();
+
+        m_constructionSection = new SectionBox(tr("Construction"), this);
+        m_constructionBar = new BarRow(QString(), m_constructionSection);
+        m_constructionSection->getContentLayout()->addWidget(m_constructionBar);
+        m_constructionSection->getContentLayout()->addWidget(
+            new EmptyNote(tr("No buffers until built"), m_constructionSection));
+        cardLayout->addWidget(m_constructionSection);
+
+        setSlot(QColor(), tr("constructing"));
+    }
+}
+
+SelectionContent::~SelectionContent() = default;
+
+void SelectionContent::refresh()
+{
+    refreshConfiguration();
+    if (m_siteId.has_value())
+    {
+        refreshConstruction();
+        return;
+    }
+    refreshRuntime();
+}
+
+QVBoxLayout* SelectionContent::getConfigurationLayout()
+{
+    return static_cast<QVBoxLayout*>(m_configurationGroup->layout());
+}
+
+QVBoxLayout* SelectionContent::getRuntimeLayout()
+{
+    return static_cast<QVBoxLayout*>(m_runtimeGroup->layout());
+}
+
+void SelectionContent::setIdentity(const QPixmap& symbol, const QString& name)
+{
+    m_symbolLabel->setPixmap(symbol);
+    m_symbolLabel->setVisible(!symbol.isNull());
+    m_nameLabel->setText(name);
+}
+
+void SelectionContent::setBuildingIdentity(BuildingType type, const QString& name)
+{
+    const std::string iconName = buildingTypeId(type);
+    setIdentity(m_context.buildingIcons->getChip(iconName, kSymbolSizePx), name);
+}
+
+void SelectionContent::setSlot(const QColor& dotColor, const QString& caption)
+{
+    m_statusPill->setStatus(dotColor, m_context.visuals->statusLight.outline, caption);
+}
+
+void SelectionContent::setCountSlot(int count)
+{
+    setSlot(QColor(), tr("x%1").arg(count));
+}
+
+void SelectionContent::clearSlot()
+{
+    setSlot(QColor(), QString());
+}
+
+void SelectionContent::setProductionStatusSlot(const Building& building)
+{
+    // The classification is the simulation's, so the panel and the world's status light
+    // can never disagree (REQ-UI-SELECTION-STATUS, REQ-UI-STATUS-LIGHT).
+    const std::optional<ProductionStatus> status =
+        getProductionStatus(*m_context.config, building);
+    if (!status.has_value())
+    {
+        clearSlot();
+        return;
+    }
+
+    const StatusLightVisuals& colors = m_context.visuals->statusLight;
+    // The Salvage Bay has no recipe and no cycle: its two states say whether it is
+    // holding scrap, not whether it is producing (REQ-BLD-SALVAGE-BAY).
+    const bool isSalvageBay = (building.type == BuildingType::SalvageBay);
+    switch (*status)
+    {
+        case ProductionStatus::Unconfigured:
+            setSlot(colors.grey, tr("no recipe"));
+            break;
+        case ProductionStatus::Producing:
+            setSlot(colors.green, isSalvageBay ? tr("holding scrap") : tr("producing"));
+            break;
+        case ProductionStatus::Starved:
+            setSlot(colors.red, isSalvageBay ? tr("empty") : tr("missing input"));
+            break;
+        case ProductionStatus::Blocked:
+            setSlot(colors.yellow, tr("output full"));
+            break;
+    }
+}
+
+void SelectionContent::refreshConstruction()
+{
+    const ConstructionSite* site =
+        findSite(m_context.sim->getFactoryState(), *m_siteId);
+    if (!site)
+    {
+        // The site finished or was removed under the card. SelectionPanel rebuilds on
+        // the same refresh, so this only has to avoid reading a dead site.
+        return;
+    }
+
+    if (site->completesAt == 0)
+    {
+        // Placed but not yet at the head of the construction queue (REQ-BLD-QUEUE), so
+        // there is no progress to show yet.
+        m_constructionBar->setValue(0.0, tr("Queued"));
+        return;
+    }
+
+    const BuildingDef* def = m_context.config->buildings.findBuildingDef(site->type);
+    if (!def || def->constructionTimeSeconds <= 0)
+    {
+        m_constructionBar->setValue(0.0, tr("Building..."));
+        return;
+    }
+
+    const Tick duration = secondsToTicks(def->constructionTimeSeconds);
+    const Tick elapsed =
+        m_context.sim->getCurrentTick() - (site->completesAt - duration);
+    const Tick clamped = std::max(Tick(0), std::min(duration, elapsed));
+    const int percent = static_cast<int>(clamped * 100 / duration);
+    m_constructionBar->setValue(static_cast<double>(clamped) / duration,
+                                tr("%1%").arg(percent));
+}

src/ui/selection/SelectionContent.h

@@ -0,0 +1,104 @@
+#pragma once
+
+#include <optional>
+
+#include <QColor>
+#include <QPixmap>
+#include <QString>
+#include <QWidget>
+
+#include "BuildingId.h"
+#include "BuildingType.h"
+#include "SelectionContext.h"
+
+struct Building;
+class BarRow;
+class QLabel;
+class QVBoxLayout;
+class SectionBox;
+class StatusPill;
+
+// One card of the selection panel: the content shown for a particular kind of selection
+// (REQ-UI-SELECTION-CARD). Every content is this base plus the parts its constructor
+// puts into the two groups; which content is shown for which selection is decided in
+// SelectionContentFactory (REQ-UI-SELECTION-CONTENT).
+//
+// The card has three parts, top to bottom:
+//   * the header  -- identity symbol, name, and one optional right slot (a status
+//     indicator, a ship's behavior, or an object count);
+//   * the configuration group -- controls that change how the object is set up;
+//   * the runtime group -- what the object is currently doing.
+//
+// A construction site keeps its configuration group and has its whole runtime group
+// replaced by the construction section (REQ-BLD-SITE-CONFIG). That rule lives here and
+// nowhere else: a subclass fills both groups unconditionally in its constructor and
+// never asks whether it is showing a site.
+class SelectionContent : public QWidget
+{
+    Q_OBJECT
+
+public:
+    ~SelectionContent() override;
+
+    // Re-reads the live values behind the card. It never changes the card's structure:
+    // a change that would (a site finishing, the selection changing) is a rebuild, and
+    // SelectionPanel owns that decision.
+    void refresh();
+
+protected:
+    // constructionSiteId is set only while the card shows a construction site, in which
+    // case this base builds and drives the construction section in place of whatever the
+    // subclass puts into the runtime group.
+    SelectionContent(const SelectionContext& context,
+                     std::optional<BuildingId> constructionSiteId,
+                     QWidget* parent);
+
+    // Live values of the runtime group. Not called while the card shows a construction
+    // site, which has neither buffers nor a production cycle (REQ-BLD-SITE-CONFIG).
+    virtual void refreshRuntime() = 0;
+
+    // Live values of the configuration group. Called for a site too, because a site is
+    // configured exactly like the building it will become (REQ-BLD-SITE-CONFIG).
+    virtual void refreshConfiguration() {}
+
+    const SelectionContext& getContext() const { return m_context; }
+
+    // The two group layouts a subclass adds its parts to, in its constructor.
+    QVBoxLayout* getConfigurationLayout();
+    QVBoxLayout* getRuntimeLayout();
+
+    void setIdentity(const QPixmap& symbol, const QString& name);
+    // Header symbol for a building type: its chip icon, or nothing when the icon file is
+    // missing -- which is not an error (REQ-UI-BUILD-ICON, REQ-UI-SELECTION-CARD).
+    void setBuildingIdentity(BuildingType type, const QString& name);
+
+    // Fills the header's right slot. A null dot color leaves the dot off, for the slots
+    // that are a plain caption (a construction site, a ship's behavior).
+    void setSlot(const QColor& dotColor, const QString& caption);
+    // "x<count>", for an aggregated multi-selection (REQ-UI-SELECTION-AGGREGATE).
+    void setCountSlot(int count);
+    void clearSlot();
+
+    // Fills the right slot from the building's production status, mapped to the same
+    // colors and states the world's status light uses (REQ-UI-SELECTION-STATUS). Leaves
+    // the slot empty for a type that has no status light.
+    void setProductionStatusSlot(const Building& building);
+
+private:
+    void refreshConstruction();
+
+    SelectionContext m_context;
+    // Set while this card shows a construction site rather than a finished object.
+    std::optional<BuildingId> m_siteId;
+
+    QLabel*     m_symbolLabel;
+    QLabel*     m_nameLabel;
+    StatusPill* m_statusPill;
+
+    QWidget* m_configurationGroup;
+    QWidget* m_runtimeGroup;
+    // Replaces the runtime group while this card shows a construction site; both null
+    // otherwise.
+    SectionBox* m_constructionSection;
+    BarRow*     m_constructionBar;
+};

src/ui/selection/SelectionContentFactory.cpp

@@ -0,0 +1,187 @@
+#include "SelectionContentFactory.h"
+
+#include "AutoProductionContent.h"
+#include "BeltContent.h"
+#include "DebrisContent.h"
+#include "FactoryQueries.h"
+#include "FieldMultiContent.h"
+#include "HqContent.h"
+#include "MultiBuildingContent.h"
+#include "RecipeProductionContent.h"
+#include "ShipContent.h"
+#include "ShipIdentityComponent.h"
+#include "ShipyardContent.h"
+#include "SplitterContent.h"
+#include "StationBodyComponent.h"
+#include "StationContent.h"
+#include "StorageContent.h"
+#include "Simulation.h"
+
+namespace
+{
+
+// The catalog row a single building type belongs to (REQ-UI-SELECTION-CONTENT).
+SelectionContentKind getKindForType(BuildingType type)
+{
+    switch (type)
+    {
+        case BuildingType::Miner:
+        case BuildingType::Assembler:
+            return SelectionContentKind::RecipeProduction;
+        case BuildingType::Smelter:
+        case BuildingType::ReprocessingPlant:
+            return SelectionContentKind::AutoProduction;
+        case BuildingType::Shipyard:
+            return SelectionContentKind::Shipyard;
+        case BuildingType::SalvageBay:
+            return SelectionContentKind::Storage;
+        case BuildingType::Hq:
+            return SelectionContentKind::Hq;
+        case BuildingType::Belt:
+        case BuildingType::TunnelEntry:
+        case BuildingType::TunnelExit:
+            return SelectionContentKind::Belt;
+        case BuildingType::Splitter:
+            return SelectionContentKind::Splitter;
+        case BuildingType::PlayerDefenceStation:
+        case BuildingType::EnemyDefenceStation:
+            // Defence stations are field objects backed by entities; these two enum
+            // values exist only for cost and visuals lookup and never reach the panel as
+            // a building selection. The count summary is the harmless fallback.
+            return SelectionContentKind::MultiBuilding;
+    }
+    return SelectionContentKind::MultiBuilding;
+}
+
+// A belt, tunnel entry or tunnel exit -- the types whose card is the clear action alone
+// and therefore aggregates (REQ-UI-SELECTION-AGGREGATE). The splitter is deliberately
+// excluded: it carries per-object output filters, which have no aggregate.
+bool isAggregatableBeltType(BuildingType type)
+{
+    return type == BuildingType::Belt
+        || type == BuildingType::TunnelEntry
+        || type == BuildingType::TunnelExit;
+}
+
+ContentKey chooseBuildingContent(const SelectionRequest& request, Simulation& sim)
+{
+    const FactoryState& state = sim.getFactoryState();
+
+    if (request.buildings.size() == 1)
+    {
+        const BuildingId id = request.buildings.front();
+        const Building* building = findBuilding(state, id);
+        if (building)
+        {
+            return { getKindForType(building->type), false };
+        }
+        const ConstructionSite* site = findSite(state, id);
+        if (site)
+        {
+            return { getKindForType(site->type), true };
+        }
+        // The building went away under the panel; the selection is stale and there is
+        // nothing to show (REQ-UI-EMPTY-SELECTION).
+        return {};
+    }
+
+    // Several buildings aggregate into one card only when every part of that card
+    // aggregates (REQ-UI-SELECTION-AGGREGATE). Construction sites are excluded from the
+    // belt case: a site's card is its own construction progress, which several sites
+    // cannot share.
+    bool allAggregatableBelts = true;
+    for (BuildingId id : request.buildings)
+    {
+        const Building* building = findBuilding(state, id);
+        if (!building || !isAggregatableBeltType(building->type))
+        {
+            allAggregatableBelts = false;
+            break;
+        }
+    }
+    if (allAggregatableBelts)
+    {
+        return { SelectionContentKind::Belt, false };
+    }
+    return { SelectionContentKind::MultiBuilding, false };
+}
+
+ContentKey chooseFieldContent(const SelectionRequest& request, Simulation& sim)
+{
+    // A full single-object card is shown for a lone actor, and for debris whether one
+    // piece or several -- debris is the field category's other aggregating content
+    // (REQ-UI-FIELD-MULTI-SELECTION, REQ-UI-SELECTION-AGGREGATE).
+    if (request.actors.size() == 1 && request.debris.empty())
+    {
+        EntityAdmin& admin = sim.getAdmin();
+        const entt::entity actor = request.actors.front();
+        if (admin.isValid(actor) && admin.hasAll<ShipIdentityComponent>(actor))
+        {
+            return { SelectionContentKind::Ship, false };
+        }
+        if (admin.isValid(actor) && admin.hasAll<StationBodyComponent>(actor))
+        {
+            return { SelectionContentKind::Station, false };
+        }
+        return {};
+    }
+
+    if (request.actors.empty() && !request.debris.empty())
+    {
+        return { SelectionContentKind::Debris, false };
+    }
+    return { SelectionContentKind::FieldMulti, false };
+}
+
+}  // namespace
+
+
+ContentKey chooseContent(const SelectionRequest& request, Simulation& sim)
+{
+    if (request.isEmpty())
+    {
+        return {};
+    }
+    // Buildings win, so a non-empty building selection is the whole selection
+    // (REQ-UI-SELECTION-CATEGORIES).
+    if (!request.buildings.empty())
+    {
+        return chooseBuildingContent(request, sim);
+    }
+    return chooseFieldContent(request, sim);
+}
+
+SelectionContent* createContent(const ContentKey& key, const SelectionRequest& request,
+                                const SelectionContext& context, QWidget* parent)
+{
+    switch (key.kind)
+    {
+        case SelectionContentKind::None:
+            return nullptr;
+        case SelectionContentKind::RecipeProduction:
+            return new RecipeProductionContent(context, request, parent);
+        case SelectionContentKind::AutoProduction:
+            return new AutoProductionContent(context, request, parent);
+        case SelectionContentKind::Shipyard:
+            return new ShipyardContent(context, request, parent);
+        case SelectionContentKind::Storage:
+            return new StorageContent(context, request, parent);
+        case SelectionContentKind::Hq:
+            return new HqContent(context, request, parent);
+        case SelectionContentKind::Belt:
+            return new BeltContent(context, request, parent);
+        case SelectionContentKind::Splitter:
+            return new SplitterContent(context, request, parent);
+        case SelectionContentKind::MultiBuilding:
+            return new MultiBuildingContent(context, request, parent);
+        case SelectionContentKind::Ship:
+            return new ShipContent(context, request, parent);
+        case SelectionContentKind::Station:
+            return new StationContent(context, request, parent);
+        case SelectionContentKind::Debris:
+            return new DebrisContent(context, request, parent);
+        case SelectionContentKind::FieldMulti:
+            return new FieldMultiContent(context, request, parent);
+    }
+    return nullptr;
+}

src/ui/selection/SelectionContentFactory.h

@@ -0,0 +1,70 @@
+#pragma once
+
+#include <vector>
+
+#include "entt/entity/entity.hpp"
+
+#include "BuildingId.h"
+#include "SelectionContext.h"
+
+class QWidget;
+class SelectionContent;
+class Simulation;
+
+// What is currently selected, in the selection panel's terms. The two categories are
+// mutually exclusive (REQ-UI-SELECTION-CATEGORIES): either buildings is non-empty, or
+// actors and/or debris are, never both.
+struct SelectionRequest
+{
+    std::vector<BuildingId>   buildings;
+    std::vector<entt::entity> actors;
+    std::vector<entt::entity> debris;
+
+    bool isEmpty() const
+    {
+        return buildings.empty() && actors.empty() && debris.empty();
+    }
+};
+
+// One entry of the content catalog (REQ-UI-SELECTION-CONTENT). Selections that share an
+// entry get the same content and differ only in the name and symbol in the header.
+enum class SelectionContentKind
+{
+    None,              // nothing selected: the panel hides itself entirely
+    RecipeProduction,  // Miner, Assembler
+    AutoProduction,    // Smelter, Reprocessing Plant
+    Shipyard,
+    Storage,           // Salvage Bay
+    Hq,
+    Belt,              // Belt, Tunnel Entry, Tunnel Exit
+    Splitter,
+    MultiBuilding,
+    Ship,
+    Station,
+    Debris,
+    FieldMulti,
+};
+
+// Identifies the card on screen. The panel rebuilds when this changes and only refreshes
+// otherwise, so a construction site finishing swaps the card while a progress counter
+// running does not.
+struct ContentKey
+{
+    SelectionContentKind kind   = SelectionContentKind::None;
+    bool                 isSite = false;
+
+    bool operator==(const ContentKey& other) const
+    {
+        return kind == other.kind && isSite == other.isSite;
+    }
+    bool operator!=(const ContentKey& other) const { return !(*this == other); }
+};
+
+// The card this selection calls for. This is where REQ-UI-SELECTION-AGGREGATE is
+// decided: a multi-selection that aggregates resolves to the single-object kind, and
+// everything else to one of the two count summaries.
+ContentKey chooseContent(const SelectionRequest& request, Simulation& sim);
+
+// Builds the card. Returns nullptr for SelectionContentKind::None.
+SelectionContent* createContent(const ContentKey& key, const SelectionRequest& request,
+                                const SelectionContext& context, QWidget* parent);

src/ui/selection/SelectionContext.h

@@ -0,0 +1,29 @@
+#pragma once
+
+struct GameConfig;
+struct VisualsConfig;
+class BuildingIconCache;
+class ItemIconCache;
+class Simulation;
+
+// Everything a selection panel content reads that is not the selection itself: the
+// simulation it queries live values from, the immutable config, and the window-wide
+// rendering resources. Bundled so a content's constructor stays short and adding a
+// shared resource does not touch every content (REQ-UI-SELECTION-CONTENT).
+//
+// Nothing here is owned: the whole struct is a view onto objects living in MainWindow
+// and must not outlive it. Passed by const reference and copied into each content.
+struct SelectionContext
+{
+    Simulation*          sim           = nullptr;
+    const GameConfig*    config        = nullptr;
+    const VisualsConfig* visuals       = nullptr;
+    ItemIconCache*       itemIcons     = nullptr;
+    BuildingIconCache*   buildingIcons = nullptr;
+
+    // Whether debug draw is currently on (REQ-UI-DEBUG-DRAW), which the ship card shows
+    // its threat cost under (REQ-UI-SHIP-STATS-PANEL). A pointer rather than a copy
+    // because cards outlive a toggle: the panel owns the flag, so a card reading it per
+    // refresh always sees the current value without subscribing to the event itself.
+    const bool*          debugDrawEnabled = nullptr;
+};

src/ui/selection/SelectionNames.cpp

@@ -0,0 +1,35 @@
+#include "SelectionNames.h"
+
+#include <QObject>
+
+#include "DisplayName.h"
+
+QString getBuildingTypeName(BuildingType type)
+{
+    // "Hq" would read as a word rather than an acronym through the generic conversion,
+    // and the player's own base deserves naming as such.
+    if (type == BuildingType::Hq)
+    {
+        return QObject::tr("Player HQ");
+    }
+    return QString::fromStdString(toDisplayName(buildingTypeId(type)));
+}
+
+QString getBehaviorLabel(BehaviorKind kind)
+{
+    // Only the winning behavior is named; the salvage and repair cycles that run
+    // regardless of it are not behaviors here (REQ-UI-SHIP-BEHAVIOR).
+    switch (kind)
+    {
+        case BehaviorKind::Retreat:      return QObject::tr("Retreating");
+        case BehaviorKind::Attack:       return QObject::tr("Engaging");
+        case BehaviorKind::SalvageScrap:
+        case BehaviorKind::DeliverScrap: return QObject::tr("Salvaging");
+        case BehaviorKind::Repair:       return QObject::tr("Repairing");
+        case BehaviorKind::Rally:        return QObject::tr("Rallying");
+        case BehaviorKind::Standby:      return QObject::tr("Standby");
+        case BehaviorKind::Advance:      return QObject::tr("Advancing");
+        case BehaviorKind::None:         break;
+    }
+    return QString();
+}

src/ui/selection/SelectionNames.h

@@ -0,0 +1,15 @@
+#pragma once
+
+#include <QString>
+
+#include "BehaviorKind.h"
+#include "BuildingType.h"
+
+// Display name of a building type for the selection panel's header and count rows
+// (REQ-UI-SELECTION-CARD, REQ-UI-MULTI-SELECTION). The name is derived from the type's
+// config id, so a new building type needs no entry here.
+QString getBuildingTypeName(BuildingType type);
+
+// Name of the behavior currently governing a ship, for the ship card's header slot
+// (REQ-UI-SHIP-BEHAVIOR). Empty when no behavior has won yet, which shows no slot.
+QString getBehaviorLabel(BehaviorKind kind);

src/ui/selection/ShipContent.cpp

@@ -0,0 +1,67 @@
+#include "ShipContent.h"
+
+#include <QVBoxLayout>
+
+#include "EntityAdmin.h"
+#include "GameConfig.h"
+#include "HealthComponent.h"
+#include "SelectedBehaviorComponent.h"
+#include "SelectionNames.h"
+#include "ShipIdentityComponent.h"
+#include "ShipStatsCalculator.h"
+#include "ShipStatsPanel.h"
+#include "Simulation.h"
+#include "ThreatCostCalculator.h"
+
+ShipContent::ShipContent(const SelectionContext& context,
+                         const SelectionRequest& request, QWidget* parent)
+    : SelectionContent(context, std::nullopt, parent)
+    , m_entity(request.actors.front())
+{
+    m_statsPanel = new ShipStatsPanel(context.config, this);
+    getRuntimeLayout()->addWidget(m_statsPanel);
+
+    EntityAdmin& admin = context.sim->getAdmin();
+    if (admin.isValid(m_entity) && admin.hasAll<ShipIdentityComponent>(m_entity))
+    {
+        setIdentity(QPixmap(), tr("Ship: %1").arg(QString::fromStdString(
+            admin.get<ShipIdentityComponent>(m_entity).schematicId)));
+    }
+}
+
+void ShipContent::refreshRuntime()
+{
+    EntityAdmin& admin = getContext().sim->getAdmin();
+    if (!admin.isValid(m_entity) || !admin.hasAll<HealthComponent>(m_entity))
+    {
+        // The ship died or despawned. GameWorldView prunes it from the selection and
+        // re-emits (REQ-UI-ENTITY-CLICK-SELECT), which rebuilds the card; this only has
+        // to avoid reading it in the meantime.
+        return;
+    }
+
+    const HealthComponent& health = admin.get<HealthComponent>(m_entity);
+    if (health.hp <= 0.0f)
+    {
+        return;
+    }
+
+    const ShipStats stats = buildShipStatsFromEntity(admin, m_entity);
+    m_statsPanel->refreshFromLive(stats, health.hp);
+    m_statsPanel->setDebugDrawEnabled(*getContext().debugDrawEnabled);
+
+    // The behavior is the header's right slot rather than a stat row, so it reads as
+    // what the ship is doing rather than as another number (REQ-UI-SHIP-BEHAVIOR).
+    setSlot(QColor(), getBehaviorLabel(
+        admin.get<SelectedBehaviorComponent>(m_entity).winner));
+
+    const ShipIdentityComponent& identity = admin.get<ShipIdentityComponent>(m_entity);
+    const ShipDef* schematicDef =
+        getContext().config->ships.findShipDef(identity.schematicId);
+    if (schematicDef)
+    {
+        m_statsPanel->setThreatCost(calculateShipThreatCost(
+            getContext().config->threatCosts, *getContext().config,
+            schematicDef->id, schematicDef->defaultModules));
+    }
+}

src/ui/selection/ShipContent.h

@@ -0,0 +1,28 @@
+#pragma once
+
+#include "entt/entity/entity.hpp"
+
+#include "SelectionContent.h"
+#include "SelectionContentFactory.h"
+
+class ShipStatsPanel;
+
+// The card for one selected ship (REQ-UI-SHIP-STATS-PANEL): its live hull stats and the
+// summaries of the capability modules it carries, computed from what is actually
+// installed (REQ-MOD-STAT-CALC). Applies to player and enemy ships alike
+// (REQ-UI-ENTITY-CLICK-SELECT).
+class ShipContent : public SelectionContent
+{
+    Q_OBJECT
+
+public:
+    ShipContent(const SelectionContext& context, const SelectionRequest& request,
+                QWidget* parent = nullptr);
+
+protected:
+    void refreshRuntime() override;
+
+private:
+    entt::entity    m_entity;
+    ShipStatsPanel* m_statsPanel;
+};

src/ui/selection/ShipyardContent.cpp

@@ -0,0 +1,102 @@
+#include "ShipyardContent.h"
+
+#include <QPushButton>
+#include <QVBoxLayout>
+
+#include "BuildingTarget.h"
+#include "EventManager.h"
+#include "GameConfig.h"
+#include "LayoutDialogRequestedEvent.h"
+#include "ProductionRules.h"
+#include "RecipeSelectionControl.h"
+#include "SectionBox.h"
+#include "ShipLayoutPreview.h"
+
+ShipyardContent::ShipyardContent(const SelectionContext& context,
+                                 const SelectionRequest& request, QWidget* parent)
+    : BufferedBuildingContent(context, request.buildings.front(), parent)
+{
+    m_schematicControl = new RecipeSelectionControl(context, getBuildingId(),
+                                                    BuildingType::Shipyard, this);
+
+    m_layoutSection   = new SectionBox(tr("Layout"), this);
+    m_layoutPreview   = new ShipLayoutPreview(m_layoutSection);
+    m_configureButton = new QPushButton(tr("Configure Layout"), m_layoutSection);
+    m_layoutSection->getContentLayout()->addWidget(m_layoutPreview);
+    m_layoutSection->getContentLayout()->addWidget(m_configureButton);
+
+    // Ahead of the recipe summary the base adds, so the card reads schematic, layout,
+    // then what one ship costs.
+    getConfigurationLayout()->insertWidget(0, m_schematicControl);
+    getConfigurationLayout()->insertWidget(1, m_layoutSection);
+
+    const BuildingId id = getBuildingId();
+    connect(m_configureButton, &QPushButton::clicked, this, [id]() {
+        EventManager::getInstance()->sendEventImmediately(
+            std::make_shared<LayoutDialogRequestedEvent>(id));
+    });
+}
+
+void ShipyardContent::refreshControls(const BuildingTarget& target)
+{
+    m_schematicControl->setRecipeId(target.recipeId);
+
+    // The preview and Configure button are always shown for a shipyard and are only
+    // enabled once a schematic is selected (REQ-MOD-UI-PREVIEW). The schematic arrives
+    // by queued command, so this refresh is what picks it up rather than the click that
+    // chose it.
+    const ShipDef* shipDef = target.recipeId.empty()
+        ? nullptr
+        : getContext().config->ships.findShipDef(target.recipeId);
+    const bool hasSchematic = shipDef && !shipDef->layout.empty();
+    if (hasSchematic)
+    {
+        m_layoutPreview->setShipAndLayout(
+            shipDef->layout,
+            target.shipLayout.has_value() ? *target.shipLayout : ShipLayoutConfig(),
+            &getContext().config->modules);
+    }
+    else
+    {
+        m_layoutPreview->showPlaceholder();
+    }
+    m_layoutPreview->setEnabled(hasSchematic);
+    m_configureButton->setEnabled(hasSchematic);
+}
+
+BufferedBuildingContent::CycleInfo ShipyardContent::getCycleInfo(
+    const BuildingTarget& target) const
+{
+    CycleInfo info;
+    const ShipDef* shipDef = target.recipeId.empty()
+        ? nullptr
+        : getContext().config->ships.findShipDef(target.recipeId);
+    if (!shipDef)
+    {
+        return info;
+    }
+
+    // The schematic's materials plus every placed module's, which is also what sized the
+    // input buffers (REQ-BLD-SHIPYARD). The simulation owns that sum, so the panel asks
+    // it rather than adding the modules up a second time.
+    info.perCycleInputs = computeShipyardRequiredMaterials(
+        *getContext().config, target.recipeId, target.shipLayout);
+
+    // A shipyard's output is the ship itself, which never lands in an item buffer -- so
+    // the summary shows one ship rather than an item id.
+    info.durationSeconds = shipDef->schematic.productionTimeSeconds;
+    if (target.shipLayout.has_value())
+    {
+        for (const PlacedModule& placed : target.shipLayout->placedModules)
+        {
+            const ModuleDef* moduleDef =
+                getContext().config->modules.findModuleDef(placed.moduleId);
+            if (moduleDef)
+            {
+                info.durationSeconds += moduleDef->productionTimeSeconds;
+            }
+        }
+    }
+    info.runsProduction = true;
+    return info;
+}

src/ui/selection/ShipyardContent.h

@@ -0,0 +1,34 @@
+#pragma once
+
+#include "BufferedBuildingContent.h"
+#include "SelectionContentFactory.h"
+
+class QPushButton;
+class RecipeSelectionControl;
+class SectionBox;
+class ShipLayoutPreview;
+
+// The card for a Shipyard (REQ-UI-SELECTION-CONTENT): the schematic selection, the
+// module layout preview and its Configure button (REQ-MOD-UI-PREVIEW), plus the buffers
+// and production progress every buffered building shows.
+//
+// It is the one card whose cycle is not a recipe: a shipyard's materials and production
+// time are its schematic's plus every placed module's (REQ-BLD-SHIPYARD).
+class ShipyardContent : public BufferedBuildingContent
+{
+    Q_OBJECT
+
+public:
+    ShipyardContent(const SelectionContext& context, const SelectionRequest& request,
+                    QWidget* parent = nullptr);
+
+protected:
+    void refreshControls(const BuildingTarget& target) override;
+    CycleInfo getCycleInfo(const BuildingTarget& target) const override;
+
+private:
+    RecipeSelectionControl* m_schematicControl;
+    SectionBox*             m_layoutSection;
+    ShipLayoutPreview*      m_layoutPreview;
+    QPushButton*            m_configureButton;
+};

src/ui/selection/SplitterContent.cpp

@@ -0,0 +1,211 @@
+#include "SplitterContent.h"
+
+#include <algorithm>
+#include <optional>
+#include <set>
+#include <string>
+#include <vector>
+
+#include <QLabel>
+#include <QListWidget>
+#include <QVBoxLayout>
+
+#include "BeltSystem.h"
+#include "BuildingTarget.h"
+#include "ClearBeltControl.h"
+#include "Command.h"
+#include "CommandRequestedEvent.h"
+#include "EventManager.h"
+#include "FactoryQueries.h"
+#include "GameConfig.h"
+#include "ItemType.h"
+#include "Rotation.h"
+#include "SelectionNames.h"
+#include "Simulation.h"
+
+namespace
+{
+
+// Height cap on a filter list, so two of them plus the rest of the card still fit.
+const int kFilterListHeightPx = 100;
+
+QString getRotationLabel(Rotation rotation)
+{
+    // Written as code points because the sources are read as ASCII by the compiler.
+    const QChar upArrow(0x2191);     // U+2191 UPWARDS ARROW
+    const QChar rightArrow(0x2192);  // U+2192 RIGHTWARDS ARROW
+    const QChar downArrow(0x2193);   // U+2193 DOWNWARDS ARROW
+    const QChar leftArrow(0x2190);   // U+2190 LEFTWARDS ARROW
+
+    switch (rotation)
+    {
+        case Rotation::North: return QObject::tr("North (%1)").arg(upArrow);
+        case Rotation::East:  return QObject::tr("East (%1)").arg(rightArrow);
+        case Rotation::South: return QObject::tr("South (%1)").arg(downArrow);
+        case Rotation::West:  return QObject::tr("West (%1)").arg(leftArrow);
+    }
+    return QString();
+}
+
+// Every item type the economy knows, from both sides of every recipe.
+std::vector<std::string> getAllItemIds(const RecipesConfig& recipes)
+{
+    std::set<std::string> seen;
+    for (const RecipeDef& recipe : recipes.recipes)
+    {
+        for (const RecipeIngredient& ingredient : recipe.inputs)
+        {
+            seen.insert(ingredient.item);
+        }
+        for (const RecipeOutput& output : recipe.outputs)
+        {
+            seen.insert(output.item);
+        }
+    }
+    return std::vector<std::string>(seen.begin(), seen.end());
+}
+
+std::vector<ItemType> collectCheckedItems(const QListWidget* list)
+{
+    std::vector<ItemType> filter;
+    for (int row = 0; row < list->count(); ++row)
+    {
+        const QListWidgetItem* item = list->item(row);
+        if (item->checkState() == Qt::Checked)
+        {
+            filter.push_back(ItemType{ item->text().toStdString() });
+        }
+    }
+    return filter;
+}
+
+}  // namespace
+
+
+SplitterContent::SplitterContent(const SelectionContext& context,
+                                 const SelectionRequest& request, QWidget* parent)
+    : SelectionContent(context, asConstructionSite(context, request.buildings.front()),
+                       parent)
+    , m_id(request.buildings.front())
+    , m_isSite(asConstructionSite(context, m_id).has_value())
+    , m_tile(0, 0)
+{
+    m_filterALabel = new QLabel(this);
+    m_filterAList  = new QListWidget(this);
+    m_filterBLabel = new QLabel(this);
+    m_filterBList  = new QListWidget(this);
+    m_filterAList->setMaximumHeight(kFilterListHeightPx);
+    m_filterBList->setMaximumHeight(kFilterListHeightPx);
+
+    getConfigurationLayout()->addWidget(m_filterALabel);
+    getConfigurationLayout()->addWidget(m_filterAList);
+    getConfigurationLayout()->addWidget(m_filterBLabel);
+    getConfigurationLayout()->addWidget(m_filterBList);
+
+    getRuntimeLayout()->addWidget(
+        new ClearBeltControl(context, request.buildings, this));
+
+    // Populated once, here, rather than on every refresh: re-checking the boxes at 30 Hz
+    // would fight the player's clicks.
+    populateFilters();
+
+    connect(m_filterAList, &QListWidget::itemChanged,
+            this, [this]() { applyFilters(); });
+    connect(m_filterBList, &QListWidget::itemChanged,
+            this, [this]() { applyFilters(); });
+}
+
+void SplitterContent::refreshConfiguration()
+{
+    const BuildingTarget target = resolveBuildingTarget(getContext(), m_id);
+    if (!target.isValid())
+    {
+        return;
+    }
+    setBuildingIdentity(target.type, getBuildingTypeName(target.type));
+}
+
+void SplitterContent::populateFilters()
+{
+    const BuildingTarget target = resolveBuildingTarget(getContext(), m_id);
+    if (!target.isValid())
+    {
+        return;
+    }
+
+    // An operational splitter's outputs and filters live in the belt subsystem, keyed by
+    // tile; a site's are stored on the site itself (REQ-BLD-SITE-CONFIG).
+    std::optional<BeltSystem::SplitterInfo> info;
+    if (m_isSite)
+    {
+        info = getSiteSplitterInfo(getContext().sim->getFactoryState(),
+                                   *getContext().config, m_id);
+    }
+    else
+    {
+        m_tile = target.anchor;
+        info = getContext().sim->getBelts().getSplitterInfo(m_tile);
+    }
+    if (!info.has_value())
+    {
+        m_filterALabel->hide();
+        m_filterAList->hide();
+        m_filterBLabel->hide();
+        m_filterBList->hide();
+        return;
+    }
+
+    const std::vector<std::string> itemIds = getAllItemIds(getContext().config->recipes);
+
+    auto fillList = [&](QListWidget* list, QLabel* label, const QString& directionLabel,
+                        const std::vector<ItemType>& filter)
+    {
+        label->setText(tr("%1 filter (empty = all):").arg(directionLabel));
+        list->blockSignals(true);
+        list->clear();
+        for (const std::string& itemId : itemIds)
+        {
+            // Only implicitly unlocked item types are offered (REQ-LOCK-UI-SPLITTER).
+            if (!getContext().sim->isItemUnlocked(itemId)) { continue; }
+
+            QListWidgetItem* row =
+                new QListWidgetItem(QString::fromStdString(itemId), list);
+            const bool checked = !filter.empty()
+                && std::find(filter.begin(), filter.end(), ItemType{ itemId })
+                       != filter.end();
+            row->setCheckState(checked ? Qt::Checked : Qt::Unchecked);
+            row->setFlags(row->flags() | Qt::ItemIsUserCheckable);
+        }
+        list->blockSignals(false);
+        label->show();
+        list->show();
+    };
+
+    fillList(m_filterAList, m_filterALabel, getRotationLabel(info->outputA),
+             info->filterA);
+    fillList(m_filterBList, m_filterBLabel, getRotationLabel(info->outputB),
+             info->filterB);
+}
+
+void SplitterContent::applyFilters()
+{
+    if (m_isSite)
+    {
+        std::shared_ptr<SetSiteSplitterFiltersCommand> command =
+            std::make_shared<SetSiteSplitterFiltersCommand>();
+        command->id      = m_id;
+        command->filterA = collectCheckedItems(m_filterAList);
+        command->filterB = collectCheckedItems(m_filterBList);
+        EventManager::getInstance()->sendEventImmediately(
+            std::make_shared<CommandRequestedEvent>(command));
+        return;
+    }
+
+    std::shared_ptr<SetSplitterFiltersCommand> command =
+        std::make_shared<SetSplitterFiltersCommand>();
+    command->tile    = m_tile;
+    command->filterA = collectCheckedItems(m_filterAList);
+    command->filterB = collectCheckedItems(m_filterBList);
+    EventManager::getInstance()->sendEventImmediately(
+        std::make_shared<CommandRequestedEvent>(command));
+}

src/ui/selection/SplitterContent.h

@@ -0,0 +1,47 @@
+#pragma once
+
+#include <QPoint>
+
+#include "BuildingId.h"
+#include "SelectionContent.h"
+#include "SelectionContentFactory.h"
+
+class QLabel;
+class QListWidget;
+
+// The card for a Splitter (REQ-UI-SELECTION-CONTENT): its two per-output item filters
+// (REQ-BLD-SPLITTER) plus the clear action every belt-subsystem tile has
+// (REQ-UI-BELT-CLEAR).
+//
+// The filters are configuration, so they are shown for a construction site too and set
+// through the site's own command (REQ-BLD-SITE-CONFIG); the clear action is runtime and
+// therefore is not, because a site's tile is not registered with the belt subsystem yet.
+class SplitterContent : public SelectionContent
+{
+    Q_OBJECT
+
+public:
+    SplitterContent(const SelectionContext& context, const SelectionRequest& request,
+                    QWidget* parent = nullptr);
+
+protected:
+    void refreshConfiguration() override;
+    void refreshRuntime() override {}
+
+private:
+    // Sends the checked items of both lists as the splitter's new filters. Routed to the
+    // site command or the live command depending on what the id names.
+    void applyFilters();
+    // Rebuilds both lists from the splitter's current outputs and filters. Only run when
+    // the lists are not already populated, so a per-tick refresh cannot uncheck a box
+    // the player is in the middle of clicking.
+    void populateFilters();
+
+    BuildingId   m_id;
+    bool         m_isSite;
+    QPoint       m_tile;
+    QLabel*      m_filterALabel;
+    QListWidget* m_filterAList;
+    QLabel*      m_filterBLabel;
+    QListWidget* m_filterBList;
+};

src/ui/selection/StatRow.cpp

@@ -0,0 +1,54 @@
+#include "StatRow.h"
+
+#include <QHBoxLayout>
+#include <QLabel>
+#include <QPalette>
+
+namespace
+{
+
+// Left inset of an indented row, in device-independent pixels.
+const int kIndentPx = 12;
+
+}  // namespace
+
+
+StatRow::StatRow(const QString& label, QWidget* parent)
+    : QWidget(parent)
+{
+    QHBoxLayout* layout = new QHBoxLayout(this);
+    layout->setContentsMargins(0, 0, 0, 0);
+    layout->setSpacing(8);
+
+    m_labelLabel = new QLabel(label, this);
+    m_valueLabel = new QLabel(this);
+    m_valueLabel->setAlignment(Qt::AlignRight | Qt::AlignVCenter);
+
+    layout->addWidget(m_labelLabel);
+    layout->addStretch(1);
+    layout->addWidget(m_valueLabel);
+}
+
+void StatRow::setLabel(const QString& label)
+{
+    m_labelLabel->setText(label);
+}
+
+void StatRow::setValue(const QString& value)
+{
+    m_valueLabel->setText(value);
+}
+
+void StatRow::setValueEmphasized(bool emphasized)
+{
+    QPalette valuePalette = m_valueLabel->palette();
+    valuePalette.setColor(QPalette::WindowText,
+                          palette().color(emphasized ? QPalette::Highlight
+                                                     : QPalette::WindowText));
+    m_valueLabel->setPalette(valuePalette);
+}
+
+void StatRow::setIndented(bool indented)
+{
+    layout()->setContentsMargins(indented ? kIndentPx : 0, 0, 0, 0);
+}

src/ui/selection/StatRow.h

@@ -0,0 +1,33 @@
+#pragma once
+
+#include <QString>
+#include <QWidget>
+
+class QLabel;
+
+// One label/value line: the name on the left, the value hard right
+// (REQ-UI-SELECTION-CARD). The panel's plainest part, shared by the ship and station
+// stats, the debris scrap, the HQ block stock, and the multi-selection's total cost.
+//
+// Like the other card parts it knows nothing about the simulation: it is given the two
+// strings and lays them out.
+class StatRow : public QWidget
+{
+    Q_OBJECT
+
+public:
+    explicit StatRow(const QString& label, QWidget* parent = nullptr);
+
+    void setLabel(const QString& label);
+    void setValue(const QString& value);
+    // Draws the value in the palette's highlight color rather than its text color, for
+    // the one value a card is really about.
+    void setValueEmphasized(bool emphasized);
+    // Indents the row, so it reads as belonging to the row above it -- the scrap total
+    // under a debris count (REQ-UI-FIELD-MULTI-SELECTION).
+    void setIndented(bool indented);
+
+private:
+    QLabel* m_labelLabel;
+    QLabel* m_valueLabel;
+};

src/ui/selection/StationContent.cpp

@@ -0,0 +1,83 @@
+#include "StationContent.h"
+
+#include <QVBoxLayout>
+
+#include "BarRow.h"
+#include "EntityAdmin.h"
+#include "FactionComponent.h"
+#include "HealthComponent.h"
+#include "ModuleOwnerComponent.h"
+#include "Simulation.h"
+#include "StatRow.h"
+#include "WeaponComponent.h"
+
+StationContent::StationContent(const SelectionContext& context,
+                               const SelectionRequest& request, QWidget* parent)
+    : SelectionContent(context, std::nullopt, parent)
+    , m_entity(request.actors.front())
+{
+    m_hpBar       = new BarRow(tr("HP"), this);
+    m_damageRow   = new StatRow(tr("Damage"), this);
+    m_rangeRow    = new StatRow(tr("Range"), this);
+    m_fireRateRow = new StatRow(tr("Fire rate"), this);
+
+    getRuntimeLayout()->addWidget(m_hpBar);
+    getRuntimeLayout()->addWidget(m_damageRow);
+    getRuntimeLayout()->addWidget(m_rangeRow);
+    getRuntimeLayout()->addWidget(m_fireRateRow);
+
+    EntityAdmin& admin = context.sim->getAdmin();
+    const bool isEnemy = admin.isValid(m_entity)
+        && admin.hasAll<FactionComponent>(m_entity)
+        && admin.get<FactionComponent>(m_entity).isEnemy;
+    setIdentity(QPixmap(), isEnemy ? tr("Enemy Defence Station")
+                                   : tr("Player Defence Station"));
+}
+
+void StationContent::refreshRuntime()
+{
+    EntityAdmin& admin = getContext().sim->getAdmin();
+    if (!admin.isValid(m_entity) || !admin.hasAll<HealthComponent>(m_entity))
+    {
+        return;
+    }
+    const HealthComponent& health = admin.get<HealthComponent>(m_entity);
+
+    const double hpFraction = (health.maxHp > 0.0f)
+        ? static_cast<double>(health.hp) / health.maxHp
+        : 0.0;
+    m_hpBar->setValue(hpFraction, tr("%1 / %2")
+        .arg(static_cast<int>(health.hp + 0.5f))
+        .arg(static_cast<int>(health.maxHp + 0.5f)));
+
+    // A station's weapons are child module entities pointing back at it, so its damage,
+    // range and fire rate are read off those rather than off the station itself.
+    float totalDamage   = 0.0f;
+    float maxRange      = 0.0f;
+    float maxFireRateHz = 0.0f;
+    bool  hasWeapon     = false;
+    const entt::entity station = m_entity;
+    admin.forEach<ModuleOwnerComponent, WeaponComponent>(
+        [&](entt::entity /*child*/, const ModuleOwnerComponent& owner,
+            const WeaponComponent& weapon)
+        {
+            if (owner.owner != station) { return; }
+            hasWeapon = true;
+            totalDamage += weapon.damage;
+            if (weapon.range_tiles > maxRange)      { maxRange = weapon.range_tiles; }
+            if (weapon.fireRateHz  > maxFireRateHz) { maxFireRateHz = weapon.fireRateHz; }
+        });
+
+    m_damageRow->setVisible(hasWeapon);
+    m_rangeRow->setVisible(hasWeapon);
+    m_fireRateRow->setVisible(hasWeapon);
+    if (hasWeapon)
+    {
+        m_damageRow->setValue(
+            QString::number(static_cast<double>(totalDamage), 'f', 1));
+        m_rangeRow->setValue(tr("%1 tiles")
+            .arg(QString::number(static_cast<double>(maxRange), 'f', 1)));
+        m_fireRateRow->setValue(tr("%1 /s")
+            .arg(QString::number(static_cast<double>(maxFireRateHz), 'f', 1)));
+    }
+}

src/ui/selection/StationContent.h

@@ -0,0 +1,31 @@
+#pragma once
+
+#include "entt/entity/entity.hpp"
+
+#include "SelectionContent.h"
+#include "SelectionContentFactory.h"
+
+class BarRow;
+class StatRow;
+
+// The card for one selected defence station, player or enemy
+// (REQ-UI-STATION-STATS-PANEL): its HP plus the combined damage, range and fire rate of
+// the weapon modules mounted on it.
+class StationContent : public SelectionContent
+{
+    Q_OBJECT
+
+public:
+    StationContent(const SelectionContext& context, const SelectionRequest& request,
+                   QWidget* parent = nullptr);
+
+protected:
+    void refreshRuntime() override;
+
+private:
+    entt::entity m_entity;
+    BarRow*      m_hpBar;
+    StatRow*     m_damageRow;
+    StatRow*     m_rangeRow;
+    StatRow*     m_fireRateRow;
+};

src/ui/selection/StatusPill.cpp

@@ -0,0 +1,68 @@
+#include "StatusPill.h"
+
+#include <QGuiApplication>
+#include <QHBoxLayout>
+#include <QLabel>
+#include <QPainter>
+#include <QPixmap>
+#include <QRectF>
+
+namespace
+{
+
+// Diameter of the status dot, in device-independent pixels.
+const int kDotSizePx = 8;
+
+QPixmap renderDot(const QColor& fill, const QColor& outline)
+{
+    const qreal dpr = qApp ? qApp->devicePixelRatio() : 1.0;
+    QPixmap pixmap(static_cast<int>(kDotSizePx * dpr),
+                   static_cast<int>(kDotSizePx * dpr));
+    pixmap.setDevicePixelRatio(dpr);
+    pixmap.fill(Qt::transparent);
+
+    QPainter painter(&pixmap);
+    painter.setRenderHint(QPainter::Antialiasing, true);
+    painter.setPen(outline.isValid() ? QPen(outline) : QPen(Qt::NoPen));
+    painter.setBrush(fill);
+    // Inset by half the pen width so the outline stays inside the pixmap.
+    painter.drawEllipse(QRectF(0.5, 0.5, kDotSizePx - 1.0, kDotSizePx - 1.0));
+    return pixmap;
+}
+
+}  // namespace
+
+
+StatusPill::StatusPill(QWidget* parent)
+    : QWidget(parent)
+{
+    QHBoxLayout* layout = new QHBoxLayout(this);
+    layout->setContentsMargins(0, 0, 0, 0);
+    layout->setSpacing(4);
+
+    m_dotLabel     = new QLabel(this);
+    m_captionLabel = new QLabel(this);
+
+    layout->addWidget(m_dotLabel);
+    layout->addWidget(m_captionLabel);
+
+    hide();
+}
+
+void StatusPill::setStatus(const QColor& dotColor, const QColor& outlineColor,
+                           const QString& caption)
+{
+    if (dotColor.isValid())
+    {
+        m_dotLabel->setPixmap(renderDot(dotColor, outlineColor));
+        m_dotLabel->show();
+    }
+    else
+    {
+        m_dotLabel->hide();
+    }
+
+    m_captionLabel->setText(caption);
+    m_captionLabel->setVisible(!caption.isEmpty());
+    setVisible(dotColor.isValid() || !caption.isEmpty());
+}

src/ui/selection/StatusPill.h

@@ -0,0 +1,29 @@
+#pragma once
+
+#include <QColor>
+#include <QString>
+#include <QWidget>
+
+class QLabel;
+
+// The card header's right slot (REQ-UI-SELECTION-CARD): a colored dot with a short
+// caption beside it. It carries a building's production status
+// (REQ-UI-SELECTION-STATUS), a ship's current behavior (REQ-UI-SHIP-BEHAVIOR), or an
+// aggregated selection's object count (REQ-UI-SELECTION-AGGREGATE) -- never more than
+// one of them, which is why they share one part.
+class StatusPill : public QWidget
+{
+    Q_OBJECT
+
+public:
+    explicit StatusPill(QWidget* parent = nullptr);
+
+    // An invalid dot color leaves the dot off, for the slots that are a plain caption.
+    // An empty caption hides the pill entirely.
+    void setStatus(const QColor& dotColor, const QColor& outlineColor,
+                   const QString& caption);
+
+private:
+    QLabel* m_dotLabel;
+    QLabel* m_captionLabel;
+};

src/ui/selection/StorageContent.cpp

@@ -0,0 +1,17 @@
+#include "StorageContent.h"
+
+#include "BuildingTarget.h"
+
+StorageContent::StorageContent(const SelectionContext& context,
+                               const SelectionRequest& request, QWidget* parent)
+    : BufferedBuildingContent(context, request.buildings.front(), parent)
+{
+}
+
+BufferedBuildingContent::CycleInfo StorageContent::getCycleInfo(
+    const BuildingTarget& /*target*/) const
+{
+    // No recipe, no cycle: the card shows the output buffer alone, with no per-cycle
+    // denominators and no production progress (REQ-BLD-SALVAGE-BAY).
+    return CycleInfo();
+}

src/ui/selection/StorageContent.h

@@ -0,0 +1,21 @@
+#pragma once
+
+#include "BufferedBuildingContent.h"
+#include "SelectionContentFactory.h"
+
+// The card for a Salvage Bay (REQ-UI-SELECTION-CONTENT): its held scrap and nothing
+// else. It has no recipe to configure and runs no production cycle
+// (REQ-BLD-SALVAGE-BAY), so it is the buffered-building card with both of those left
+// out -- its header status says whether it is holding scrap rather than whether it is
+// producing (REQ-UI-SELECTION-STATUS).
+class StorageContent : public BufferedBuildingContent
+{
+    Q_OBJECT
+
+public:
+    StorageContent(const SelectionContext& context, const SelectionRequest& request,
+                   QWidget* parent = nullptr);
+
+protected:
+    CycleInfo getCycleInfo(const BuildingTarget& target) const override;
+};