implement ship modules

src/ui/CMakeLists.txt

@@ -8,6 +8,8 @@ SET(HDRS
     ${CMAKE_CURRENT_SOURCE_DIR}/BuildButtonGrid.h
     ${CMAKE_CURRENT_SOURCE_DIR}/SelectedBuildingPanel.h
     ${CMAKE_CURRENT_SOURCE_DIR}/BlueprintPanel.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/ShipLayoutDialog.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/ShipLayoutPreview.h
     PARENT_SCOPE
 )
 
@@ -20,5 +22,7 @@ SET(SRCS
     ${CMAKE_CURRENT_SOURCE_DIR}/BuildButtonGrid.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/SelectedBuildingPanel.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/BlueprintPanel.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/ShipLayoutDialog.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/ShipLayoutPreview.cpp
     PARENT_SCOPE
 )

src/ui/MainWindow.cpp

@@ -9,10 +9,12 @@
 
 #include "BlueprintPanel.h"
 #include "BuildButtonGrid.h"
+#include "BuildingSystem.h"
 #include "ConfigLoader.h"
 #include "GameWorldView.h"
 #include "HeaderBar.h"
 #include "SelectedBuildingPanel.h"
+#include "ShipLayoutDialog.h"
 #include "Simulation.h"
 #include "Tick.h"
 #include "VisualsLoader.h"
@@ -62,6 +64,9 @@ MainWindow::MainWindow(Simulation* sim, const std::string& configDir, QWidget* p
     connect(m_gameWorldView, &GameWorldView::escapeMenuRequested,
             this, &MainWindow::onEscapeMenuRequested);
 
+    connect(m_selectedBuildingPanel, &SelectedBuildingPanel::layoutDialogRequested,
+            this, &MainWindow::onLayoutDialogRequested);
+
     // Signals: build grid → game world
     connect(m_buildButtonGrid, &BuildButtonGrid::buildingTypeSelected,
             m_gameWorldView, &GameWorldView::enterBuilderMode);
@@ -176,6 +181,33 @@ void MainWindow::onEscapeMenuRequested()
     }
 }
 
+void MainWindow::onLayoutDialogRequested(EntityId shipyardId)
+{
+    const double prevSpeed = m_gameWorldView->gameSpeed();
+    m_gameWorldView->setGameSpeed(0.0);
+
+    const Building* b = m_sim->buildings().findBuilding(shipyardId);
+    if (!b)
+    {
+        m_gameWorldView->setGameSpeed(prevSpeed);
+        return;
+    }
+
+    ShipLayoutConfig currentLayout;
+    if (b->shipLayout.has_value())
+    {
+        currentLayout = *b->shipLayout;
+    }
+
+    ShipLayoutDialog dialog(&m_sim->config(), b->recipeId, currentLayout, this);
+    if (dialog.exec() == QDialog::Accepted && dialog.result().has_value())
+    {
+        m_sim->buildings().setShipLayout(shipyardId, *dialog.result());
+    }
+
+    m_gameWorldView->setGameSpeed(prevSpeed);
+}
+
 void MainWindow::onGameOver()
 {
     const Tick tick = m_sim->currentTick();

src/ui/MainWindow.h

@@ -4,6 +4,7 @@
 
 #include <QWidget>
 
+#include "EntityId.h"
 #include "Tick.h"
 #include "VisualsConfig.h"
 
@@ -29,6 +30,7 @@ private slots:
     void onGameOver();
     void onStateUpdated(Tick tick, int blocks, double speed);
     void onEscapeMenuRequested();
+    void onLayoutDialogRequested(EntityId shipyardId);
 
 private:
     void layoutPanels();

src/ui/SelectedBuildingPanel.cpp

@@ -17,7 +17,9 @@
 #include "BuildingSystem.h"
 #include "BuildingType.h"
 #include "ItemType.h"
+#include "ModulesConfig.h"
 #include "Rotation.h"
+#include "ShipLayoutPreview.h"
 #include "Simulation.h"
 
 namespace
@@ -99,6 +101,8 @@ SelectedBuildingPanel::SelectedBuildingPanel(Simulation* sim,
     m_filterAList  = new QListWidget(this);
     m_filterBLabel = new QLabel(this);
     m_filterBList  = new QListWidget(this);
+    m_layoutPreview      = new ShipLayoutPreview(this);
+    m_configureLayoutBtn = new QPushButton("Configure Layout", this);
     m_buffersLabel = new QLabel(this);
     m_buffersLabel->setWordWrap(true);
 
@@ -107,6 +111,8 @@ SelectedBuildingPanel::SelectedBuildingPanel(Simulation* sim,
 
     m_layout->addWidget(m_titleLabel);
     m_layout->addWidget(m_recipeCombo);
+    m_layout->addWidget(m_layoutPreview);
+    m_layout->addWidget(m_configureLayoutBtn);
     m_layout->addWidget(m_clearBeltBtn);
     m_layout->addWidget(m_filterALabel);
     m_layout->addWidget(m_filterAList);
@@ -118,6 +124,12 @@ SelectedBuildingPanel::SelectedBuildingPanel(Simulation* sim,
             this, &SelectedBuildingPanel::onRecipeChanged);
     connect(m_clearBeltBtn, &QPushButton::clicked,
             this, &SelectedBuildingPanel::onClearBelt);
+    connect(m_configureLayoutBtn, &QPushButton::clicked, this, [this]() {
+        if (m_singleId != kInvalidEntityId)
+        {
+            emit layoutDialogRequested(m_singleId);
+        }
+    });
     connect(m_filterAList, &QListWidget::itemChanged,
             this, &SelectedBuildingPanel::onSplitterFilterChanged);
     connect(m_filterBList, &QListWidget::itemChanged,
@@ -153,6 +165,8 @@ void SelectedBuildingPanel::buildEmpty()
     m_singleId = kInvalidEntityId;
     m_titleLabel->hide();
     m_recipeCombo->hide();
+    m_layoutPreview->hide();
+    m_configureLayoutBtn->hide();
     m_clearBeltBtn->hide();
     m_filterALabel->hide();
     m_filterAList->hide();
@@ -248,10 +262,39 @@ void SelectedBuildingPanel::buildSingle(EntityId id)
         m_recipeCombo->setCurrentIndex(currentIdx >= 0 ? currentIdx : 0);
         m_recipeCombo->blockSignals(false);
         m_recipeCombo->show();
+
+        if (b->type == BuildingType::Shipyard && !b->recipeId.empty())
+        {
+            const ShipDef* sDef = findShipDef(b->recipeId);
+            if (sDef && !sDef->layout.empty())
+            {
+                ShipLayoutConfig layout;
+                if (b->shipLayout.has_value())
+                {
+                    layout = *b->shipLayout;
+                }
+                m_layoutPreview->setShipAndLayout(
+                    sDef->layout, layout, &m_config->modules.modules);
+                m_layoutPreview->show();
+                m_configureLayoutBtn->show();
+            }
+            else
+            {
+                m_layoutPreview->hide();
+                m_configureLayoutBtn->hide();
+            }
+        }
+        else
+        {
+            m_layoutPreview->hide();
+            m_configureLayoutBtn->hide();
+        }
     }
     else
     {
         m_recipeCombo->hide();
+        m_layoutPreview->hide();
+        m_configureLayoutBtn->hide();
     }
 
     if (isBeltLike(b->type))
@@ -307,6 +350,26 @@ void SelectedBuildingPanel::refreshBuffers(const Building* b)
                 {
                     if (mat.item == entry.first.id) { perCycle = mat.amount; break; }
                 }
+                if (b->shipLayout.has_value())
+                {
+                    for (const PlacedModule& pm : b->shipLayout->placedModules)
+                    {
+                        for (const ModuleDef& modDef : m_config->modules.modules)
+                        {
+                            if (modDef.id == pm.moduleId)
+                            {
+                                for (const RecipeIngredient& ing : modDef.materials)
+                                {
+                                    if (ing.item == entry.first.id)
+                                    {
+                                        perCycle += ing.amount;
+                                    }
+                                }
+                                break;
+                            }
+                        }
+                    }
+                }
             }
             bufText += QString::fromStdString(entry.first.id)
                 + ": " + QString::number(entry.second);
@@ -354,10 +417,25 @@ void SelectedBuildingPanel::refreshBuffers(const Building* b)
 
     if (isProductionBuilding(b->type) && (recipe || shipDef))
     {
-        const double durationSeconds = recipe
+        double durationSeconds = recipe
             ? recipe->durationSeconds
             : shipDef->schematic.productionTimeSeconds;
 
+        if (shipDef && b->shipLayout.has_value())
+        {
+            for (const PlacedModule& pm : b->shipLayout->placedModules)
+            {
+                for (const ModuleDef& modDef : m_config->modules.modules)
+                {
+                    if (modDef.id == pm.moduleId)
+                    {
+                        durationSeconds += modDef.productionTimeSeconds;
+                        break;
+                    }
+                }
+            }
+        }
+
         bufText += QString("Cycle: %1 s\n").arg(durationSeconds, 0, 'f', 1);
 
         if (b->production.has_value())
@@ -377,6 +455,17 @@ void SelectedBuildingPanel::refreshBuffers(const Building* b)
     }
 
     m_buffersLabel->setText(bufText);
+
+    if (b->type == BuildingType::Shipyard && shipDef && !shipDef->layout.empty())
+    {
+        ShipLayoutConfig layout;
+        if (b->shipLayout.has_value())
+        {
+            layout = *b->shipLayout;
+        }
+        m_layoutPreview->setShipAndLayout(
+            shipDef->layout, layout, &m_config->modules.modules);
+    }
 }
 
 const RecipeDef* SelectedBuildingPanel::findRecipe(const Building* b) const
@@ -481,6 +570,7 @@ void SelectedBuildingPanel::onRecipeChanged(int comboIndex)
     }
     const QString recipeId = m_recipeCombo->itemData(comboIndex).toString();
     m_sim->buildings().setRecipe(m_singleId, recipeId.toStdString());
+    rebuild();
 }
 
 void SelectedBuildingPanel::buildSplitterFilters(QPoint splitterTile)

src/ui/SelectedBuildingPanel.h

@@ -10,10 +10,12 @@
 #include "EntityId.h"
 #include "GameConfig.h"
 #include "RecipesConfig.h"
+#include "ShipLayout.h"
 #include "ShipsConfig.h"
 #include "Tick.h"
 
 class Simulation;
+class ShipLayoutPreview;
 class QLabel;
 class QComboBox;
 class QListWidget;
@@ -28,6 +30,9 @@ public:
     SelectedBuildingPanel(Simulation* sim, const GameConfig* config,
                           QWidget* parent = nullptr);
 
+signals:
+    void layoutDialogRequested(EntityId shipyardId);
+
 public slots:
     void onSelectionChanged(const std::vector<EntityId>& ids);
     void onStateUpdated(Tick tick, int blocks, double speed);
@@ -63,6 +68,9 @@ private:
     QListWidget* m_filterBList;
     QLabel*      m_buffersLabel;
 
+    ShipLayoutPreview* m_layoutPreview;
+    QPushButton*       m_configureLayoutBtn;
+
     EntityId     m_singleId;
     QPoint       m_splitterTile;
     std::string  m_currentRecipeId;

src/ui/ShipLayoutDialog.cpp

@@ -0,0 +1,616 @@
+#include "ShipLayoutDialog.h"
+
+#include <cctype>
+
+#include <QGridLayout>
+#include <QHBoxLayout>
+#include <QKeyEvent>
+#include <QMouseEvent>
+#include <QPainter>
+#include <QPushButton>
+#include <QSignalMapper>
+#include <QVBoxLayout>
+
+namespace
+{
+
+const int kCellSize = 32;
+
+QString displayName(const std::string& id)
+{
+    QString result;
+    bool nextUpper = true;
+    for (char c : id)
+    {
+        if (c == '_')
+        {
+            result += ' ';
+            nextUpper = true;
+        }
+        else if (nextUpper)
+        {
+            result += static_cast<char>(std::toupper(static_cast<unsigned char>(c)));
+            nextUpper = false;
+        }
+        else
+        {
+            result += c;
+        }
+    }
+    return result;
+}
+
+std::vector<std::string> rotateMaskCW(const std::vector<std::string>& grid)
+{
+    if (grid.empty())
+    {
+        return {};
+    }
+    const int srcH = static_cast<int>(grid.size());
+    int srcW = 0;
+    for (const std::string& row : grid)
+    {
+        const int w = static_cast<int>(row.size());
+        if (w > srcW)
+        {
+            srcW = w;
+        }
+    }
+    const int dstW = srcH;
+    const int dstH = srcW;
+    std::vector<std::string> dst(dstH, std::string(dstW, 'X'));
+    for (int row = 0; row < srcH; ++row)
+    {
+        for (int col = 0; col < srcW; ++col)
+        {
+            const char ch = (col < static_cast<int>(grid[row].size()))
+                                ? grid[row][col]
+                                : 'X';
+            dst[col][srcH - 1 - row] = ch;
+        }
+    }
+    return dst;
+}
+
+}  // namespace
+
+
+// ---------------------------------------------------------------------------
+// Grid rendering widget (nested inside dialog)
+// ---------------------------------------------------------------------------
+
+class LayoutGridWidget : public QWidget
+{
+public:
+    LayoutGridWidget(ShipLayoutDialog* dialog, QWidget* parent = nullptr)
+        : QWidget(parent)
+        , m_dialog(dialog)
+    {
+        setMouseTracking(true);
+    }
+
+    void setGridData(const std::vector<std::vector<ShipLayoutDialog::CellInfo>>* grid,
+                     int rows, int cols,
+                     const std::vector<PlacedModule>* placed,
+                     const GameConfig* config)
+    {
+        m_grid = grid;
+        m_rows = rows;
+        m_cols = cols;
+        m_placed = placed;
+        m_config = config;
+        setFixedSize(cols * kCellSize + 1, rows * kCellSize + 1);
+    }
+
+    void setGhostData(int moduleIndex, Rotation rotation)
+    {
+        m_ghostModuleIdx = moduleIndex;
+        m_ghostRotation = rotation;
+    }
+
+protected:
+    void paintEvent(QPaintEvent* /*event*/) override
+    {
+        if (!m_grid || m_rows == 0 || m_cols == 0)
+        {
+            return;
+        }
+
+        QPainter painter(this);
+        painter.setRenderHint(QPainter::Antialiasing, false);
+
+        for (int r = 0; r < m_rows; ++r)
+        {
+            for (int c = 0; c < m_cols; ++c)
+            {
+                const QRect cellRect(c * kCellSize, r * kCellSize, kCellSize, kCellSize);
+                const ShipLayoutDialog::CellInfo& cell = (*m_grid)[r][c];
+
+                if (!cell.buildable)
+                {
+                    painter.fillRect(cellRect, QColor(30, 30, 30));
+                }
+                else if (cell.moduleIndex >= 0)
+                {
+                    const PlacedModule& pm = (*m_placed)[cell.moduleIndex];
+                    const ModuleDef* def = findModule(pm.moduleId);
+                    QColor color(Qt::gray);
+                    QString glyph;
+                    if (def)
+                    {
+                        color = QColor(QString::fromStdString(def->fillColor));
+                        glyph = QString::fromStdString(def->glyph);
+                    }
+                    painter.fillRect(cellRect, color);
+                    if (!glyph.isEmpty())
+                    {
+                        painter.setPen(Qt::white);
+                        painter.drawText(cellRect, Qt::AlignCenter, glyph);
+                    }
+                }
+                else
+                {
+                    painter.fillRect(cellRect, QColor(240, 240, 240));
+                }
+
+                painter.setPen(QColor(100, 100, 100));
+                painter.drawRect(cellRect);
+            }
+        }
+
+        // Draw ghost
+        if (m_ghostModuleIdx >= 0 && m_hoverCell.x() >= 0 && m_config)
+        {
+            const ModuleDef& def = m_config->modules.modules[m_ghostModuleIdx];
+            const std::vector<std::string> mask = rotateMask(def.surfaceMask, m_ghostRotation);
+            QColor ghostColor(QString::fromStdString(def.fillColor));
+            ghostColor.setAlpha(100);
+
+            for (int mr = 0; mr < static_cast<int>(mask.size()); ++mr)
+            {
+                for (int mc = 0; mc < static_cast<int>(mask[mr].size()); ++mc)
+                {
+                    if (mask[mr][mc] != 'O')
+                    {
+                        continue;
+                    }
+                    const int gr = m_hoverCell.y() + mr;
+                    const int gc = m_hoverCell.x() + mc;
+                    if (gr >= 0 && gr < m_rows && gc >= 0 && gc < m_cols)
+                    {
+                        const QRect cellRect(gc * kCellSize, gr * kCellSize,
+                                             kCellSize, kCellSize);
+                        painter.fillRect(cellRect, ghostColor);
+                    }
+                }
+            }
+        }
+    }
+
+    void mouseMoveEvent(QMouseEvent* event) override
+    {
+        const QPoint pos = event->pos();
+        const QPoint cell(pos.x() / kCellSize, pos.y() / kCellSize);
+        if (cell != m_hoverCell)
+        {
+            m_hoverCell = cell;
+            update();
+        }
+    }
+
+    void mousePressEvent(QMouseEvent* event) override
+    {
+        if (event->button() != Qt::LeftButton)
+        {
+            return;
+        }
+        const QPoint pos = event->pos();
+        const QPoint cell(pos.x() / kCellSize, pos.y() / kCellSize);
+        emit m_dialog->gridCellClicked(cell);
+    }
+
+    void leaveEvent(QEvent* /*event*/) override
+    {
+        m_hoverCell = QPoint(-1, -1);
+        update();
+    }
+
+private:
+    const ModuleDef* findModule(const std::string& id) const
+    {
+        if (!m_config)
+        {
+            return nullptr;
+        }
+        for (const ModuleDef& def : m_config->modules.modules)
+        {
+            if (def.id == id)
+            {
+                return &def;
+            }
+        }
+        return nullptr;
+    }
+
+    std::vector<std::string> rotateMask(const std::vector<std::string>& mask,
+                                        Rotation rotation) const
+    {
+        int steps = 0;
+        switch (rotation)
+        {
+            case Rotation::East:  steps = 0; break;
+            case Rotation::South: steps = 1; break;
+            case Rotation::West:  steps = 2; break;
+            case Rotation::North: steps = 3; break;
+        }
+        std::vector<std::string> result = mask;
+        for (int i = 0; i < steps; ++i)
+        {
+            result = rotateMaskCW(result);
+        }
+        return result;
+    }
+
+    ShipLayoutDialog* m_dialog;
+    const std::vector<std::vector<ShipLayoutDialog::CellInfo>>* m_grid = nullptr;
+    int m_rows = 0;
+    int m_cols = 0;
+    const std::vector<PlacedModule>* m_placed = nullptr;
+    const GameConfig* m_config = nullptr;
+    int m_ghostModuleIdx = -2;
+    Rotation m_ghostRotation = Rotation::East;
+    QPoint m_hoverCell = QPoint(-1, -1);
+};
+
+
+// ---------------------------------------------------------------------------
+// ShipLayoutDialog implementation
+// ---------------------------------------------------------------------------
+
+ShipLayoutDialog::ShipLayoutDialog(const GameConfig* config,
+                                   const std::string& shipId,
+                                   const ShipLayoutConfig& currentLayout,
+                                   QWidget* parent)
+    : QDialog(parent)
+    , m_config(config)
+    , m_shipId(shipId)
+    , m_rows(0)
+    , m_cols(0)
+    , m_placedModules(currentLayout.placedModules)
+    , m_activeModuleIndex(-2)
+    , m_currentRotation(Rotation::East)
+    , m_removeButton(nullptr)
+    , m_gridWidget(nullptr)
+{
+    setWindowTitle("Configure Ship Layout");
+    setModal(true);
+
+    // Find the ship's layout grid.
+    for (const ShipDef& def : config->ships.ships)
+    {
+        if (def.id == shipId)
+        {
+            m_shipLayout = def.layout;
+            break;
+        }
+    }
+
+    m_rows = static_cast<int>(m_shipLayout.size());
+    m_cols = 0;
+    for (const std::string& row : m_shipLayout)
+    {
+        const int w = static_cast<int>(row.size());
+        if (w > m_cols)
+        {
+            m_cols = w;
+        }
+    }
+
+    // Initialize grid.
+    m_grid.assign(m_rows, std::vector<CellInfo>(m_cols, {false, -1}));
+    for (int r = 0; r < m_rows; ++r)
+    {
+        for (int c = 0; c < static_cast<int>(m_shipLayout[r].size()); ++c)
+        {
+            if (m_shipLayout[r][c] == 'O')
+            {
+                m_grid[r][c].buildable = true;
+            }
+        }
+    }
+    rebuildOccupancy();
+
+    // --- UI layout ---
+    QHBoxLayout* mainLayout = new QHBoxLayout(this);
+
+    // Left: grid widget.
+    LayoutGridWidget* gridW = new LayoutGridWidget(this, this);
+    gridW->setGridData(&m_grid, m_rows, m_cols, &m_placedModules, m_config);
+    gridW->setGhostData(m_activeModuleIndex, m_currentRotation);
+    m_gridWidget = gridW;
+    mainLayout->addWidget(m_gridWidget);
+
+    // Right: module buttons + confirm/cancel.
+    QVBoxLayout* rightLayout = new QVBoxLayout();
+
+    QGridLayout* buttonGrid = new QGridLayout();
+    buttonGrid->setSpacing(4);
+
+    QSignalMapper* mapper = new QSignalMapper(this);
+    int col = 0;
+    int row = 0;
+    const int kCols = 2;
+
+    for (int i = 0; i < static_cast<int>(config->modules.modules.size()); ++i)
+    {
+        const ModuleDef& def = config->modules.modules[i];
+        const QString label = displayName(def.id)
+            + "\n" + QString::fromStdString(def.glyph);
+        QPushButton* btn = new QPushButton(label, this);
+        btn->setCheckable(true);
+        btn->setFixedHeight(48);
+        buttonGrid->addWidget(btn, row, col);
+        m_moduleButtons.push_back(btn);
+
+        mapper->setMapping(btn, i);
+        connect(btn, &QPushButton::clicked, mapper, qOverload<>(&QSignalMapper::map));
+
+        ++col;
+        if (col >= kCols)
+        {
+            col = 0;
+            ++row;
+        }
+    }
+    connect(mapper, qOverload<int>(&QSignalMapper::mapped),
+            this, &ShipLayoutDialog::onModuleButtonClicked);
+
+    // Remove button.
+    m_removeButton = new QPushButton("Remove", this);
+    m_removeButton->setCheckable(true);
+    m_removeButton->setFixedHeight(48);
+    if (col > 0)
+    {
+        ++row;
+    }
+    buttonGrid->addWidget(m_removeButton, row, 0, 1, kCols);
+    connect(m_removeButton, &QPushButton::clicked, this, [this]() {
+        if (m_activeModuleIndex == -1)
+        {
+            m_activeModuleIndex = -2;
+            m_removeButton->setChecked(false);
+        }
+        else
+        {
+            for (QPushButton* btn : m_moduleButtons)
+            {
+                btn->setChecked(false);
+            }
+            m_activeModuleIndex = -1;
+            m_removeButton->setChecked(true);
+        }
+        updateGridWidget();
+    });
+
+    rightLayout->addLayout(buttonGrid);
+    rightLayout->addStretch();
+
+    // Confirm / Cancel buttons.
+    QHBoxLayout* bottomBar = new QHBoxLayout();
+    QPushButton* confirmBtn = new QPushButton("Confirm", this);
+    QPushButton* cancelBtn = new QPushButton("Cancel", this);
+    bottomBar->addWidget(confirmBtn);
+    bottomBar->addWidget(cancelBtn);
+    rightLayout->addLayout(bottomBar);
+
+    connect(confirmBtn, &QPushButton::clicked, this, &ShipLayoutDialog::onConfirm);
+    connect(cancelBtn, &QPushButton::clicked, this, &ShipLayoutDialog::onCancel);
+
+    mainLayout->addLayout(rightLayout);
+
+    // Grid click handler.
+    connect(this, &ShipLayoutDialog::gridCellClicked, this, [this](QPoint cell) {
+        if (m_activeModuleIndex == -2)
+        {
+            return;
+        }
+
+        if (m_activeModuleIndex == -1)
+        {
+            // Remove mode: find and remove module at cell.
+            if (cell.y() >= 0 && cell.y() < m_rows && cell.x() >= 0 && cell.x() < m_cols)
+            {
+                const int idx = m_grid[cell.y()][cell.x()].moduleIndex;
+                if (idx >= 0)
+                {
+                    m_placedModules.erase(m_placedModules.begin() + idx);
+                    rebuildOccupancy();
+                    updateGridWidget();
+                }
+            }
+            return;
+        }
+
+        // Place module.
+        const ModuleDef& def = m_config->modules.modules[m_activeModuleIndex];
+        if (canPlaceModule(def, cell, m_currentRotation))
+        {
+            PlacedModule pm;
+            pm.moduleId = def.id;
+            pm.position = cell;
+            pm.rotation = m_currentRotation;
+            m_placedModules.push_back(pm);
+            rebuildOccupancy();
+            updateGridWidget();
+        }
+    });
+}
+
+std::optional<ShipLayoutConfig> ShipLayoutDialog::result() const
+{
+    return m_result;
+}
+
+void ShipLayoutDialog::keyPressEvent(QKeyEvent* event)
+{
+    if (event->key() == Qt::Key_Q)
+    {
+        // Rotate CCW = 3 CW steps.
+        switch (m_currentRotation)
+        {
+            case Rotation::East:  m_currentRotation = Rotation::North; break;
+            case Rotation::North: m_currentRotation = Rotation::West;  break;
+            case Rotation::West:  m_currentRotation = Rotation::South; break;
+            case Rotation::South: m_currentRotation = Rotation::East;  break;
+        }
+        updateGridWidget();
+    }
+    else if (event->key() == Qt::Key_E)
+    {
+        // Rotate CW.
+        switch (m_currentRotation)
+        {
+            case Rotation::East:  m_currentRotation = Rotation::South; break;
+            case Rotation::South: m_currentRotation = Rotation::West;  break;
+            case Rotation::West:  m_currentRotation = Rotation::North; break;
+            case Rotation::North: m_currentRotation = Rotation::East;  break;
+        }
+        updateGridWidget();
+    }
+    else
+    {
+        QDialog::keyPressEvent(event);
+    }
+}
+
+void ShipLayoutDialog::onModuleButtonClicked(int index)
+{
+    if (m_activeModuleIndex == index)
+    {
+        m_moduleButtons[index]->setChecked(false);
+        m_activeModuleIndex = -2;
+    }
+    else
+    {
+        for (int i = 0; i < static_cast<int>(m_moduleButtons.size()); ++i)
+        {
+            m_moduleButtons[i]->setChecked(i == index);
+        }
+        m_removeButton->setChecked(false);
+        m_activeModuleIndex = index;
+    }
+    updateGridWidget();
+}
+
+void ShipLayoutDialog::onConfirm()
+{
+    ShipLayoutConfig layout;
+    layout.placedModules = m_placedModules;
+    m_result = layout;
+    accept();
+}
+
+void ShipLayoutDialog::onCancel()
+{
+    m_result = std::nullopt;
+    reject();
+}
+
+void ShipLayoutDialog::rebuildOccupancy()
+{
+    for (int r = 0; r < m_rows; ++r)
+    {
+        for (int c = 0; c < m_cols; ++c)
+        {
+            m_grid[r][c].moduleIndex = -1;
+        }
+    }
+
+    for (int i = 0; i < static_cast<int>(m_placedModules.size()); ++i)
+    {
+        const PlacedModule& pm = m_placedModules[i];
+        const ModuleDef* def = nullptr;
+        for (const ModuleDef& d : m_config->modules.modules)
+        {
+            if (d.id == pm.moduleId) { def = &d; break; }
+        }
+        if (!def)
+        {
+            continue;
+        }
+        const std::vector<std::string> mask = rotatedMask(*def, pm.rotation);
+        for (int mr = 0; mr < static_cast<int>(mask.size()); ++mr)
+        {
+            for (int mc = 0; mc < static_cast<int>(mask[mr].size()); ++mc)
+            {
+                if (mask[mr][mc] != 'O')
+                {
+                    continue;
+                }
+                const int gr = pm.position.y() + mr;
+                const int gc = pm.position.x() + mc;
+                if (gr >= 0 && gr < m_rows && gc >= 0 && gc < m_cols)
+                {
+                    m_grid[gr][gc].moduleIndex = i;
+                }
+            }
+        }
+    }
+}
+
+void ShipLayoutDialog::updateGridWidget()
+{
+    LayoutGridWidget* gridW = static_cast<LayoutGridWidget*>(m_gridWidget);
+    gridW->setGhostData(m_activeModuleIndex, m_currentRotation);
+    gridW->update();
+}
+
+bool ShipLayoutDialog::canPlaceModule(const ModuleDef& def, QPoint position,
+                                      Rotation rotation) const
+{
+    const std::vector<std::string> mask = rotatedMask(def, rotation);
+    for (int mr = 0; mr < static_cast<int>(mask.size()); ++mr)
+    {
+        for (int mc = 0; mc < static_cast<int>(mask[mr].size()); ++mc)
+        {
+            if (mask[mr][mc] != 'O')
+            {
+                continue;
+            }
+            const int gr = position.y() + mr;
+            const int gc = position.x() + mc;
+            if (gr < 0 || gr >= m_rows || gc < 0 || gc >= m_cols)
+            {
+                return false;
+            }
+            if (!m_grid[gr][gc].buildable)
+            {
+                return false;
+            }
+            if (m_grid[gr][gc].moduleIndex >= 0)
+            {
+                return false;
+            }
+        }
+    }
+    return true;
+}
+
+std::vector<std::string> ShipLayoutDialog::rotatedMask(const ModuleDef& def,
+                                                       Rotation rotation) const
+{
+    int steps = 0;
+    switch (rotation)
+    {
+        case Rotation::East:  steps = 0; break;
+        case Rotation::South: steps = 1; break;
+        case Rotation::West:  steps = 2; break;
+        case Rotation::North: steps = 3; break;
+    }
+    std::vector<std::string> result = def.surfaceMask;
+    for (int i = 0; i < steps; ++i)
+    {
+        result = rotateMaskCW(result);
+    }
+    return result;
+}

src/ui/ShipLayoutDialog.h

@@ -0,0 +1,70 @@
+#pragma once
+
+#include <optional>
+#include <string>
+#include <vector>
+
+#include <QDialog>
+#include <QPoint>
+
+#include "GameConfig.h"
+#include "Rotation.h"
+#include "ShipLayout.h"
+
+class QPushButton;
+
+class ShipLayoutDialog : public QDialog
+{
+    Q_OBJECT
+
+public:
+    ShipLayoutDialog(const GameConfig* config,
+                     const std::string& shipId,
+                     const ShipLayoutConfig& currentLayout,
+                     QWidget* parent = nullptr);
+
+    std::optional<ShipLayoutConfig> result() const;
+
+protected:
+    void keyPressEvent(QKeyEvent* event) override;
+
+signals:
+    void gridCellClicked(QPoint cell);
+
+private slots:
+    void onModuleButtonClicked(int index);
+    void onConfirm();
+    void onCancel();
+
+public:
+    struct CellInfo
+    {
+        bool buildable;
+        int moduleIndex; // -1 if empty
+    };
+
+private:
+
+    void rebuildOccupancy();
+    void updateGridWidget();
+    bool canPlaceModule(const ModuleDef& def, QPoint position, Rotation rotation) const;
+    std::vector<std::string> rotatedMask(const ModuleDef& def, Rotation rotation) const;
+
+    const GameConfig* m_config;
+    std::string m_shipId;
+    std::vector<std::string> m_shipLayout;
+    int m_rows;
+    int m_cols;
+
+    std::vector<PlacedModule> m_placedModules;
+    std::vector<std::vector<CellInfo>> m_grid;
+
+    int m_activeModuleIndex; // -1 = remove mode, -2 = no selection
+    Rotation m_currentRotation;
+
+    std::vector<QPushButton*> m_moduleButtons;
+    QPushButton* m_removeButton;
+    QWidget* m_gridWidget;
+
+    std::optional<ShipLayoutConfig> m_result;
+};

src/ui/ShipLayoutPreview.cpp

@@ -0,0 +1,198 @@
+#include "ShipLayoutPreview.h"
+
+#include <QPainter>
+#include <QPaintEvent>
+
+namespace
+{
+
+const int kCellSize = 8;
+
+const ModuleDef* findModuleDef(const std::vector<ModuleDef>& modules,
+                               const std::string& id)
+{
+    for (const ModuleDef& def : modules)
+    {
+        if (def.id == id)
+        {
+            return &def;
+        }
+    }
+    return nullptr;
+}
+
+std::vector<std::string> rotateMaskCW(const std::vector<std::string>& grid)
+{
+    if (grid.empty())
+    {
+        return {};
+    }
+    const int srcH = static_cast<int>(grid.size());
+    int srcW = 0;
+    for (const std::string& row : grid)
+    {
+        const int w = static_cast<int>(row.size());
+        if (w > srcW)
+        {
+            srcW = w;
+        }
+    }
+    const int dstW = srcH;
+    const int dstH = srcW;
+    std::vector<std::string> dst(dstH, std::string(dstW, 'X'));
+    for (int row = 0; row < srcH; ++row)
+    {
+        for (int col = 0; col < srcW; ++col)
+        {
+            const char ch = (col < static_cast<int>(grid[row].size()))
+                                ? grid[row][col]
+                                : 'X';
+            dst[col][srcH - 1 - row] = ch;
+        }
+    }
+    return dst;
+}
+
+std::vector<std::string> rotateMask(const std::vector<std::string>& mask,
+                                    Rotation rotation)
+{
+    int steps = 0;
+    switch (rotation)
+    {
+        case Rotation::East:  steps = 0; break;
+        case Rotation::South: steps = 1; break;
+        case Rotation::West:  steps = 2; break;
+        case Rotation::North: steps = 3; break;
+    }
+    std::vector<std::string> result = mask;
+    for (int i = 0; i < steps; ++i)
+    {
+        result = rotateMaskCW(result);
+    }
+    return result;
+}
+
+}  // namespace
+
+
+ShipLayoutPreview::ShipLayoutPreview(QWidget* parent)
+    : QWidget(parent)
+    , m_modules(nullptr)
+    , m_rows(0)
+    , m_cols(0)
+{
+}
+
+void ShipLayoutPreview::clear()
+{
+    m_grid.clear();
+    m_placedModules.clear();
+    m_modules = nullptr;
+    m_rows = 0;
+    m_cols = 0;
+    setFixedSize(0, 0);
+    update();
+}
+
+void ShipLayoutPreview::setShipAndLayout(const std::vector<std::string>& shipLayout,
+                                         const ShipLayoutConfig& layout,
+                                         const std::vector<ModuleDef>* modules)
+{
+    m_modules = modules;
+    m_placedModules = layout.placedModules;
+    m_rows = static_cast<int>(shipLayout.size());
+    m_cols = 0;
+    for (const std::string& row : shipLayout)
+    {
+        const int w = static_cast<int>(row.size());
+        if (w > m_cols)
+        {
+            m_cols = w;
+        }
+    }
+
+    m_grid.assign(m_rows, std::vector<CellInfo>(m_cols, {false, -1}));
+    for (int r = 0; r < m_rows; ++r)
+    {
+        for (int c = 0; c < static_cast<int>(shipLayout[r].size()); ++c)
+        {
+            if (shipLayout[r][c] == 'O')
+            {
+                m_grid[r][c].buildable = true;
+            }
+        }
+    }
+
+    for (int i = 0; i < static_cast<int>(m_placedModules.size()); ++i)
+    {
+        const PlacedModule& pm = m_placedModules[i];
+        const ModuleDef* def = findModuleDef(*m_modules, pm.moduleId);
+        if (!def)
+        {
+            continue;
+        }
+        const std::vector<std::string> rotated = rotateMask(def->surfaceMask, pm.rotation);
+        for (int mr = 0; mr < static_cast<int>(rotated.size()); ++mr)
+        {
+            for (int mc = 0; mc < static_cast<int>(rotated[mr].size()); ++mc)
+            {
+                if (rotated[mr][mc] != 'O')
+                {
+                    continue;
+                }
+                const int gr = pm.position.y() + mr;
+                const int gc = pm.position.x() + mc;
+                if (gr >= 0 && gr < m_rows && gc >= 0 && gc < m_cols)
+                {
+                    m_grid[gr][gc].moduleIndex = i;
+                }
+            }
+        }
+    }
+
+    setFixedSize(m_cols * kCellSize, m_rows * kCellSize);
+    update();
+}
+
+void ShipLayoutPreview::paintEvent(QPaintEvent* /*event*/)
+{
+    if (m_rows == 0 || m_cols == 0)
+    {
+        return;
+    }
+
+    QPainter painter(this);
+    painter.setRenderHint(QPainter::Antialiasing, false);
+
+    for (int r = 0; r < m_rows; ++r)
+    {
+        for (int c = 0; c < m_cols; ++c)
+        {
+            const QRect cellRect(c * kCellSize, r * kCellSize, kCellSize, kCellSize);
+            const CellInfo& cell = m_grid[r][c];
+
+            if (!cell.buildable)
+            {
+                painter.fillRect(cellRect, Qt::black);
+            }
+            else if (cell.moduleIndex >= 0)
+            {
+                const PlacedModule& pm = m_placedModules[cell.moduleIndex];
+                const ModuleDef* def = findModuleDef(*m_modules, pm.moduleId);
+                QColor color(Qt::gray);
+                if (def)
+                {
+                    color = QColor(QString::fromStdString(def->fillColor));
+                }
+                painter.fillRect(cellRect, color);
+            }
+            else
+            {
+                painter.fillRect(cellRect, Qt::white);
+            }
+
+            painter.setPen(QColor(128, 128, 128));
+            painter.drawRect(cellRect);
+        }
+    }
+}

src/ui/ShipLayoutPreview.h

@@ -0,0 +1,38 @@
+#pragma once
+
+#include <string>
+#include <vector>
+
+#include <QWidget>
+
+#include "ModulesConfig.h"
+#include "ShipLayout.h"
+
+class ShipLayoutPreview : public QWidget
+{
+    Q_OBJECT
+
+public:
+    explicit ShipLayoutPreview(QWidget* parent = nullptr);
+
+    void setShipAndLayout(const std::vector<std::string>& shipLayout,
+                          const ShipLayoutConfig& layout,
+                          const std::vector<ModuleDef>* modules);
+    void clear();
+
+protected:
+    void paintEvent(QPaintEvent* event) override;
+
+private:
+    struct CellInfo
+    {
+        bool buildable;
+        int moduleIndex; // -1 if empty
+    };
+
+    std::vector<std::vector<CellInfo>> m_grid;
+    std::vector<PlacedModule> m_placedModules;
+    const std::vector<ModuleDef>* m_modules;
+    int m_rows;
+    int m_cols;
+};