implement copy building settings with shift + click gesture

src/lib/sim/BuildingConfig.cpp

@@ -0,0 +1,51 @@
+#include "BuildingConfig.h"
+
+#include "BeltSystem.h"
+#include "Building.h"
+#include "BuildingSystem.h"
+#include "Simulation.h"
+
+std::optional<BuildingConfig> readBuildingConfig(const Simulation& sim, BuildingId id)
+{
+    const Building*         building = sim.buildings().findBuilding(id);
+    const ConstructionSite* site     = building ? nullptr : sim.buildings().findSite(id);
+    if (!building && !site)
+    {
+        return std::nullopt;
+    }
+
+    BuildingConfig config;
+    config.type = building ? building->type : site->type;
+
+    const std::string& recipeId = building ? building->recipeId : site->recipeId;
+    if (!recipeId.empty())
+    {
+        config.recipeId = recipeId;
+    }
+
+    config.shipLayout = building ? building->shipLayout : site->shipLayout;
+
+    if (config.type == BuildingType::Splitter)
+    {
+        config.isSplitter = true;
+        if (building)
+        {
+            // Operational splitter filters live in the BeltSystem, keyed by tile.
+            const std::optional<BeltSystem::SplitterInfo> info =
+                sim.belts().getSplitterInfo(building->anchor);
+            if (info.has_value())
+            {
+                config.splitterFilterA = info->filterA;
+                config.splitterFilterB = info->filterB;
+            }
+        }
+        else
+        {
+            // A site keeps its pre-completion filters on the ConstructionSite.
+            config.splitterFilterA = site->splitterFilterA;
+            config.splitterFilterB = site->splitterFilterB;
+        }
+    }
+
+    return config;
+}

src/lib/sim/BuildingConfig.h

@@ -0,0 +1,40 @@
+#pragma once
+
+#include <optional>
+#include <string>
+#include <vector>
+
+#include "BuildingId.h"
+#include "BuildingType.h"
+#include "ItemType.h"
+#include "ShipLayout.h"
+
+class Simulation;
+
+// The user-configurable settings of a single building or construction site: the
+// selected recipe / ship schematic, the shipyard module layout, and (for
+// splitters) the two output filters. Shared by the copy-settings gesture
+// (REQ-BLD-COPY-CONFIG) and blueprint capture (REQ-UI-BLUEPRINT-STORAGE).
+struct BuildingConfig
+{
+    BuildingType type = BuildingType::Miner;
+
+    // Selected recipe (Miner / Assembler) or ship schematic id (Shipyard); unset
+    // when nothing is selected.
+    std::optional<std::string> recipeId;
+
+    // Shipyard module layout (REQ-MOD-LAYOUT).
+    std::optional<ShipLayoutConfig> shipLayout;
+
+    // Splitter output filters (empty = accept all). isSplitter distinguishes an
+    // empty-filter splitter (a valid accept-all configuration) from a building
+    // type that has no splitter filters at all.
+    bool                  isSplitter = false;
+    std::vector<ItemType> splitterFilterA;
+    std::vector<ItemType> splitterFilterB;
+};
+
+// Reads the current configuration of the building or construction site identified
+// by id, handling operational buildings and sites alike. Returns std::nullopt if
+// no such building or site exists.
+std::optional<BuildingConfig> readBuildingConfig(const Simulation& sim, BuildingId id);

src/lib/sim/CMakeLists.txt

@@ -10,6 +10,7 @@ SET(HDRS
     ${CMAKE_CURRENT_SOURCE_DIR}/TickDriver.h
     ${CMAKE_CURRENT_SOURCE_DIR}/BeltSystem.h
     ${CMAKE_CURRENT_SOURCE_DIR}/Building.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/BuildingConfig.h
     ${CMAKE_CURRENT_SOURCE_DIR}/BuildingSystem.h
     ${CMAKE_CURRENT_SOURCE_DIR}/EntityHitTest.h
     ${CMAKE_CURRENT_SOURCE_DIR}/ShipLayout.h
@@ -31,6 +32,7 @@ SET(SRCS
     ${CMAKE_CURRENT_SOURCE_DIR}/ReplayPlayer.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/TickDriver.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/BeltSystem.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/BuildingConfig.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/BuildingSystem.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/EntityHitTest.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/ShipStatsCalculator.cpp