Add building status light

src/test/BuildingTest.cpp

@@ -1308,3 +1308,116 @@ TEST_CASE("BuildingSystem: splitter filters configured on a construction site ca
     REQUIRE(builtInfo->filterA == filterA);
     REQUIRE(builtInfo->filterB.empty());
 }
+
+// ---------------------------------------------------------------------------
+// Production status classifier (REQ-UI-STATUS-LIGHT)
+// ---------------------------------------------------------------------------
+
+TEST_CASE("BuildingSystem: getProductionStatus classifies production state", "[building]")
+{
+    PlacementFixture f;
+
+    // Pick representative config ids so the test survives content edits.
+    std::string minerRecipeId;
+    for (const RecipeDef& r : f.cfg.recipes.recipes)
+    {
+        if (r.building == BuildingType::Miner) { minerRecipeId = r.id; break; }
+    }
+    REQUIRE_FALSE(minerRecipeId.empty());
+
+    const RecipeDef* assemblerRecipe = nullptr;
+    for (const RecipeDef& r : f.cfg.recipes.recipes)
+    {
+        if (r.building == BuildingType::Assembler && !r.inputs.empty())
+        {
+            assemblerRecipe = &r;
+            break;
+        }
+    }
+    REQUIRE(assemblerRecipe != nullptr);
+
+    std::string shipId;
+    for (const ShipDef& s : f.cfg.ships.ships)
+    {
+        if (!s.schematic.materials.empty()) { shipId = s.id; break; }
+    }
+    REQUIRE_FALSE(shipId.empty());
+
+    const auto statusOf = [&f](const Building& b) { return f.bs.getProductionStatus(b); };
+
+    SECTION("non-production buildings show no status light")
+    {
+        Building belt; belt.type = BuildingType::Belt;
+        Building hq;   hq.type   = BuildingType::Hq;
+        REQUIRE_FALSE(statusOf(belt).has_value());
+        REQUIRE_FALSE(statusOf(hq).has_value());
+    }
+
+    SECTION("Miner: unconfigured, producing, output-blocked")
+    {
+        Building miner; miner.type = BuildingType::Miner;
+        REQUIRE(statusOf(miner) == ProductionStatus::Unconfigured);  // no recipe -> grey
+
+        miner.recipeId   = minerRecipeId;
+        miner.production = Production{};
+        REQUIRE(statusOf(miner) == ProductionStatus::Producing);     // active cycle -> green
+
+        // A miner has no inputs, so its only idle reason is a full output buffer.
+        miner.production = std::nullopt;
+        miner.outputBuffer.capacity = 2;
+        miner.outputBuffer.items    = { makeItem("iron_ore"), makeItem("iron_ore") };
+        REQUIRE(statusOf(miner) == ProductionStatus::Blocked);       // -> yellow
+    }
+
+    SECTION("Assembler: starved vs blocked, input-missing takes precedence")
+    {
+        Building assembler; assembler.type = BuildingType::Assembler;
+        assembler.recipeId = assemblerRecipe->id;
+
+        // Idle with inputs missing -> red.
+        REQUIRE(statusOf(assembler) == ProductionStatus::Starved);
+
+        // Inputs present but idle -> the only remaining reason is a full output
+        // buffer -> yellow.
+        for (const RecipeIngredient& ing : assemblerRecipe->inputs)
+        {
+            assembler.inputBuffer.counts[ItemType{ing.item}] = ing.amount;
+        }
+        REQUIRE(statusOf(assembler) == ProductionStatus::Blocked);
+
+        // Inputs missing AND output full -> red wins over yellow.
+        assembler.inputBuffer.counts.clear();
+        assembler.outputBuffer.capacity = 2;
+        assembler.outputBuffer.items    = { makeItem("x"), makeItem("x") };
+        REQUIRE(statusOf(assembler) == ProductionStatus::Starved);
+    }
+
+    SECTION("Smelter (auto-recipe) is never grey")
+    {
+        Building smelter; smelter.type = BuildingType::Smelter;
+        // No player-selectable recipe and empty inputs -> red, not grey.
+        REQUIRE(statusOf(smelter) == ProductionStatus::Starved);
+    }
+
+    SECTION("Shipyard: unconfigured, then starved without materials, then producing")
+    {
+        Building yard; yard.type = BuildingType::Shipyard;
+        REQUIRE(statusOf(yard) == ProductionStatus::Unconfigured);   // no schematic -> grey
+
+        yard.recipeId = shipId;
+        REQUIRE(statusOf(yard) == ProductionStatus::Starved);        // no materials -> red
+
+        yard.production = Production{};
+        REQUIRE(statusOf(yard) == ProductionStatus::Producing);      // active cycle -> green
+    }
+
+    SECTION("Salvage Bay: red when empty, green when holding scrap")
+    {
+        Building bay; bay.type = BuildingType::SalvageBay;
+        bay.outputBuffer.capacity = 20;
+        REQUIRE(statusOf(bay) == ProductionStatus::Starved);         // empty -> red
+
+        bay.outputBuffer.items = { makeItem("scrap") };
+        REQUIRE(statusOf(bay) == ProductionStatus::Producing);       // holding scrap -> green
+    }
+}