show recipes visually instead of describing them in text

src/ui/ItemProducers.h

@@ -0,0 +1,35 @@
+#pragma once
+
+#include <string>
+#include <vector>
+
+struct GameConfig;
+struct RecipeDef;
+class Simulation;
+
+// Where an item comes from, as far as the player has discovered (REQ-UI-ITEM-TOOLTIP).
+enum class ItemOrigin
+{
+    Produced,      // at least one recipe the player can run makes it
+    Undiscovered,  // recipes make it, but none of them is available yet
+    Salvaged,      // no recipe makes it at all -- scrap, which comes from debris
+};
+
+struct ItemProduction
+{
+    ItemOrigin                    origin = ItemOrigin::Salvaged;
+    // The available producers, in config order. Empty unless origin is Produced.
+    std::vector<const RecipeDef*> recipes;
+};
+
+// Every way the player can currently produce the given item, for the tooltip that
+// explains an item chip (REQ-UI-ITEM-TOOLTIP).
+//
+// What counts as available differs by building type, because only Miner and Assembler
+// recipes are individually unlocked (REQ-LOCK-UI-RECIPE): those are filtered by the
+// unlock state, while a Smelter's or Reprocessing Plant's implicit recipes
+// (REQ-BLD-SMELTER, REQ-BLD-REPROCESSING) are filtered by whether their building is
+// unlocked yet (REQ-LOCK-BUILDING) -- there is no sense in naming a path through a
+// plant the player cannot place.
+ItemProduction findItemProduction(const std::string& itemId, const Simulation& sim,
+                                  const GameConfig& config);