Standardized on using only DinkyECS:Entity for most inventory:::Model operations, then create swap based on the same entities.

gui/status_ui.cpp

@@ -129,7 +129,8 @@ namespace gui {
     dbc::log(fmt::format("removing slot: {}", slot_id));
     auto& slot_name = $slot_to_name.at(slot_id);
     auto& inventory = $level.world->get_the<inventory::Model>();
-    inventory.remove(slot_name);
+    auto world_entity = inventory.get(slot_name);
+    inventory.remove(world_entity);
 
     $gui.remove<guecs::GrabSource>(slot_id);
     $gui.remove<guecs::Sprite>(slot_id);

inventory.cpp

@@ -1,7 +1,7 @@
 #include "inventory.hpp"
 
 namespace inventory {
-  bool Model::add(const Slot &in_slot, DinkyECS::Entity ent) {
+  bool Model::add(const std::string &in_slot, DinkyECS::Entity ent) {
     invariant();
 
     if(by_slot.contains(in_slot)) return false;
@@ -12,11 +12,11 @@ namespace inventory {
     return true;
   }
 
-  Slot& Model::get(DinkyECS::Entity ent) {
+  const std::string& Model::get(DinkyECS::Entity ent) {
     return by_entity.at(ent);
   }
 
-  DinkyECS::Entity Model::get(const Slot& slot) {
+  DinkyECS::Entity Model::get(const std::string& slot) {
     return by_slot.at(slot);
   }
 
@@ -24,25 +24,14 @@ namespace inventory {
     return by_entity.contains(ent);
   }
 
-  bool Model::has(const Slot& slot) {
+  bool Model::has(const std::string& slot) {
     return by_slot.contains(slot);
   }
 
-  void Model::remove(const Slot& slot, DinkyECS::Entity ent) {
-    by_entity.erase(ent);
-    by_slot.erase(slot);
-    invariant();
-  }
-
   void Model::remove(DinkyECS::Entity ent) {
     auto& slot = by_entity.at(ent);
-    remove(slot, ent);
-    invariant();
-  }
-
-  void Model::remove(const Slot& slot) {
-    auto ent = by_slot.at(slot);
-    remove(slot, ent);
+    by_entity.erase(ent);
+    by_slot.erase(slot);
     invariant();
   }
 
@@ -70,4 +59,28 @@ namespace inventory {
           slot, ent, by_entity.contains(ent), by_entity.at(ent) == slot);
     }
   }
+
+  void Model::swap(DinkyECS::Entity a_ent, DinkyECS::Entity b_ent) {
+    dbc::check(by_entity.contains(a_ent), "a_entity not in inventory");
+    dbc::check(by_entity.contains(b_ent), "b_entity not in inventory");
+
+    if(a_ent == b_ent) return;
+
+    auto a_slot = get(a_ent);
+    auto b_slot = get(b_ent);
+
+    dbc::check(a_slot != b_slot, "somehow I got two different entities but they gave the same slot?");
+
+    by_slot.insert_or_assign(a_slot, b_ent);
+    by_entity.insert_or_assign(b_ent, a_slot);
+
+    by_slot.insert_or_assign(b_slot, a_ent);
+    by_entity.insert_or_assign(a_ent, b_slot);
+  }
+
+  size_t Model::count() {
+    dbc::check(by_slot.size() == by_entity.size(), "entity and slot maps have different sizes");
+
+    return by_entity.size();
+  }
 }

inventory.hpp

@@ -6,21 +6,19 @@
 // dance when using it.  Idea is the System:: ops for this would get it
 // and then look at the bool and add the constant ops as needed.
 namespace inventory {
-  using Slot = std::string;
-
   struct Model {
-    std::unordered_map<Slot, DinkyECS::Entity> by_slot;
-    std::unordered_map<DinkyECS::Entity, Slot> by_entity;
+    std::unordered_map<std::string, DinkyECS::Entity> by_slot;
+    std::unordered_map<DinkyECS::Entity, std::string> by_entity;
 
-    bool add(const Slot &in_slot, DinkyECS::Entity ent);
-    Slot& get(DinkyECS::Entity ent);
-    DinkyECS::Entity get(const Slot& slot);
+    bool add(const std::string &in_slot, DinkyECS::Entity ent);
+    const std::string& get(DinkyECS::Entity ent);
+    DinkyECS::Entity get(const std::string& slot);
     bool has(DinkyECS::Entity ent);
-    bool has(const Slot& slot);
-    void remove(const Slot& slot, DinkyECS::Entity ent);
+    bool has(const std::string& slot);
     void remove(DinkyECS::Entity ent);
-    void remove(const Slot& slot);
     void invariant();
     void dump();
+    void swap(DinkyECS::Entity a_ent, DinkyECS::Entity b_ent);
+    size_t count();
   };
 }

systems.cpp

@@ -548,7 +548,8 @@ bool System::place_in_container(World& world, Entity cont_id, const std::string&
   }
 }
 
-void System::remove_from_container(World& world, Entity cont_id, const std::string& name) {
+void System::remove_from_container(World& world, Entity cont_id, const std::string& slot_id) {
   auto& container = world.get<inventory::Model>(cont_id);
-  container.remove(name);
+  auto entity = container.get(slot_id);
+  container.remove(entity);
 }

systems.hpp

@@ -34,6 +34,6 @@ namespace System {
 
   bool place_in_container(World& world, Entity cont_id, const string& name, Entity world_entity);
 
-  void remove_from_container(World& world, Entity cont_id, const string& name);
+  void remove_from_container(World& world, Entity cont_id, const std::string& name);
   void remove_from_world(GameLevel &level, Entity entity);
 }

tests/inventory.cpp

@@ -27,28 +27,24 @@ TEST_CASE("base test", "[inventory]") {
   REQUIRE(inv.has(slot));
 
   // test base remove
-  inv.remove(slot, ent);
+  inv.remove(ent);
   REQUIRE(!inv.has(slot));
   REQUIRE(!inv.has(ent));
+}
 
-  // test remove just by slot
-  good = inv.add("hand_r", test_ent);
-  REQUIRE(good);
-  REQUIRE(inv.has("hand_r"));
-  REQUIRE(inv.has(test_ent));
-  inv.invariant();
+TEST_CASE("test swapping items", "[inventory-swap]") {
+  inventory::Model inv;
+  DinkyECS::Entity hand_l_ent = 10;
+  DinkyECS::Entity hand_r_ent = 20;
 
-  inv.remove("hand_r");
-  REQUIRE(!inv.has("hand_r"));
-  REQUIRE(!inv.has(test_ent));
+  inv.add("hand_l", hand_l_ent);
+  inv.add("hand_r", hand_r_ent);
+  REQUIRE(inv.count() == 2);
 
-  // test remove just by entity
-  good = inv.add("pocket_l", test_ent);
-  REQUIRE(good);
-  REQUIRE(inv.has("pocket_l"));
-  REQUIRE(inv.has(test_ent));
-  inv.invariant();
-  inv.remove(test_ent);
-  REQUIRE(!inv.has("pocket_l"));
-  REQUIRE(!inv.has(test_ent));
+  inv.swap(hand_l_ent, hand_r_ent);
+
+  REQUIRE(inv.get("hand_l") == hand_r_ent);
+  REQUIRE(inv.get("hand_r") == hand_l_ent);
+
+  REQUIRE(inv.count() == 2);
 }