Better meaning API on both sides for the drag-n-drop operations, but I _swear_ there's a way to do this in the GrabSource/DropTarget instead.

gui/fsm.cpp

@@ -135,12 +135,12 @@ namespace gui {
       case LOOT_SELECT: {
           $grab_source = std::any_cast<DinkyECS::Entity>(data);
 
-          if(auto world_entity = $loot_ui.select_slot(*$grab_source)) {
+          if(auto world_entity = $loot_ui.start_grab(*$grab_source)) {
-            auto& source = $loot_ui.get_grabber(*$grab_source);
+            auto& source = $loot_ui.get_grab_source(*$grab_source);
             source.grab($window);
             source.move($router.position);
 
-            $status_ui.select_slot(*world_entity);
+            $status_ui.start_drop(*world_entity);
           } else {
             // BUG: need a cancel operation here
             $window.setMouseCursorVisible(true);
@@ -149,14 +149,11 @@ namespace gui {
         } break;
       case INV_SELECT: {
           auto gui_id = std::any_cast<DinkyECS::Entity>(data);
-          dbc::log(fmt::format("INV_SELECT $grab_source null? {} gui_id {}",
-                $grab_source == std::nullopt, gui_id));
-
           if($grab_source) {
-            auto& drop = $status_ui.$gui.get<guecs::DropTarget>(gui_id);
+            auto& drop = $status_ui.get_drop_target(gui_id);
 
-            if(drop.action()) {
+            if(drop.commit()) {
-              $loot_ui.remove_slot(*$grab_source);
+              $loot_ui.commit_drop(*$grab_source);
               $grab_source = std::nullopt;
             }
 
@@ -171,7 +168,7 @@ namespace gui {
       case MOUSE_DRAG:
       case MOUSE_MOVE: {
         if($grab_source) {
-          auto& source = $loot_ui.get_grabber(*$grab_source);
+          auto& source = $loot_ui.get_grab_source(*$grab_source);
           source.move($router.position);
         }
         mouse_action(true);

gui/guecstra.hpp

@@ -14,6 +14,6 @@ namespace guecs {
   };
 
   struct DropTarget {
-    std::function<bool()> action;
+    std::function<bool()> commit;
   };
 }

gui/loot_ui.cpp

@@ -46,7 +46,7 @@ namespace gui {
     update();
   }
 
-  std::optional<DinkyECS::Entity> LootUI::select_slot(DinkyECS::Entity slot_id) {
+  std::optional<DinkyECS::Entity> LootUI::start_grab(DinkyECS::Entity slot_id) {
     if(contents.contains(slot_id)) {
       return contents.at(slot_id);
     } else {
@@ -54,7 +54,7 @@ namespace gui {
     }
   }
 
-  void LootUI::remove_slot(DinkyECS::Entity slot_id) {
+  void LootUI::commit_drop(DinkyECS::Entity slot_id) {
     contents.erase(slot_id);
     update();
   }
@@ -80,12 +80,12 @@ namespace gui {
     }
   }
 
-  bool LootUI::has_grabber(DinkyECS::Entity gui_id) {
+  bool LootUI::has_grab_source(DinkyECS::Entity gui_id) {
     return $gui.has<guecs::Sprite>(gui_id);
   }
 
-  guecs::GrabSource& LootUI::get_grabber(DinkyECS::Entity gui_id) {
+  guecs::GrabSource& LootUI::get_grab_source(DinkyECS::Entity gui_id) {
-    dbc::check(has_grabber(gui_id), "invalid GrabSource requested, entity isn't in the GUI.");
+    dbc::check(has_grab_source(gui_id), "invalid GrabSource requested, entity isn't in the GUI.");
 
     return static_cast<guecs::GrabSource&>($gui.get<guecs::Sprite>(gui_id));
   }

gui/loot_ui.hpp

@@ -21,9 +21,9 @@ namespace gui {
       void render(sf::RenderWindow& window);
       void update_level(GameLevel &level);
       bool mouse(float x, float y, bool hover);
-      std::optional<DinkyECS::Entity> select_slot(DinkyECS::Entity slot);
+      std::optional<DinkyECS::Entity> start_grab(DinkyECS::Entity slot);
-      void remove_slot(DinkyECS::Entity slot_id);
+      guecs::GrabSource& get_grab_source(DinkyECS::Entity entity);
-      guecs::GrabSource& get_grabber(DinkyECS::Entity entity);
+      bool has_grab_source(DinkyECS::Entity gui_id);
-      bool has_grabber(DinkyECS::Entity gui_id);
+      void commit_drop(DinkyECS::Entity slot_id);
   };
 }

gui/status_ui.cpp

@@ -46,7 +46,7 @@ namespace gui {
             guecs::make_action(*$level.world, Events::GUI::INV_SELECT, {button})
           });
           $gui.set<DropTarget>(button, {
-              [&, button]() -> bool { return place_slot(button); }
+              .commit=[&, button]() -> bool { return place_slot(button); }
           });
         }
       }
@@ -83,7 +83,7 @@ namespace gui {
     init();
   }
 
-  void StatusUI::select_slot(DinkyECS::Entity entity) {
+  void StatusUI::start_drop(DinkyECS::Entity entity) {
     $selected_entity = entity;
   }
 
@@ -99,4 +99,8 @@ namespace gui {
       return false;
     }
   }
+
+  guecs::DropTarget& StatusUI::get_drop_target(DinkyECS::Entity gui_id) {
+    return $gui.get<guecs::DropTarget>(gui_id);
+  }
 }

gui/status_ui.hpp

@@ -5,6 +5,7 @@
 #include "textures.hpp"
 #include <guecs/ui.hpp>
 #include "gui/ritual_ui.hpp"
+#include "gui/guecstra.hpp"
 
 namespace gui {
   class StatusUI {
@@ -22,7 +23,8 @@ namespace gui {
       void init();
       void render(sf::RenderWindow &window);
       void update();
-      void select_slot(DinkyECS::Entity entity);
+      void start_drop(DinkyECS::Entity entity);
       bool place_slot(DinkyECS::Entity gui_id);
+      guecs::DropTarget& get_drop_target(DinkyECS::Entity gui_id);
   };
 }