undo/redo edit placed item

src/scenario/town.cpp

@@ -276,4 +276,15 @@ bool cTown::any_preset_items() const {
 		if(item.code >= 0) return true;
 	}
 	return false;
+}
+
+bool cTown::cItem::operator==(const cTown::cItem& other) {
+	CHECK_EQ(other, loc);
+	CHECK_EQ(other, code);
+	CHECK_EQ(other, ability);
+	CHECK_EQ(other, charges);
+	CHECK_EQ(other, always_there);
+	CHECK_EQ(other, property);
+	CHECK_EQ(other, contained);
+	return true;
 }

src/scenario/town.hpp

@@ -59,6 +59,9 @@ public:
 		eEnchant ability;
 		int charges = -1;
 		bool always_there = false, property = false, contained = false;
+		// For detecting actual changes to town items in the editor
+		bool operator==(const cItem& other);
+		bool operator!=(const cItem& other) { return !(*this == other); }
 		
 		void import_legacy(legacy::preset_item_type old);
 		cItem();

src/scenedit/scen.actions.cpp

@@ -856,11 +856,17 @@ static bool handle_terrain_action(location the_point, bool ctrl_hit) {
 				}
 				break;
 			case MODE_EDIT_ITEM:
-				for(short x = 0; x < town->preset_items.size(); x++)
-					if((spot_hit.x == town->preset_items[x].loc.x) &&
-					   (spot_hit.y == town->preset_items[x].loc.y) && (town->preset_items[x].code >= 0)) {
+				for(short x = 0; x < town->preset_items.size(); x++){
+					cTown::cItem old_item = town->preset_items[x];
+					if((spot_hit.x == old_item.loc.x) &&
+					   (spot_hit.y == old_item.loc.y) && (old_item.code >= 0)) {
 						edit_placed_item(x);
+						if(town->preset_items[x] != old_item){
+							undo_list.add(action_ptr(new aEditPlacedItem(x, old_item, town->preset_items[x])));
+							update_edit_menu();
+						}
 					}
+				}
 				overall_mode = MODE_DRAWING;
 				break;
 			case MODE_PASTE:

src/scenedit/scen.undo.cpp

@@ -309,4 +309,14 @@ bool aClearProperty::redo_me() {
 		item.property = false;
 	}
 	return true;
+}
+
+bool aEditPlacedItem::undo_me() {
+	town->preset_items[which] = old_item;
+	return true;
+}
+
+bool aEditPlacedItem::redo_me() {
+	town->preset_items[which] = new_item;
+	return true;
 }

src/scenedit/scen.undo.hpp

@@ -95,6 +95,19 @@ public:
 	aPlaceEraseItem(std::string name, bool place, size_t index, cTown::cItem item);
 };
 
+/// Action which edits an item in a town
+class aEditPlacedItem : public cTerrainAction {
+	size_t which;
+	cTown::cItem old_item;
+	cTown::cItem new_item;
+	bool undo_me() override;
+	bool redo_me() override;
+public:
+	aEditPlacedItem(size_t which, cTown::cItem old_item, cTown::cItem new_item) :
+		cTerrainAction("Edit Placed Item", new_item.loc),
+		which(which), old_item(old_item), new_item(new_item) {}
+};
+
 /// Action which places or erases creature(s) in a town
 class aPlaceEraseCreature : public cTerrainAction {
 	bool placed;