undo/redo for edit/clear terrain type.

src/scenedit/scen.actions.cpp

@@ -1302,8 +1302,12 @@ static bool handle_terpal_action(location cur_point, bool option_hit) {
 								// option-click type that can't be deleted (because it would break other types' numbers, or is in use somewhere):
 								// reset type info
 								else{
-									scenario.ter_types[i] = cTerrain();
-									scenario.ter_types[i].name = "Unused Terrain";
+									cTerrain before = scenario.ter_types[i];
+									cTerrain after;
+									after.name = "Unused Terrain";
+									scenario.ter_types[i] = after;
+									undo_list.add(action_ptr(new aEditClearTerrain("Clear Terrain Type", i, before, after)));
+									update_edit_menu();
 								}
 								break;
 							case DRAW_MONST:

src/scenedit/scen.core.cpp

@@ -53,6 +53,7 @@ extern ter_num_t template_terrain[64][64];
 extern cScenario scenario;
 extern cCustomGraphics spec_scen_g;
 extern location cur_out;
+extern cUndoList undo_list;
 
 const std::set<eItemAbil> items_no_strength = {
 	eItemAbil::NONE, eItemAbil::HEALING_WEAPON, eItemAbil::RETURNING_MISSILE, eItemAbil::SEEKING_MISSILE, eItemAbil::DRAIN_MISSILES,
@@ -463,8 +464,31 @@ static void fill_ter_info(cDialog& me, short ter){
 }
 
 static bool finish_editing_ter(cDialog& me, std::string id, ter_num_t& which) {
-	if(!save_ter_info(me, scenario.ter_types[which])) return true;
-	
+	cTerrain after;
+	if(!save_ter_info(me, after)) return true;
+	cTerrain before = scenario.ter_types[which];
+
+	bool changed = (after != before);
+
+	if(changed){
+		if(id == "left" || id == "right"){
+			// Confirm keeping changes
+			cChoiceDlog dlog("confirm-edit-terrain", {"keep","revert","cancel"}, &me);
+			dlog->getControl("keep-msg").replaceText("{{ter}}", after.name);
+			std::string choice = dlog.show();
+			if(choice == "keep"){
+				scenario.ter_types[which] = after;
+			}else if(choice == "cancel"){
+				return true;
+			}
+		}else{
+			scenario.ter_types[which] = after;
+		}
+		// Store an undo action
+		undo_list.add(action_ptr(new aEditClearTerrain("Edit Terrain Type", which, before, after)));
+		update_edit_menu();
+	}
+
 	if(!me.toast(true)) return true;
 	if(id == "left") {
 		me.untoast();

src/scenedit/scen.undo.cpp

@@ -110,6 +110,18 @@ bool aCreateDeleteTerrain::redo_me() {
 	return true;
 }
 
+bool aEditClearTerrain::undo_me() {
+	// TODO show the type
+	scenario.ter_types[which] = before;
+	return true;
+}
+
+bool aEditClearTerrain::redo_me() {
+	// TODO show the type
+	scenario.ter_types[which] = after;
+	return true;
+}
+
 bool aCreateDeleteMonster::undo_me() {
 	// TODO if not in MODE_EDIT_TYPES, show it
 	for(cMonster monst : monsters){

src/scenedit/scen.undo.hpp

@@ -144,4 +144,16 @@ public:
 		items(items) {}
 };
 
+/// Action which edits or clears a terrain type
+class aEditClearTerrain : public cAction {
+	ter_num_t which;
+	cTerrain before;
+	cTerrain after;
+	bool undo_me() override;
+	bool redo_me() override;
+public:
+	aEditClearTerrain(std::string name, ter_num_t which, cTerrain before, cTerrain after) :
+		cAction(name), which(which), before(before), after(after) {}
+};
+
 #endif