support scenario files in map_file (#4804)

* support scenario files in map_file

Now a scenario generated by the scenario editor can be loaded
just like a simple map file.

fixes #4803

src/config.cpp

@@ -1226,6 +1226,19 @@ void config::inherit_from(const config& c)
 	swap(scratch);
 }
 
+/**
+ * Merge the attributes of config 'c' into this config, preserving this config's values.
+ */
+void config::inherit_attributes(const config& cfg)
+{
+	check_valid(cfg);
+	for(const attribute& v : cfg.values_) {
+		attribute_value& v2 = values_[v.first];
+		if(v2.blank()) {
+			v2 = v.second;
+		}
+	}
+}
 bool config::matches(const config& filter) const
 {
 	check_valid(filter);

src/config.hpp

@@ -693,6 +693,10 @@ class config
 	 * Merge config 'c' into this config, preserving this config's values.
 	 */
 	void inherit_from(const config& c);
+	/**
+	 * Merge the attributes of config 'c' into this config, preserving this config's values.
+	 */
+	void inherit_attributes(const config& c);
 
 	bool matches(const config &filter) const;
 

src/gui/dialogs/multiplayer/mp_create_game.cpp

@@ -709,14 +709,13 @@ void mp_create_game::update_details(window& win)
 			create_engine_.get_state().classification().campaign = "";
 
 			find_widget<stacked_widget>(&win, "minimap_stack", false).select_layer(0);
-			const std::string map_data = !current_scenario->data()["map_data"].empty()
-				? current_scenario->data()["map_data"]
-				: filesystem::read_map(current_scenario->data()["map_file"]);
-			if (current_scenario->data()["map_data"].empty()) {
-				current_scenario->data()["map_data"] = map_data;
+
+			if(current_scenario->data()["map_data"].empty()) {
+				saved_game::expand_map_file(current_scenario->data());
 				current_scenario->set_metadata();
 			}
-			find_widget<minimap>(&win, "minimap", false).set_map_data(map_data);
+
+			find_widget<minimap>(&win, "minimap", false).set_map_data(current_scenario->data()["map_data"]);
 
 			players.set_label(std::to_string(current_scenario->num_players()));
 			map_size.set_label(current_scenario->map_size());

src/saved_game.cpp

@@ -432,6 +432,40 @@ void saved_game::expand_mp_options()
 	}
 }
 
+static void inherit_scenario(config& scenario, config& map_scenario)
+{
+	config sides;
+	sides.splice_children(map_scenario, "side");
+	scenario.append_children(map_scenario);
+	for(config& side_from : sides.child_range("side")) {
+		config& side_to = scenario.find_child("side", "side", side_from["side"]);
+		if(side_to) {
+			side_to.inherit_attributes(side_from);
+			side_to.append_children(side_from);
+		}
+		else {
+			scenario.add_child("side", side_from);
+		}
+	}
+}
+
+void saved_game::expand_map_file(config& scenario)
+{
+	if(scenario["map_data"].empty() && !scenario["map_file"].empty()) {
+		std::string map_data = filesystem::read_map(scenario["map_file"]);
+		if (map_data.find("map_data") != std::string::npos) {
+			//we have a scenario, gnerated by the editor
+			config map_data_cfg;
+			read(map_data_cfg, map_data);
+			inherit_scenario(scenario, map_data_cfg);
+		}
+		else {
+			//we have an plain map_data file
+			scenario["map_data"]= map_data;
+		}	
+	}
+}
+
 void saved_game::expand_random_scenario()
 {
 	expand_scenario();
@@ -453,10 +487,7 @@ void saved_game::expand_random_scenario()
 		}
 
 		// If no map_data is provided, try to load the specified file directly
-		if(starting_point_["map_data"].empty() && !starting_point_["map_file"].empty()) {
-			starting_point_["map_data"] = filesystem::read_map(starting_point_["map_file"]);
-		}
-
+		expand_map_file(starting_point_);
 		// If the map should be randomly generated
 		// We don’t want that we accidentally to this twice so we check for starting_point_["map_data"].empty()
 		if(starting_point_["map_data"].empty() && !starting_point_["map_generation"].empty()) {

src/saved_game.hpp

@@ -82,6 +82,8 @@ class saved_game
 	void expand_random_scenario();
 	/// copies attributes & tags from the 'outer' [scenario] to the scenario that is generated by scenario_generation=
 	static void post_scenario_generation(const config& old_scenario, config& generated_scenario);
+	/// reads scenario["map_file"]
+	static void expand_map_file(config& scenario);
 	/// Add addon_id information if needed.
 	void check_require_scenario();
 	bool valid() const;