Improve the Load dialog's UX when there are no save files or corrupte…

…d files

Re-add the popup that appears when "Load" is pressed on the title screen if
there are no files, but now check for files from previous versions too.

Improve handling of switching from a version with files to a version without
files, disabling buttons on the load dialog when there are no files in the
current directory. Versions with no files will still be shown in the drop-down.

This adds a todo about the error path at the start of evaluate_summary_string,
this path is reached by creating empty files in the save dir. The dialog's state
is reasonable, so it seemed a low priority and I don't want to introduce new
bugs by refactoring this path now.

Deleting all files now doesn't automatically close the dialog.

changelog.md

@@ -11,6 +11,8 @@
  ### Translations
  ### Units
  ### User interface
+   * Improved the Load dialog when there are no saved games for the current version, and also when there are corrupted files.
+   * Re-added the pop-up when there are no saved games at all (issue #5517).
  ### WML Engine
    * Standard Location Filters now support gives_income=yes|no to make it simpler to match villages regardless of owner
  ### Miscellaneous and Bug Fixes

src/gui/dialogs/game_load.cpp

@@ -58,6 +58,27 @@ namespace gui2::dialogs
 
 REGISTER_DIALOG(game_load)
 
+bool game_load::execute(const game_config_view& cache_config, savegame::load_game_metadata& data)
+{
+	if(savegame::save_index_class::default_saves_dir()->get_saves_list().empty()) {
+		bool found_files = false;
+		for(const auto& dir : filesystem::find_other_version_saves_dirs()) {
+			if(!found_files) {
+				// this needs to be a shared_ptr because get_saves_list() uses shared_from_this
+				auto index = std::make_shared<savegame::save_index_class>(dir.path);
+				found_files = !index->get_saves_list().empty();
+			}
+		}
+
+		if(!found_files) {
+			gui2::show_transient_message(_("No Saved Games"), _("There are no saved games to load."));
+			return false;
+		}
+	}
+
+	return game_load(cache_config, data).show();
+}
+
 game_load::game_load(const game_config_view& cache_config, savegame::load_game_metadata& data)
 	: filename_(data.filename)
 	, save_index_manager_(data.manager)
@@ -122,12 +143,10 @@ void game_load::set_save_dir_list(menu_button& dir_list)
 	options.emplace_back("label",  _("game_version^Current Version"), "path", "");
 
 	for(const auto& known_dir : other_dirs) {
-		if(!known_dir.path.empty()) {
-			options.emplace_back(
-				"label", VGETTEXT("game_version^Wesnoth $version", utils::string_map{{"version", known_dir.version}}),
-				"path", known_dir.path
-			);
-		}
+		options.emplace_back(
+			"label", VGETTEXT("game_version^Wesnoth $version", utils::string_map{{"version", known_dir.version}}),
+			"path", known_dir.path
+		);
 	}
 
 	dir_list.set_values(options);
@@ -159,16 +178,8 @@ void game_load::populate_game_list()
 	find_widget<button>(get_window(), "delete", false).set_active(!save_index_manager_->read_only());
 }
 
-void game_load::display_savegame_internal()
+void game_load::display_savegame_internal(const savegame::save_info& game)
 {
-	const int selected_row =
-		find_widget<listbox>(get_window(), "savegame_list", false).get_selected_row();
-
-	if(selected_row == -1) {
-		return;
-	}
-
-	savegame::save_info& game = games_[selected_row];
 	filename_ = game.name();
 	summary_  = game.summary();
 
@@ -257,18 +268,30 @@ void game_load::display_savegame_internal()
 // the first in the list) from making the dialog fail to open.
 void game_load::display_savegame()
 {
+	bool successfully_displayed_a_game = false;
+
 	try {
-		game_load::display_savegame_internal();
+		const int selected_row = find_widget<listbox>(get_window(), "savegame_list", false).get_selected_row();
+		if(selected_row < 0) {
+			find_widget<button>(get_window(), "delete", false).set_active(false);
+		} else {
+			find_widget<button>(get_window(), "delete", false).set_active(!save_index_manager_->read_only());
+			game_load::display_savegame_internal(games_[selected_row]);
+			successfully_displayed_a_game = true;
+		}
 	} catch(const config::error& e) {
 		// Clear the UI widgets, show an error message.
 		const std::string preamble = _("The selected file is corrupt: ");
 		const std::string message = e.message.empty() ? "(no details)" : e.message;
 		ERR_GAMELOADDLG << preamble << message << "\n";
+	}
+
+	if(!successfully_displayed_a_game) {
 		find_widget<minimap>(get_window(), "minimap", false).set_map_data("");
 		find_widget<label>(get_window(), "lblScenario", false)
-			.set_label(preamble);
+			.set_label("");
 		find_widget<scroll_label>(get_window(), "slblSummary", false)
-			.set_label(message);
+			.set_label("");
 
 		listbox& leader_list = find_widget<listbox>(get_window(), "leader_list", false);
 		leader_list.clear();
@@ -281,6 +304,12 @@ void game_load::display_savegame()
 		cancel_orders_toggle.set_active(false);
 		change_difficulty_toggle.set_active(false);
 	}
+
+	// Disable Load button if nothing is selected or if the currently selected file can't be loaded
+	find_widget<button>(get_window(), "ok", false).set_active(successfully_displayed_a_game);
+
+	// Disable 'Enter' loading in the same circumstance
+	get_window()->set_enter_disabled(!successfully_displayed_a_game);
 }
 
 void game_load::filter_text_changed(const std::string& text)
@@ -319,22 +348,17 @@ void game_load::filter_text_changed(const std::string& text)
 	}
 
 	list.set_row_shown(show_items);
-
-	const bool any_shown = list.any_rows_shown();
-
-	// Disable Load button if no games are available
-	find_widget<button>(get_window(), "ok", false).set_active(any_shown);
-
-	// Disable 'Enter' loading if no games are available
-	get_window()->set_enter_disabled(!any_shown);
 }
 
 void game_load::evaluate_summary_string(std::stringstream& str, const config& cfg_summary)
 {
 	std::string difficulty_human_str = string_table[cfg_summary["difficulty"]];
 	if(cfg_summary["corrupt"].to_bool()) {
 		str << "\n<span color='#f00'>" << _("(Invalid)") << "</span>";
-
+		// \todo: this skips the catch() statement in display_savegame. Low priority, as the
+		// dialog's state is reasonable; the "load" button is inactive, the "delete" button is
+		// active, and (cosmetic bug) it leaves the "change difficulty" toggle active. Can be
+		// triggered by creating an empty file in the save directory.
 		return;
 	}
 
@@ -452,11 +476,6 @@ void game_load::delete_button_callback()
 
 		list.remove_row(index);
 
-		// Close the dialog if there are no more saves
-		if(list.get_item_count() == 0) {
-			set_retval(retval::CANCEL);
-		}
-
 		display_savegame();
 	}
 }

src/gui/dialogs/game_load.hpp

@@ -50,10 +50,7 @@ class game_load : public modal_dialog
 public:
 	game_load(const game_config_view& cache_config, savegame::load_game_metadata& data);
 
-	static bool execute(const game_config_view& cache_config, savegame::load_game_metadata& data)
-	{
-		return game_load(cache_config, data).show();
-	}
+	static bool execute(const game_config_view& cache_config, savegame::load_game_metadata& data);
 
 private:
 	/** Inherited from modal_dialog. */
@@ -72,7 +69,8 @@ class game_load : public modal_dialog
 	void delete_button_callback();
 	void handle_dir_select();
 
-	void display_savegame_internal();
+	/** Part of display_savegame that might throw a config::error if the savegame data is corrupt. */
+	void display_savegame_internal(const savegame::save_info& game);
 	void display_savegame();
 	void evaluate_summary_string(std::stringstream& str, const config& cfg_summary);