Fix crash when switching to Fonts

scripts/Catapult.gd

@@ -418,5 +418,5 @@ func _refresh_currently_installed() -> void:
 		_btn_play.disabled = true
 		_btn_game_dir.visible = false
 
-	for i in [1, 2]:
+	for i in [1, 2, 3]:
 		_tabs.set_tab_disabled(i, not _is_selected_game_installed())

scripts/FontManager.gd

@@ -66,6 +66,14 @@ func load_available_fonts() -> void:
 	available_fonts = json_result.result
 
 
+func font_config_file_exists() -> bool:
+
+	var config_file: String = _workdir.plus_file(_settings.read("game")).\
+			plus_file("current").plus_file("config").plus_file("fonts.json")
+
+	return Directory.new().file_exists(config_file)
+
+
 func load_font_config() -> void:
 
 	var result: Dictionary = {}
@@ -87,11 +95,19 @@ func load_font_config() -> void:
 			emit_signal("status_message", "Could not open font config file %s (error code: %s)."
 					% [config_file, err], Enums.MSG_ERROR)
 	else:
-		emit_signal("status_message", "Font config file %s is not found!", Enums.MSG_ERROR)
+		emit_signal("status_message", "Font config file %s is not found!" % config_file, Enums.MSG_ERROR)
 
 	font_config = result
 
 
+func options_file_exists() -> bool:
+
+	var options_file: String = _workdir.plus_file(_settings.read("game")).\
+		plus_file("current").plus_file("config").plus_file("options.json")
+
+	return Directory.new().file_exists(options_file)
+
+
 func load_game_options() -> void:
 
 	var options_file: String = _workdir.plus_file(_settings.read("game")).\
@@ -112,7 +128,7 @@ func load_game_options() -> void:
 			emit_signal("status_message", "Could not open game options file %s (error code: %s)."
 					% [options_file, err], Enums.MSG_ERROR)
 	else:
-		emit_signal("status_message", "Game options file %s is not found!", Enums.MSG_ERROR)
+		emit_signal("status_message", "Game options file %s is not found!" % options_file, Enums.MSG_ERROR)
 
 
 func _write_font_config() -> void:

scripts/FontsUI.gd

@@ -55,6 +55,7 @@ const _PREVIEW_TEXT_NUM := "1234567890 !@#$ %^&* ()[]{}"
 
 onready var _rng := RandomNumberGenerator.new()
 onready var _geom := $"/root/WindowGeometry"
+onready var _tabs := $".."
 onready var _settings := $"/root/SettingsManager"
 onready var _fonts := $"/root/Catapult/Fonts"
 onready var _list := $FontSelection/RightPane/FontsList
@@ -127,6 +128,16 @@ func _on_Tabs_tab_changed(tab: int) -> void:
 	if tab != 3:
 		return
 
+	if not _fonts.font_config_file_exists():
+		emit_signal("status_message", "Can't manage fonts at this time: font config file does not exist. Make sure you've started the game at least once to create it.", Enums.MSG_WARN)
+		_tabs.current_tab = 0
+		return
+
+	if not _fonts.options_file_exists():
+		emit_signal("status_message", "Can't manage fonts at this time: options file does not exist. Make sure you've started the game at least once to create it.", Enums.MSG_WARN)
+		_tabs.current_tab = 0
+		return
+
 	_fonts.load_available_fonts()
 	_fonts.load_font_config()