Show soundtrack covers and edit alternative names (#49)

Covers: statistics cards show the soundtrack's cover on the left, and the
statistics popup shows it large. Until it arrives, and without a cover, the
soundtrack's initials stand in. Covers load only for cards on or near the
screen, three at a time, and are cached in covers/ next to the settings
(CoverCache), downloaded again only when cover_modified changes. The index and
file handling are shared with CharacterCache in a new FileCache.

Alternative names: the popup shows them and has an editor (add, remove, save)
that sends PUT /soundtracks/{uuid}/alternative-names. The statistics search and
the Search popup find soundtracks by them; Search shows the matching name after
the real one. Search now loads /soundtracks, falling back to the plain list.

The API types are regenerated from the server's spec, with a SoundtrackCover
theme style in every theme.

Closes #49

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

common/character_cache.gd

@@ -14,15 +14,15 @@ extends RefCounted
 ## can't be reached at all, the cached pictures are used as they are.
 
 const FOLDER_NAME: String = "characters"
-const INDEX_FILE_NAME: String = "index.json"
+const INDEX_FILE_NAME: String = FileCache.INDEX_FILE_NAME
 ## How long a picture is used before downloading it again, when the server can't tell
 ## whether it changed.
 const MAX_AGE_SECONDS: int = 7 * 24 * 60 * 60
 ## The change time of a picture when the server can't tell it.
-const UNKNOWN_TIME: int = -1
+const UNKNOWN_TIME: int = FileCache.UNKNOWN_TIME
 
-# What index.json holds: name -> {"modified": int, "downloaded": int}
-var _index: Dictionary = {}
+# The pictures on disk and their index
+var _files: FileCache = FileCache.new(FOLDER_NAME)
 # When the server last changed each picture on the list, or UNKNOWN_TIME
 var _modified: Dictionary[String, int] = {}
 # True when the server could not be reached and only cached pictures are shown
@@ -38,7 +38,7 @@ static func folder() -> String:
 ## [code]Array[String][/code]. Cached pictures of characters no longer on the server are
 ## deleted.
 func load_list(on_done: Callable) -> void:
-	_load_index()
+	_files.load_index()
 	_cache_only = false
 	var details_fetched: Callable = func details_fetched(details: Array) -> void:
 		_modified.clear()
@@ -51,9 +51,8 @@ func load_list(on_done: Callable) -> void:
 ## Calls [param on_done] with the picture of [param character_name] as an [Image], from
 ## disk when the cached one is still fresh, otherwise from the server.
 func fetch_image(character_name: String, on_done: Callable) -> void:
-	var path: String = _file_path(character_name)
-	if (_cache_only || _is_fresh(character_name)) && FileAccess.file_exists(path):
-		var cached: Image = CharacterCard.image_from_bytes(FileAccess.get_file_as_bytes(path))
+	if (_cache_only || _is_fresh(character_name)) && _files.has_file(character_name):
+		var cached: Image = CharacterCard.image_from_bytes(_files.read(character_name))
 		if cached != null:
 			on_done.call(cached)
 			return
@@ -63,7 +62,7 @@ func fetch_image(character_name: String, on_done: Callable) -> void:
 		if picture == null:
 			GameLog.warning("Could not load the picture of ", character_name)
 			return
-		_store(character_name, bytes)
+		_files.store(character_name, bytes, _modified.get(character_name, UNKNOWN_TIME))
 		on_done.call(picture)
 	MusicServerClient.fetch_character_image(character_name, image_fetched)
 
@@ -84,71 +83,24 @@ func _load_cached_only(on_done: Callable) -> void:
 	GameLog.warning("Could not get the characters from the server, showing the cached ones")
 	_cache_only = true
 	var names: Array[String] = []
-	for character_name: String in _index:
-		if FileAccess.file_exists(_file_path(character_name)):
+	for character_name: String in _files.keys():
+		if _files.has_file(character_name):
 			names.append(character_name)
 	names.sort_custom(func(a: String, b: String) -> bool: return a.naturalnocasecmp_to(b) < 0)
 	on_done.call(names)
 
 
 func _list_loaded(on_done: Callable) -> void:
-	var removed: bool = false
-	for character_name: String in _index.keys():
-		if !_modified.has(character_name):
-			DirAccess.remove_absolute(_file_path(character_name))
-			_index.erase(character_name)
-			removed = true
-	if removed:
-		_save_index()
+	_files.keep_only(_modified)
 	var names: Array[String] = []
 	names.assign(_modified.keys())
 	on_done.call(names)
 
 
 func _is_fresh(character_name: String) -> bool:
-	if !_index.has(character_name):
+	if !_files.keys().has(character_name):
 		return false
-	var entry: Dictionary = _index[character_name]
 	var modified: int = _modified.get(character_name, UNKNOWN_TIME)
 	if modified != UNKNOWN_TIME:
-		return int(entry.get("modified", UNKNOWN_TIME)) == modified
-	var age: float = Time.get_unix_time_from_system() - float(entry.get("downloaded", 0))
-	return age < MAX_AGE_SECONDS
-
-
-func _store(character_name: String, bytes: PackedByteArray) -> void:
-	DirAccess.make_dir_recursive_absolute(folder())
-	var file: FileAccess = FileAccess.open(_file_path(character_name), FileAccess.WRITE)
-	if file == null:
-		GameLog.warning("Could not cache the picture of ", character_name, ": ",
-				error_string(FileAccess.get_open_error()))
-		return
-	file.store_buffer(bytes)
-	file.close()
-	_index[character_name] = {
-		"modified": _modified.get(character_name, UNKNOWN_TIME),
-		"downloaded": int(Time.get_unix_time_from_system()),
-	}
-	_save_index()
-
-
-func _load_index() -> void:
-	_index = {}
-	var path: String = folder().path_join(INDEX_FILE_NAME)
-	if FileAccess.file_exists(path):
-		var parsed: Variant = JSON.parse_string(FileAccess.get_file_as_string(path))
-		if parsed is Dictionary:
-			_index = parsed
-
-
-func _save_index() -> void:
-	var file: FileAccess = FileAccess.open(folder().path_join(INDEX_FILE_NAME),
-			FileAccess.WRITE)
-	if file != null:
-		file.store_string(JSON.stringify(_index, "\t", true))
-
-
-# The server's names are plain file names, but they are made safe anyway since they
-# become paths on this computer
-func _file_path(character_name: String) -> String:
-	return folder().path_join(character_name.validate_filename())
+		return _files.modified(character_name) == modified
+	return _files.age(character_name) < MAX_AGE_SECONDS