extends Node
## The songs of the current quiz, in the order they were added, and which of them are
## played, answered and playing.
##
## Registered as the [code]Playlist[/code] autoload.
##
## Downloaded songs are kept on disk in the [code]songs[/code] folder next to the
## settings, not in memory. The folder only holds the current playlist: when the game
## starts, songs the saved quiz does not use are deleted (see [QuizSave]), and the folder
## is emptied when the playlist is reset.

const SONGS_FOLDER_NAME: String = "songs"

var song_object_array: Array[SongObject] = []
var latest_played_song: int = 0
var currently_playing_song: int = -1
var first_song_downloaded: bool = false
var first_song_played: bool = false
var number_of_tracks_to_preload: int = 1
var is_song_downloading: bool = false
## The first song of the current game. Songs before it belong to earlier games, which
## ended with Reset points.
var game_start_song: int = 0

# How many song files have been written, so each gets a name of its own
var _song_files_written: int = 0


## The folder downloaded songs are kept in.
static func songs_folder() -> String:
	return Settings.config_dir().path_join(SONGS_FOLDER_NAME)


func get_next_song() -> SongObject:
	return song_object_array[latest_played_song]


func set_latest_played_song() -> void:
	latest_played_song += 1
	if latest_played_song > song_object_array.size() - 1:
		latest_played_song = song_object_array.size() - 1


func update_last_played_song() -> void:
	latest_played_song = song_object_array.size()


func get_preloaded_songs() -> int:
	var number_of_tracks_preloaded: int = 0
	for song: SongObject in song_object_array:
		if !song.has_played:
			number_of_tracks_preloaded += 1
	return number_of_tracks_preloaded


func should_preload_more_songs() -> bool:
	return number_of_tracks_to_preload > get_preloaded_songs()


func song_is_answered(song_no: int = currently_playing_song) -> void:
	# Nothing is playing yet (-1); a negative index would answer the last, unplayed song
	if song_no < 0 || song_no >= song_object_array.size():
		return
	GameLog.debug("show_answer_pressed song_object: ", song_object_array[song_no]._to_string())
	song_object_array[song_no].is_answered = true
	if Settings.add_to_stats && !Settings.is_offline():
		GameLog.debug("add to stats: ", song_no)
		MusicServerClient.mark_song_played(song_no)


func add_to_playlist(new_song_object: SongObject) -> void:
	song_object_array.append(new_song_object)


func get_playlist() -> Array[SongObject]:
	if Settings.is_debug:
		return song_object_array
	else:
		var temp_list: Array[SongObject] = []
		for s: SongObject in song_object_array:
			if s.has_played:
				temp_list.append(s)
		return temp_list


func reset_playlist() -> void:
	currently_playing_song = -1
	latest_played_song = 0
	game_start_song = 0
	clear_song_list()
	clear_song_files()


func clear_song_list() -> void:
	song_object_array.clear()


func unset_is_playing() -> void:
	for song_object: SongObject in song_object_array:
		song_object.is_playing = false


func set_currently_playing_song(value: int) -> void:
	currently_playing_song = value


func get_current_soundtrack_title() -> String:
	return song_object_array[currently_playing_song].get_soundtrack_title()


func get_current_soundtrack_uuid() -> String:
	return song_object_array[currently_playing_song].get_soundtrack_uuid()


func get_current_song_title() -> String:
	return song_object_array[currently_playing_song].get_song_title()


func add_point(player_id: String) -> void:
	song_object_array[currently_playing_song].add_point(player_id)


func remove_point(player_id: String) -> void:
	song_object_array[currently_playing_song].remove_point(player_id)


## Removes every player's points from every song, for a new game.
func clear_points() -> void:
	for song_object: SongObject in song_object_array:
		song_object.players_given_point.clear()


## Removes a player's points from every song.
func remove_player_from_list(player_id: String) -> void:
	for song_object: SongObject in song_object_array:
		song_object.remove_point(player_id)


## The song of [param song_no], read from its file. Returns null if the file is gone, so
## the song can be downloaded again.
func get_song(song_no: int) -> AudioStream:
	var song_object: SongObject = song_object_array[song_no]
	if song_object.song_path.is_empty():
		return song_object.song
	return AudioFile.load(song_object.song_path)


func add_song_to_song_object(song_no: int, mp3: PackedByteArray) -> void:
	store_song(song_object_array[song_no], mp3)


## Keeps a downloaded song in a file in [method songs_folder]. If the file can't be
## written, the song is kept in memory instead.
func store_song(song_object: SongObject, mp3: PackedByteArray) -> void:
	DirAccess.make_dir_recursive_absolute(songs_folder())
	# Songs kept from a saved quiz already have files, which must not be written over
	var path: String = songs_folder().path_join("song_%d.mp3" % _song_files_written)
	while FileAccess.file_exists(path):
		_song_files_written += 1
		path = songs_folder().path_join("song_%d.mp3" % _song_files_written)
	_song_files_written += 1
	var file: FileAccess = FileAccess.open(path, FileAccess.WRITE)
	if file == null:
		GameLog.warning("Could not save a song to ", path, ", keeping it in memory: ",
				error_string(FileAccess.get_open_error()))
		var sound: AudioStreamMP3 = AudioStreamMP3.new()
		sound.data = mp3
		song_object.song = sound
		song_object.song_path = ""
		return
	file.store_buffer(mp3)
	file.close()
	song_object.song = null
	song_object.song_path = path


## Deletes the files of the songs downloaded so far, except those in [param keep].
func clear_song_files(keep: PackedStringArray = []) -> void:
	if !DirAccess.dir_exists_absolute(songs_folder()):
		return
	for file_name: String in DirAccess.get_files_at(songs_folder()):
		var path: String = songs_folder().path_join(file_name)
		if !keep.has(path):
			DirAccess.remove_absolute(path)


func song_has_played(song_no: int = latest_played_song) -> void:
	song_object_array[song_no].has_played = true


func song_is_playing(song_no: int = latest_played_song) -> void:
	song_object_array[song_no].is_playing = true