Sort the scripts and scenes into folders

main/ holds the main window and top bar, quiz/ the quiz and its parts,
player/ the music player, popups/ every popup and what they share, data/ the
songs, players, playlist and settings, server/ the MusicServer client,
common/ the list row and GameLog, and themes/ the themes and style boxes.

data/playlist.gd

@@ -0,0 +1,122 @@
+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.
+
+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
+
+
+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:
+		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
+	clear_song_list()
+
+
+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_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 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)
+
+
+func get_song(song_no: int) -> AudioStream:
+	return song_object_array[song_no].song
+
+
+func add_song_to_song_object(song_no: int, sound: AudioStream) -> void:
+	song_object_array[song_no].song = sound
+
+
+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