Imagine yourself as a game developer on Godot 4. 

Analyze the logic of this code and check it for errors. 

As an output, provide changes that can be made.

extends Node

# Constants
const MUSIC_DIR: String = "res://music"

# Audio player and UI elements
@onready var audio_player: AudioStreamPlayer = $AudioStreamPlayer
@onready var next_button: Button = $MarginContainer/HBoxContainer/NextButton
@onready var prev_button: Button = $MarginContainer/HBoxContainer/PrevButton
@onready var play_button: Button = $MarginContainer/HBoxContainer/PlayButton
@onready var current_track_label: Label = $MarginContainer/HBoxContainer/Panel/MarginContainer/TrackLabel

# Music-related variables
var music_tracks: Array = []
var current_track_index: int = 0
var fade_duration: float = 1.0
var paused_playback_position: float = 0.0

# Called when the node is added to the scene
func _ready() -> void:
	load_music_files()
	update_track_label()

	# Connect button signals to their respective functions
	play_button.connect("pressed", self, "_on_play_button_pressed")
	next_button.connect("pressed", self, "_on_next_button_pressed")
	prev_button.connect("pressed", self, "_on_prev_button_pressed")

# Load music files asynchronously to avoid blocking the main thread
func load_music_files() -> void:
	var loader_thread = Thread.new()
	loader_thread.start(self, "_load_music_files_background")

# Background task to load music files
func _load_music_files_background() -> void:
	var dir = DirAccess.open(MUSIC_DIR)
	if dir:
		dir.list_dir_begin()
		var file_name = dir.get_next()

		while file_name != "":
			if file_name.ends_with(".mp3"):
				var file_path = MUSIC_DIR + "/" + file_name
				music_tracks.append(file_path)
			file_name = dir.get_next()
		dir.list_dir_end()

		if music_tracks.size() == 0:
			print("No music files found")
		else:
			print("Music loaded successfully")

# Helper function to handle both fade in and fade out logic
func fade(target_volume: float, start_volume: float) -> void:
	var timer = 0.0
	audio_player.volume_db = start_volume
	if target_volume == 0:
		audio_player.play()
	while timer < fade_duration:
		timer += get_process_delta_time()
		audio_player.volume_db = lerp(start_volume, target_volume, timer / fade_duration)
		await get_tree().create_timer(0.01).timeout
	if target_volume == -80:
		audio_player.stop()
		paused_playback_position = 0  # Reset playback position when stopping

# Fade in the audio
func fade_in() -> void:
	await fade(0, -80)

# Fade out the audio
func fade_out() -> void:
	await fade(-80, 0)

# Play the current track
func play_music() -> void:
	if music_tracks.size() == 0:
		return  # No music files to play

	var track_path = music_tracks[current_track_index]
	var stream = load(track_path) as AudioStream

	if stream:
		audio_player.stream = stream
		if paused_playback_position > 0:
			audio_player.play(paused_playback_position)
		else:
			fade_in()

# Stop the current track
func stop_music() -> void:
	paused_playback_position = audio_player.get_playback_position()
	fade_out()

# Helper function to switch tracks with an offset
func change_track(offset: int) -> void:
	if music_tracks.size() == 0:
		return  # No tracks to switch to

	await fade_out()
	paused_playback_position = 0
	current_track_index = (current_track_index + offset + music_tracks.size()) % music_tracks.size()
	play_music()
	update_track_label()

# Go to the next track
func next_track() -> void:
	change_track(1)

# Go to the previous track
func prev_track() -> void:
	if audio_player.get_playback_position() > 10:
		audio_player.seek(0)
	else:
		change_track(-1)

# Update the track label to show the current track name
func update_track_label() -> void:
	if music_tracks.size() > 0:
		var track_name = music_tracks[current_track_index].get_file().get_basename()
		current_track_label.text = track_name
	else:
		current_track_label.text = "No music found"

# Handle play button press
func _on_play_button_pressed() -> void:
	if audio_player.playing:
		stop_music()
	else:
		play_music()

# Handle next button press
func _on_next_button_pressed() -> void:
	next_track()

# Handle previous button press
func _on_prev_button_pressed() -> void:
	prev_track()