extends Node

const SETTINGS_PATH := "user://settings.cfg"
const SETTINGS_SECTION := "audio"
const SETTINGS_KEY := "ui_sounds_enabled"
const PLAYER_COUNT := 8
const DEFAULT_VOLUME_DB := -12.0
const SOUND_PATHS := {
	"click": "res://assets/audio/kenney_interface_sounds/click_003.ogg",
	"select": "res://assets/audio/kenney_interface_sounds/select_003.ogg",
	"toggle": "res://assets/audio/kenney_interface_sounds/toggle_002.ogg",
	"eliminate": "res://assets/audio/kenney_interface_sounds/scratch_002.ogg",
	"open": "res://assets/audio/kenney_interface_sounds/open_001.ogg",
	"close": "res://assets/audio/kenney_interface_sounds/close_002.ogg",
	"correct": "res://assets/audio/kenney_interface_sounds/confirmation_002.ogg",
	"error": "res://assets/audio/kenney_interface_sounds/error_004.ogg",
	"back": "res://assets/audio/kenney_interface_sounds/back_002.ogg",
	"question": "res://assets/audio/kenney_interface_sounds/question_001.ogg"
}

var sounds := {}
var players: Array[AudioStreamPlayer] = []
var sounds_enabled := true
var next_player_index := 0


func _ready() -> void:
	_load_setting()
	_load_sounds()
	_build_player_pool()
	get_tree().node_added.connect(_on_node_added)
	call_deferred("_wire_existing_buttons")


func play_sound(sound_name: String) -> void:
	if not sounds_enabled or not sounds.has(sound_name) or players.is_empty():
		return
	var player := _next_available_player()
	player.stream = sounds[sound_name]
	player.play()


func set_sounds_enabled(is_enabled: bool) -> void:
	if sounds_enabled == is_enabled:
		return
	sounds_enabled = is_enabled
	if not sounds_enabled:
		for player in players:
			player.stop()
	_save_setting()
	if sounds_enabled:
		play_sound("toggle")


func are_sounds_enabled() -> bool:
	return sounds_enabled


func set_button_sound(button: Button, sound_name: String) -> void:
	button.set_meta("ui_sound", sound_name)
	_wire_button(button)


func _load_sounds() -> void:
	for sound_name in SOUND_PATHS:
		var stream := load(str(SOUND_PATHS[sound_name])) as AudioStream
		if stream != null:
			sounds[sound_name] = stream
		else:
			push_warning("Unable to load UI sound: %s" % SOUND_PATHS[sound_name])


func _build_player_pool() -> void:
	for _player_index in range(PLAYER_COUNT):
		var player := AudioStreamPlayer.new()
		player.volume_db = DEFAULT_VOLUME_DB
		add_child(player)
		players.append(player)


func _next_available_player() -> AudioStreamPlayer:
	for player in players:
		if not player.playing:
			return player
	var player := players[next_player_index]
	next_player_index = (next_player_index + 1) % players.size()
	return player


func _on_node_added(node: Node) -> void:
	if node is Button:
		_wire_button(node)


func _wire_existing_buttons() -> void:
	_wire_node(get_tree().root)


func _wire_node(node: Node) -> void:
	if not is_instance_valid(node):
		return
	if node is Button:
		_wire_button(node)
	for child in node.get_children():
		_wire_node(child)


func _wire_button(button: Button) -> void:
	if button.has_meta("ui_sound_wired"):
		return
	button.set_meta("ui_sound_wired", true)
	button.pressed.connect(_on_button_pressed.bind(button))


func _on_button_pressed(button: Button) -> void:
	var sound_name := str(button.get_meta("ui_sound", "click"))
	if sound_name != "none":
		play_sound(sound_name)


func _load_setting() -> void:
	var config := ConfigFile.new()
	if config.load(SETTINGS_PATH) == OK:
		sounds_enabled = bool(config.get_value(SETTINGS_SECTION, SETTINGS_KEY, true))


func _save_setting() -> void:
	var config := ConfigFile.new()
	config.load(SETTINGS_PATH)
	config.set_value(SETTINGS_SECTION, SETTINGS_KEY, sounds_enabled)
	var save_error := config.save(SETTINGS_PATH)
	if save_error != OK:
		push_warning("Unable to save UI sound preference.")