# audio_driver.gd —— 桥接 40250 Python/MilesLib 音频调用至 Godot 引擎。
# 每帧通过 Metin2PythonHost.audio_commands() 拉取原生端产生的音频播放/音量指令并执行。
class_name AudioDriver
extends Node

const AssetRoot = preload("res://asset_root.gd")

var _cache := {}                       # 绝对路径 -> AudioStream
var _bgm_root: String
var _sound_roots: PackedStringArray = []

var _bgm := [null, null]               # 两个 AudioStreamPlayer 用于 BGM 交叉淡入淡出
var _bgm_cur := 0
var _bgm_name := ""
var _bgm_fade_tween: Tween = null

var _ui_pool: Array[AudioStreamPlayer] = []
var _ui_next := 0

var master_sound := 1.0
var master_music := 1.0

# 3D 循环音效实例：id -> AudioStreamPlayer3D
var _active_3d := {}

func _ready() -> void:
	_init_roots()
	_init_players()

func _init_roots() -> void:
	var client := AssetRoot.client_path()
	var assets := AssetRoot.path()

	# BGM 根目录：优先 Client/BGM，次选 assets/BGM
	if DirAccess.dir_exists_absolute(client.path_join("BGM")):
		_bgm_root = client.path_join("BGM")
	elif DirAccess.dir_exists_absolute(assets.path_join("BGM")):
		_bgm_root = assets.path_join("BGM")
	else:
		_bgm_root = client.path_join("BGM")

	# 音效查找根目录
	var candidate_roots := [
		assets.path_join("Sound/sound"),
		assets.path_join("sound2/sound"),
		assets.path_join("sound_m/sound"),
		assets.path_join("metin2_patch_w20_sound/sound"),
		assets.path_join("Sound"),
		assets,
		client,
	]
	for r in candidate_roots:
		if DirAccess.dir_exists_absolute(r) and not _sound_roots.has(r):
			_sound_roots.append(r)

func _init_players() -> void:
	# 2 个 BGM 播放器
	for i in 2:
		var pl := AudioStreamPlayer.new()
		pl.bus = "Master"
		pl.name = "BgmPlayer%d" % i
		add_child(pl)
		_bgm[i] = pl

	# 16 个 2D 音效池播放器
	for i in 16:
		var pl := AudioStreamPlayer.new()
		pl.bus = "Master"
		pl.name = "UiPlayer%d" % i
		add_child(pl)
		_ui_pool.append(pl)

func _process(_delta: float) -> void:
	if not ClassDB.class_exists("Metin2PythonHost") or not Metin2PythonHost.is_running():
		return

	var commands: Array = Metin2PythonHost.audio_commands()
	if commands.is_empty():
		return

	for cmd in commands:
		var type: String = cmd.get("type", "")
		match type:
			"play_sound_2d":
				play_sound_2d(cmd.get("filename", ""), cmd.get("volume", 1.0))
			"play_sound_3d":
				play_sound_3d(cmd.get("filename", ""), Vector3(cmd.get("x", 0.0) / 100.0, cmd.get("z", 0.0) / 100.0, -cmd.get("y", 0.0) / 100.0), cmd.get("volume", 1.0), cmd.get("id", 0))
			"stop_sound_3d":
				stop_sound_3d(cmd.get("id", 0))
			"stop_all_sound_3d":
				stop_all_sound_3d()
			"play_music":
				play_music(cmd.get("filename", ""), cmd.get("volume", 1.0))
			"fade_out_music":
				fade_out_music(cmd.get("speed", 0.0))
			"fade_out_all_music":
				fade_out_all_music()
			"set_sound_volume":
				set_sound_volume(cmd.get("volume", 1.0))
			"set_music_volume":
				set_music_volume(cmd.get("volume", 1.0))

# --- 音效路径检索与加载 ---------------------------------------------------

func _find_sound(rel: String) -> String:
	if rel.is_empty():
		return ""
	rel = rel.replace("\\", "/").strip_edges()
	if rel.begins_with("d:/ymir work/") or rel.begins_with("D:/ymir work/"):
		rel = rel.substr(13)
	elif rel.begins_with("d:/") or rel.begins_with("D:/"):
		rel = rel.substr(3)

	# 1. 尝试直接路径
	if FileAccess.file_exists(rel):
		return rel

	# 2. 补全扩展名候选
	var cands := PackedStringArray([rel])
	if rel.get_extension().is_empty():
		cands = PackedStringArray([rel + ".wav", rel + ".mp3", rel + ".ogg"])

	# 3. 在所有已知根目录中遍历查找
	for root in _sound_roots:
		for c in cands:
			var p := root.path_join(c)
			if FileAccess.file_exists(p):
				return p
			# 若路径带 sound/，剥掉后再试一次（防止 root 自身已带 sound/）
			if c.begins_with("sound/"):
				var p_sub := root.path_join(c.substr(6))
				if FileAccess.file_exists(p_sub):
					return p_sub

	return ""

func _load_stream(path: String) -> AudioStream:
	if _cache.has(path):
		return _cache[path]
	var s: AudioStream = null
	var ext := path.get_extension().to_lower()
	if ext == "mp3":
		var m := AudioStreamMP3.new()
		m.data = FileAccess.get_file_as_bytes(path)
		s = m if m.data.size() > 0 else null
	elif ext == "ogg":
		s = AudioStreamOggVorbis.load_from_file(path)
	elif ext == "wav":
		s = AudioStreamWAV.load_from_file(path)
	_cache[path] = s
	return s

# --- 2D 音效播放 -----------------------------------------------------------

func play_sound_2d(rel: String, volume_scale := 1.0) -> void:
	var path := _find_sound(rel)
	if path.is_empty():
		return
	var stream := _load_stream(path)
	if stream == null:
		return
	if _ui_pool.is_empty():
		return
	var pl := _ui_pool[_ui_next]
	_ui_next = (_ui_next + 1) % _ui_pool.size()
	pl.stream = stream
	var vol: float = clampf(master_sound * volume_scale, 0.0, 1.0)
	pl.volume_db = linear_to_db(vol) if vol > 0.001 else -80.0
	pl.play()

# --- 3D 空间音效播放 -------------------------------------------------------

func play_sound_3d(rel: String, pos: Vector3, volume_scale := 1.0, sound_id := 0) -> void:
	var path := _find_sound(rel)
	if path.is_empty():
		return
	var stream := _load_stream(path)
	if stream == null:
		return
	var pl := AudioStreamPlayer3D.new()
	pl.stream = stream
	pl.unit_size = 8.0
	pl.max_distance = 80.0
	var vol: float = clampf(master_sound * volume_scale, 0.0, 1.0)
	pl.volume_db = linear_to_db(vol) if vol > 0.001 else -80.0
	add_child(pl)
	pl.global_position = pos
	pl.play()
	if sound_id > 0:
		_active_3d[sound_id] = pl
		pl.finished.connect(func(): _active_3d.erase(sound_id); pl.queue_free())
	else:
		pl.finished.connect(pl.queue_free)

func stop_sound_3d(sound_id: int) -> void:
	if _active_3d.has(sound_id):
		var pl: AudioStreamPlayer3D = _active_3d[sound_id]
		if is_instance_valid(pl):
			pl.stop()
			pl.queue_free()
		_active_3d.erase(sound_id)

func stop_all_sound_3d() -> void:
	for id in _active_3d.keys():
		stop_sound_3d(id)
	_active_3d.clear()

# --- BGM 背景音乐播放 -----------------------------------------------------

func play_music(name: String, volume_scale := 1.0) -> void:
	if name.is_empty() or name == _bgm_name:
		return
	_bgm_name = name

	var path := name.replace("\\", "/")
	if not path.is_absolute_path():
		var direct := _bgm_root.path_join(name)
		if FileAccess.file_exists(direct):
			path = direct
		elif FileAccess.file_exists(direct + ".mp3"):
			path = direct + ".mp3"
		else:
			path = _find_sound(name)

	var stream := _load_stream(path)
	if stream == null:
		return
	if stream is AudioStreamMP3:
		stream.loop = true

	var nxt := 1 - _bgm_cur
	_bgm[nxt].stream = stream
	_bgm[nxt].volume_db = -40.0
	_bgm[nxt].play()

	var target_vol: float = clampf(master_music * volume_scale, 0.0, 1.0)
	var target_db: float = linear_to_db(target_vol) if target_vol > 0.001 else -80.0

	if _bgm_fade_tween and _bgm_fade_tween.is_valid():
		_bgm_fade_tween.kill()
	_bgm_fade_tween = create_tween()
	_bgm_fade_tween.parallel().tween_property(_bgm[nxt], "volume_db", target_db, 1.2)
	var cur_player: AudioStreamPlayer = _bgm[_bgm_cur]
	if cur_player and cur_player.playing:
		_bgm_fade_tween.parallel().tween_property(cur_player, "volume_db", -40.0, 1.2)
		_bgm_fade_tween.chain().tween_callback(cur_player.stop)
	_bgm_cur = nxt

func fade_out_music(speed := 0.0) -> void:
	_bgm_name = ""
	var dur := 1.5 if speed <= 0.0 else maxf(0.5, 3.0 / speed)
	var cur_player: AudioStreamPlayer = _bgm[_bgm_cur]
	if cur_player and cur_player.playing:
		if _bgm_fade_tween and _bgm_fade_tween.is_valid():
			_bgm_fade_tween.kill()
		_bgm_fade_tween = create_tween()
		_bgm_fade_tween.tween_property(cur_player, "volume_db", -50.0, dur)
		_bgm_fade_tween.tween_callback(cur_player.stop)

func fade_out_all_music() -> void:
	fade_out_music(0.0)

# --- 音量控制 -------------------------------------------------------------

func set_sound_volume(v: float) -> void:
	master_sound = clampf(v, 0.0, 1.0)

func set_music_volume(v: float) -> void:
	master_music = clampf(v, 0.0, 1.0)
	var pl: AudioStreamPlayer = _bgm[_bgm_cur]
	if pl and pl.playing:
		pl.volume_db = linear_to_db(master_music) if master_music > 0.001 else -80.0