## AudioManager — floor music with cross-fade and SFX for player interactions.
## Autoload registered in project.godot. No class_name (Godot 4 autoload conflict).
extends Node

const CROSSFADE_DURATION: float = 0.8

const _MUSIC_MAP: Dictionary = {
	0: "res://assets/audio/music/floor_0.ogg",
	1: "res://assets/audio/music/floor_1.ogg",
	2: "res://assets/audio/music/floor_2.ogg",
	3: "res://assets/audio/music/floor_3.ogg",
}

const _SFX_MAP: Dictionary = {
	"chest_tap":         "res://assets/audio/sfx/chest_tap.ogg",
	"item_spawn":        "res://assets/audio/sfx/item_spawn.ogg",
	"item_drag_start":   "res://assets/audio/sfx/item_drag_start.ogg",
	"item_drop_hand":    "res://assets/audio/sfx/item_drop_hand.ogg",
	"item_drop_outfit":  "res://assets/audio/sfx/item_drop_outfit.ogg",
	"item_return_chest": "res://assets/audio/sfx/item_return_chest.ogg",
	"item_drop_floor":   "res://assets/audio/sfx/item_drop_floor.ogg",
}

var _current_floor: int = -1
var _is_crossfading: bool = false
var _active_player: AudioStreamPlayer
var _last_room: String = ""

var _music_a: AudioStreamPlayer
var _music_b: AudioStreamPlayer
var _sfx_player: AudioStreamPlayer


func _ready() -> void:
	_music_a = AudioStreamPlayer.new()
	_music_b = AudioStreamPlayer.new()
	_sfx_player = AudioStreamPlayer.new()
	add_child(_music_a)
	add_child(_music_b)
	add_child(_sfx_player)
	_active_player = _music_a
	_music_a.volume_db = linear_to_db(GameState.music_volume)
	_music_b.volume_db = linear_to_db(0.0)
	_sfx_player.volume_db = linear_to_db(GameState.sfx_volume)
	GameState.state_changed.connect(_on_game_state_changed)
	_last_room = GameState.current_room
	var initial_floor: int = _derive_floor_from_room(GameState.current_room)
	if initial_floor != -1:
		play_floor_music(initial_floor)


func play_floor_music(floor: int) -> void:
	if floor == _current_floor:
		return
	if not _MUSIC_MAP.has(floor):
		return
	if _is_crossfading:
		return
	_is_crossfading = true
	_current_floor = floor
	var inactive: AudioStreamPlayer = _music_b if _active_player == _music_a else _music_a
	var path: String = _MUSIC_MAP[floor]
	if not ResourceLoader.exists(path):
		_is_crossfading = false
		return
	var stream: AudioStream = load(path) as AudioStream
	if stream == null:
		_is_crossfading = false
		return
	inactive.stream = stream
	inactive.volume_db = linear_to_db(0.0)
	inactive.play()
	var tween: Tween = create_tween().set_parallel(true)
	tween.tween_property(inactive, "volume_db", linear_to_db(GameState.music_volume), CROSSFADE_DURATION)
	tween.tween_property(_active_player, "volume_db", linear_to_db(0.0), CROSSFADE_DURATION)
	await tween.finished
	_active_player.stop()
	_active_player = inactive
	_is_crossfading = false


func play_sfx(event: String) -> void:
	if not _SFX_MAP.has(event):
		return
	var path: String = _SFX_MAP[event]
	if not ResourceLoader.exists(path):
		return
	var stream: AudioStream = load(path) as AudioStream
	if stream == null:
		return
	_sfx_player.stream = stream
	_sfx_player.play()


func set_music_volume(vol: float) -> void:
	GameState.music_volume = vol
	_active_player.volume_db = linear_to_db(vol)


func set_sfx_volume(vol: float) -> void:
	GameState.sfx_volume = vol
	_sfx_player.volume_db = linear_to_db(vol)


func get_current_floor() -> int:
	return _current_floor


func _on_game_state_changed() -> void:
	if GameState.current_room == _last_room:
		return
	_last_room = GameState.current_room
	var floor: int = _derive_floor_from_room(GameState.current_room)
	if floor != -1:
		play_floor_music(floor)


func _derive_floor_from_room(room: String) -> int:
	match room:
		"reception", "giftshop", "restaurant", "emergency":
			return 0
		"xray", "pharmacy", "lab", "patient_rooms":
			return 1
		"ultrasound", "delivery_room", "nursery":
			return 2
		"garden_party":
			return 3
	return -1