extends Node

## Autoload: central sound playback with variation + pitch randomization.
##
## Why: identical samples played back-to-back sound robotic. Real games ship
## 3-5 variations per event and randomize pitch a few percent per shot. This
## manager makes that the default for every sound in the game.
##
## Usage:
##   AudioManager.play_3d("ak47_fire", muzzle_global_pos)
##   AudioManager.play_ui("hit_confirm")
##   AudioManager.register_sound("footstep_metal", [
##       "res://assets/sounds/footstep_metal_01.wav",
##       "res://assets/sounds/footstep_metal_02.wav",
##   ], "Footsteps")
##
## Sounds are auto-registered from assets/sounds/*.wav on startup (the file
## stem is the sound id). Drop variations next to the original with _01/_02/…
## suffixes and they are picked up as one id with random selection:
##   footstep.wav, footstep_01.wav, footstep_02.wav -> id "footstep" (3 vars)
##
## Buses: Master <- SFX <- {Weapons, Footsteps, UI}, Master <- Music.
## See docs/SOUND_DESIGN.md for where to get good source audio.

const SOUNDS_DIR := "res://assets/sounds"
const POOL_SIZE_3D := 32
const POOL_SIZE_2D := 8

# id -> { "streams": Array[AudioStream], "bus": String, "pitch_var": float, "volume_db": float }
var _library: Dictionary = {}
var _pool_3d: Array[AudioStreamPlayer3D] = []
var _pool_2d: Array[AudioStreamPlayer] = []
var _next_3d: int = 0
var _next_2d: int = 0

# Default routing/tuning per id prefix (applied during auto-registration).
const BUS_HINTS := {
	"footstep": "Footsteps",
	"fire": "Weapons",
	"reload": "Weapons",
}

## weapon_name (as broadcast in fire RPCs) -> fire sound id.
const WEAPON_SOUND_IDS := {
	"AK-47": "ak47_fire", "M4": "m4_fire", "MP7": "mp7_fire",
	"DMR": "dmr_fire", "AWP": "awp_fire",
	"Double Barrel Shotgun": "shotgun_fire", "Nail Gun": "nailgun_fire",
	"Plasma Gun": "plasma_fire", "Rocket Launcher": "rocket_fire",
	"Rocket Swarm": "swarm_fire", "Mortar": "mortar_fire",
	"Knife": "knife_swing",
}

## Sounds loud enough to slap back off nearby walls (early reflections).
const OCCLUSION_TICK := 0.12
var _occlusion_accum := 0.0


func _ready() -> void:
	_setup_buses()
	_build_pools()
	_auto_register_sounds()
	print("AudioManager: %d sounds registered" % _library.size())


func _physics_process(delta: float) -> void:
	# Re-filter playing positional sounds as the listener/source move so
	# walking behind a wall audibly muffles loops and long tails too.
	_occlusion_accum += delta
	if _occlusion_accum < OCCLUSION_TICK:
		return
	_occlusion_accum = 0.0
	var cam := get_viewport().get_camera_3d()
	if cam == null:
		return
	var listener := cam.global_position
	for p in _pool_3d:
		if p.playing and not p.get_meta("is_reflection", false):
			Acoustics.apply_occlusion(p, Acoustics.occlusion(
				cam.get_world_3d(), listener, p.global_position))
	# External looping players (projectile flight sounds, etc.) opt in by
	# joining this group.
	for node in get_tree().get_nodes_in_group("acoustic_occluded"):
		if node is AudioStreamPlayer3D and node.playing and node.is_inside_tree():
			Acoustics.apply_occlusion(node, Acoustics.occlusion(
				cam.get_world_3d(), listener, node.global_position))


func weapon_sound_id(weapon_name: String) -> String:
	return WEAPON_SOUND_IDS.get(weapon_name, "")


# ── Bus layout ────────────────────────────────────────────────────────────────

func _setup_buses() -> void:
	_ensure_bus("SFX", "Master")
	_ensure_bus("Weapons", "SFX")
	_ensure_bus("Footsteps", "SFX")
	_ensure_bus("UI", "SFX")
	_ensure_bus("Music", "Master")


func _ensure_bus(bus_name: String, send_to: String) -> void:
	if AudioServer.get_bus_index(bus_name) != -1:
		return
	var idx := AudioServer.bus_count
	AudioServer.add_bus(idx)
	AudioServer.set_bus_name(idx, bus_name)
	AudioServer.set_bus_send(idx, send_to)


func set_bus_volume_linear(bus_name: String, linear: float) -> void:
	var idx := AudioServer.get_bus_index(bus_name)
	if idx != -1:
		AudioServer.set_bus_volume_db(idx, linear_to_db(clampf(linear, 0.0001, 1.0)))


# ── Registration ──────────────────────────────────────────────────────────────

func register_sound(id: String, paths: Array, bus: String = "SFX",
		pitch_var: float = 0.06, volume_db: float = 0.0) -> void:
	var streams: Array = []
	for p in paths:
		if ResourceLoader.exists(p):
			var s = load(p)
			if s:
				streams.append(s)
	if streams.is_empty():
		return
	_library[id] = {
		"streams": streams,
		"bus": bus,
		"pitch_var": pitch_var,
		"volume_db": volume_db,
	}


func _auto_register_sounds() -> void:
	var dir := DirAccess.open(SOUNDS_DIR)
	if not dir:
		return
	# Group files: "footstep_01.wav" and "footstep.wav" both map to "footstep".
	var groups: Dictionary = {}
	for fname in dir.get_files():
		if not (fname.ends_with(".wav") or fname.ends_with(".ogg") or fname.ends_with(".mp3")):
			continue
		var stem := fname.get_basename()
		var base := stem
		var parts := stem.rsplit("_", true, 1)
		if parts.size() == 2 and parts[1].is_valid_int():
			base = parts[0]
		if not groups.has(base):
			groups[base] = []
		groups[base].append(SOUNDS_DIR + "/" + fname)

	for id in groups:
		var bus := "SFX"
		for hint in BUS_HINTS:
			if id.findn(hint) != -1:
				bus = BUS_HINTS[hint]
				break
		register_sound(id, groups[id], bus)


func has_sound(id: String) -> bool:
	return _library.has(id)


## Build an AudioStreamRandomizer for a registered id: every play() picks a
## random variation with random pitch. For nodes that own their own player
## (weapons) instead of going through the pools. Falls back to a plain load
## of fallback_path if the id isn't registered.
func stream_for(id: String, fallback_path: String = "") -> AudioStream:
	var entry = _library.get(id)
	if entry == null:
		return load(fallback_path) if fallback_path != "" and ResourceLoader.exists(fallback_path) else null
	var r := AudioStreamRandomizer.new()
	r.random_pitch = 1.0 + entry["pitch_var"]
	for s in entry["streams"]:
		r.add_stream(-1, s)
	return r


# ── Playback ──────────────────────────────────────────────────────────────────

func _build_pools() -> void:
	for i in POOL_SIZE_3D:
		var p := AudioStreamPlayer3D.new()
		p.name = "Pool3D_%d" % i
		p.max_distance = 80.0
		p.unit_size = 8.0
		add_child(p)
		_pool_3d.append(p)
	for i in POOL_SIZE_2D:
		var p := AudioStreamPlayer.new()
		p.name = "Pool2D_%d" % i
		add_child(p)
		_pool_2d.append(p)


## Play a positional sound with material-aware occlusion; loud sounds also
## spawn early reflections off nearby surfaces so they can be located.
## Safe to call every frame — players are pooled.
func play_3d(id: String, global_pos: Vector3, volume_db_offset: float = 0.0,
		pitch_scale: float = 1.0) -> AudioStreamPlayer3D:
	var entry = _library.get(id)
	if entry == null:
		return null
	var player := _pool_3d[_next_3d]
	_next_3d = (_next_3d + 1) % POOL_SIZE_3D
	player.stream = entry["streams"].pick_random()
	player.bus = entry["bus"]
	player.volume_db = entry["volume_db"] + volume_db_offset
	player.pitch_scale = pitch_scale * randf_range(1.0 - entry["pitch_var"], 1.0 + entry["pitch_var"])
	player.global_position = global_pos
	player.set_meta("is_reflection", false)
	var cam := get_viewport().get_camera_3d()
	if cam:
		var occ := Acoustics.occlusion(cam.get_world_3d(), cam.global_position, global_pos)
		Acoustics.apply_occlusion(player, occ)
		if _is_loud(id):
			_spawn_reflections(player.stream, global_pos, cam, entry, volume_db_offset)
	else:
		Acoustics.apply_occlusion(player, { "db": 0.0, "cutoff": Acoustics.OPEN_CUTOFF, "surfaces": 0 })
	player.play()
	return player


func _is_loud(id: String) -> bool:
	return id.findn("fire") != -1 or id.findn("explosion") != -1


## Delayed, filtered copies of a loud sound from nearby wall mirror points.
func _spawn_reflections(stream: AudioStream, source: Vector3, cam: Camera3D,
		entry: Dictionary, volume_db_offset: float) -> void:
	var refls := Acoustics.reflections(cam.get_world_3d(), source, cam.global_position)
	for r in refls:
		get_tree().create_timer(r.delay).timeout.connect(func():
			var p := _pool_3d[_next_3d]
			_next_3d = (_next_3d + 1) % POOL_SIZE_3D
			p.stream = stream
			p.bus = entry["bus"]
			p.volume_db = entry["volume_db"] + volume_db_offset + r.db
			p.pitch_scale = randf_range(0.97, 1.0)
			p.global_position = r.point
			p.set_meta("is_reflection", true)
			p.attenuation_filter_cutoff_hz = r.cutoff
			p.attenuation_filter_db = Acoustics.DEFAULT_FILTER_DB
			p.play()
		)


## Play a non-positional sound (UI clicks, local confirms).
func play_ui(id: String, volume_db_offset: float = 0.0) -> AudioStreamPlayer:
	var entry = _library.get(id)
	if entry == null:
		return null
	var player := _pool_2d[_next_2d]
	_next_2d = (_next_2d + 1) % POOL_SIZE_2D
	player.stream = entry["streams"].pick_random()
	player.bus = "UI"
	player.volume_db = entry["volume_db"] + volume_db_offset
	player.pitch_scale = randf_range(1.0 - entry["pitch_var"], 1.0 + entry["pitch_var"])
	player.play()
	return player