extends Node

# Dependency-free audio foundation. Authored assets can replace these tones
# later without changing gameplay call sites or the multiplayer event flow.

const SAMPLE_RATE := 44100
const MAX_INTENSITY := 1.0

var enabled := true
var _engine_player: AudioStreamPlayer
var _engine_turbo := false
var _last_wall_scrape_ms := -1000


func bind_tree_buttons(root: Node) -> void:
	if root == null:
		return
	for node in root.find_children("*", "BaseButton", true, false):
		bind_button(node as BaseButton)


func bind_button(button: BaseButton) -> void:
	if button == null:
		return
	var callback := Callable(self, "play_ui_click")
	if not button.pressed.is_connected(callback):
		button.pressed.connect(callback)


func play_ui_click() -> void:
	_play_tone(880.0, 0.045, 0.10)


func play_countdown(count: int) -> void:
	if count <= 0:
		_play_tone(1046.5, 0.12, 0.18)
	else:
		_play_tone(countdown_frequency(count), 0.08, 0.14)


func play_impact(intensity: float) -> void:
	var amount := clamp_intensity(intensity)
	if amount <= 0.0:
		return
	_play_tone(150.0 + 180.0 * amount, 0.06 + 0.08 * amount, 0.08 + 0.18 * amount)


func play_wall_scrape(intensity: float) -> void:
	var amount := clamp_intensity(intensity)
	if amount <= 0.0:
		return
	var now_ms := Time.get_ticks_msec()
	if now_ms - _last_wall_scrape_ms < 80:
		return
	_last_wall_scrape_ms = now_ms
	_play_tone(110.0 + 90.0 * amount, 0.05 + 0.07 * amount, 0.05 + 0.10 * amount)


func play_goal() -> void:
	_play_tone(523.25, 0.22, 0.22)
	_play_tone(783.99, 0.30, 0.18)


func set_engine_state(thrust: float, turbo: bool) -> void:
	var amount := clamp_intensity(thrust)
	var rising_turbo := should_play_turbo_cue(_engine_turbo, turbo, amount)
	if not enabled or amount <= 0.01:
		stop_engine()
		return
	if rising_turbo:
		_play_tone(260.0, 0.16, 0.16)
	_engine_turbo = turbo
	if _engine_player == null or not is_instance_valid(_engine_player):
		_engine_player = AudioStreamPlayer.new()
		_engine_player.stream = _engine_stream()
		add_child(_engine_player)
		_engine_player.play()
	_engine_player.pitch_scale = engine_pitch(amount, turbo)
	_engine_player.volume_db = linear_to_db(engine_volume(amount, turbo))


func stop_engine() -> void:
	if _engine_player != null and is_instance_valid(_engine_player):
		_engine_player.stop()
	_engine_turbo = false


static func engine_pitch(thrust: float, turbo: bool) -> float:
	var amount := clamp_intensity(thrust)
	return 0.75 + amount * 0.55 + (0.30 if turbo and amount > 0.01 else 0.0)


static func engine_volume(thrust: float, turbo: bool) -> float:
	var amount := clamp_intensity(thrust)
	return clampf(0.015 + amount * 0.045 + (0.025 if turbo and amount > 0.01 else 0.0), 0.0, 0.1)


static func should_play_turbo_cue(previous_turbo: bool, turbo: bool, thrust: float) -> bool:
	return turbo and not previous_turbo and clamp_intensity(thrust) > 0.01


static func clamp_intensity(value: float) -> float:
	if not is_finite(value):
		return 0.0
	return clampf(value, 0.0, MAX_INTENSITY)


static func countdown_frequency(count: int) -> float:
	return 440.0 + float(clampi(count, 1, 9)) * 55.0


func _play_tone(frequency: float, duration: float, volume: float) -> void:
	if not enabled or frequency <= 0.0 or duration <= 0.0 or volume <= 0.0:
		return
	var stream := AudioStreamWAV.new()
	stream.format = AudioStreamWAV.FORMAT_16_BITS
	stream.mix_rate = SAMPLE_RATE
	stream.stereo = false
	stream.data = _tone_data(frequency, duration, volume)
	var player := AudioStreamPlayer.new()
	player.stream = stream
	add_child(player)
	player.finished.connect(player.queue_free)
	player.play()


func _engine_stream() -> AudioStreamWAV:
	var stream := AudioStreamWAV.new()
	stream.format = AudioStreamWAV.FORMAT_16_BITS
	stream.mix_rate = SAMPLE_RATE
	stream.stereo = false
	stream.loop_mode = AudioStreamWAV.LOOP_FORWARD
	stream.data = _tone_data(92.0, 1.0, 0.65)
	stream.loop_end = SAMPLE_RATE
	return stream


func _tone_data(frequency: float, duration: float, volume: float) -> PackedByteArray:
	var frames := maxi(1, int(duration * SAMPLE_RATE))
	var data := PackedByteArray()
	data.resize(frames * 2)
	for index in frames:
		var envelope := minf(1.0, float(index) / 256.0) * minf(1.0, float(frames - index) / 1024.0)
		var sample := int(sin(TAU * frequency * float(index) / SAMPLE_RATE) * volume * envelope * 32767.0)
		if sample < 0:
			sample += 65536
		data[index * 2] = sample & 0xff
		data[index * 2 + 1] = (sample >> 8) & 0xff
	return data