extends Node
## Sound effects, played from the events the client already receives.
##
## Strictly a view concern: sound is triggered by server events arriving, never
## by anything the client decides for itself, so what you hear matches what
## actually happened. Nothing under src/sim/ knows this exists.

## Voices in the pool. Bullet-hell fire rates mean sounds overlap constantly;
## one player would cut its own tail off on every shot.
const VOICES := 16
## Identical sounds landing within this many frames are collapsed into one, so
## a boss ring hitting eight bullets at once is a bang rather than a wall of
## clipping.
const DEDUPE_FRAMES := 2

var _voices: Array[AudioStreamPlayer] = []
var _next: int = 0
var _last_played: Dictionary = {}
var _frame: int = 0


func _ready() -> void:
	for i in VOICES:
		var p := AudioStreamPlayer.new()
		p.bus = "Master"
		add_child(p)
		_voices.append(p)


func _process(_delta: float) -> void:
	_frame += 1


func play(stream: AudioStream, volume_db: float = 0.0) -> void:
	if stream == null:
		return
	var last: int = _last_played.get(stream, -999)
	if _frame - last < DEDUPE_FRAMES:
		return
	_last_played[stream] = _frame
	# Round-robin rather than "find a free voice": with this many voices the
	# oldest is always the best one to steal, and it needs no search.
	var v := _voices[_next]
	_next = (_next + 1) % _voices.size()
	v.stream = stream
	v.volume_db = volume_db
	v.play()