extends CPUParticles3D
## Root helper for a one-shot effect scene: fires this emitter (and any CPUParticles3D children)
## once when spawned, then frees the whole scene after the longest-lived particle has died. This
## is what lets an effect be nothing but a tunable CPUParticles3D scene — no per-effect code, so
## Siim owns the look entirely in the inspector. Fired by the Fx autoload; see fx/README.md.

const _FREE_MARGIN := 0.5


func _ready() -> void:
	var ttl := _arm(self)
	for emitter: CPUParticles3D in _child_emitters():
		ttl = maxf(ttl, _arm(emitter))
	get_tree().create_timer(ttl + _FREE_MARGIN).timeout.connect(queue_free)


func _arm(p: CPUParticles3D) -> float:
	p.one_shot = true
	p.emitting = true
	return p.lifetime


func _child_emitters() -> Array[CPUParticles3D]:
	var out: Array[CPUParticles3D] = []
	_gather(self, out)
	return out


func _gather(node: Node, out: Array[CPUParticles3D]) -> void:
	for child: Node in node.get_children():
		if child is CPUParticles3D:
			out.append(child)
		_gather(child, out)