extends Node

signal combo_changed(count: int, multiplier: float)
signal combo_broken(final_count: int)

const WINDOW_SEC: float = 1.8
const STEP_BONUS: float = 0.15  # +15% per combo step
const MAX_MULT: float = 3.0

var count: int = 0
var multiplier: float = 1.0
var _timer: float = 0.0
var _active: bool = false


func _process(delta: float) -> void:
	if not _active:
		return
	_timer -= delta
	if _timer <= 0.0:
		_break()


func bump() -> float:
	# Advances combo and returns multiplier to apply to the triggering gain.
	count += 1
	multiplier = minf(1.0 + float(count - 1) * STEP_BONUS, MAX_MULT)
	_timer = WINDOW_SEC
	_active = true
	combo_changed.emit(count, multiplier)
	return multiplier


func _break() -> void:
	var final_count: int = count
	_active = false
	combo_changed.emit(0, 1.0)
	if final_count >= 2:
		combo_broken.emit(final_count)
	count = 0
	multiplier = 1.0
	_timer = 0.0


func time_remaining_ratio() -> float:
	if not _active:
		return 0.0
	return clampf(_timer / WINDOW_SEC, 0.0, 1.0)