package debouncer

import "time"

type Debouncer struct {
	input <-chan bool
	C     <-chan bool
}

func New(ch <-chan bool, window time.Duration) *Debouncer {
	output := make(chan bool)
	var currentState bool
	var lastState bool
	falseTimer := time.NewTimer(0)
	falseTimer.Stop()
	go func() {
		for {
			select {
			case <-falseTimer.C:
				if !currentState && lastState {
					output <- false
					lastState = false
				} else {
					falseTimer.Reset(window)
				}
			case v, ok := <-ch:
				if !ok {
					falseTimer.Reset(window)
					<-falseTimer.C
					output <- false
					close(output)
					return
				}
				if v {
					if !lastState {
						output <- true
						lastState = true
						falseTimer.Reset(window)
					}

					currentState = true
				} else {
					falseTimer.Reset(window)

					currentState = false
				}
			}
		}
	}()
	d := &Debouncer{input: ch, C: output}

	return d
}