type Ticker struct {
	C      chan time.Time
	stop   chan struct{}
	unleak chan struct{}
	stopped bool

	sync.Mutex
	tt *time.Ticker
}

func NewTicker(d time.Duration) *Ticker {

	c := make(chan time.Time, 1)
	t := &Ticker{
		C:      c,
		stop:   make(chan struct{}),
		unleak: make(chan struct{}),
		tt:     time.NewTicker(d),
		stopped: false,
	}

	go func() {
		for {
			select {
			case now := <-t.tt.C:
				t.C <- now
			case <-t.unleak:
				return
			case <-t.stop:
				return
			}
		}

	}()

	return t
}

func (t *Ticker) Stop() {
	t.Lock()
	defer t.Unlock()

	if t.stopped {
		return
	}

	t.stop <- struct{}{}
	t.tt.Stop()
	t.stopped = true
}

func (t *Ticker) SetDuration(d time.Duration) {
	t.Lock()
	defer t.Unlock()

	if t.stopped {
		return
	}

	t.tt.Stop()
	t.tt = time.NewTicker(d)
	t.unleak <- struct{}{}

	go func() {
		for {
			select {
			case now := <-t.tt.C:
				t.C <- now
			case <-t.unleak:
				return
			case <-t.stop:
				return
			}
		}
	}()
}