package ticker

import (
	"context"
	"fmt"
	"time"
)

var _ Ticker = (*ticker)(nil)

type Ticker interface {
	worker()

	Process(fun any) error
	Stop()
}

type ticker struct {
	ticker *time.Ticker
	ctx    context.Context
	cancel context.CancelFunc
	f      func()
}

func New(d time.Duration) Ticker {
	ctx, cancelFunc := context.WithCancel(context.Background())
	return &ticker{
		ticker: time.NewTicker(d),
		ctx:    ctx,
		cancel: cancelFunc,
	}
}

func (t *ticker) worker() {
	for {
		select {
		case <-t.ticker.C:
			t.f()
		case <-t.ctx.Done():
			return
		}
	}
}

func (t *ticker) Process(fun any) error {
	f, ok := fun.(func())
	if !ok {
		return fmt.Errorf("fun is not func")
	}
	t.f = f

	go t.worker()

	return nil
}

func (t *ticker) Stop() {
	t.ticker.Stop()
	t.cancel()
}