package main

import (
	"fmt"
	"os"
	"time"
	"sync"
)

const filename string = "countdown.txt"
var until time.Time = time.Now().Add(time.Minute)

func main() {
	d, err := time.ParseDuration("1s")
	if err != nil {
		fmt.Println(err)
		os.Exit(1)
	}

	fmt.Printf("until: %s\n", until)

	wg := sync.WaitGroup{}
	wg.Add(1)
	ticker := time.NewTicker(d)
	go func(c <-chan time.Time) {
		fmt.Println("XX")
		_ = <-c
		count := time.Until(until)
		for ; count >= 0; count = time.Until(until) {
			_ = <-c
			str := fmt.Sprintf("%02.0f:%02.0f:%02.0f\n", count.Hours(), count.Minutes(), count.Seconds())
			err = os.WriteFile(filename, []byte(str), 0777)
			if err != nil {
				fmt.Println("unable to write file: %v\n", err)
			}
		}
		wg.Done()
	}(ticker.C)

	wg.Wait()

	err = os.WriteFile(filename, []byte("00:00:00"), 0777)
	if err != nil {
		fmt.Println("unable to write file: %v\n", err)
	}

	fmt.Println("\nDONE")
}