package log

import (
	"fmt"
	"github.com/robfig/cron"
	"log"
	"sync"
	"time"
)

var (
	logPath string
	once    sync.Once
	Spec    = "@daily"
)

// RegisterRotationWithSpec set up crontab scheduler for log rotation
//
//	spec, "* * * * * *"; "@daily"
func RegisterRotationWithSpec(path, spec string) {
	if "" == spec {
		spec = Spec
	}
	listening(path, spec)
}

func RegisterRotation(path string) {
	listening(path, Spec)
}

func listening(path, spec string) {
	once.Do(func() {
		logPath = path
		rotate()
		go _listening(spec)
	})
}

func _listening(spec string) {
	_c := cron.New()
	if err := _c.AddFunc(spec, rotate); nil != err {
		panic(fmt.Sprintf("failed to establish crontab job: %s", err.Error()))
	} else {
		log.Println("log rotation started ...")
	}

	_c.Start()
	select {}
}

func rotate() {
	RotateLogger(New(logPath+time.Now().Format("2006-01-02"), logPath))
}