package crontab

import (
	"github.com/pkg/errors"
	cron "github.com/robfig/cron/v3"
	"sync"
)

// Crontab crontab struct
type Crontab struct {
	inner *cron.Cron
	ids   map[string]cron.EntryID
	mutex *sync.RWMutex
}

// NewCrontab new crontab
func NewCrontab() *Crontab {
	return &Crontab{
		inner: cron.New(cron.WithSeconds()), // 支持秒級別的Cron表達(dá)式
		ids:   make(map[string]cron.EntryID),
		mutex: new(sync.RWMutex),
	}
}

// IDs 獲取所有有效的Cron任務(wù)ID
func (c *Crontab) IDs() []string {
	c.mutex.RLock()
	defer c.mutex.RUnlock()

	validIDs := make([]string, 0, len(c.ids))
	invalidIDs := make([]string, 0)
	for sid, eid := range c.ids {
		if e := c.inner.Entry(eid); e.ID != eid {
			invalidIDs = append(invalidIDs, sid)
			continue
		}
		validIDs = append(validIDs, sid)
	}

	// 清理無效的任務(wù)ID
	for _, id := range invalidIDs {
		delete(c.ids, id)
	}

	return validIDs
}

// Start 啟動(dòng)定時(shí)任務(wù)調(diào)度器
func (c *Crontab) Start() {
	c.inner.Start()
}

// Stop 停止定時(shí)任務(wù)調(diào)度器
func (c *Crontab) Stop() {
	c.inner.Stop()
}

// DelByID 根據(jù)ID刪除定時(shí)任務(wù)
func (c *Crontab) DelByID(id string) error {
	c.mutex.Lock()
	defer c.mutex.Unlock()

	eid, ok := c.ids[id]
	if !ok {
		return errors.Errorf("crontab id not exists!")
	}
	c.inner.Remove(eid)
	delete(c.ids, id)

	return nil
}

// AddByID 根據(jù)ID添加定時(shí)任務(wù)
// spec 是Cron表達(dá)式，cmd 是執(zhí)行的任務(wù)
func (c *Crontab) AddByID(id, spec string, cmd cron.Job) error {
	c.mutex.Lock()
	defer c.mutex.Unlock()

	if _, ok := c.ids[id]; ok {
		return errors.Errorf("crontab id exists!")
	}
	eid, err := c.inner.AddJob(spec, cmd)
	if err != nil {
		return err
	}
	c.ids[id] = eid
	return nil
}

// AddByFunc 根據(jù)ID添加函數(shù)作為定時(shí)任務(wù)
func (c *Crontab) AddByFunc(id, spec string, f func()) error {
	c.mutex.Lock()
	defer c.mutex.Unlock()

	if _, ok := c.ids[id]; ok {
		return errors.Errorf("crontab id exists!")
	}
	eid, err := c.inner.AddFunc(spec, f)
	if err != nil {
		return err
	}
	c.ids[id] = eid
	return nil
}

// IsExists 判斷某個(gè)任務(wù)ID是否已存在
func (c *Crontab) IsExists(jid string) bool {
	c.mutex.RLock()
	defer c.mutex.RUnlock()

	_, exist := c.ids[jid]
	return exist
}

package main

import (
	"fmt"
	"github.com/robfig/cron/v3"
	"time"
	"your_project/crontab"
)

func main() {
	// 創(chuàng)建一個(gè)新的 Crontab 實(shí)例
	c := crontab.NewCrontab()

	// 定義一個(gè)定時(shí)任務(wù)
	task := func() {
		fmt.Println("Task executed at", time.Now())
	}

	// 添加定時(shí)任務(wù)
	err := c.AddByFunc("task1", "*/5 * * * * *", task) // 每5秒執(zhí)行一次
	if err != nil {
		fmt.Println("Error adding task:", err)
		return
	}

	// 啟動(dòng)任務(wù)調(diào)度器
	c.Start()

	// 等待一段時(shí)間后停止
	time.Sleep(20 * time.Second)
	c.Stop()

	// 刪除任務(wù)
	err = c.DelByID("task1")
	if err != nil {
		fmt.Println("Error deleting task:", err)
	}
}