package singleton

import (
	"bytes"
	"fmt"
	"sync"

	"github.com/robfig/cron/v3"

	"github.com/naiba/nezha/model"
	pb "github.com/naiba/nezha/proto"
)

var (
	Cron     *cron.Cron
	Crons    map[uint64]*model.Cron // [CrondID] -> *model.Cron
	CronLock sync.RWMutex
)

func InitCronTask() {
	Cron = cron.New(cron.WithSeconds(), cron.WithLocation(Loc))
	Crons = make(map[uint64]*model.Cron)
}

// LoadCronTasks 加载计划任务
func LoadCronTasks() {
	InitCronTask()
	var crons []model.Cron
	DB.Find(&crons)
	var err error
	var notificationTagList []string
	notificationMsgMap := make(map[string]*bytes.Buffer)
	for i := range crons {
		// 旧版本计划任务可能不存在通知组 为其添加默认通知组
		if crons[i].NotificationTag == "" {
			AddDefaultCronNotificationTag(&crons[i])
		}
		// 注册计划任务
		crons[i].CronJobID, err = Cron.AddFunc(crons[i].Scheduler, CronTrigger(crons[i]))
		if err == nil {
			Crons[crons[i].ID] = &crons[i]
		} else {
			// 当前通知组首次出现 将其加入通知组列表并初始化通知组消息缓存
			if _, ok := notificationMsgMap[crons[i].NotificationTag]; !ok {
				notificationTagList = append(notificationTagList, crons[i].NotificationTag)
				notificationMsgMap[crons[i].NotificationTag] = bytes.NewBufferString("")
				notificationMsgMap[crons[i].NotificationTag].WriteString("调度失败的计划任务：[")
			}
			notificationMsgMap[crons[i].NotificationTag].WriteString(fmt.Sprintf("%d,", crons[i].ID))
		}
	}
	// 向注册错误的计划任务所在通知组发送通知
	for _, tag := range notificationTagList {
		notificationMsgMap[tag].WriteString("] 这些任务将无法正常执行,请进入后点重新修改保存。")
		SendNotification(tag, notificationMsgMap[tag].String(), false)
	}
	Cron.Start()
}

// AddDefaultCronNotificationTag 添加默认的计划任务通知组
func AddDefaultCronNotificationTag(c *model.Cron) {
	CronLock.Lock()
	defer CronLock.Unlock()

	if c.NotificationTag == "" {
		c.NotificationTag = "default"
	}
	DB.Save(c)
}

func ManualTrigger(c model.Cron) {
	CronTrigger(c)()
}

func CronTrigger(cr model.Cron) func() {
	crIgnoreMap := make(map[uint64]bool)
	for j := 0; j < len(cr.Servers); j++ {
		crIgnoreMap[cr.Servers[j]] = true
	}
	return func() {
		ServerLock.RLock()
		defer ServerLock.RUnlock()
		for _, s := range ServerList {
			if cr.Cover == model.CronCoverAll && crIgnoreMap[s.ID] {
				continue
			}
			if cr.Cover == model.CronCoverIgnoreAll && !crIgnoreMap[s.ID] {
				continue
			}
			if s.TaskStream != nil {
				s.TaskStream.Send(&pb.Task{
					Id:   cr.ID,
					Data: cr.Command,
					Type: model.TaskTypeCommand,
				})
			} else {
				SendNotification(cr.NotificationTag, fmt.Sprintf("[任务失败] %s，服务器 %s 离线，无法执行。", cr.Name, s.Name), false)
			}
		}
	}
}