package plugin

import (
	"fmt"
	"sync"
	"time"

	"apigo.cc/gojs"
	"github.com/robfig/cron/v3"
	"github.com/ssgo/log"
	"github.com/ssgo/u"
)

type Task struct {
	file    string
	vm      *gojs.Runtime
	lock    sync.RWMutex
	mtime   time.Time
	entryId cron.EntryID
	policy  string
}

func (obj *PluginObject) AsyncStart() {
	obj.lock.Lock()
	defer obj.lock.Unlock()
	if !obj.isStarted {
		obj.skipCron = cron.New(cron.WithSeconds(), cron.WithChain(cron.SkipIfStillRunning(cron.DefaultLogger)))
		obj.skipCron.Start()
		obj.delayCron = cron.New(cron.WithSeconds())
		obj.delayCron.Start()
		// obj.asyncCron = cron.New(cron.WithSeconds())
		// obj.asyncCron.Start()
		obj.isStarted = true
		obj.stopChan = make(chan struct{})
		obj.skipCron.AddFunc("@every 5s", func() {
			tasks := []*Task{}
			obj.lock.RLock()
			for _, task := range obj.tasks {
				tasks = append(tasks, task)
			}
			obj.lock.RUnlock()

			for _, task := range tasks {
				if fi := u.GetFileInfo(task.file); fi != nil {
					if !fi.ModTime.Equal(task.mtime) {
						// 文件变化，重新加载
						rt := gojs.New()
						if _, err := rt.RunFile(task.file); err == nil {
							task.lock.Lock()
							task.vm = rt
							task.mtime = fi.ModTime
							task.lock.Unlock()
						} else {
							// 发生错误时仅更新 mtime，防止不断重新加载
							log.DefaultLogger.Error("failed to reload task code", "err", err.Error(), "file", task.file)
							task.lock.Lock()
							task.mtime = fi.ModTime
							task.lock.Unlock()
						}
					}
				}
			}
		})
	}
}

func (obj *PluginObject) Start() {
	obj.AsyncStart()
	<-obj.stopChan
}

func (obj *PluginObject) Stop() {
	obj.lock.RLock()
	isStarted := obj.isStarted
	obj.lock.RUnlock()
	if !isStarted {
		return
	}
	defer close(obj.stopChan)
	ctx1 := obj.skipCron.Stop()
	ctx2 := obj.delayCron.Stop()
	// ctx3 := obj.asyncCron.Stop()
	<-ctx1.Done()
	<-ctx2.Done()
	// <-ctx3.Done()

	obj.lock.Lock()
	defer obj.lock.Unlock()
	for _, task := range obj.tasks {
		task.RunFunc("onStop")
	}

	obj.isStarted = false
	obj.tasks = map[string]*Task{}
}

func (obj *PluginObject) NewTask(spec string, file string, policy *string) error {
	fi := u.GetFileInfo(file)
	if fi == nil {
		return u.Error("task file not exists")
	}

	rt := gojs.New()
	if _, err := rt.RunFile(file); err != nil {
		return u.Error(err.Error())
	}

	task := &Task{
		file:   file,
		vm:     rt,
		mtime:  fi.ModTime,
		policy: u.String(policy),
	}
	if err := task.RunFunc("onStart"); err != nil {
		return u.Error(err.Error())
	}

	var err error
	switch task.policy {
	case "skip":
		task.entryId, err = obj.skipCron.AddFunc(spec, func() {
			task.RunFunc("onRun")
		})
	// case "async":
	// 	task.entryId, err = obj.asyncCron.AddFunc(spec, func() {
	// 		go func() {
	// 			task.RunFunc("onRun")
	// 		}()
	// 	})
	default:
		task.policy = "delay"
		task.entryId, err = obj.delayCron.AddFunc(spec, func() {
			task.RunFunc("onRun")
		})
	}

	if err != nil {
		return u.Error(err.Error())
	}

	obj.lock.Lock()
	defer obj.lock.Unlock()
	obj.tasks[spec+file] = task
	return nil
}

func (obj *PluginObject) RemoveTask(spec string, file string) error {
	obj.lock.RLock()
	task := obj.tasks[spec+file]
	obj.lock.RUnlock()
	if task == nil {
		return nil
	}
	task.RunFunc("onStop")
	switch task.policy {
	case "skip":
		obj.skipCron.Remove(task.entryId)
	// case "async":
	// 	obj.asyncCron.Remove(task.entryId)
	default:
		obj.delayCron.Remove(task.entryId)
	}

	obj.lock.Lock()
	defer obj.lock.Unlock()
	delete(obj.tasks, spec+file)
	return nil
}

func (task *Task) RunFunc(fnName string) error {
	task.lock.RLock()
	rt := task.vm
	task.lock.RUnlock()
	_, err := rt.RunCode(fmt.Sprintf("if(%s)%s()", fnName, fnName))
	return err
}