package main

import "time"

type Job interface {
	Schedule()
	Stop()
	Run()
}

type jobIdentifier int

const (
	JobIdCloseDecisions jobIdentifier = iota
	JobIdRemindVotersJob
)

var rescheduleChannel = make(chan jobIdentifier, 1)

func JobScheduler(quitChannel chan int) {
	var jobs = map[jobIdentifier]Job{
		JobIdCloseDecisions:  NewCloseDecisionsJob(),
		JobIdRemindVotersJob: NewRemindVotersJob(),
	}
	log.Info("started job scheduler")

	for {
		select {
		case jobId := <-rescheduleChannel:
			job := jobs[jobId]
			log.Infof("reschedule job %s", job)
			job.Schedule()
		case <-quitChannel:
			for _, job := range jobs {
				job.Stop()
			}
			log.Info("stop job scheduler")
			return
		}
	}
}

type CloseDecisionsJob struct {
	timer *time.Timer
}

func NewCloseDecisionsJob() *CloseDecisionsJob {
	job := &CloseDecisionsJob{}
	job.Schedule()
	return job
}

func (j *CloseDecisionsJob) Schedule() {
	var nextDue *time.Time
	nextDue, err := GetNextPendingDecisionDue()
	if err != nil {
		log.Error("Could not get next pending due date")
		if j.timer != nil {
			j.timer.Stop()
			j.timer = nil
		}
		return
	}
	if nextDue == nil {
		log.Info("no next planned execution of CloseDecisionsJob")
		j.Stop()
	} else {
		nextDue := nextDue.Add(time.Second)
		log.Infof("scheduling CloseDecisionsJob for %s", nextDue)
		when := nextDue.Sub(time.Now())
		if j.timer != nil {
			j.timer.Reset(when)
		} else {
			j.timer = time.AfterFunc(when, j.Run)
		}
	}
}

func (j *CloseDecisionsJob) Stop() {
	if j.timer != nil {
		j.timer.Stop()
		j.timer = nil
	}
}

func (j *CloseDecisionsJob) Run() {
	log.Debug("running CloseDecisionsJob")
	err := CloseDecisions()
	if err != nil {
		log.Errorf("closing decisions %v", err)
	}
	rescheduleChannel <- JobIdCloseDecisions
}

func (j *CloseDecisionsJob) String() string {
	return "CloseDecisionsJob"
}

type RemindVotersJob struct {
	timer *time.Timer
}

func NewRemindVotersJob() *RemindVotersJob {
	job := &RemindVotersJob{}
	job.Schedule()
	return job
}

func (j *RemindVotersJob) Schedule() {
	year, month, day := time.Now().UTC().Date()
	nextExecution := time.Date(year, month, day, 0, 0, 0, 0, time.UTC).AddDate(0, 0, 3)
	log.Infof("scheduling RemindVotersJob for %s", nextExecution)
	when := nextExecution.Sub(time.Now())
	if j.timer != nil {
		j.timer.Reset(when)
	} else {
		j.timer = time.AfterFunc(when, j.Run)
	}
}

func (j *RemindVotersJob) Stop() {
	if j.timer != nil {
		j.timer.Stop()
		j.timer = nil
	}
}

func (j *RemindVotersJob) Run() {
	log.Info("running RemindVotersJob")
	defer func() { rescheduleChannel <- JobIdRemindVotersJob }()

	voters, err := GetReminderVoters()
	if err != nil {
		log.Errorf("problem getting voters %v", err)
		return
	}

	for _, voter := range *voters {
		decisions, err := FindUnvotedDecisionsForVoter(&voter)
		if err != nil {
			log.Errorf("problem getting unvoted decisions: %v", err)
			return
		}
		if len(*decisions) > 0 {
			NotifyMailChannel <- &RemindVoterNotification{voter: voter, decisions: *decisions}
		}
	}
}