package worker

import (
	"bufio"
	"bytes"
	"context"
	"fmt"
	"os/exec"

	"git.sr.ht/~gabrielgio/midr/db"
	work "git.sr.ht/~sircmpwn/dowork"
)

const (
	statusNotQueued = "NOTQUEUED"
	statusQueued    = "QUEUED"
	statusStarted   = "RUNNING"

	commandStart   = "START"
	commandEnqueue = "ENQUEUE"
	commandDequeue = "DEQUEUE"
)

type command struct {
	action string
	index  uint
}

type Worker struct {
	jobs map[uint]string
	c    chan command
}

type Job struct {
	Id     uint
	Status string
}

func NewWorkder() Worker {
	return Worker{
		c:    make(chan command),
		jobs: make(map[uint]string),
	}
}

func RunYtDlpProcess(entry *db.Entry) (error, []byte, []byte) {
	args := []string{entry.Link}
	var stdout bytes.Buffer
	var stderr bytes.Buffer

	output_template := fmt.Sprintf("%s/%%(title)s.%%(ext)s", entry.OutputFolder)
	args = append(args, "-o", output_template)

	downloaded_txt := fmt.Sprintf("%s/downloaded.txt", entry.OutputFolder)
	args = append(args, "--download-archive", downloaded_txt)

	if len(entry.DateAfter) > 0 {
		args = append(args, "--dateafter", entry.DateAfter)
	}

	cmd := exec.Command("yt-dlp", args...)
	cmd.Stdout = bufio.NewWriter(&stdout)
	cmd.Stderr = bufio.NewWriter(&stderr)

	err := cmd.Run()

	return err, stdout.Bytes(), stderr.Bytes()
}

func (w *Worker) CanEnqueue(index uint) bool {
	v, found := w.jobs[index]
	return !found || v == statusNotQueued
}

func (w *Worker) RemoveJob(id uint) {
	delete(w.jobs, id)
}

func (w *Worker) RunYtDlpWorker(entry *db.Entry) <-chan []byte {
	if !w.CanEnqueue(entry.ID) {
		return nil
	}

	log := make(chan []byte)

	w.c <- command{action: commandEnqueue, index: entry.ID}
	task := work.NewTask(func(ctx context.Context) error {

		w.c <- command{action: commandStart, index: entry.ID}
		err, stdout, stderr := RunYtDlpProcess(entry)

		log <- stdout
		log <- stderr

		return err
	}).After(func(ctx context.Context, task *work.Task) {
		w.c <- command{action: commandDequeue, index: entry.ID}
		close(log)
	})

	work.Enqueue(task)

	return log
}

func (w *Worker) startReader() {
	for {
		command := <-w.c

		if command.action == commandEnqueue {
			w.jobs[command.index] = statusQueued
		} else if command.action == commandStart {
			w.jobs[command.index] = statusStarted
		} else if command.action == commandDequeue {
			w.jobs[command.index] = statusNotQueued
		} else {
			panic(1)
		}
	}
}

func (w *Worker) StartReader() {
	go w.startReader()
}

func (w *Worker) GetJobs() []Job {
	jobs := make([]Job, len(w.jobs))
	count := 0

	for k, v := range w.jobs {
		jobs[count] = Job{Id: k, Status: v}
		count++
	}

	return jobs
}