package service

import (
	"context"
	"fmt"

	"git.kmsign.ru/royalcat/tstor/pkg/uuid"
	"git.kmsign.ru/royalcat/tstor/src/host/controller"
	"github.com/anacrolix/torrent"
	"github.com/anacrolix/torrent/types/infohash"
)

type TorrentDownloadTask struct {
	ID       uuid.UUID
	InfoHash infohash.T
	File     string
}

func (s *Service) Download(ctx context.Context, task *TorrentDownloadTask) error {
	t, ok := s.c.Torrent(task.InfoHash)
	if !ok {
		return fmt.Errorf("torrent with IH %s not found", task.InfoHash.HexString())
	}

	if task.File != "" {
		var file *torrent.File
		for _, tf := range t.Files() {
			if tf.Path() == task.File {
				file = tf
				break
			}
		}

		if file == nil {
			return fmt.Errorf("file %s not found in torrent torrent with IH %s", task.File, task.InfoHash.HexString())
		}

		file.Download()
	} else {
		for _, file := range t.Files() {
			file.Download()
		}
	}

	return nil
}

// func (s *Service) DownloadAndWait(ctx context.Context, task *TorrentDownloadTask) error {
// 	t, ok := s.c.Torrent(task.InfoHash)
// 	if !ok {
// 		return fmt.Errorf("torrent with IH %s not found", task.InfoHash.HexString())
// 	}

// 	if task.File != "" {
// 		var file *torrent.File
// 		for _, tf := range t.Files() {
// 			if tf.Path() == task.File {
// 				file = tf
// 				break
// 			}
// 		}

// 		if file == nil {
// 			return fmt.Errorf("file %s not found in torrent torrent with IH %s", task.File, task.InfoHash.HexString())
// 		}

// 		file.Download()
// 		return waitPieceRange(ctx, t, file.BeginPieceIndex(), file.EndPieceIndex())

// 	}

// 	t.DownloadAll()
// 	select {
// 	case <-ctx.Done():
// 		return ctx.Err()
// 	case <-t.Complete.On():
// 		return nil
// 	}
// }

// func waitPieceRange(ctx context.Context, t *torrent.Torrent, start, end int) error {
// 	for i := start; i < end; i++ {
// 		timer := time.NewTimer(time.Millisecond)
// 		for {
// 			select {
// 			case <-ctx.Done():
// 				return ctx.Err()
// 			case <-timer.C:
// 				if t.PieceState(i).Complete {
// 					continue
// 				}
// 			}

// 		}
// 	}
// 	return nil
// }

type TorrentProgress struct {
	Torrent *controller.Torrent
	Current int64
	Total   int64
}

func (s *Service) DownloadProgress(ctx context.Context) (<-chan TorrentProgress, error) {
	torrents, err := s.ListTorrents(ctx)
	if err != nil {
		return nil, err
	}

	out := make(chan TorrentProgress, 1)
	go func() {
		defer close(out)
		for _, t := range torrents {
			sub := t.Torrent().SubscribePieceStateChanges()
			go func(t *controller.Torrent) {
				for stateChange := range sub.Values {
					if !stateChange.Complete && !stateChange.Partial {
						continue
					}

					out <- TorrentProgress{
						Torrent: t,
						Current: t.BytesCompleted(),
						Total:   t.Length(),
					}
				}
			}(t)
			defer sub.Close()
		}

		<-ctx.Done()
	}()

	return out, nil
}