package dvr

import (
	"context"
	"fmt"
	"log"
	"net/http"
	"net/url"
	"sync"
	"time"

	"github.com/grafov/m3u8"
)

// playlistRefresher periodically fetches the playlist and enqueues new segments
func PlaylistRefresher(ctx context.Context, playlistURL string, segmentsChan chan<- string, seen *sync.Map, interval time.Duration) {
	ticker := time.NewTicker(interval)
	defer ticker.Stop()

	for {
		select {
		case <-ctx.Done():
			close(segmentsChan)
			return
		case <-ticker.C:
			segments, err := fetchPlaylistSegments(playlistURL)
			if err != nil {
				log.Printf("Error fetching playlist: %v", err)
				continue
			}
			for _, seg := range segments {
				if _, exists := seen.LoadOrStore(seg, true); !exists {
					segmentsChan <- seg
				}
			}
		}
	}
}

// fetchPlaylistSegments is a placeholder that parses the M3U8 and returns full URLs
func fetchPlaylistSegments(playlistURL string) ([]string, error) {
	resp, err := http.Get(playlistURL)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	playlist, listType, err := m3u8.DecodeFrom(resp.Body, true)
	if err != nil {
		return nil, err
	}

	if listType == m3u8.MASTER {
		return nil, fmt.Errorf("playlist is a master playlist")
	}

	media := playlist.(*m3u8.MediaPlaylist)
	base, err := url.Parse(playlistURL)
	if err != nil {
		return nil, err
	}
	var segments []string
	for _, segment := range media.Segments {
		if segment == nil {
			continue
		}
		rel, err := url.Parse(segment.URI)
		if err != nil {
			return nil, err
		}
		segments = append(segments, base.ResolveReference(rel).String())
	}
	return segments, nil
}