package downloader

import (
	"fmt"
	"strings"
)

type PlaylistMetadata struct {
	URL      string
	Domain   string
	StreamID string
}

func NewPlaylistMetadata(masterURL string) *PlaylistMetadata {
	strippedURL := strings.Replace(masterURL, HTTPSPrefix, "", 1)
	urlPrefix := strings.Split(strippedURL, "/")[0]

	return &PlaylistMetadata{
		URL:      masterURL,
		Domain:   urlPrefix,
		StreamID: strings.Split(strippedURL, "/")[2],
	}
}

type StreamSet struct {
	Metadata     *PlaylistMetadata
	VideoStreams []VideoStream
	AudioStreams []AudioStream
}

func (s *StreamSet) BuildStreamURL(endpoint string) string {
	return fmt.Sprintf("%s%s/streams/%s/%s",
		HTTPSPrefix, s.Metadata.Domain, s.Metadata.StreamID, endpoint)
}

func ParseMasterPlaylist(masterURL string) (*StreamSet, error) {
	metadata := NewPlaylistMetadata(masterURL)

	content, err := FetchPlaylistContent(masterURL)
	if err != nil {
		return nil, err
	}

	videoStreams, audioStreams := parsePlaylistLines(content)

	return &StreamSet{
		Metadata:     metadata,
		VideoStreams: videoStreams,
		AudioStreams: audioStreams,
	}, nil
}

func parsePlaylistLines(content string) ([]VideoStream, []AudioStream) {
	lines := strings.Split(content, "\n")
	var videoStreams []VideoStream
	var audioStreams []AudioStream

	for i, line := range lines {
		if strings.HasPrefix(line, ExtXStreamInf) && i+1 < len(lines) {
			if video, err := NewVideoStream(line, lines[i+1]); err == nil {
				videoStreams = append(videoStreams, *video)
			}
		} else if strings.HasPrefix(line, ExtXMedia) {
			if audio, err := NewAudioStream(line); err == nil {
				audioStreams = append(audioStreams, *audio)
			}
		}
	}

	return videoStreams, audioStreams
}