seek-tune/spotify/youtube.go

package spotify

import (
	"context"
	"fmt"
	"log"

	"errors"
	"io"
	"io/ioutil"
	"net/http"
	"net/url"
	"strconv"
	"strings"

	"github.com/buger/jsonparser"
	"google.golang.org/api/option"
	"google.golang.org/api/youtube/v3"
)

const developerKey = "AIzaSyC3nBFKqudeMItXnYKEeOUryLKhXnqBL7M"

// https://github.com/BharatKalluri/spotifydl/blob/v0.1.0/src/youtube.go
func VideoID(spTrack Track) (string, error) {
	service, err := youtube.NewService(context.TODO(), option.WithAPIKey(developerKey))
	if err != nil {
		log.Fatalf("Error creating new YouTube client: %v", err)
		return "", err
	}

	// Video category ID 10 is for music videos
	query := fmt.Sprintf("'%s' %s %s", spTrack.Title, spTrack.Artist, spTrack.Album) /* example: 'Lovesong' The Cure Disintegration */
	call := service.Search.List([]string{"id", "snippet"}).Q(query).VideoCategoryId("10").Type("video")

	response, err := call.Do()
	if err != nil {
		log.Fatalf("Error making search API call: %v", err)
		return "", err
	}
	for _, item := range response.Items {
		switch item.Id.Kind {
		case "youtube#video":
			return item.Id.VideoId, nil
		}
	}
	// TODO: Handle when the query returns no songs (highly unlikely since the query is coming from spotify though)
	return "", nil
}

var httpClient = &http.Client{}
var durationMatchThreshold = 5

type SearchResult struct {
	Title, Uploader, URL, Duration, ID string
	Live                               bool
	SourceName                         string
	Extra                              []string
}

func convertStringDurationToSeconds(durationStr string) int {
	splitEntities := strings.Split(durationStr, ":")
	if len(splitEntities) == 1 {
		seconds, _ := strconv.Atoi(splitEntities[0])
		return seconds
	} else if len(splitEntities) == 2 {
		seconds, _ := strconv.Atoi(splitEntities[1])
		minutes, _ := strconv.Atoi(splitEntities[0])
		return (minutes * 60) + seconds
	} else if len(splitEntities) == 3 {
		seconds, _ := strconv.Atoi(splitEntities[2])
		minutes, _ := strconv.Atoi(splitEntities[1])
		hours, _ := strconv.Atoi(splitEntities[0])
		return ((hours * 60) * 60) + (minutes * 60) + seconds
	} else {
		return 0
	}
}

// GetYoutubeId takes the query as string and returns the search results video ID's
func GetYoutubeId(spTrack Track) (string, error) {
	artists := strings.Join(spTrack.Artists, ", ")
	songDurationInSeconds := spTrack.Duration * 60
	searchQuery := fmt.Sprintf("'%s' %s %s", spTrack.Title, artists, spTrack.Album)

	searchResults, err := ytSearch(searchQuery, 10)
	if err != nil {
		return "", err
	}
	if len(searchResults) == 0 {
		errorMessage := fmt.Sprintf("no songs found for %s", searchQuery)
		return "", errors.New(errorMessage)
	}
	// Try for the closest match timestamp wise
	for _, result := range searchResults {
		allowedDurationRangeStart := songDurationInSeconds - durationMatchThreshold
		allowedDurationRangeEnd := songDurationInSeconds + durationMatchThreshold
		resultSongDuration := convertStringDurationToSeconds(result.Duration)
		if resultSongDuration >= allowedDurationRangeStart && resultSongDuration <= allowedDurationRangeEnd {
			return result.ID, nil
		}
	}
	// Else return the first result if nothing is found
	return searchResults[0].ID, nil
}

func getContent(data []byte, index int) []byte {
	id := fmt.Sprintf("[%d]", index)
	contents, _, _, _ := jsonparser.Get(data, "contents", "twoColumnSearchResultsRenderer", "primaryContents", "sectionListRenderer", "contents", id, "itemSectionRenderer", "contents")
	return contents
}

func ytSearch(searchTerm string, limit int) (results []*SearchResult, err error) {
	ytSearchUrl := fmt.Sprintf(
		"https://www.youtube.com/results?search_query=%s", url.QueryEscape(searchTerm),
	)

	req, err := http.NewRequest("GET", ytSearchUrl, nil)
	if err != nil {
		return nil, errors.New("cannot get youtube page")
	}
	req.Header.Add("Accept-Language", "en")
	res, err := httpClient.Do(req)
	if err != nil {
		return nil, errors.New("cannot get youtube page")
	}

	defer func(Body io.ReadCloser) {
		_ = Body.Close()
	}(res.Body)

	if res.StatusCode != 200 {
		return nil, errors.New("failed to make a request to youtube")
	}

	buffer, err := ioutil.ReadAll(res.Body)
	if err != nil {
		return nil, errors.New("cannot read response from youtube")
	}

	body := string(buffer)
	splitScript := strings.Split(body, `window["ytInitialData"] = `)
	if len(splitScript) != 2 {
		splitScript = strings.Split(body, `var ytInitialData = `)
	}

	if len(splitScript) != 2 {
		return nil, errors.New("invalid response from youtube")
	}
	splitScript = strings.Split(splitScript[1], `window["ytInitialPlayerResponse"] = null;`)
	jsonData := []byte(splitScript[0])

	index := 0
	var contents []byte

	for {
		contents = getContent(jsonData, index)
		_, _, _, err = jsonparser.Get(contents, "[0]", "carouselAdRenderer")

		if err == nil {
			index++
		} else {
			break
		}
	}

	_, err = jsonparser.ArrayEach(contents, func(value []byte, t jsonparser.ValueType, i int, err error) {
		if err != nil {
			return
		}

		if limit > 0 && len(results) >= limit {
			return
		}

		id, err := jsonparser.GetString(value, "videoRenderer", "videoId")
		if err != nil {
			return
		}

		title, err := jsonparser.GetString(value, "videoRenderer", "title", "runs", "[0]", "text")
		if err != nil {
			return
		}

		uploader, err := jsonparser.GetString(value, "videoRenderer", "ownerText", "runs", "[0]", "text")
		if err != nil {
			return
		}

		live := false
		duration, err := jsonparser.GetString(value, "videoRenderer", "lengthText", "simpleText")

		if err != nil {
			duration = ""
			live = true
		}

		results = append(results, &SearchResult{
			Title:      title,
			Uploader:   uploader,
			Duration:   duration,
			ID:         id,
			URL:        fmt.Sprintf("https://youtube.com/watch?v=%s", id),
			Live:       live,
			SourceName: "youtube",
		})
	})

	if err != nil {
		return results, err
	}

	return results, nil
}