1package app
  2
  3import (
  4	"errors"
  5	"fmt"
  6	"log"
  7	"regexp"
  8	"strconv"
  9	"strings"
 10	"time"
 11
 12	g "github.com/birabittoh/gopipe/src/globals"
 13	"github.com/kkdai/youtube/v2"
 14)
 15
 16const (
 17	maxMB                = 20
 18	maxContentLength     = maxMB * 1048576
 19	defaultCacheDuration = 6 * time.Hour
 20)
 21
 22var (
 23	expireRegex = regexp.MustCompile(`(?i)expire=(\d+)`)
 24)
 25
 26func parseExpiration(url string) time.Duration {
 27	expireString := expireRegex.FindStringSubmatch(url)
 28	expireTimestamp, err := strconv.ParseInt(expireString[1], 10, 64)
 29	if err != nil {
 30		log.Println("parseExpiration ERROR:", err)
 31		return defaultCacheDuration
 32	}
 33
 34	return time.Until(time.Unix(expireTimestamp, 0))
 35}
 36
 37func getFormat(video youtube.Video, formatID int) *youtube.Format {
 38	if formatID != 0 {
 39		f := video.Formats.Select(formatsSelectFn)
 40		l := len(f)
 41		if l > 0 {
 42			return &f[(formatID-1)%l]
 43		}
 44	}
 45
 46	f := video.Formats.Select(formatsSelectFnBest)
 47	if len(f) > 0 {
 48		return &f[0]
 49	}
 50
 51	return nil
 52}
 53
 54func getCaptions(video youtube.Video) map[string]Captions {
 55	c := make(map[string]Captions)
 56	for _, caption := range video.CaptionTracks {
 57		c[caption.LanguageCode] = Captions{
 58			VideoID:  video.ID,
 59			Language: caption.LanguageCode,
 60			URL:      caption.BaseURL,
 61		}
 62	}
 63
 64	return c
 65}
 66
 67func formatsSelectFn(f youtube.Format) bool {
 68	return f.AudioChannels > 0 && f.ContentLength < maxContentLength && strings.HasPrefix(f.MimeType, "video/mp4")
 69}
 70
 71func formatsSelectFnBest(f youtube.Format) bool {
 72	return f.AudioChannels > 0 && strings.HasPrefix(f.MimeType, "video/mp4")
 73}
 74
 75func formatsSelectFnAudioVideo(f youtube.Format) bool {
 76	return f.AudioChannels > 0 && f.QualityLabel != ""
 77}
 78
 79func formatsSelectFnVideo(f youtube.Format) bool {
 80	return f.QualityLabel != "" && f.AudioChannels == 0
 81}
 82
 83func formatsSelectFnAudio(f youtube.Format) bool {
 84	return f.QualityLabel == ""
 85}
 86
 87func getURL(videoID string) string {
 88	return fmt.Sprintf(fmtYouTubeURL, videoID)
 89}
 90
 91func getFromCache(videoID string, formatID int) (video *youtube.Video, format *youtube.Format, err error) {
 92	video, err = g.KS.Get(videoID)
 93	if err != nil {
 94		return
 95	}
 96
 97	if video == nil {
 98		err = errors.New("video should not be nil")
 99		return
100	}
101
102	format = getFormat(*video, formatID)
103	return
104}
105
106func getFromYT(videoID string, formatID int) (video *youtube.Video, format *youtube.Format, err error) {
107	url := getURL(videoID)
108
109	log.Println("Requesting video", url)
110	video, err = g.YT.GetVideo(url)
111	if err != nil || video == nil {
112		return
113	}
114
115	format = getFormat(*video, formatID)
116	duration := defaultCacheDuration
117	if format != nil {
118		duration = parseExpiration(format.URL)
119	}
120
121	g.KS.Set(videoID, *video, duration)
122	return
123}
124
125func getVideo(videoID string, formatID int) (video *youtube.Video, format *youtube.Format, err error) {
126	video, format, err = getFromCache(videoID, formatID)
127	if err != nil {
128		video, format, err = getFromYT(videoID, formatID)
129	}
130	return
131}