1package app
  2
  3import (
  4	"errors"
  5	"fmt"
  6	"log"
  7	"regexp"
  8	"strconv"
  9	"time"
 10
 11	g "github.com/birabittoh/gopipe/src/globals"
 12	"github.com/kkdai/youtube/v2"
 13)
 14
 15const (
 16	maxMB                = 20
 17	maxContentLength     = maxMB * 1048576
 18	defaultCacheDuration = 6 * time.Hour
 19)
 20
 21var (
 22	emptyVideo  = youtube.Video{}
 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) *youtube.Format {
 38	formats := video.Formats.Select(formatsSelectFn)
 39	if len(formats) == 0 {
 40		return nil
 41	}
 42
 43	return &formats[0]
 44}
 45
 46func formatsSelectFn(f youtube.Format) bool {
 47	return f.AudioChannels > 1 && f.ContentLength < maxContentLength
 48}
 49
 50func getURL(videoID string) string {
 51	return fmt.Sprintf(fmtYouTubeURL, videoID)
 52}
 53
 54func getFromCache(videoID string) (video *youtube.Video, format *youtube.Format, err error) {
 55	video, err = g.KS.Get(videoID)
 56	if err != nil {
 57		return
 58	}
 59
 60	if video == nil {
 61		err = errors.New("video should not be nil")
 62		return
 63	}
 64
 65	if video.ID == emptyVideo.ID {
 66		err = errors.New("no formats for this video")
 67		return
 68	}
 69
 70	format = getFormat(*video)
 71	return
 72}
 73
 74func getFromYT(videoID string) (video *youtube.Video, format *youtube.Format, err error) {
 75	url := getURL(videoID)
 76
 77	log.Println("Requesting video ", url)
 78	video, err = g.YT.GetVideo(url)
 79	if err != nil {
 80		return
 81	}
 82
 83	format = getFormat(*video)
 84	duration := defaultCacheDuration
 85	v := emptyVideo
 86	if format != nil {
 87		v = *video
 88		duration = parseExpiration(format.URL)
 89	}
 90
 91	g.KS.Set(videoID, v, duration)
 92	return
 93}
 94
 95func getVideo(videoID string) (video *youtube.Video, format *youtube.Format, err error) {
 96	video, format, err = getFromCache(videoID)
 97	if err != nil {
 98		video, format, err = getFromYT(videoID)
 99	}
100	return
101}