package m3u8

import (
	"bytes"
	"fmt"
	"io"
	"strings"
	"videoweb/pub/common/enum/redisconst"
	"videoweb/pub/common/errors"
	"videoweb/pub/common/http"
	"videoweb/pub/common/log"
	"videoweb/pub/common/utils"
	"videoweb/pub/redis"
	"videoweb/pub/storage/proxy"

	"github.com/grafov/m3u8"
)

const (
	keyUri       = "/enkey"
	webkeyUri    = "/api/web/enkey"
	h5KeyUri     = "/enkey"
	AuthKey      = "fT5xSg4hltHpzVy6aV9rVECDJ1J1pN"
	keyUriLsj    = "/lsjenkey"
	keyUriWebLsj = "/api/web/lsjenkey"
)

// resolveTsAuthKey 优先使用传入的 tsAuthKey，为空则回退默认 AuthKey。
func resolveTsAuthKey(tsAuthKey string) string {
	if key := strings.TrimSpace(tsAuthKey); key != "" {
		return key
	}
	return AuthKey
}

var headerMediaPlayList *m3u8.MediaPlaylist

// TransFormWithSafely 被检查权限的播放列表。
// tsAuthKey: 普通 TS CDN 鉴权；lsjM3u8Yuan: 老司机源站；cdnAuthKey: 老司机分片 CDN 鉴权。
func TransFormWithSafely(req *Req, cdnDomain, origDomain string, web bool, tsAuthKey, lsjM3u8Yuan, cdnAuthKey string) (*m3u8.MediaPlaylist, *bytes.Buffer, error) {
	if req.Name == "" {
		return nil, nil, errors.MakeWithMsg(errors.M3u8FileName, "file name is empty")
	}
	if cdnDomain == "" || origDomain == "" {
		return nil, nil, errors.MakeWithMsg(errors.DomainErr, "cdnDomain or origDomain is empty")
	}
	if strings.Contains(req.Name, "hc237") {
		req.Name = "/laosiji" + req.Name
	}
	if strings.Contains(req.Name, "laosiji") {
		return TransformLaosiji(req.Name, cdnDomain, web, lsjM3u8Yuan, cdnAuthKey)
	}
	return transform(req.Name, cdnDomain, origDomain, web, tsAuthKey)
}

func TransformLaosiji(name, cdnDomain string, web bool, lsjM3u8Yuan, cdnAuthKey string, customKeyUri ...string) (media *m3u8.MediaPlaylist, buff *bytes.Buffer, err error) {
	// fMP4/HEVC 分片 CDN 使用传入的视频 CDN（web 为 MediaWebCdn，app/h5 为 TsCdn），
	// 与 mdsm GetCDNUrlList()[0] 一致；拉取源 m3u8 仍走 lsjM3u8Yuan。
	m3u8reader, err := readFromRedis(laosijiUpstreamPath(name), lsjM3u8Yuan)
	if err != nil {
		return
	}
	p, t, err := m3u8.DecodeFrom(m3u8reader, false)
	if err != nil {
		err = errors.MakeWithErr(errors.M3u8Read, err)
		return
	}

	authKey := strings.TrimSpace(cdnAuthKey)
	keyurl := keyUriLsj
	if web {
		keyurl = keyUriWebLsj
	}
	if len(customKeyUri) > 0 && customKeyUri[0] != "" {
		keyurl = customKeyUri[0]
	}

	switch t {
	case m3u8.MEDIA:
		pl := p.(*m3u8.MediaPlaylist)
		dirPath := utils.PathForInfo(name).Dir
		media, err = makeMediaPlayListLaosiji(pl, cdnDomain, dirPath, keyurl, authKey)
		if err != nil {
			return
		}
		buff = media.Encode()
	case m3u8.MASTER:
		mpl := p.(*m3u8.MasterPlaylist)
		buff = mpl.Encode()
	default:
		err = errors.MakeWithMsg(errors.M3u8FileName, fmt.Sprintf("invalid m3u8 type %d", t))
	}
	return
}

func transform(name, cdnDomain, origDomain string, web bool, tsAuthKey string) (media *m3u8.MediaPlaylist, buff *bytes.Buffer, err error) {
	mediaVerson := proxy.AppendsMediaS3Version(name)
	if len(mediaVerson) > 0 {
		name = mediaVerson + name
	}

	m3u8reader, err := readFromRedis(name, origDomain)
	if err != nil {
		return
	}
	p, t, err := m3u8.DecodeFrom(m3u8reader, false)
	if err != nil {
		err = errors.MakeWithErr(errors.M3u8Read, err)
		return
	}

	authKey := resolveTsAuthKey(tsAuthKey)
	keyurl := keyUri
	if web {
		keyurl = webkeyUri
	}

	switch t {
	case m3u8.MEDIA:
		pl := p.(*m3u8.MediaPlaylist)
		dirPath := utils.PathForInfo(name).Dir
		media, err = makeMediaPlayList(pl, cdnDomain, dirPath, keyurl, authKey)
		if err != nil {
			return
		}
		buff = media.Encode()
	case m3u8.MASTER:
		mpl := p.(*m3u8.MasterPlaylist)
		buff = mpl.Encode()
	default:
		err = errors.MakeWithMsg(errors.M3u8FileName, fmt.Sprintf("invalid m3u8 type %d", t))
	}
	return
}

func readFromCDN(name, domain string) (reader io.Reader, err error) {
	requestUrl := utils.JoinUrlPath(domain, name)
	resp, err := http.GetLargeFile(requestUrl, nil)
	if err != nil {
		return
	}
	if resp.StatusCode != 200 {
		msg := fmt.Sprintf("read m3u8 fail, url: %s, status code %d", requestUrl, resp.StatusCode)
		err = errors.MakeWithMsg(errors.M3u8Read, msg)
		return
	}
	reader = bytes.NewReader(resp.Data)
	return
}

func readFromRedis(name, domain string) (reader io.Reader, err error) {
	m3u8Key := redisconst.MediaM3U8Key(name)
	data, err := redis.GetBytes(m3u8Key)
	if err == nil && len(data) > 0 {
		reader = bytes.NewReader(data)
		return
	}
	if strings.Contains(name, "hc237") {
		name = "/m3m/" + name
	}
	requestUrl := utils.JoinUrlPath(domain, name)
	resp, err := http.GetLargeFile(requestUrl, nil)
	if err != nil {
		return
	}
	if resp.StatusCode != 200 {
		msg := fmt.Sprintf("read m3u8 fail, url: %s, status code %d", requestUrl, resp.StatusCode)
		err = errors.MakeWithMsg(errors.M3u8Read, msg)
		return
	}
	if err := redis.Set(m3u8Key, resp.Data,
		redisconst.MediaM3U8CacheExpire); err != nil {
		log.Info("m3u8:readFromRedis redis set err", log.E(err))
	}
	reader = bytes.NewReader(resp.Data)
	return
}

func GetHeaderMediaSegUrls() []string {
	urls := make([]string, 0)
	if headerMediaPlayList == nil {
		return urls
	}
	for _, segment := range headerMediaPlayList.Segments {
		if segment == nil {
			continue
		}
		urls = append(urls, segment.URI)
	}
	return urls
}

// laosijiUpstreamPath maps internal laosiji m3u8 path to upstream m3m path.
func laosijiUpstreamPath(name string) string {
	name = strings.TrimPrefix(name, "/")
	name = strings.TrimPrefix(name, "laosiji/m3m/")
	name = strings.TrimPrefix(name, "laosiji/")
	return "m3m/" + name
}