package m3u8

import (
	"bytes"
	"fmt"
	"strings"
	"videoweb/pub/common/errors"
	"videoweb/pub/common/utils"
	"videoweb/pub/storage/proxy"

	"github.com/grafov/m3u8"
)

const lsjKeyIV = "0x64cf692cebc516e4a86ac6081aae50ce"

// TransformForTranscode 生成转码专用播放列表，供老司机转码服务器拉取。
func TransformForTranscode(name, origDomain, cdnDomain, webM3u8Host, lsjM3u8Yuan, lsjTsYuan string) (media *m3u8.MediaPlaylist, buff *bytes.Buffer, err error) {
	if strings.Contains(name, "hc237") {
		name = "/laosiji" + name
	}
	if strings.Contains(name, "laosiji") {
		return transcodeLaosiji(name, webM3u8Host, lsjM3u8Yuan, lsjTsYuan)
	}
	return transcodeNormal(name, origDomain, cdnDomain, webM3u8Host)
}

func transcodeLaosiji(name, webM3u8Host, lsjM3u8Yuan, lsjTsYuan string) (media *m3u8.MediaPlaylist, buff *bytes.Buffer, err error) {
	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
	}
	switch t {
	case m3u8.MEDIA:
		pl := p.(*m3u8.MediaPlaylist)
		keyURI := utils.JoinUrlPath(webM3u8Host, keyUriWebLsj)
		// ts 走 CDN（TsYuan/laosiji），与正常播放的 CDN 路径一致。
		media, err = makeTranscodeSegList(pl, utils.JoinUrlPath(lsjTsYuan, "/laosiji"), "", keyURI, lsjKeyIV, true)
		if err != nil {
			return
		}
		buff = media.Encode()
	case m3u8.MASTER:
		buff = p.(*m3u8.MasterPlaylist).Encode()
	default:
		err = errors.MakeWithMsg(errors.M3u8FileName, fmt.Sprintf("invalid m3u8 type %d", t))
	}
	return
}

func transcodeNormal(name, origDomain, cdnDomain, webM3u8Host string) (media *m3u8.MediaPlaylist, buff *bytes.Buffer, err error) {
	if v := proxy.AppendsMediaS3Version(name); len(v) > 0 {
		name = v + 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
	}
	switch t {
	case m3u8.MEDIA:
		pl := p.(*m3u8.MediaPlaylist)
		dirPath := utils.PathForInfo(name).Dir
		keyURI := utils.JoinUrlPath(webM3u8Host, webkeyUri)
		// ts 走 CDN（CdnDomain），与正常播放一致。
		media, err = makeTranscodeSegList(pl, cdnDomain, dirPath, keyURI, "", false)
		if err != nil {
			return
		}
		buff = media.Encode()
	case m3u8.MASTER:
		buff = p.(*m3u8.MasterPlaylist).Encode()
	default:
		err = errors.MakeWithMsg(errors.M3u8FileName, fmt.Sprintf("invalid m3u8 type %d", t))
	}
	return
}

func makeTranscodeSegList(from *m3u8.MediaPlaylist, srcDomain, dirPath, keyURI, iv string, laosiji bool) (media *m3u8.MediaPlaylist, err error) {
	media, err = m3u8.NewMediaPlaylist(0, from.Count())
	if err != nil {
		return
	}
	base := utils.JoinUrlPath(srcDomain, dirPath)
	for _, segment := range from.Segments {
		if segment == nil {
			continue
		}
		sg := new(m3u8.MediaSegment)
		if laosiji {
			if u, e := replaceDomainAndPath(segment.URI, srcDomain); e == nil {
				sg.URI = u
			} else {
				sg.URI = segment.URI
			}
		} else {
			sg.URI = utils.JoinUrlPath(base, segment.URI)
		}
		sg.Title = segment.Title
		sg.Duration = segment.Duration
		if err = media.AppendSegment(sg); err != nil {
			return
		}
	}
	_ = media.SetDefaultKey("AES-128", keyURI, iv, "", "")
	media.Close()
	return
}