package m3u8

import (
	"bytes"
	"crypto/md5"
	"encoding/hex"
	"fmt"
	"strconv"
	"strings"
	"time"
	"videoweb/pub/common/errors"
	"videoweb/pub/common/utils"
	"videoweb/pub/pubdef"
	"videoweb/pub/storage/proxy"

	"github.com/grafov/m3u8"
)

// TransformEx m3u8 文件转换。
// apiType(1:app,2:h5app,3:web)
// authKey: TS CDN 鉴权（空则回退默认 AuthKey）
// lsjM3u8Yuan / cdnAuthKey: 老司机源站与分片鉴权
// customKeyUri: 非空时直接使用，用于将鉴权参数嵌入 EXT-X-KEY URI
func TransformEx(name, cdnDomain, origDomain string, apiType int, authKey, lsjM3u8Yuan, cdnAuthKey string, customKeyUri ...string) (
	media *m3u8.MediaPlaylist, buff *bytes.Buffer, err error) {
	return transformEx(name, cdnDomain, origDomain, apiType, authKey, lsjM3u8Yuan, cdnAuthKey, true, customKeyUri...)
}

// TransformExOriginalPath 按数据库中的原始路径读取 m3u8，不自动追加 v1/v2/v3 前缀。
// 短剧水印未完成时仍播放原片，原片路径如 k12/...，需要保留原路径。
func TransformExOriginalPath(name, cdnDomain, origDomain string, apiType int, authKey, lsjM3u8Yuan, cdnAuthKey string, customKeyUri ...string) (
	media *m3u8.MediaPlaylist, buff *bytes.Buffer, err error) {
	return transformEx(name, cdnDomain, origDomain, apiType, authKey, lsjM3u8Yuan, cdnAuthKey, false, customKeyUri...)
}

func transformEx(name, cdnDomain, origDomain string, apiType int, authKey, lsjM3u8Yuan, cdnAuthKey string, appendMediaVersion bool, customKeyUri ...string) (
	media *m3u8.MediaPlaylist, buff *bytes.Buffer, err error) {

	if name == "" {
		err = errors.MakeWithMsg(errors.M3u8FileName, "m3u8 file name is empty")
		return
	}
	if cdnDomain == "" || origDomain == "" {
		err = errors.MakeWithMsg(errors.DomainErr, "cdnDomain or origDomain is empty")
		return
	}
	if strings.Contains(name, "hc237") {
		name = "/laosiji" + name
	}
	if strings.Contains(name, "laosiji") {
		return TransformLaosiji(name, cdnDomain, false, lsjM3u8Yuan, cdnAuthKey, customKeyUri...)
	}

	if appendMediaVersion {
		mediaVerson := proxy.AppendsMediaS3Version(name)
		if len(mediaVerson) > 0 {
			name = mediaVerson + name
		}
	}
	authKey = resolveTsAuthKey(authKey)

	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
	}
	apiPath := keyUri
	if len(customKeyUri) > 0 && customKeyUri[0] != "" {
		apiPath = customKeyUri[0]
	} else if apiType == 2 {
		apiPath = h5KeyUri
	} else if apiType == 3 {
		apiPath = webkeyUri
	}

	switch t {
	case m3u8.MEDIA:
		pl := p.(*m3u8.MediaPlaylist)
		dirPath := utils.PathForInfo(name).Dir
		media, err = makeTSList(pl, cdnDomain, dirPath, apiPath, 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 makeTSList(from *m3u8.MediaPlaylist, cdnDomain string,
	dirPath string, apiPath string, authKey string) (
	media *m3u8.MediaPlaylist, err error) {
	media, err = m3u8.NewMediaPlaylist(from.WinSize(), from.Count())
	if err != nil {
		return
	}
	now := time.Now()
	base := utils.JoinUrlPath(cdnDomain, dirPath)
	for _, segment := range from.Segments {
		if segment == nil {
			continue
		}
		sg := new(m3u8.MediaSegment)
		sg.URI = utils.JoinUrlPath(base, segment.URI)
		if len(authKey) > 0 {
			urlPath := utils.JoinUrlPath(dirPath, segment.URI)
			urlAuth := generateUrlAuth(now, urlPath, authKey)
			sg.URI = sg.URI + urlAuth
		}
		sg.Title = segment.Title
		sg.Duration = segment.Duration
		if err = media.AppendSegment(sg); err != nil {
			return
		}
	}
	_ = media.SetDefaultKey("AES-128", apiPath, "", "", "")
	media.Close()
	return
}

func generateUrlAuth(now time.Time, path string, authKey string) string {
	timestamp := now.Unix()
	signStr := fmt.Sprintf("%s-%d-0-0-%s", path, timestamp, authKey)
	md5Str := getMD5Sign(signStr)
	// TS CDN 鉴权参数后追加应用标识，便于流量统计。
	urlAuth := fmt.Sprintf("?md=%d-0-0-%s&c=%d", timestamp, md5Str, pubdef.AppId)
	return urlAuth
}

func generateUrlAuthQiniu(now time.Time, path string, authKey string) string {
	timestamp := strconv.FormatInt(now.Add(2*time.Hour).Unix(), 16)
	base64 := path
	signStr := authKey + base64 + timestamp
	md5Str := getMD5Sign(signStr)
	urlAuth := fmt.Sprintf("?sign=%s&t=%s", md5Str, timestamp)
	return urlAuth
}

func getMD5Sign(buf string) string {
	md5Ctx := md5.New()
	md5Ctx.Write([]byte(buf))
	cipherStr := md5Ctx.Sum(nil)
	nsign := hex.EncodeToString(cipherStr)
	return nsign
}