package huya

import (
	"encoding/base64"
	"math/rand"
	"net/url"

	"huya-go/internal/taf"
)

const (
	HTTPHuyaUA  = "webh5&0.0.1&websocket&&diypc_52775"
	PCUserAgent = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) " +
		"AppleWebKit/537.36 (KHTML, like Gecko) Chrome/149.0.0.0 Safari/537.36"
)

type WSConnectParaInfo struct {
	UID           int64
	GUID          string
	UA            string
	AppSrc        string
	MID           string
	Exp           string
	TokenType     int32
	Token         string
	Cookie        string
	TraceID       string
	CustomHeaders map[string]string
}

func NewWSConnectParaInfo(uid int64, guid, cookie string) WSConnectParaInfo {
	return WSConnectParaInfo{
		UID:           uid,
		GUID:          guid,
		UA:            HTTPHuyaUA,
		AppSrc:        "HUYA&ZH&2052",
		Cookie:        cookie,
		TraceID:       NewTraceID(),
		CustomHeaders: map[string]string{},
	}
}

func (i WSConnectParaInfo) WriteTo(w *taf.Writer) error {
	if err := w.WriteInt64(0, i.UID); err != nil {
		return err
	}
	if err := w.WriteString(1, i.GUID); err != nil {
		return err
	}
	if err := w.WriteString(2, i.UA); err != nil {
		return err
	}
	if err := w.WriteString(3, i.AppSrc); err != nil {
		return err
	}
	if err := w.WriteString(4, i.MID); err != nil {
		return err
	}
	if err := w.WriteString(5, i.Exp); err != nil {
		return err
	}
	if err := w.WriteInt32(6, int64(i.TokenType)); err != nil {
		return err
	}
	if err := w.WriteString(7, i.Token); err != nil {
		return err
	}
	if err := w.WriteString(8, i.Cookie); err != nil {
		return err
	}
	if err := w.WriteString(9, i.TraceID); err != nil {
		return err
	}
	return w.WriteMapStringString(10, i.CustomHeaders)
}

func NewTraceID() string {
	// 与前端 traceId 格式保持一致：hex16:hex16:0:0。
	v := rand.Uint64()
	s := lowerHex16(v)
	return s + ":" + s + ":0:0"
}

func lowerHex16(v uint64) string {
	const digits = "0123456789abcdef"
	var b [16]byte
	for i := 15; i >= 0; i-- {
		b[i] = digits[v&0xf]
		v >>= 4
	}
	return string(b[:])
}

func GenerateHTTPBaseinfo(uid int64, guid, cookie string) (string, error) {
	info := NewWSConnectParaInfo(uid, guid, cookie)
	w := taf.NewWriter()
	if err := info.WriteTo(w); err != nil {
		return "", err
	}
	return url.QueryEscape(base64.StdEncoding.EncodeToString(w.Bytes())), nil
}

// GenerateWSSBaseinfo 生成浏览器 WSS 握手里的 baseinfo。
//
// 手动抓包里 WSS 握手带 uid/guid/ua/appSrc/mid/exp/.../customHeaders 共 11 个字段，
// cookie 为空、通过后续 VerifyCookie 命令发送；exp 为 mobileui.getConfig 下发的
// 版本串（形如 "58664.107263"），首次连接时为空。
func GenerateWSSBaseinfo(uid int64, guid, exp string) (string, error) {
	w := taf.NewWriter()
	if err := w.WriteInt64(0, uid); err != nil {
		return "", err
	}
	if err := w.WriteString(1, guid); err != nil {
		return "", err
	}
	if err := w.WriteString(2, HTTPHuyaUA); err != nil {
		return "", err
	}
	if err := w.WriteString(3, "HUYA&ZH&2052"); err != nil {
		return "", err
	}
	if err := w.WriteString(4, ""); err != nil {
		return "", err
	}
	if err := w.WriteString(5, exp); err != nil {
		return "", err
	}
	if err := w.WriteInt32(6, 0); err != nil {
		return "", err
	}
	if err := w.WriteString(7, ""); err != nil {
		return "", err
	}
	if err := w.WriteString(8, ""); err != nil {
		return "", err
	}
	if err := w.WriteString(9, ""); err != nil {
		return "", err
	}
	if err := w.WriteMapStringString(10, nil); err != nil {
		return "", err
	}
	return url.QueryEscape(base64.StdEncoding.EncodeToString(w.Bytes())), nil
}