package huya

import (
	"fmt"
	"math/rand"

	"huya-go/internal/taf"
)

const (
	WSSCmdNull                 int32 = 0
	WSSCmdRegisterReq          int32 = 1
	WSSCmdRegisterRsp          int32 = 2
	WSSCmdWupReq               int32 = 3
	WSSCmdWupRsp               int32 = 4
	WSSCmdHeartBeat            int32 = 5
	WSSCmdHeartBeatAck         int32 = 6
	WSSCmdMsgPushReq           int32 = 7
	WSSCmdDeregisterReq        int32 = 8
	WSSCmdDeregisterRsp        int32 = 9
	WSSCmdVerifyCookieReq      int32 = 10
	WSSCmdVerifyCookieRsp      int32 = 11
	WSSCmdVerifyHuyaTokenReq   int32 = 12
	WSSCmdVerifyHuyaTokenRsp   int32 = 13
	WSSCmdUnverifyReq          int32 = 14
	WSSCmdUnverifyRsp          int32 = 15
	WSSCmdRegisterGroupReq     int32 = 16
	WSSCmdRegisterGroupRsp     int32 = 17
	WSSCmdUnregisterGroupReq   int32 = 18
	WSSCmdUnregisterGroupRsp   int32 = 19
	WSSCmdHeartBeatReq         int32 = 20
	WSSCmdHeartBeatRsp         int32 = 21
	WSSCmdMsgPushReqV2         int32 = 22
	WSSCmdUpdateUserExpsReq    int32 = 23
	WSSCmdUpdateUserExpsRsp    int32 = 24
	WSSCmdUpdateUserInfoReq    int32 = 33
	WSSCmdUpdateUserInfoRsp    int32 = 34
	WSSCmdMsgAckReq            int32 = 35
	WSSCmdMsgAckRsp            int32 = 36
	WSSCmdS2CRpcReq            int32 = 40
	WSSCmdC2SRpcRsp            int32 = 41
	WSSCmdS2CRpcRspRsp         int32 = 42
	WSSCmdSignalUpgradeReq     int32 = 105
	WSSCmdSignalUpgradeRsp     int32 = 106
	defaultWSSTraceEnableValue       = 0
)

// WSSCommand 是浏览器 JS 里的 HUYA.WebSocketCommand。
//
// 注意：这不是旧版的 6 字节自定义头。浏览器实际把这个 TAF/JCE
// 结构直接作为 WebSocket binary payload 发送。
type WSSCommand struct {
	CmdType     int32
	Data        []byte
	RequestID   int64
	TraceID     string
	EncryptType int32
	Time        int64
	MD5         string
}

func (c *WSSCommand) WriteTo(w *taf.Writer) error {
	if err := w.WriteInt32(0, int64(c.CmdType)); err != nil {
		return err
	}
	if err := w.WriteBytes(1, c.Data); err != nil {
		return err
	}
	if err := w.WriteInt64(2, c.RequestID); err != nil {
		return err
	}
	if err := w.WriteString(3, c.TraceID); err != nil {
		return err
	}
	if err := w.WriteInt32(4, int64(c.EncryptType)); err != nil {
		return err
	}
	if err := w.WriteInt64(5, c.Time); err != nil {
		return err
	}
	return w.WriteString(6, c.MD5)
}

func (c *WSSCommand) ReadFrom(r *taf.Reader) error {
	var err error
	if c.CmdType, err = r.ReadInt32(0, false, c.CmdType); err != nil {
		return err
	}
	if c.Data, err = r.ReadBytes(1, false, c.Data); err != nil {
		return err
	}
	if c.RequestID, err = r.ReadInt64(2, false, c.RequestID); err != nil {
		return err
	}
	if c.TraceID, err = r.ReadString(3, false, c.TraceID); err != nil {
		return err
	}
	if c.EncryptType, err = r.ReadInt32(4, false, c.EncryptType); err != nil {
		return err
	}
	if c.Time, err = r.ReadInt64(5, false, c.Time); err != nil {
		return err
	}
	c.MD5, err = r.ReadString(6, false, c.MD5)
	return err
}

func (c WSSCommand) Encode() ([]byte, error) {
	w := taf.NewWriter()
	if err := c.WriteTo(w); err != nil {
		return nil, err
	}
	return append([]byte(nil), w.Bytes()...), nil
}

func DecodeWSSCommand(data []byte) (WSSCommand, error) {
	var cmd WSSCommand
	if len(data) == 0 {
		return cmd, fmt.Errorf("wss: 空消息")
	}
	if err := cmd.ReadFrom(taf.NewReader(data)); err != nil {
		return cmd, err
	}
	return cmd, nil
}

func EncodeWSSCommand(cmdType int32, data []byte, traceID string) ([]byte, error) {
	return WSSCommand{
		CmdType: cmdType,
		Data:    append([]byte(nil), data...),
		TraceID: traceID,
	}.Encode()
}

func encodeWSSStructCommand(cmdType int32, value taf.Marshaler) ([]byte, error) {
	w := taf.NewWriter()
	if value != nil {
		if err := value.WriteTo(w); err != nil {
			return nil, err
		}
	}
	return EncodeWSSCommand(cmdType, w.Bytes(), "")
}

func NewWSSCommandTrace() string {
	trace := lowerHex16(rand.Uint64())
	return fmt.Sprintf("%s:%s:0:%d", trace, trace, defaultWSSTraceEnableValue)
}