package gws_server

import (
	"context"
	"fmt"
	"github.com/lxzan/gws"
	"google.golang.org/protobuf/proto"
	"regexp"
	"sonet/api/gen/auth"
	"sonet/api/gen/postal"
	"sonet/pkg/grpc/generic"
	"sonet/pkg/protocol"
	"sonet/pkg/protocol/session"
	"sonet/pkg/utils/logger"
	"time"
)

const (
	PingInterval      = 5 * time.Second
	PingWait          = 10 * time.Second
	SessionGwsConnKey = "gws"
)

type soRequest struct {
	conn    *gwsConn
	payload *protocol.Payload
}

type GwsHandler struct {
	grpcFactory  *generic.GrpcGenericClientFactory
	sessionStore session.Store // <string, *session.NetSubject> 当前连接用户,内存缓存
	requests     chan *soRequest
}

func NewGwsHandler(
	grpcFactory *generic.GrpcGenericClientFactory,
	sessionStore session.Store,
) *GwsHandler {
	return &GwsHandler{
		grpcFactory:  grpcFactory,
		sessionStore: sessionStore,
	}
}

func (c *GwsHandler) Init(ctx context.Context) {
	c.requests = make(chan *soRequest, 1024*16)

	// todo 针对不同服务的协程池
	for i := 0; i < 32; i++ {
		go c.dispatchRequest(ctx)
	}
}

// dispatchRequest 多个 goroutine 进行请求 dispatch
func (c *GwsHandler) dispatchRequest(ctx context.Context) {
	for {
		select {
		case <-ctx.Done():
			return
		case request := <-c.requests:
			func() {
				conn, payload := request.conn, request.payload
				header := payload.Header
				service, method := header.Svc, header.Target

				// grpc generic call
				ctx := context.Background()
				ctx2, cancel2 := context.WithTimeout(ctx, time.Second*3)
				defer cancel2()
				grpcClient, err := c.grpcFactory.GetClient(ctx2, service)
				if err != nil {
					logger.Error("get grpc generic client error: ", err)
					writeError(conn, header.SeqId, fmt.Sprintf("service %s not avaliable: %s", header.Svc, err.Error()))
					return
				}

				// put grpc request session
				if conn.uid != "" {
					ctx = session.PutSubject(ctx, session.NewRpcSubject(conn.uid))
				}
				ctx3, cancel3 := context.WithTimeout(ctx, time.Second*10)
				defer cancel3()
				resp, err := grpcClient.InvokeUnary(ctx3, header.Target, payload.Body)
				if err != nil {
					writeError(conn, header.SeqId, unwrapRpcError(err.Error()))
					logger.Error("grpc generic call error: ", err)
					return
				}

				// write response
				if resp == nil { // proto.Empty
					header.Target = ""
				} else {
					payload.Body, err = resp.Marshal()
					if err != nil {
						logger.Error("generic call response marshal error: ", err)
						writeError(conn, header.SeqId, "server error")
						return
					}
					header.Target = resp.XXX_MessageName()
				}

				// auth verify success
				if service == "Auth" && method == "Verify" {
					var channel *session.Channel
					conn.uid, channel, err = c.extractAuthVerify(conn, payload.Body)
					if err != nil {
						logger.Error("extractAuthVerify error: ", err)
						writeError(conn, header.SeqId, "server error")
						return
					}
					// channel todo  dispatch on conn open
					go c.dispatch(channel)
				}

				header.Type = protocol.TypeResponse
				resMessage, err := protocol.EncodeSo(payload)
				if err != nil {
					logger.Error("grpc generic call error: ", err)
					return
				}
				err = conn.Write(resMessage)
				if err != nil {
					logger.Error("gws write response error: ", err)
					return
				}
			}()
		}
	}
}

func (c *GwsHandler) OnOpen(socket *gws.Conn) {
	_ = socket.SetDeadline(time.Time{}) // time.Now().Add(PingInterval + PingWait)
	socket.Session().Store(SessionGwsConnKey, newGwsConn(socket))
}

func (c *GwsHandler) OnClose(socket *gws.Conn, err error) {
	if err != nil {
		logger.Error("gws conn close error: ", err)
	}
	val, ok := socket.Session().Load(SessionGwsConnKey)
	if !ok {
		return
	}
	conn := val.(*gwsConn)
	if conn.uid != "" {
		c.sessionStore.Delete(conn.uid)
		logger.Info("subject offline: ", conn.uid)
	}
}

func (c *GwsHandler) OnPing(socket *gws.Conn, payload []byte) {
	_ = socket.SetDeadline(time.Now().Add(PingInterval + PingWait))
	_ = socket.WritePong(nil)
}

func (c *GwsHandler) OnPong(socket *gws.Conn, payload []byte) {}

func (c *GwsHandler) OnMessage(socket *gws.Conn, message *gws.Message) {
	defer func() {
		err := message.Close()
		if err != nil {
			logger.Error("gws message close error: ", err)
		}
	}()
	if message.Opcode != gws.OpcodeBinary {
		logger.Info("receive websocket message type: ", message.Opcode)
		return
	}

	val, ok := socket.Session().Load(SessionGwsConnKey)
	if !ok {
		logger.Error("gws socket session error: conn not exists")
		return
	}
	conn := val.(*gwsConn)
	authorized := conn.uid != ""

	messageBytes := message.Bytes()
	payload, err := protocol.DecodeSo(messageBytes)
	if err != nil {
		logger.Errorf("decode message error: len=%d", len(messageBytes), err)
		return
	}

	header := payload.Header
	service, method := header.Svc, header.Target
	if !authorized && !(service == "Auth" && method == "Verify") {
		writeError(conn, header.SeqId, session.UnauthorizedRequestError.Error())
		return
	}

	// payload -> processing channel
	request := &soRequest{conn: conn, payload: payload}
	select {
	case c.requests <- request:
	default:
		writeError(conn, header.SeqId, "server busy")
	}
}

func encodeDeliverMessage(msg *postal.Message) (bytes []byte, err error) {
	header := &protocol.Header{
		Magic:         protocol.Magic,
		Type:          protocol.TypeNotice,
		UrlType:       1,
		SerializeType: 1,
		Svc:           msg.Svc,
		Target:        msg.Msg,
	}
	payload := &protocol.Payload{Header: header, Body: msg.Body}
	bytes, err = protocol.EncodeSo(payload)
	if err != nil {
		logger.Error("encode deliver message error: ", err)
	}
	return
}

// todo close
func (c *GwsHandler) dispatch(channel *session.Channel) {
	for {
		msg := channel.Ready()
		bytes, err := encodeDeliverMessage(msg)
		if err != nil {
			logger.Error("encode dispatch message error:", err)
			continue
		}
		err = channel.Conn.Write(bytes)
		if err != nil {
			logger.Error("write dispatch message error:", err)
		}
	}
}

func (c *GwsHandler) extractAuthVerify(conn *gwsConn, resp []byte) (sessionUid string, channel *session.Channel, err error) {
	authSubject := &auth.Subject{}
	err = proto.Unmarshal(resp, authSubject)
	if err != nil {
		logger.Error("grpc generic call error: ", err)
		return
	}
	// 设置连接身份信息
	sessionUid = authSubject.Uid

	// 关闭旧的链接
	oldChannel, ok := c.sessionStore.Load(sessionUid)
	if ok {
		oldChannel.Conn.(*gwsConn).conn.WriteClose(1000, nil)
		logger.Infof("close subject old conn: %s\n", sessionUid)
	}
	// 存储session到内存
	channel = session.NewChannel(sessionUid, conn)
	c.sessionStore.Store(sessionUid, channel)
	logger.Infof("subject online: %s\n", sessionUid)
	return
}

var reg = regexp.MustCompile("^rpc error:.*?desc ?= ?(.*)$")

// unwrapRpcError 提取 grpc err: fmt.Sprintf("rpc error: code = %s desc = %s", s.Code(), s.Message())
func unwrapRpcError(err string) string {
	finds := reg.FindStringSubmatch(err)
	if len(finds) > 1 {
		return finds[1]
	}
	return err
}

func writeError(conn session.NetConn, seqId int32, errMsg string) {
	header := &protocol.Header{}
	payload := &protocol.Payload{Header: header}

	header.Magic = protocol.Magic
	header.Type = protocol.TypeError
	header.Status = 50
	header.SeqId = seqId
	payload.Body = []byte(errMsg)
	message, err := protocol.EncodeSo(payload)
	if err != nil {
		logger.Error("NetClient writeError encode error: ", err)
		return
	}
	err = conn.Write(message)
	if err != nil {
		logger.Error("net conn write error msg fail: ", err)
		return
	}
	return
}