package gws_server

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

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

type GwsHandler struct {
	postalServerAddress string
	grpcFactory         *generic.GrpcGenericClientFactory
	sessionStore        session.Store // <string, *session.NetSubject> 当前连接用户,内存缓存
	subjectStore        cache.MultiLevelCache
}

func NewGwsHandler(postalServerAddress string,
	grpcFactory *generic.GrpcGenericClientFactory,
	sessionStore session.Store,
	subjectStore cache.MultiLevelCache) *GwsHandler {
	return &GwsHandler{
		grpcFactory:         grpcFactory,
		postalServerAddress: postalServerAddress,
		sessionStore:        sessionStore,
		subjectStore:        subjectStore,
	}
}

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(SessionUidKey)
	if !ok {
		return
	}
	uid := val.(string)
	c.sessionStore.Delete(uid)
	if err = c.subjectStore.Del(context.Background(), uid); err != nil {
		logger.Error("del offline subject store error: ", err)
	}
	logger.Info("subject offline: ", 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 {
		return
	}

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

	val, authorized := socket.Session().Load(SessionUidKey)
	var sessionUid string
	if authorized {
		sessionUid = val.(string)
	}

	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
	}

	// grpc generic call
	ctx := context.Background()
	grpcClient, err := c.grpcFactory.GetClient(ctx, 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 session
	if authorized {
		ctx = session.PutSubject(ctx, session.NewRpcSubject(sessionUid))
	}
	resp, err := grpcClient.InvokeUnary(ctx, 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" {
		sessionUid, err = c.extractAuthVerify(conn, payload.Body)
		if err != nil {
			logger.Error("extractAuthVerify error: ", err)
			writeError(conn, header.SeqId, "server error")
			return
		}
		socket.Session().Store(SessionUidKey, sessionUid)
	}

	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) extractAuthVerify(conn *gwsConn, resp []byte) (sessionUid string, 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
	gateSubject := &session.GateSubject{
		Uid:    authSubject.Uid,
		Online: 1,
		Time:   time.Now().UnixMilli(),
		Gate:   c.postalServerAddress,
	}
	// 存储session
	err = c.subjectStore.Set(context.Background(), sessionUid, gateSubject) // store to redis cluster cache
	if err != nil {
		return
	}

	// 关闭旧的链接
	oldConn, ok := c.sessionStore.Load(sessionUid)
	if ok {
		// TODO nats offline / force load subject target cluster call offline
		oldConn.(*gwsConn).conn.WriteClose(1000, nil)
		logger.Infof("close subject old conn: %s\n", sessionUid)
	}
	// 存储session到内存
	c.sessionStore.Store(sessionUid, conn)
	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
}