package servlet

import (
	"context"
	"encoding/json"
	"fmt"

	"github.com/valyala/fasthttp"

	"git.loafle.net/commons/logging-go"
	"git.loafle.net/commons/server-go"
	"git.loafle.net/commons/server-go/socket"
	occp "git.loafle.net/overflow/commons-go/config/probe"
	ocmp "git.loafle.net/overflow/commons-go/model/probe"
	og "git.loafle.net/overflow/gateway"
	"git.loafle.net/overflow/gateway/external/grpc"
	ogs "git.loafle.net/overflow/gateway/subscribe"
	ogrs "git.loafle.net/overflow/gateway_rpc/servlet"
	"git.loafle.net/overflow/probe_gateway_rpc/subscribe"
)

type ProbeServlet interface {
	ogrs.RPCServlet
}

type ProbeServlets struct {
	ogrs.RPCServlets
}

func (s *ProbeServlets) Init(serverCtx server.ServerCtx) error {
	if err := s.RPCServlets.Init(serverCtx); nil != err {
		return err
	}

	return nil
}

func (s *ProbeServlets) OnStart(serverCtx server.ServerCtx) error {
	if err := s.RPCServlets.OnStart(serverCtx); nil != err {
		return err
	}

	subscribeChan, err := subscribe.Subscriber.Subscribe(occp.HTTPEntry_Probe)
	if nil != err {
		return err
	}
	go s.handleSubscribe(serverCtx, subscribeChan)

	return nil
}

func (s *ProbeServlets) OnStop(serverCtx server.ServerCtx) {
	if err := subscribe.Subscriber.Unsubscribe(occp.HTTPEntry_Probe); nil != err {
		logging.Logger().Warn(err)
	}

	s.RPCServlets.OnStop(serverCtx)
}

func (s *ProbeServlets) Destroy(serverCtx server.ServerCtx) {

	s.RPCServlets.Destroy(serverCtx)
}

func (s *ProbeServlets) Handshake(servletCtx server.ServletCtx, ctx *fasthttp.RequestCtx) (*fasthttp.ResponseHeader, error) {
	bMethod := ctx.Request.Header.Peek(occp.HTTPRequestHeaderKey_Probe_Method)
	if nil == bMethod {
		return nil, fmt.Errorf("Unexpected probe method: %v", bMethod)
	}

	method := string(bMethod)

	switch method {
	case occp.HTTPRequestHeaderValue_Probe_Method_Connect:
	default:
		return nil, fmt.Errorf("Unexpected probe method: %s", method)
	}

	bProbeKey := ctx.Request.Header.Peek(occp.HTTPRequestHeaderKey_Probe_ProbeKey)
	if nil == bProbeKey {
		return nil, fmt.Errorf("Unexpected probe key : %v", bProbeKey)
	}

	probeKey := string(bProbeKey)

	grpcCTX := context.Background()
	r, err := grpc.Exec(grpcCTX, "ProbeService.readByProbeKey", probeKey)
	if nil != err {
		return nil, fmt.Errorf("grpc call Error: %s", err.Error())
	}

	probe := &ocmp.Probe{}
	err = json.Unmarshal([]byte(r), probe)
	if nil != err {
		return nil, fmt.Errorf("grpc result unMarshal Error: %s", err.Error())
	}

	extHeader := &fasthttp.ResponseHeader{}
	extHeader.Add(occp.HTTPResponseHeaderKey_Probe_Method, occp.HTTPResponseHeaderValue_Probe_Method_EncryptionKey)
	extHeader.Add(occp.HTTPResponseHeaderKey_Probe_Method_Param, probe.EncryptionKey)

	servletCtx.SetAttribute(og.SessionIDKey, probeKey)
	servletCtx.SetAttribute(og.SessionClientTypeKey, og.PROBE)
	servletCtx.SetAttribute(og.SessionTargetIDKey, probeKey)

	return extHeader, nil
}

func (s *ProbeServlets) OnConnect(servletCtx server.ServletCtx, conn socket.Conn) {
	s.RPCServlets.OnConnect(servletCtx, conn)

	_probeKey := servletCtx.GetAttribute(og.SessionIDKey)
	if nil != _probeKey {
		grpcCTX := context.Background()
		_, err := grpc.Exec(grpcCTX, "ProbeService.onConnect", _probeKey.(string), conn.RemoteAddr().String())
		if nil != err {
			logging.Logger().Errorf("onConnect error %v", err)
		}
	}
}

func (s *ProbeServlets) OnDisconnect(servletCtx server.ServletCtx) {
	s.RPCServlets.OnDisconnect(servletCtx)

	_probeKey := servletCtx.GetAttribute(og.SessionIDKey)
	if nil != _probeKey {
		grpcCTX := context.Background()
		_, err := grpc.Exec(grpcCTX, "ProbeService.onDisconnect", _probeKey.(string))
		if nil != err {
			logging.Logger().Errorf("onDisconnect error %v", err)
		}
	}
}

func (s *ProbeServlets) handleSubscribe(serverCtx server.ServerCtx, subscribeChan <-chan *ogs.Message) {
	var sessions []*ogrs.Session

LOOP:
	for {
		select {
		case msg, ok := <-subscribeChan:
			if !ok {
				return
			}

			switch msg.TargetType {
			case ogs.PROBE:
				sessions = s.GetSessions(msg.Targets)
			default:
				logging.Logger().Warnf("Subscriber: Unknown TargetType %s", msg.TargetType)
				continue LOOP
			}

			if nil == sessions || 0 == len(sessions) {
				continue LOOP
			}

			for _, session := range sessions {
				_writeChan := session.ServletCtx.GetAttribute(og.SessionWriteChanKey)
				if nil != _writeChan {
					writeChan := _writeChan.(chan<- []byte)
					writeChan <- *msg.Message
				}
			}

		}
	}
}