package nnet

import (
	"encoding/json"
	"git.noahlan.cn/noahlan/nnet"
	"git.noahlan.cn/noahlan/nnet/conn"
	"git.noahlan.cn/noahlan/nnet/event"
	"git.noahlan.cn/noahlan/nnet/packet"
	"git.noahlan.cn/noahlan/ntool/nlog"
)

type (
	HandshakeValidatorFunc  func(*HandshakeReq) error
	HandshakeAckPayloadFunc func() any
)

func withNNetEvents(
	handshakeResp *HandshakeResp,
	validator HandshakeValidatorFunc,
	packer packet.Packer,
) nnet.RunOption {
	return func(ngin *nnet.Engine) {
		ngin.EventManager().RegisterEventFront(event.EvtOnReceive, onServerReceiveEvent(handshakeResp, validator, packer))
	}
}

func onServerReceiveEvent(
	handshakeResp *HandshakeResp,
	validator HandshakeValidatorFunc,
	packer packet.Packer, ) event.OnReceiveFn {
	return func(nc *conn.Connection, p packet.IPacket) {
		pkg, ok := p.(*Packet)
		if !ok {
			nlog.Error(packet.ErrWrongPacketType)
			return
		}
		switch pkg.PacketType {
		case Handshake:
			var handshakeData HandshakeReq
			err := json.Unmarshal(pkg.Data, &handshakeData)
			nlog.Must(err)

			if err := validator(&handshakeData); err != nil {
				nlog.Error(err)
				return
			}
			handshakeResp.Payload = handshakeData.Payload

			data, err := json.Marshal(handshakeResp)
			nlog.Must(err)

			hrd, _ := packer.Pack(Header{
				PacketType:    Handshake,
				MessageHeader: MessageHeader{},
			}, data)
			if err := nc.SendBytes(hrd); err != nil {
				nlog.Error(err)
				return
			}
			nc.SetStatus(conn.StatusPrepare)
			nlog.Debugf("connection handshake Id=%d, Remote=%s", nc.Session().ID(), nc.Conn().RemoteAddr())
		case HandshakeAck:
			nc.SetStatus(conn.StatusPending)
			nlog.Debugf("receive handshake ACK Id=%d, Remote=%s", nc.Session().ID(), nc.Conn().RemoteAddr())
		case Data:
			if nc.Status() < conn.StatusPending {
				nlog.Errorf("receive data on socket which not yet ACK, session will be closed immediately, remote=%s",
					nc.Conn().RemoteAddr())
				return
			}
			nc.SetStatus(conn.StatusWorking)

			var lastMid uint64
			switch pkg.MsgType {
			case Request:
				lastMid = pkg.ID
			case Notify:
				lastMid = 0
			default:
				nlog.Errorf("Invalid message type: %s ", pkg.MsgType.String())
			}
			nc.SetLastMID(lastMid)
		}
	}
}