package nnet

import (
	"encoding/json"
	"errors"
	"fmt"
	"git.noahlan.cn/noahlan/nnet"
	"git.noahlan.cn/noahlan/nnet/connection"
	"git.noahlan.cn/noahlan/nnet/packet"
	"git.noahlan.cn/noahlan/ntool/nlog"
)

type (
	HandshakeValidatorFunc  func(*HandshakeReq) error
	HandshakeAckPayloadFunc func() interface{}
)

func withNNetPipeline(
	handshakeResp *HandshakeResp,
	validator HandshakeValidatorFunc,
	packer packet.Packer,
) nnet.RunOption {
	return func(ngin *nnet.Engine) {
		ngin.Pipeline().Inbound().PushFront(func(conn *connection.Connection, v interface{}) error {
			pkg, ok := v.(*Packet)
			if !ok {
				return packet.ErrWrongPacketType
			}
			nc, _ := conn.Conn()

			switch pkg.PacketType {
			case Handshake:
				var handshakeData HandshakeReq
				err := json.Unmarshal(pkg.Data, &handshakeData)
				nlog.Must(err)

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

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

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

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