package core

import (
	"encoding/json"
	"errors"
	"fmt"
	"git.noahlan.cn/northlan/nnet/internal/log"
	"git.noahlan.cn/northlan/nnet/internal/packet"
	"time"
)

var (
	hrd []byte // handshake response data
	hbd []byte // heartbeat packet data
)

type NNetProcessor struct {
}

func NewNNetProcessor() *NNetProcessor {
	// TODO custom hrd hbd
	data, _ := json.Marshal(map[string]interface{}{
		"code": 200,
		"sys":  map[string]float64{"heartbeat": time.Second.Seconds()},
	})
	packer := packet.NewNNetPacker()
	hrd, _ = packer.Pack(packet.Handshake, data)

	return &NNetProcessor{}
}

func (n *NNetProcessor) Process(conn *Connection, p packet.IPacket) error {
	h, ok := p.(*packet.Packet)
	if !ok {
		return packet.ErrWrongPacketType
	}

	switch h.PacketType {
	case packet.Handshake:
		// TODO validate handshake
		if err := conn.SendBytes(hrd); err != nil {
			return err
		}

		conn.SetStatus(StatusPrepare)
		log.Debugf("connection handshake Id=%d, Remote=%s", conn.ID(), conn.Conn().RemoteAddr())
	case packet.HandshakeAck:
		conn.SetStatus(StatusPending)
		log.Debugf("receive handshake ACK Id=%d, Remote=%s", conn.ID(), conn.Conn().RemoteAddr())
	case packet.Heartbeat:
		// Expected
	case packet.Data:
		if conn.Status() < StatusPending {
			return errors.New(fmt.Sprintf("receive data on socket which not yet ACK, session will be closed immediately, remote=%s",
				conn.Conn().RemoteAddr()))
		}
		conn.SetStatus(StatusWorking)

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