package proxy

import (
	"encoding/binary"
	"net"
	"strconv"
	"time"
)

var (
	packetEndian        = binary.LittleEndian
	RemoteID     uint32 = 1
	sid                 = RemoteID
	maxSid       uint32 = 1024 * 1024
	HeaderSize          = 16
	Magic               = "anki"
	InitBuf             = func() []byte {
		buf := make([]byte, HeaderSize)
		copy(buf[:len(Magic)], Magic)
		return buf
	}()
)

func IncID() uint32 {
	if sid > maxSid {
		sid = RemoteID
	}
	sid++
	return sid
}

type PacketConnect struct {
	net.Conn
	header   []byte
	id       uint32
	readErr  error
	writeErr error
	name     string
}

func NewPacketConnect(conn net.Conn, name string) *PacketConnect {
	pc := &PacketConnect{Conn: conn, header: make([]byte, HeaderSize)}
	pc.SetRemote(name, 0)
	copy(pc.header, InitBuf)
	return pc
}
func (pc *PacketConnect) Name() string {
	return pc.name
}
func (pc *PacketConnect) SetRemote(name string, id uint32) {
	pc.id = id
	pc.name = "(" + name + ")" + strconv.Itoa(int(id)) + "::" + pc.RemoteAddr().String()
}

func (pc *PacketConnect) Write(data []byte) int {
	n, err := pc.Conn.Write(data)
	pc.writeErr = err
	return n
}
func (pc *PacketConnect) Read(data []byte) int {
	n, err := pc.Conn.Read(data)
	pc.readErr = err
	return n
}
func (pc *PacketConnect) ReadHeader() []byte {
	pc.Read(pc.header)
	return pc.header
}
func (pc *PacketConnect) WriteHeader(id uint32) {
	packetEndian.PutUint32(pc.header[4:8], id)
	pc.Write(pc.header)
}
func (pc *PacketConnect) Forward(dst *PacketConnect, rn int) {
	if rn > 0 {
		dst.Write(pc.header[:rn])
	}
	defer func() {
		_ = pc.Close()
	}()
	data := make([]byte, 1024)
	for pc.readErr == nil && dst.writeErr == nil {
		_ = pc.SetReadDeadline(time.Now().Add(time.Second))
		n := pc.Read(data)
		rn += n
		dst.Write(data[:n])
	}
}