package udp

import (
	"../com"
	"bytes"
	"log"
	"net"
	"sync"
)

type Connect struct {
	con    *net.UDPConn
	mutex  sync.Mutex
	logger *log.Logger
}

func NewConnect(con *net.UDPConn, logger *log.Logger) *Connect {
	ret := Connect{con: con, logger: logger}
	return &ret
}

func (ptr *Connect) Run(packet chan com.Packet) {
	buffer, cur := bytes.Buffer{}, make([]byte, com.BuffSize)
	for {
		n, _, err := ptr.con.ReadFromUDP(cur)
		if err != nil {
			packet <- com.Packet{Event: "error"}
			break
		}
		buffer.Write(cur[:n])
		for {
			if index := bytes.Index(buffer.Bytes(), com.SockEndBytes); index != -1 {
				pool := make([]byte, index+com.SockEndLen)
				_, e := buffer.Read(pool)
				if e != nil {
					ptr.logger.Printf("buffer read error: %s", e)
					buffer.Reset()
				}
				if index = bytes.Index(pool, com.SockStartBytes); index != -1 {
					pool = pool[index+com.SockStartLen:]
					index = bytes.Index(pool, com.SockSplitBytes)
					event, data := string(pool[:index]), pool[index+com.SockSplitLen:len(pool)-com.SockEndLen]
					packet <- com.Packet{Event: event, Data: data}
				}
			} else {
				break
			}
		}
	}
}

func parsePacket(packet com.Packet) []byte  {
	message := append(com.SockStartBytes, []byte(packet.Event)...)
	message = append(message, com.SockSplitBytes...)
	message = append(message, packet.Data...)
	message = append(message, com.SockEndBytes...)
	return message
}

func (ptr *Connect) Emit(packet com.Packet) {
	message := parsePacket(packet)
	ptr.mutex.Lock()
	_, err := ptr.con.Write(message)
	ptr.mutex.Unlock()
	if err != nil {
		ptr.logger.Printf("Failed to emit on event: %s.", packet.Event)
	}
}

func (ptr *Connect) UdpDownEmit(packet com.Packet, addr *net.UDPAddr) {
	message := parsePacket(packet)
	ptr.mutex.Lock()
	_, err := ptr.con.WriteToUDP(message, addr)
	ptr.mutex.Unlock()
	if err != nil {
		ptr.logger.Printf("Failed to emit on event: %s.", packet.Event)
	}
}

func (ptr *Connect) Close() {
	err := ptr.con.Close()
	if err != nil {
		ptr.logger.Printf("Fail to close connection: %s", err)
	}
}