// 필요한 객체를 선언합니다.
var net  = require('net');

// net.Socket event handlers
function onSocketConnect()
{
    console.log('onSocketConnect: connection established');
}

function onSocketData(socket, buffer)
{
    console.log('onSocketData: data received');
    process.stdout.write(buffer);
}

// emitted when the other side of the socket sends a FIN packet
function onSocketEnd()
{
    console.log('onSocketEnd: a client sent a FIN packet.');
}

function onSocketTimeOut()
{
    console.log('onSocketTimeOut: called.');
}

// when the write buffer becomes empty
function onSocketDrain()
{
    console.log('onSocketDrain: called.');
}

function onSocketError(err)
{
    console.log('onSocketError: called.');
}

function onSocketClose(had_error)
{
    console.log('onSocketClose: connection closed.');
    
    if(had_error)
    {
        console.log('onSocketClose: some error happend :(');
    }
    else
    {
        console.log('onSocketClose: no error :)');
    }
    
    process.exit(0);
}

function onStdinData(socket, data)
{
    socket.write(data);
    console.log('onStdinData: data sent');
}


////////////////////////////////////////////////////////////////////////////////
// Beginning
// argument parsing
if (process.argv.length != 4)
{
    console.log('Usage: node echo_client.js <host> <port>');
    process.exit(0);    
}

var host = process.argv[2];
var port = process.argv[3];

// 소켓 생성
var options = {'port': port, 'host': host};
var socket  = net.createConnection(options);

// 핸들러 설정
socket.on('connect', onSocketConnect);
socket.on('end',     onSocketEnd);
socket.on('timeout', onSocketTimeOut);
socket.on('drain',   onSocketDrain);
socket.on('error',   onSocketError);
socket.on('close',   onSocketClose);

// socket에 효과적으로 접근하기 위해서는 이 방법이 효과적입니다.
socket.on('data', function (buffer) {
    onSocketData(socket, buffer)
});

// stdin 활성화
process.stdin.resume();
process.stdin.on('data', function(data){onStdinData(socket, data);});