class Telnet {
/*
Sent	Received	Meaning
WILL	DO			Sender want to use a facility, receiver can handle it, option in effect
WILL	DONT		Sender want to use a facility, receiver can not, option disabled
DO		WILL		Sender is handling a facility, receiver will send, option in effect
DO		WONT		Sender is handling a facility, receiver can not, option disabled
WONT	DONT		Option Disabled, only valid response
DONT	WONT		Option Disabled, only valid response
*/	
};


Telnet.IAC = 0xFF;
Telnet.DONT = 0xFE;
Telnet.DO = 0xFD;
Telnet.WONT = 0xFC;
Telnet.WILL = 0xFB;
Telnet.StartSubNegotiation = 0xFA;
Telnet.GoAhead = 0xF9;
Telnet.EraseLine = 0xF8;
Telnet.EraseCharacter = 0xF7;
Telnet.AreYouThere = 0xF6;
Telnet.AbortOutput = 0xF5;
Telnet.Interrupt = 0xF4;
Telnet.Break = 0xF3;
Telnet.Mark = 0xF2;
Telnet.NOP = 0xF1;
Telnet.EndSubNegotiation = 0xF0;

Telnet.Echo = 0x01;
Telnet.SuppressGoAhead = 0x03;
Telnet.Status = 0x05;
Telnet.TimingMark = 0x06;
Telnet.TerminalType = 0x18;
Telnet.WindowSize = 0x1F;
Telnet.TerminalSpeed = 0x20;
Telnet.RemoteFlowControl = 0x21;
Telnet.LineMode = 0x22;
Telnet.EnvironmentVars = 0x24;


Telnet.RequestTurnOffEcho = [Telnet.IAC, Telnet.WONT, Telnet.Echo];
Telnet.RequestTurnOnEcho = [Telnet.IAC, Telnet.WILL, Telnet.Echo];

Telnet.sendBinary = function(socket, data) {
	var length = data.length;
	var buffer = new ArrayBuffer( length * 2 );
	var view = new Uint16Array(buffer);
	for ( var i = 0; i < length; i++) {
		view[i] = data[i];
	}
	socket.write(Buffer.from(view));
};

Telnet.sendString = function(socket, message) {
	socket.write(message);
};

Telnet.negotiate = function(data) {
	if(data[0] == Telnet.IAC) {
			//TODO: actually listen to the client and negotiate
		}
}

module.exports = Telnet;