Complete voice connection

src/client/voice/VoiceConnectionUDPClient.js

@@ -1,4 +1,73 @@
-class VoiceConnectionUDPClient {
+const udp = require('dgram');
+const dns = require('dns');
+const Constants = require('../../util/Constants');
+const EventEmitter = require('events').EventEmitter;
+
+class VoiceConnectionUDPClient extends EventEmitter {
+
+  constructor(voiceConnection, data) {
+    super();
+    this.voiceConnection = voiceConnection;
+    this.count = 0;
+    this.data = data;
+    this.dnsLookup();
+  }
+
+  dnsLookup() {
+    dns.lookup(this.voiceConnection.endpoint, (err, address) => {
+      if (err) {
+        return this.emit('error', err);
+      }
+      this.connectUDP(address);
+    });
+  }
+
+  send(packet) {
+    if (this.udpSocket) {
+      try {
+        this.udpSocket.send(packet, 0, packet.length, this.data.port, this.udpIP);
+      } catch (err) {
+        return this.emit('error', err);
+      }
+    }
+  }
+
+  connectUDP(address) {
+    this.udpIP = address;
+    this.udpSocket = udp.createSocket('udp4');
+
+    // finding local IP
+    // https://discordapp.com/developers/docs/topics/voice-connections#ip-discovery
+    this.udpSocket.once('message', message => {
+      const packet = new Buffer(message);
+      this.localIP = '';
+      for (let i = 4; i < packet.indexOf(0, i); i++) {
+        this.localIP += String.fromCharCode(packet[i]);
+      }
+
+      this.localPort = parseInt(packet.readUIntLE(packet.length - 2, 2).toString(10), 10);
+
+      this.voiceConnection.websocket.send({
+        op: Constants.VoiceOPCodes.SELECT_PROTOCOL,
+        d: {
+          protocol: 'udp',
+          data: {
+            address: this.localIP,
+            port: this.localPort,
+            mode: 'xsalsa20_poly1305',
+          },
+        },
+      });
+    });
+
+    this.udpSocket.on('error', (error, message) => {
+      this.emit('error', { error, message });
+    });
+
+    const blankMessage = new Buffer(70);
+    blankMessage.writeUIntBE(this.data.ssrc, 0, 4);
+    this.send(blankMessage);
+  }
 
 }