!7

import java.nio.*;
import java.nio.channels.*;

static long timeout = 30000+10000; // idle time + latency
static ConnectedInstances cI;
static ReliableSingleThread rst = new(r update);
static int theNumber;
static int port = 6000;
static Map<SocketChannel, State> dataMapper = synchroMap();
static ServerSocketChannel serverChannel;
static Selector selector;

sclass State {
  S computerID = "?";
  int countSeen = -1;
  new LineBuffer lineBuffer; // TODO: max length
}

p {
  cI = new ConnectedInstances;
  cI.connected2.onChange(rst);
  
  selector = Selector.open();
	serverChannel = ServerSocketChannel.open();
	serverChannel.configureBlocking(false);
	
  InetSocketAddress sockAddr = new InetSocketAddress(port);
	serverChannel.socket().bind(sockAddr);
	serverChannel.register(selector, SelectionKey.OP_ACCEPT);
	
	thread "Server Accept Loop" { acceptLoop(); }
}

svoid cleanMeUp() ctex {
  if (serverChannel != null)
    serverChannel.close();
}

svoid acceptLoop ctex {
  while licensed {
    // wait for events
    selector.select();

	  Iterator<SelectionKey> keys = selector.selectedKeys().iterator();
	  while (keys.hasNext()) {
      SelectionKey key = keys.next();
	    keys.remove();
	    
	    if (!key.isValid()) continue;
	    pcall {
        if (key.isAcceptable())
          acceptOnSocket(key);
	      else if (key.isReadable())
          readFromSocket(key);
      }
	  }
	}
}

//accept a connection made to this channel's socket
static void acceptOnSocket(SelectionKey key) throws IOException {
  ServerSocketChannel serverChannel = cast key.channel();
  SocketChannel channel = serverChannel.accept();
  channel.configureBlocking(false);
  Socket socket = channel.socket();
  SocketAddress remoteAddr = socket.getRemoteSocketAddress();
  print("Connected to: " + remoteAddr);
  
  // register channel with selector for further IO
	dataMapper.put(channel, new State);
	channel.register(selector, SelectionKey.OP_READ);
}

static void readFromSocket(SelectionKey key) throws IOException {
	SocketChannel channel = cast key.channel();
  ByteBuffer buffer = ByteBuffer.allocate(1024);
  int numRead = channel.read(buffer);
  if (numRead == -1) {
    Socket socket = channel.socket();
    SocketAddress remoteAddr = socket.getRemoteSocketAddress();
	  print("Connection closed by client: " + remoteAddr);
	  State state = dataMapper.get(channel);
	  if (state != null && state.computerID != null)
	    cI.lostConnection(state.computerID);
	  dataMapper.remove(channel);
    channel.close();
    key.cancel();
    ret;
  }

  S s = new String(buffer.array(), 0, numRead);
  print("Got data from client: " + s);
  final State state = dataMapper.get(channel);
  if (state != null)
    state.lineBuffer.append(s, voidfunc(S line) {
      new Matches m;
      print("Got line: " + line);
      if (jmatch("computerID=*", line, m)) {
        if (state.computerID != null || !possibleComputerID($1)) ret;
        print("Got computer ID: " + $1);
        state.computerID = $1;
        cI.gotConnection(state.computerID);
      }
    });
}

html { ret "Use port " + port; }

svoid sendNumber(SocketChannel socket) ctex {
  State s = dataMapper.get(socket);
  if (s != null && theNumber != s.countSeen) {
    s.countSeen = theNumber;
    print("Sending number to " + s.computerID + ": " + theNumber);
    socket.write(ByteBuffer.wrap(toUtf8(theNumber + "\n")));
  }
}

svoid update {
  print("OS Instances update");
  if (empty(dataMapper)) ret;

  int value = cI.value();
  //if (value == theNumber) ret;
  theNumber = value;
  for (SocketChannel socket : keysList(dataMapper)) pcall {
    sendNumber(socket);
  }
  print("OS Instances update done");
}