package fr.upem.net.udp;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.DatagramChannel;
import java.nio.charset.Charset;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.nio.file.StandardOpenOption;
import java.util.Arrays;
import java.util.BitSet;
import java.util.List;
import java.util.logging.Logger;

public class ClientIdUpperCaseUDPBurst {

    private static Logger logger = Logger.getLogger(ClientIdUpperCaseUDPBurst.class.getName());
    private static final Charset UTF8 = Charset.forName("UTF8");
    private static final int BUFFER_SIZE = 1024;
    private final List<String> lines;
    private final int nbLines;
    private final String[] upperCaseLines;
    private final int timeout;
    private final String outFilename;
    private final InetSocketAddress serverAddress;
    private final DatagramChannel dc;
    private volatile BitSet received;

    private static void usage() {
        System.out.println("Usage : ClientIdUpperCaseUDPBurst in-filename out-filename timeout host port");
    }

    private ClientIdUpperCaseUDPBurst(List<String> lines, int timeout, InetSocketAddress serverAddress, String outFilename) throws IOException {
        this.lines = lines;
        this.nbLines = lines.size();
        this.timeout = timeout;
        this.outFilename = outFilename;
        this.serverAddress = serverAddress;
        this.dc = DatagramChannel.open();
        dc.bind(null);
        this.received = new BitSet(nbLines);
        this.upperCaseLines = new String[nbLines];
    }

    private void senderThreadRun() throws IOException, InterruptedException {
        while(!Thread.interrupted() && received.cardinality() != 0) {
            for (int id = 0; id < nbLines; id++) {
                if (!received.get(id)) {
                    ByteBuffer buffer = ByteBuffer.allocateDirect(BUFFER_SIZE);
                    String line = lines.get(id);
                    buffer.putLong(id);
                    buffer.put(UTF8.encode(line));
                    buffer.flip();
                    dc.send(buffer, serverAddress);
                }
            }
            Thread.sleep(timeout);
        }
    }

    private void launch () throws IOException {
        Thread senderThread = new Thread(() -> {
            try {
                senderThreadRun();
            } catch (IOException | InterruptedException e) {
                throw new IllegalStateException("Sender failed to send");
            }
        });
        senderThread.start();
        ByteBuffer buffer = ByteBuffer.allocateDirect(BUFFER_SIZE);
        while(received.cardinality() < nbLines) {
            buffer.clear();
            dc.receive(buffer);
            buffer.flip();

            if (buffer.remaining() < Long.BYTES) {
                continue;
            }
            int id = (int)buffer.getLong();
            String msg = UTF8.decode(buffer).toString();
            System.out.println(msg);

            if (!received.get(id)) {
                upperCaseLines[id] = msg;
                received.set(id);
            }
        }
        senderThread.interrupt();
        Files.write(Paths.get(outFilename), Arrays.asList(upperCaseLines), UTF8, StandardOpenOption.CREATE, StandardOpenOption.WRITE, StandardOpenOption.TRUNCATE_EXISTING);
    }

    public static void main(String[] args) throws IOException {
        if (args.length != 5) {
            usage();
            return;
        }

        String inFilename = args[0];
        String outFilename = args[1];
        int timeout = Integer.valueOf(args[2]);
        String host = args[3];
        int port = Integer.valueOf(args[4]);
        InetSocketAddress serverAddress = new InetSocketAddress(host, port);

        //Read all lines of inFilename opened in UTF-8
        List<String> lines = Files.readAllLines(Paths.get(inFilename), UTF8);
        //Create client with the parameters and launch it
        ClientIdUpperCaseUDPBurst client = new ClientIdUpperCaseUDPBurst(lines, timeout, serverAddress, outFilename);
        client.launch();
    }
}