package net.rubeta.legacyping;

import org.bukkit.Server;

import java.io.*;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Arrays;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;

public class ServerThread extends Thread {

    // Queries start
    private static final byte[] RUBETA_MODDED_CLIENT = new byte[]{0, 0, 0, 1, (byte) 254};
    private static final byte[] LEGACY_PING_B1_8_TO_R1_3 = new byte[]{(byte) 254};
    private static final byte[] PING_R1_4_TO_R1_5 = new byte[]{(byte) 254, 1};
    // Queries end
    private final ServerSocket serverSocket;
    private final AtomicBoolean working = new AtomicBoolean(false);
    private final Server minecraftServer;

    public ServerThread(final Server server, final String host, int port) throws IOException {
        this.minecraftServer = server;
        final InetAddress address = InetAddress.getByName(host);
        this.serverSocket = new ServerSocket(port, 10, address);
        this.serverSocket.setSoTimeout((int) TimeUnit.SECONDS.toMillis(10L));
    }

    @Override
    public void run() {
        this.working.set(true);
        while (this.working.get() || !this.serverSocket.isClosed()) {
            try {
                final Socket newConnection = this.serverSocket.accept();
                final InputStream inputStream = newConnection.getInputStream();
                final ByteArrayOutputStream result = new ByteArrayOutputStream();
                byte[] buffer = new byte[16];
                for (int length; (length = inputStream.read(buffer)) != -1; ) {
                    result.write(buffer, 0, length);
                }
                final byte[] query = result.toByteArray();
                final OutputStream outputStream = newConnection.getOutputStream();
                if (Arrays.equals(RUBETA_MODDED_CLIENT, query)) {
                    this.responseForRuBetaModdedClient(outputStream);
                } else if (Arrays.equals(LEGACY_PING_B1_8_TO_R1_3, query)) {
                    this.responseForLegacyPing(outputStream);
                } else if (Arrays.equals(PING_R1_4_TO_R1_5, query)) {
                    this.responseForR14Ping(outputStream);
                }
                newConnection.close();
            } catch (IOException ignore) {
            }
        }
    }

    public void shutdown() {
        this.working.set(false);
        try {
            this.serverSocket.close();
        } catch (IOException ignore) {
        }
    }

    private void responseForRuBetaModdedClient(final OutputStream outputStream) throws IOException {
        final ByteArrayOutputStream result = new ByteArrayOutputStream();
        final DataOutputStream dos = new DataOutputStream(result);
        dos.write(255); // Packet 0xFF (PacketDisconnect)
        final String response = this.minecraftServer.getMotd()
                + '\u0000' + this.minecraftServer.getOnlinePlayers().size()
                + '\u0000' + this.minecraftServer.getMaxPlayers();
        dos.writeShort(response.length());
        for (char c : response.toCharArray()) {
            dos.writeChar(c);
        }
        // Packet data end
        final DataOutputStream clientOutput = new DataOutputStream(outputStream);
        clientOutput.writeInt(result.size());
        clientOutput.write(result.toByteArray());
    }

    private void responseForLegacyPing(final OutputStream outputStream) throws IOException {
        final DataOutputStream clientOutput = new DataOutputStream(outputStream);
        clientOutput.write(255); // Packet 0xFF (PacketDisconnect)
        final String response = this.minecraftServer.getMotd()
                + '\u0000' + this.minecraftServer.getOnlinePlayers().size()
                + '\u0000' + this.minecraftServer.getMaxPlayers();
        clientOutput.writeShort(response.length());
        for (char c : response.toCharArray()) {
            clientOutput.writeChar(c);
        }
        // Packet data end
    }

    private void responseForR14Ping(final OutputStream outputStream) throws IOException {
        final DataOutputStream clientOutput = new DataOutputStream(outputStream);
        clientOutput.write(255); // Packet 0xFF (PacketDisconnect)
        final String response = '§' + 1
                + '\u0000' + "b1.7.3m" + '\u0000' + 17 // Protocol version
                + '\u0000' + this.minecraftServer.getMotd()
                + '\u0000' + this.minecraftServer.getOnlinePlayers().size()
                + '\u0000' + this.minecraftServer.getMaxPlayers();
        clientOutput.writeShort(response.length());
        for (char c : response.toCharArray()) {
            clientOutput.writeChar(c);
        }
        // Packet data end
    }
}