/*

 * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

/**

 * A JVM with JDP on should send multicast JDP packets regularly.

 * Look at JdpOnTestCase.java and JdpOffTestCase.java

 */

import sun.management.jdp.JdpJmxPacket;

import java.io.IOException;

import java.io.UnsupportedEncodingException;

import java.net.DatagramPacket;

import java.net.MulticastSocket;

import java.net.SocketTimeoutException;

import java.util.Arrays;

import java.util.Map;

import java.util.logging.Level;

import java.util.logging.Logger;

public abstract class JdpTestCase {

    final Logger log = Logger.getLogger("sun.management.jdp");

    final int MAGIC = 0xC0FFEE42;                       // Jdp magic number.

    private static final int BUFFER_LENGTH = 64 * 1024;   // max UDP size, except for IPv6 jumbograms.

    private final int TIME_OUT_FACTOR = 10;             // Socket times out after 10 times the jdp pause.

    protected int timeOut;

    private long startTime;

    protected ClientConnection connection;

    public JdpTestCase(ClientConnection connection) {

        this.connection = connection;

        JdpTestUtil.enableConsoleLogging(log, Level.ALL);

    }

    public void run() throws Exception {

        log.fine("Test started.");

        log.fine("Listening for multicast packets at " + connection.address.getHostAddress()

                + ":" + String.valueOf(connection.port));

        log.fine(initialLogMessage());

        log.fine("Pause in between packets is: " + connection.pauseInSeconds + " seconds.");

        startTime = System.currentTimeMillis();

        timeOut = connection.pauseInSeconds * TIME_OUT_FACTOR;

        log.fine("Timeout set to " + String.valueOf(timeOut) + " seconds.");

        MulticastSocket socket = connection.connectWithTimeout(timeOut * 1000);

        byte[] buffer = new byte[BUFFER_LENGTH];

        DatagramPacket datagram = new DatagramPacket(buffer, buffer.length);

        do {

            try {

                socket.receive(datagram);

                onReceived(extractUDPpayload(datagram));

            } catch (SocketTimeoutException e) {

                onSocketTimeOut(e);

            }

            if (hasTestLivedLongEnough()) {

                shutdown();

            }

        } while (shouldContinue());

        log.fine("Test ended successfully.");

    }

    /**

     * Subclasses: JdpOnTestCase and JdpOffTestCase have different messages.

     */

    protected abstract String initialLogMessage();

    /**

     * Executed when the socket receives a UDP packet.

     */

    private void onReceived(byte[] packet) throws Exception {

        if (isJDP(packet)) {

            Map<String, String> payload = checkStructure(packet);

            jdpPacketReceived(payload);

        } else {

            log.fine("Non JDP packet received, ignoring it.");

        }

    }

    /**

     * Determine whether the test should end.

     *

     * @return

     */

    abstract protected boolean shouldContinue();

    /**

     * This method is executed when the socket has not received any packet for timeOut seconds.

     */

    abstract protected void onSocketTimeOut(SocketTimeoutException e) throws Exception;

    /**

     * This method is executed after a correct Jdp packet has been received.

     *

     * @param payload A dictionary containing the data if the received Jdp packet.

     */

    private void jdpPacketReceived(Map<String, String> payload) throws Exception {

        final String instanceName = payload.get("INSTANCE_NAME");

        if (instanceName != null && instanceName.equals(connection.instanceName)) {

            packetFromThisVMReceived(payload);

        } else {

            packetFromOtherVMReceived(payload);

        }

    }

    /**

     * This method is executed after a correct Jdp packet, coming from this VM has been received.

     *

     * @param payload A dictionary containing the data if the received Jdp packet.

     */

    protected abstract void packetFromThisVMReceived(Map<String, String> payload) throws Exception;

    /**

     * This method is executed after a correct Jdp packet, coming from another VM has been received.

     *

     * @param payload A dictionary containing the data if the received Jdp packet.

     */

    protected void packetFromOtherVMReceived(Map<String, String> payload) {

        final String jdpName = payload.get("INSTANCE_NAME");

        log.fine("Ignoring JDP packet sent by other VM, jdp.name=" + jdpName);

    }

    /**

     * The test should stop if it has been 12 times the jdp.pause.

     * jdp.pause is how many seconds in between packets.

     * <p/>

     * This timeout (12 times)is slightly longer than the socket timeout (10 times) on purpose.

     * In the off test case, the socket should time out first.

     *

     * @return

     */

    protected boolean hasTestLivedLongEnough() {

        long now = System.currentTimeMillis();

        boolean haslivedLongEnough = (now - startTime) > (timeOut * 1.2 * 1000);

        return haslivedLongEnough;

    }

    /**

     * This exit condition arises when we receive UDP packets but they are not valid Jdp.

     */

    protected void shutdown() throws Exception {

        log.severe("Shutting down the test.");

        throw new Exception("Not enough JDP packets received before timeout!");

    }

    /**

     * Assert that this Jdp packet contains the required two keys.

     * <p/>

     * We expect zero packet corruption and thus fail on the first corrupted packet.

     * This might need revision.

     */

    protected Map<String, String> checkStructure(byte[] packet) throws UnsupportedEncodingException {

        Map<String, String> payload = JdpTestUtil.readPayload(packet);

        assertTrue(payload.size() >= 2, "JDP should have minimun 2 entries.");

        assertTrue(payload.get(JdpJmxPacket.UUID_KEY).length() > 0);

        assertTrue(payload.get(JdpJmxPacket.JMX_SERVICE_URL_KEY).length() > 0);

        return payload;

    }

    /**

     * Check if packet has correct JDP magic number.

     *

     * @param packet

     * @return

     * @throws IOException

     */

    private boolean isJDP(byte[] packet) throws IOException {

        int magic = JdpTestUtil.decode4ByteInt(packet, 0);

        return (magic == MAGIC);

    }

    private byte[] extractUDPpayload(DatagramPacket datagram) {

        byte[] data = Arrays.copyOf(datagram.getData(), datagram.getLength());

        return data;

    }

    /**

     * Hack until I find a way to use TestNG's assertions.

     */

    private void assertTrue(boolean assertion, String message) {

        if (assertion == false) {

            log.severe(message);

            assert (false);

        }

    }

    private void assertTrue(boolean assertion) {

        assertTrue(assertion, "");

    }

}