/*

 * Copyright (c) 2016, 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.

 */

import java.io.IOException;

import java.net.ServerSocket;

import java.util.StringTokenizer;

import jdk.test.lib.JDKToolFinder;

import jdk.test.lib.Utils;

import static jdk.test.lib.Asserts.assertFalse;

/**

 * Launches the debuggee with the necessary JDWP options and handles the output

 */

public class DebuggeeLauncher implements StreamHandler.Listener {

    public interface Listener {

        /**

         * Callback to use when a module name is received from the debuggee

         *

         * @param modName module name reported by the debuggee

         */

        void onDebuggeeModuleInfo(String modName);

        /**

         * Callback to use when the debuggee completes sending out the info

         */

        void onDebuggeeSendingCompleted();

        /**

         * Callback to handle any debuggee error

         *

         * @param line line from the debuggee's stderr

         */

        void onDebuggeeError(String line);

    }

    private static int jdwpPort = -1;

    private static final String CLS_DIR = System.getProperty("test.classes", "").trim();

    private static final String DEBUGGEE = "AllModulesCommandTestDebuggee";

    private Process p;

    private final Listener listener;

    private StreamHandler inputHandler;

    private StreamHandler errorHandler;

    /**

     * @param listener the listener we report the debuggee events to

     */

    public DebuggeeLauncher(Listener listener) {

        this.listener = listener;

    }

    /**

     * Starts the debuggee with the necessary JDWP options and handles the

     * debuggee's stdout and stderr outputs

     *

     * @throws Throwable

     */

    public void launchDebuggee() throws Throwable {

        ProcessBuilder pb = new ProcessBuilder(getCommand());

        p = pb.start();

        inputHandler = new StreamHandler(p.getInputStream(), this);

        errorHandler = new StreamHandler(p.getErrorStream(), this);

        inputHandler.start();

        errorHandler.start();

    }

    /**

     * Command to start the debuggee with the JDWP options and using the JDK

     * under test

     *

     * @return the command

     */

    private String[] getCommand() {

        return new String[]{

            JDKToolFinder.getTestJDKTool("java"),

            getJdwpOptions(),

            "-cp",

            CLS_DIR,

            DEBUGGEE

        };

    }

    /**

     * Terminates the debuggee

     */

    public void terminateDebuggee() {

        if (p.isAlive()) {

            p.destroyForcibly();

        }

    }

    /**

     * Debuggee JDWP options

     *

     * @return the JDWP options to start the debuggee with

     */

    private static String getJdwpOptions() {

        return "-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=" + getJdwpPort();

    }

    /**

     * Find an available port for the JDWP session

     *

     * @return JDWP port

     */

    public static int getJdwpPort() {

        if (jdwpPort == -1) {

            jdwpPort = findFreePort();

            assertFalse(jdwpPort == -1, "Can not find vailbale port for JDWP");

        }

        return jdwpPort;

    }

    private static int findFreePort() {

        try (ServerSocket socket = new ServerSocket(0)) {

            return socket.getLocalPort();

        } catch (IOException e) {

        }

        return -1;

    }

    @Override

    public void onStringRead(StreamHandler handler, String line) {

        if (handler.equals(errorHandler)) {

            terminateDebuggee();

            listener.onDebuggeeError(line);

        } else {

            processDebuggeeOutput(line);

        }

    }

    private void processDebuggeeOutput(String line) {

        StringTokenizer st = new StringTokenizer(line);

        String token = st.nextToken();

        switch (token) {

            case "module":

                listener.onDebuggeeModuleInfo(st.nextToken());

                break;

            case "ready":

                listener.onDebuggeeSendingCompleted();

                break;

        }

    }

}