/*

 * 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.io.InputStream;

import java.io.ObjectInput;

import java.io.ObjectOutput;

import java.io.OutputStream;

import java.net.ServerSocket;

import java.net.Socket;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import java.util.function.Consumer;

import com.sun.jdi.VMDisconnectedException;

import com.sun.jdi.VirtualMachine;

import jdk.jshell.execution.JdiExecutionControl;

import jdk.jshell.execution.JdiInitiator;

import jdk.jshell.execution.Util;

import jdk.jshell.spi.ExecutionControl;

import jdk.jshell.spi.ExecutionControl.EngineTerminationException;

import jdk.jshell.spi.ExecutionEnv;

import static org.testng.Assert.fail;

import static jdk.jshell.execution.Util.remoteInputOutput;

class MyExecutionControl extends JdiExecutionControl {

    private static final String REMOTE_AGENT = MyRemoteExecutionControl.class.getName();

    private static final int TIMEOUT = 2000;

    private VirtualMachine vm;

    private Process process;

    /**

     * Creates an ExecutionControl instance based on a JDI

     * {@code ListeningConnector} or {@code LaunchingConnector}.

     *

     * Initialize JDI and use it to launch the remote JVM. Set-up a socket for

     * commands and results. This socket also transports the user

     * input/output/error.

     *

     * @param env the context passed by

         * {@link jdk.jshell.spi.ExecutionControl#start(jdk.jshell.spi.ExecutionEnv) }

     * @return the channel

     * @throws IOException if there are errors in set-up

     */

    static ExecutionControl make(ExecutionEnv env, UserJdiUserRemoteTest test) throws IOException {

        try (final ServerSocket listener = new ServerSocket(0)) {

            // timeout for socket

            listener.setSoTimeout(TIMEOUT);

            int port = listener.getLocalPort();

            // Set-up the JDI connection

            List<String> opts = new ArrayList<>(env.extraRemoteVMOptions());

            opts.add("-classpath");

            opts.add(System.getProperty("java.class.path")

                    + System.getProperty("path.separator")

                    + System.getProperty("user.dir"));

            JdiInitiator jdii = new JdiInitiator(port,

            VirtualMachine vm = jdii.vm();

            Process process = jdii.process();

            List<Consumer<String>> deathListeners = new ArrayList<>();

            deathListeners.add(s -> env.closeDown());

            Util.detectJdiExitEvent(vm, s -> {

                for (Consumer<String> h : deathListeners) {

                    h.accept(s);

                }

            });

            // Set-up the commands/reslts on the socket.  Piggy-back snippet

            // output.

            Socket socket = listener.accept();

            // out before in -- match remote creation so we don't hang

            OutputStream out = socket.getOutputStream();

            Map<String, OutputStream> outputs = new HashMap<>();

            outputs.put("out", env.userOut());

            outputs.put("err", env.userErr());

            outputs.put("aux", test.auxStream);

            Map<String, InputStream> input = new HashMap<>();

            input.put("in", env.userIn());

            ExecutionControl myec = remoteInputOutput(socket.getInputStream(),

                    out, outputs, input,

                    (objIn, objOut) -> new MyExecutionControl(objOut, objIn, vm, process, deathListeners));

            test.currentEC = myec;

            return myec;

        }

    }

    /**

     * Create an instance.

     *

     * @param out the output for commands

     * @param in the input for responses

     */

    private MyExecutionControl(ObjectOutput out, ObjectInput in,

            VirtualMachine vm, Process process,

            List<Consumer<String>> deathListeners) {

        super(out, in);

        this.vm = vm;

        this.process = process;

        deathListeners.add(s -> disposeVM());

    }

    @Override

    public void close() {

        super.close();

        disposeVM();

    }

    private synchronized void disposeVM() {

        try {

            if (vm != null) {

                vm.dispose(); // This could NPE, so it is caught below

                vm = null;

            }

        } catch (VMDisconnectedException ex) {

            // Ignore if already closed

        } catch (Throwable e) {

            fail("disposeVM threw: " + e);

        } finally {

            if (process != null) {

                process.destroy();

                process = null;

            }

        }

    }

    @Override

    protected synchronized VirtualMachine vm() throws EngineTerminationException {

        if (vm == null) {

            throw new EngineTerminationException("VM closed");

        } else {

            return vm;

        }

    }

}