/*

 * 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.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * 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.

 */

package jdk.jshell;

import com.sun.jdi.*;

import com.sun.jdi.event.*;

/**

 * Handler of Java Debug Interface events.

 * Adapted from jdb EventHandler; Handling of events not used by JShell stubbed out.

 */

class JDIEventHandler implements Runnable {

    Thread thread;

    volatile boolean connected = true;

    boolean completed = false;

    String shutdownMessageKey;

    final JDIEnv env;

    JDIEventHandler(JDIEnv env) {

        this.env = env;

        this.thread = new Thread(this, "event-handler");

        this.thread.start();

    }

    synchronized void shutdown() {

        connected = false;  // force run() loop termination

        thread.interrupt();

        while (!completed) {

            try {wait();} catch (InterruptedException exc) {}

        }

    }

    @Override

    public void run() {

        EventQueue queue = env.vm().eventQueue();

        while (connected) {

            try {

                EventSet eventSet = queue.remove();

                boolean resumeStoppedApp = false;

                EventIterator it = eventSet.eventIterator();

                while (it.hasNext()) {

                    resumeStoppedApp |= handleEvent(it.nextEvent());

                }

                if (resumeStoppedApp) {

                    eventSet.resume();

                }

            } catch (InterruptedException exc) {

                // Do nothing. Any changes will be seen at top of loop.

            } catch (VMDisconnectedException discExc) {

                handleDisconnectedException();

                break;

            }

        }

        synchronized (this) {

            completed = true;

            notifyAll();

        }

    }

    private boolean handleEvent(Event event) {

        if (event instanceof ExceptionEvent) {

            exceptionEvent(event);

        } else if (event instanceof WatchpointEvent) {

            fieldWatchEvent(event);

        } else if (event instanceof MethodEntryEvent) {

            methodEntryEvent(event);

        } else if (event instanceof MethodExitEvent) {

            methodExitEvent(event);

        } else if (event instanceof ClassPrepareEvent) {

            classPrepareEvent(event);

        } else if (event instanceof ThreadStartEvent) {

            threadStartEvent(event);

        } else if (event instanceof ThreadDeathEvent) {

            threadDeathEvent(event);

        } else if (event instanceof VMStartEvent) {

            vmStartEvent(event);

            return true;

        } else {

            handleExitEvent(event);

        }

        return true;

    }

    private boolean vmDied = false;

    private void handleExitEvent(Event event) {

        if (event instanceof VMDeathEvent) {

            vmDied = true;

            shutdownMessageKey = "The application exited";

        } else if (event instanceof VMDisconnectEvent) {

            connected = false;

            if (!vmDied) {

                shutdownMessageKey = "The application has been disconnected";

            }

        } else {

            throw new InternalError("Unexpected event type: " +

                    event.getClass());

        }

        env.shutdown();

    }

    synchronized void handleDisconnectedException() {

        /*

         * A VMDisconnectedException has happened while dealing with

         * another event. We need to flush the event queue, dealing only

         * with exit events (VMDeath, VMDisconnect) so that we terminate

         * correctly.

         */

        EventQueue queue = env.vm().eventQueue();

        while (connected) {

            try {

                EventSet eventSet = queue.remove();

                EventIterator iter = eventSet.eventIterator();

                while (iter.hasNext()) {

                    handleExitEvent(iter.next());

                }

            } catch (InterruptedException exc) {

                // ignore

            } catch (InternalError exc) {

                // ignore

            }

        }

    }

    private void vmStartEvent(Event event)  {

        VMStartEvent se = (VMStartEvent)event;

    }

    private void methodEntryEvent(Event event)  {

        MethodEntryEvent me = (MethodEntryEvent)event;

    }

    private void methodExitEvent(Event event)  {

        MethodExitEvent me = (MethodExitEvent)event;

    }

    private void fieldWatchEvent(Event event)  {

        WatchpointEvent fwe = (WatchpointEvent)event;

    }

    private void classPrepareEvent(Event event)  {

        ClassPrepareEvent cle = (ClassPrepareEvent)event;

    }

    private void exceptionEvent(Event event) {

        ExceptionEvent ee = (ExceptionEvent)event;

    }

    private void threadDeathEvent(Event event) {

        ThreadDeathEvent tee = (ThreadDeathEvent)event;

    }

    private void threadStartEvent(Event event) {

        ThreadStartEvent tse = (ThreadStartEvent)event;

    }

}