/*
 * Copyright (c) 2010, grossmann
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * * Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * * Neither the name of the jo-widgets.org nor the
 *   names of its contributors may be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL jo-widgets.org BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 */

package org.jowidgets.spi.impl.bridge.swt.awt.common.application;

import java.awt.Window;
import java.lang.reflect.Method;
import java.util.concurrent.atomic.AtomicBoolean;

import javax.swing.SwingUtilities;

import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
import org.jowidgets.common.application.IApplication;
import org.jowidgets.common.application.IApplicationLifecycle;
import org.jowidgets.common.application.IApplicationRunner;

/**
 * This application runner ensures that all swt events and all awt events will be dispatched in the same thread.
 * 
 * This can be useful if the SWT-AWT bridge is used. Usually then there are two event dispatching threads that leads
 * to many many problems.
 * 
 * This application runner runs the awt edt and then it pumps every n millis one event on the awt event queue that
 * dispatches m swt events.
 * 
 * Remark: This application runner is a prototype that was not tested very intensive yet !!!
 * Potentially known but yet unsolved problems:
 * 
 * 1. If the awt evt has uncaught exceptions, a new thread will be created by awt.
 * After that the evt of awt and swt differs. Maybe this could be fixed by installing an uncought exception handler
 * in the awt evt.
 * 
 * 
 * 2. When modal dialogs will be created with swt or awt a new event pump will be used normally.
 * In jowidgets this may be fixed by using the same events loop pattern for modal dialogs.
 * 
 */
final class BridgedSwtAwtApplicationRunner implements IApplicationRunner {

    private BridgedSwtEventLoop swtEventLoop;
    private Thread eventDispatcherThread;
    private Thread eventPumpThread;

    @Override
    public void run(final IApplication application) {

        if (eventPumpThread != null && Thread.currentThread() != eventPumpThread) {
            throw new IllegalStateException("The application runner is already running with another event pump thread");
        }

        if (SwingUtilities.isEventDispatchThread()) {
            throw new IllegalStateException(
                "The current thread is the EventDispatcherThread. A ApplicationRunner must not be used from the EventDispatcherThread");
        }

        swtEventLoop = new BridgedSwtEventLoop();
        eventPumpThread = Thread.currentThread();
        eventDispatcherThread = swtEventLoop.getEventDispatchingThread();

        final AtomicBoolean finished = new AtomicBoolean(false);

        //Create a lifecycle that disposes all windows and shells when finished
        final IApplicationLifecycle lifecycle = new IApplicationLifecycle() {

            @Override
            public synchronized void finish() {
                finished.set(true);
                if (eventPumpThread != null) {
                    eventPumpThread = null;

                    //dispose all windows
                    for (final Window window : Window.getWindows()) {
                        window.dispose();
                    }

                    //dispose all shells
                    final Display currentDisplay = Display.getCurrent();
                    if (currentDisplay != null && !currentDisplay.isDisposed()) {
                        for (final Shell shell : currentDisplay.getShells()) {
                            shell.dispose();
                        }
                        if (!currentDisplay.isDisposed()) {
                            currentDisplay.dispose();
                        }
                    }

                    //stop the swt event dispatching
                    swtEventLoop.stop(new Runnable() {
                        @Override
                        public void run() {
                            //stop the awt event dispatching
                            try {
                                if (eventDispatcherThread != null) {
                                    final Class<?> edtClass = Class.forName("java.awt.EventDispatchThread");
                                    final Method method = edtClass.getDeclaredMethod("stopDispatching");
                                    method.setAccessible(true);
                                    method.invoke(eventDispatcherThread);
                                }
                            }
                            catch (final Exception e) {
                                throw new RuntimeException(e);
                            }
                        }
                    });
                }
            }
        };

        try {
            SwingUtilities.invokeAndWait(new Runnable() {
                @Override
                public void run() {
                    application.start(lifecycle);
                }
            });
        }
        catch (final Exception e) {
            throw new RuntimeException(e);
        }

        //this will block until the lifecycle was finished
        if (!finished.get()) {
            swtEventLoop.start();
        }
    }
}