/*
 * Copyright (c) 2012, 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.impl.toolkit;

import java.util.HashSet;
import java.util.LinkedList;
import java.util.Set;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;

import org.jowidgets.api.animation.IWaitAnimationProcessor;
import org.jowidgets.api.image.IconsSmall;
import org.jowidgets.api.threads.IUiThreadAccess;
import org.jowidgets.api.toolkit.Toolkit;
import org.jowidgets.common.image.IImageConstant;
import org.jowidgets.util.concurrent.DaemonThreadFactory;
import org.jowidgets.util.event.IChangeListener;

final class DefaultWaitAnimationProcessor implements IWaitAnimationProcessor {

    private static final String TEXT_0 = "";
    private static final String TEXT_1 = ".";
    private static final String TEXT_2 = "..";
    private static final String TEXT_3 = "...";

    private final Set<IChangeListener> changeListeners;
    private final IUiThreadAccess uiThreadAccess;
    private final ScheduledExecutorService threadPool;

    private ScheduledFuture<?> scheduledFuture;
    private int animationState;

    private IImageConstant icon;
    private String text;

    DefaultWaitAnimationProcessor() {
        super();
        this.uiThreadAccess = Toolkit.getUiThreadAccess();
        this.threadPool = Executors.newScheduledThreadPool(1, new DaemonThreadFactory("WaitAnimationProcessor"));
        this.changeListeners = new HashSet<IChangeListener>();
        this.animationState = 0;
        this.icon = IconsSmall.WAIT_1;
        this.text = "";
    }

    @Override
    public void addChangeListener(final IChangeListener listener) {
        changeListeners.add(listener);
        listener.changed();
        if (changeListeners.size() == 1) {
            start();
        }
    }

    @Override
    public void removeChangeListener(final IChangeListener listener) {
        changeListeners.remove(listener);
        if (changeListeners.size() == 0) {
            stop();
        }
    }

    @Override
    public IImageConstant getWaitIcon() {
        return icon;
    }

    @Override
    public String getWaitText() {
        return text;
    }

    private void start() {
        if (scheduledFuture == null) {
            final Runnable labelAnimationRunnable = new Runnable() {
                @Override
                public void run() {
                    nextStep();
                }
            };
            this.scheduledFuture = threadPool.scheduleAtFixedRate(labelAnimationRunnable, 500, 250, TimeUnit.MILLISECONDS);
        }
    }

    private void stop() {
        if (scheduledFuture != null) {
            scheduledFuture.cancel(false);
            scheduledFuture = null;
        }
    }

    private void nextStep() {
        if (animationState == 0) {
            icon = IconsSmall.WAIT_1;
            text = TEXT_0;
        }
        else if (animationState == 1) {
            icon = IconsSmall.WAIT_2;
            text = TEXT_1;
        }
        else if (animationState == 2) {
            icon = IconsSmall.WAIT_3;
            text = TEXT_2;
        }
        else if (animationState == 3) {
            icon = IconsSmall.WAIT_4;
            text = TEXT_3;
        }

        if (animationState == 3) {
            animationState = 0;
        }
        else {
            animationState++;
        }

        fireChangedEventLater();
    }

    private void fireChangedEventLater() {
        uiThreadAccess.invokeLater(new Runnable() {
            @Override
            public void run() {
                fireChangedEvent();
            }
        });
    }

    private void fireChangedEvent() {
        for (final IChangeListener listener : new LinkedList<IChangeListener>(changeListeners)) {
            listener.changed();
        }
    }

}