/*
 * Copyright (c) 2011, 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.tools.controller;

import java.util.LinkedHashSet;
import java.util.LinkedList;
import java.util.Set;

import org.jowidgets.common.widgets.controller.IKeyEvent;
import org.jowidgets.common.widgets.controller.IKeyListener;
import org.jowidgets.common.widgets.controller.IKeyObservable;
import org.jowidgets.util.Assert;

public class KeyObservable implements IKeyObservable {

    private static final IKeyObservableCallback DUMMY_KEY_OBSERVABLE_CALLBACK = new DummyKeyObservableCallback();

    private final Set<IKeyListener> listeners;
    private final IKeyObservableCallback observableCallback;

    public KeyObservable() {
        this(DUMMY_KEY_OBSERVABLE_CALLBACK);
    }

    public KeyObservable(final IKeyObservableCallback observableCallback) {
        Assert.paramNotNull(observableCallback, "observableCallback");
        this.listeners = new LinkedHashSet<IKeyListener>();
        this.observableCallback = observableCallback;
    }

    @Override
    public final void addKeyListener(final IKeyListener listener) {
        Assert.paramNotNull(listener, "listener");
        listeners.add(listener);
        if (listeners.size() == 1) {
            observableCallback.onFirstRegistered();
        }
    }

    @Override
    public final void removeKeyListener(final IKeyListener listener) {
        Assert.paramNotNull(listener, "listener");
        listeners.remove(listener);
        if (listeners.size() == 0) {
            observableCallback.onLastUnregistered();
        }
    }

    public final void fireKeyPressed(final IKeyEvent event) {
        for (final IKeyListener listener : new LinkedList<IKeyListener>(listeners)) {
            listener.keyPressed(event);
        }
    }

    public final void fireKeyReleased(final IKeyEvent event) {
        for (final IKeyListener listener : new LinkedList<IKeyListener>(listeners)) {
            listener.keyReleased(event);
        }
    }

    public final int size() {
        return listeners.size();
    }

    public interface IKeyObservableCallback {

        void onFirstRegistered();

        void onLastUnregistered();

    }

    public static final class DummyKeyObservableCallback implements IKeyObservableCallback {

        @Override
        public void onFirstRegistered() {}

        @Override
        public void onLastUnregistered() {}

    }

}