/*******************************************************************************

 * Copyright (c) 2004, 2009 Tasktop Technologies and others.

 * All rights reserved. This program and the accompanying materials

 * are made available under the terms of the Eclipse Public License v1.0

 * which accompanies this distribution, and is available at

 * http://www.eclipse.org/legal/epl-v10.html

 *

 * Contributors:

 *     Tasktop Technologies - initial API and implementation

 *******************************************************************************/

package com.nokia.carbide.remoteconnections.internal.ui.mylyn;

import java.util.Set;

import org.eclipse.core.runtime.IProgressMonitor;

import org.eclipse.core.runtime.IStatus;

import org.eclipse.core.runtime.Status;

import org.eclipse.core.runtime.jobs.Job;

import org.eclipse.swt.widgets.Display;

import org.eclipse.swt.widgets.Shell;

import org.eclipse.swt.widgets.TreeItem;

/**

 * @author Mik Kersten

 * @author Steffen Pingel

 */

public class SwtUtil {

	public static final long FADE_RESCHEDULE_DELAY = 80;

	public static final int FADE_IN_INCREMENT = 15;

	public static final int FADE_OUT_INCREMENT = -20;

	public static void collectItemData(TreeItem[] items, Set<Object> allVisible) {

		for (TreeItem item : items) {

			allVisible.add(item.getData());

			collectItemData(item.getItems(), allVisible);

		}

	}

	public static FadeJob fastFadeIn(Shell shell, IFadeListener listener) {

		return new FadeJob(shell, 2 * FADE_IN_INCREMENT, FADE_RESCHEDULE_DELAY, listener);

	}

	public static FadeJob fadeIn(Shell shell, IFadeListener listener) {

		return new FadeJob(shell, FADE_IN_INCREMENT, FADE_RESCHEDULE_DELAY, listener);

	}

	public static FadeJob fadeOut(Shell shell, IFadeListener listener) {

		return new FadeJob(shell, FADE_OUT_INCREMENT, FADE_RESCHEDULE_DELAY, listener);

	}

	public static class FadeJob extends Job {

		private final Shell shell;

		private final int increment;

		private volatile boolean stopped;

		private volatile int currentAlpha;

		private final long delay;

		private final IFadeListener fadeListener;

		public FadeJob(Shell shell, int increment, long delay, IFadeListener fadeListener) {

			super("Fading");

			if (increment < -255 || increment == 0 || increment > 255) {

				throw new IllegalArgumentException("-255 <= increment <= 255 && increment != 0"); //$NON-NLS-1$

			}

			if (delay < 1) {

				throw new IllegalArgumentException("delay must be > 0"); //$NON-NLS-1$

			}

			this.currentAlpha = shell.getAlpha();

			this.shell = shell;

			this.increment = increment;

			this.delay = delay;

			this.fadeListener = fadeListener;

			setSystem(true);

			schedule(delay);

		}

		@Override

		protected void canceling() {

			stopped = true;

		}

		private void reschedule() {

			if (stopped) {

				return;

			}

			schedule(delay);

		}

		public void cancelAndWait(final boolean setAlpha) {

			if (stopped) {

				return;

			}

			cancel();

			Display.getDefault().syncExec(new Runnable() {

				public void run() {

					if (setAlpha) {

						shell.setAlpha(getLastAlpha());

					}

				}

			});

		}

		@Override

		protected IStatus run(IProgressMonitor monitor) {

			if (stopped) {

				return Status.OK_STATUS;

			}

			currentAlpha += increment;

			if (currentAlpha <= 0) {

				currentAlpha = 0;

			} else if (currentAlpha >= 255) {

				currentAlpha = 255;

			}

			Display.getDefault().syncExec(new Runnable() {

				public void run() {

					if (stopped) {

						return;

					}

					if (shell.isDisposed()) {

						stopped = true;

						return;

					}

					shell.setAlpha(currentAlpha);

					if (fadeListener != null) {

						fadeListener.faded(shell, currentAlpha);

					}

				}

			});

			if (currentAlpha == 0 || currentAlpha == 255) {

				stopped = true;

			}

			reschedule();

			return Status.OK_STATUS;

		}

		private int getLastAlpha() {

			return (increment < 0) ? 0 : 255;

		}

	}

	public static interface IFadeListener {

		public void faded(Shell shell, int alpha);

	}

}