/*******************************************************************************
 * Copyright (c) 2000, 2016 IBM Corporation 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:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.help.ui.internal.util;

import org.eclipse.jface.resource.CompositeImageDescriptor;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.swt.graphics.ImageData;
import org.eclipse.swt.graphics.Point;

/**
 * An OverlayIcon consists of a main icon and several adornments.
 */
public abstract class AbstractOverlayIcon extends CompositeImageDescriptor {

	static final int DEFAULT_WIDTH = 16;
	static final int DEFAULT_HEIGHT = 16;

	private Point fSize = null;

	private ImageDescriptor fOverlays[][];

	public AbstractOverlayIcon(ImageDescriptor[][] overlays) {
		this(overlays, null);
	}

	public AbstractOverlayIcon(ImageDescriptor[][] overlays, Point size) {
		fOverlays = overlays;
		if (size != null)
			fSize = size;
		else
			fSize = new Point(DEFAULT_WIDTH, DEFAULT_HEIGHT);
	}
	protected void drawBottomLeft(ImageDescriptor[] overlays) {
		if (overlays == null)
			return;
		int length = overlays.length;
		int x = 0;
		for (int i = 0; i < 3; i++) {
			if (i < length && overlays[i] != null) {
				ImageData id = overlays[i].getImageData();
				drawImage(id, x, getSize().y - id.height);
				x += id.width;
			}
		}
	}
	protected void drawBottomRight(ImageDescriptor[] overlays) {
		if (overlays == null)
			return;
		int length = overlays.length;
		int x = getSize().x;
		for (int i = 2; i >= 0; i--) {
			if (i < length && overlays[i] != null) {
				ImageData id = overlays[i].getImageData();
				x -= id.width;
				drawImage(id, x, getSize().y - id.height);
			}
		}
	}

	protected abstract ImageData getBaseImageData();

	@Override
	protected void drawCompositeImage(int width, int height) {
		ImageData base = getBaseImageData();
		drawImage(base, 0, 0);
		if (fOverlays != null) {
			if (fOverlays.length > 0)
				drawTopRight(fOverlays[0]);

			if (fOverlays.length > 1)
				drawBottomRight(fOverlays[1]);

			if (fOverlays.length > 2)
				drawBottomLeft(fOverlays[2]);

			if (fOverlays.length > 3)
				drawTopLeft(fOverlays[3]);
		}
	}
	protected void drawTopLeft(ImageDescriptor[] overlays) {
		if (overlays == null)
			return;
		int length = overlays.length;
		int x = 0;
		for (int i = 0; i < 3; i++) {
			if (i < length && overlays[i] != null) {
				ImageData id = overlays[i].getImageData();
				drawImage(id, x, 0);
				x += id.width;
			}
		}
	}
	protected void drawTopRight(ImageDescriptor[] overlays) {
		if (overlays == null)
			return;
		int length = overlays.length;
		int x = getSize().x;
		for (int i = 2; i >= 0; i--) {
			if (i < length && overlays[i] != null) {
				ImageData id = overlays[i].getImageData();
				x -= id.width;
				drawImage(id, x, 0);
			}
		}
	}

	@Override
	protected Point getSize() {
		return fSize;
	}
}
