/*******************************************************************************
 * Copyright (c) 2001, 2005 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     Jens Lukowski/Innoopract - initial renaming/restructuring
 *     
 *******************************************************************************/
package org.eclipse.wst.sse.ui.internal.preferences.ui;

import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.swt.SWT;
import org.eclipse.swt.accessibility.ACC;
import org.eclipse.swt.accessibility.AccessibleControlAdapter;
import org.eclipse.swt.accessibility.AccessibleControlEvent;
import org.eclipse.swt.events.DisposeEvent;
import org.eclipse.swt.events.DisposeListener;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.RGB;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.ColorDialog;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Display;

/**
 * A "button" of a certain color determined by the color picker.
 */
public class ColorEditor {
	Button fButton;
	Color fColor;
	RGB fColorValue;

	private Point fExtent;
	Image fImage;

	public ColorEditor(Composite parent) {

		fButton = new Button(parent, SWT.PUSH);
		fExtent = computeImageSize(parent);
		fImage = new Image(parent.getDisplay(), fExtent.x, fExtent.y);

		GC gc = new GC(fImage);
		gc.setBackground(fButton.getBackground());
		gc.fillRectangle(0, 0, fExtent.x, fExtent.y);
		gc.dispose();

		fButton.setImage(fImage);

		// bug2541 - associate color value to button's value field
		fButton.getAccessible().addAccessibleControlListener(new AccessibleControlAdapter() {
			/**
			 * @see org.eclipse.swt.accessibility.AccessibleControlAdapter#getValue(AccessibleControlEvent)
			 */
			public void getValue(AccessibleControlEvent e) {
				if (e.childID == ACC.CHILDID_SELF) {
					if (getColorValue() != null)
						e.result = getColorValue().toString();
					else
						e.result = null;
				}
			}
		});

		fButton.addSelectionListener(new SelectionAdapter() {
			public void widgetSelected(SelectionEvent event) {
				ColorDialog colorDialog = new ColorDialog(fButton.getShell());
				colorDialog.setRGB(fColorValue);
				RGB newColor = colorDialog.open();
				if (newColor != null) {
					fColorValue = newColor;
					updateColorImage();
				}
			}
		});

		fButton.addDisposeListener(new DisposeListener() {
			public void widgetDisposed(DisposeEvent event) {
				if (fImage != null) {
					fImage.dispose();
					fImage = null;
				}
				if (fColor != null) {
					fColor.dispose();
					fColor = null;
				}
			}
		});
	}

	protected Point computeImageSize(Control window) {
		GC gc = new GC(window);
		Font f = JFaceResources.getFontRegistry().get(JFaceResources.DEFAULT_FONT);
		gc.setFont(f);
		int height = gc.getFontMetrics().getHeight();
		gc.dispose();
		Point p = new Point(height * 3 - 6, height);
		return p;
	}

	public Button getButton() {
		return fButton;
	}

	public RGB getColorValue() {
		return fColorValue;
	}

	public void setColorValue(RGB rgb) {
		fColorValue = rgb;
		updateColorImage();
	}

	protected void updateColorImage() {

		Display display = fButton.getDisplay();

		GC gc = new GC(fImage);
		gc.setForeground(display.getSystemColor(SWT.COLOR_BLACK));
		gc.drawRectangle(0, 2, fExtent.x - 1, fExtent.y - 4);

		if (fColor != null)
			fColor.dispose();

		fColor = new Color(display, fColorValue);
		gc.setBackground(fColor);
		gc.fillRectangle(1, 3, fExtent.x - 2, fExtent.y - 5);
		gc.dispose();

		fButton.setImage(fImage);
	}
}
