/*******************************************************************************
 * Copyright (c) 2013, 2014 Mentor Graphics 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:
 *     Vladimir Prus (Mentor Graphics) - initial API and implementation
 *     Dmitry Kozlov (Mentor Graphics) - extend to be inheritance-friendly
 *******************************************************************************/
package org.eclipse.cdt.dsf.gdb.internal.ui.tracepoints;

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.MouseAdapter;
import org.eclipse.swt.events.MouseEvent;
import org.eclipse.swt.events.PaintEvent;
import org.eclipse.swt.events.PaintListener;
import org.eclipse.swt.events.SelectionListener;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.Cursor;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.RGB;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Canvas;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.TypedListener;

public class FlatButton extends Canvas {
	
	protected String fText;
	protected int fMargin = 4;
	protected Cursor fHandCursor;
	
	public FlatButton(Composite parent, int flags) {
		super(parent, flags);
		
		fHandCursor = getDisplay().getSystemCursor(SWT.CURSOR_HAND);
		setCursor(fHandCursor);

		addPaintListener(new PaintListener() {
			@Override
			public void paintControl(PaintEvent e) {
				onPaint(e);
			}
		});

		addMouseListener(new MouseAdapter() {
			@Override
			public void mouseDown(MouseEvent e) {
				onSelection(e);
			}
		}); 					
	}
	
	public void addSelectionListener (SelectionListener listener) {
		checkWidget ();
		if (listener == null) SWT.error (SWT.ERROR_NULL_ARGUMENT);
		TypedListener typedListener = new TypedListener (listener);
		addListener (SWT.Selection,typedListener);
		addListener (SWT.DefaultSelection,typedListener);
	}
	
	public void setText(String text) {
		fText = text;
	}
	
	public String getText()	{
		return fText;
	}
	
	public void setMargin(int margin) {
		fMargin = margin;
	}
	
	@Override
	public Point computeSize(int wHint, int hHint, boolean changed) {
		return computeSize(wHint, hHint);
	}
	
	@Override
	public Point computeSize(int wHint, int hHint) {
		
		GC gc = new GC(this);
		if (fText == null || fText.isEmpty()) {
			Point e = gc.textExtent("A"); //$NON-NLS-1$
			return new Point(0, e.y + fMargin*2);
		}
		
		
		Point e = gc.textExtent(fText);
		return new Point(e.x + fMargin*2, e.y + fMargin*2);
	}
	
	protected void onPaint(PaintEvent event) {
		GC gc = event.gc;
		Rectangle ca = getClientArea();

		Color mainColor = gc.getDevice().getSystemColor(SWT.COLOR_LIST_SELECTION);
		gc.setBackground(mainColor);
		float[] mainHSB = mainColor.getRGB().getHSB();
		float h = mainHSB[0];
		float s = mainHSB[1];
		float b = mainHSB[2];
		
				
		Color borderColor = new Color(gc.getDevice(), new RGB(h, s, (float)(b*0.7)));			
		Color shadowColor = new Color(gc.getDevice(), new RGB(h, s, (float)(b*0.5)));	
		
		gc.setForeground(borderColor);
		gc.drawRectangle(0, 0, ca.width-1, ca.height-1);
		
		gc.setForeground(shadowColor);
		gc.drawLine(0, ca.height-1, ca.width-1, ca.height-1);
					
		gc.fillRectangle(1, 1, ca.width-2, ca.height-2);
		
		gc.setForeground(gc.getDevice().getSystemColor(SWT.COLOR_LIST_SELECTION_TEXT));
		gc.drawText(fText, fMargin, fMargin, true);
		
		borderColor.dispose();
		shadowColor.dispose();
	}
	
	protected void onSelection(MouseEvent e) {
		if (isEnabled()) {
			notifyListeners(SWT.Selection, null);
		}		
	}
}