/*******************************************************************************
 * Copyright (c) 2000, 2010 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.draw2d;

import org.eclipse.swt.graphics.Color;

import org.eclipse.draw2d.geometry.Insets;

/**
 * Creates a border for a clickable type of figure, which works in conjunction
 * with the Figure and its model. This border adjusts itself to the various
 * states the model of the figure could be. This border uses an extended
 * {@link SchemeBorder.Scheme Scheme} called {@link ButtonScheme} which provides
 * more information required by border to handle the the states of the model.
 * 
 * @see SchemeBorder.Scheme
 * @see ButtonScheme
 */
public class ButtonBorder extends SchemeBorder {

	/**
	 * Default button border.
	 * 
	 * @see SCHEMES#BUTTON
	 */
	public static final Border BUTTON = new ButtonBorder(SCHEMES.BUTTON);
	/**
	 * Inverted hightlight colors from BUTTON.
	 * 
	 * @see SCHEMES#BUTTON_CONTRAST
	 */
	public static final Border BUTTON_CONTRAST = new ButtonBorder(
			SCHEMES.BUTTON_CONTRAST);
	/**
	 * Used for scrollbar buttons.
	 * 
	 * @see SCHEMES#BUTTON_SCROLLBAR
	 */
	public static final Border BUTTON_SCROLLBAR = new ButtonBorder(
			SCHEMES.BUTTON_SCROLLBAR);
	/**
	 * Used for toolbar buttons.
	 * 
	 * @see SCHEMES#TOOLBAR
	 */
	public static final Border TOOLBAR = new ButtonBorder(SCHEMES.TOOLBAR);

	/**
	 * Provides for a scheme to represent the borders of clickable figures like
	 * buttons. Though similar to the {@link SchemeBorder.Scheme Scheme} it
	 * supports an extra set of borders for the pressed states.
	 */
	public static class ButtonScheme extends Scheme {
		private Color highlightPressed[] = null, shadowPressed[] = null;

		/**
		 * Constructs a new button scheme where the input colors are the colors
		 * for the top-left and bottom-right sides of the border. These colors
		 * serve as the colors when the border is in a pressed state too. The
		 * width of each side is determined by the number of colors passed in as
		 * input.
		 * 
		 * @param highlight
		 *            Colors for the top-left sides of the border
		 * @param shadow
		 *            Colors for the bottom-right sides of the border
		 * @since 2.0
		 */
		public ButtonScheme(Color[] highlight, Color[] shadow) {
			highlightPressed = this.highlight = highlight;
			shadowPressed = this.shadow = shadow;
			init();
		}

		/**
		 * Constructs a new button scheme where the input colors are the colors
		 * for the top-left and bottom-right sides of the border, for the normal
		 * and pressed states. The width of each side is determined by the
		 * number of colors passed in as input.
		 * 
		 * @param hl
		 *            Colors for the top-left sides of the border
		 * @param sh
		 *            Colors for the bottom-right sides of the border
		 * @param hlp
		 *            Colors for the top-left sides of the border when figure is
		 *            pressed
		 * @param shp
		 *            Colors for the bottom-right sides of the border when
		 *            figure is pressed
		 * @since 2.0
		 */
		public ButtonScheme(Color[] hl, Color[] sh, Color[] hlp, Color[] shp) {
			highlight = hl;
			shadow = sh;
			highlightPressed = hlp;
			shadowPressed = shp;
			init();
		}

		/**
		 * Calculates and returns the Insets for this border. The calculations
		 * are based on the number of normal and pressed, highlight and shadow
		 * colors.
		 * 
		 * @return The insets for this border
		 * @since 2.0
		 */
		protected Insets calculateInsets() {
			int br = 1 + Math.max(getShadow().length,
					getHighlightPressed().length);
			int tl = Math.max(getHighlight().length, getShadowPressed().length);
			return new Insets(tl, tl, br, br);
		}

		/**
		 * Calculates and returns the opaque state of this border.
		 * <p>
		 * Returns false in the following conditions:
		 * <ul>
		 * <li>The number of highlight colors is different than the the number
		 * of shadow colors.
		 * <li>The number of pressed highlight colors is different than the
		 * number of pressed shadow colors.
		 * <li>Any of the highlight and shadow colors are set to
		 * <code>null</code>
		 * <li>Any of the pressed highlight and shadow colors are set to
		 * <code>null</code>
		 * </ul>
		 * This is done so that the entire region under the figure is properly
		 * covered.
		 * 
		 * @return The opaque state of this border
		 * @since 2.0
		 */
		protected boolean calculateOpaque() {
			if (!super.calculateOpaque())
				return false;
			if (getHighlight().length != getShadowPressed().length)
				return false;
			if (getShadow().length != getHighlightPressed().length)
				return false;
			Color[] colors = getHighlightPressed();
			for (int i = 0; i < colors.length; i++)
				if (colors[i] == null)
					return false;
			colors = getShadowPressed();
			for (int i = 0; i < colors.length; i++)
				if (colors[i] == null)
					return false;
			return true;
		}

		/**
		 * Returns the pressed highlight colors of this border.
		 * 
		 * @return Colors as an array of Colors
		 * @since 2.0
		 */
		protected Color[] getHighlightPressed() {
			return highlightPressed;
		}

		/**
		 * Returns the pressed shadow colors of this border.
		 * 
		 * @return Colors as an array of Colors
		 * @since 2.0
		 */
		protected Color[] getShadowPressed() {
			return shadowPressed;
		}
	}

	/**
	 * Interface defining commonly used schemes for the ButtonBorder.
	 */
	public static interface SCHEMES {

		/**
		 * Contrast button scheme
		 */
		ButtonScheme BUTTON_CONTRAST = new ButtonScheme(new Color[] { button,
				buttonLightest }, DARKEST_DARKER);
		/**
		 * Regular button scheme
		 */
		ButtonScheme BUTTON = new ButtonScheme(new Color[] { buttonLightest },
				DARKEST_DARKER);
		/**
		 * Toolbar button scheme
		 */
		ButtonScheme TOOLBAR = new ButtonScheme(new Color[] { buttonLightest },
				new Color[] { buttonDarker });
		/**
		 * Scrollbar button scheme
		 */
		ButtonScheme BUTTON_SCROLLBAR = new ButtonScheme(new Color[] { button,
				buttonLightest }, DARKEST_DARKER, new Color[] { buttonDarker },
				new Color[] { buttonDarker });
	}

	/**
	 * Constructs a ButtonBorder with a predefined button scheme set as its
	 * default.
	 * 
	 * @since 2.0
	 */
	public ButtonBorder() {
		setScheme(SCHEMES.BUTTON);
	}

	/**
	 * Constructs a ButtonBorder with the input ButtonScheme set as its Scheme.
	 * 
	 * @param scheme
	 *            ButtonScheme for this ButtonBorder.
	 * @since 2.0
	 */
	public ButtonBorder(ButtonScheme scheme) {
		setScheme(scheme);
	}

	/**
	 * Paints this border with the help of the set scheme, the model of the
	 * clickable figure, and other inputs. The scheme is used in conjunction
	 * with the state of the model to get the appropriate colors for the border.
	 * 
	 * @param figure
	 *            The Clickable that this border belongs to
	 * @param graphics
	 *            The graphics used for painting
	 * @param insets
	 *            The insets
	 */
	public void paint(IFigure figure, Graphics graphics, Insets insets) {
		Clickable clickable = (Clickable) figure;
		ButtonModel model = clickable.getModel();
		ButtonScheme colorScheme = (ButtonScheme) getScheme();

		if (clickable.isRolloverEnabled() && !model.isMouseOver()
				&& !model.isSelected())
			return;

		Color tl[], br[];
		if (model.isSelected() || model.isArmed()) {
			tl = colorScheme.getShadowPressed();
			br = colorScheme.getHighlightPressed();
		} else {
			tl = colorScheme.getHighlight();
			br = colorScheme.getShadow();
		}

		paint(graphics, figure, insets, tl, br);
	}

}