/*******************************************************************************
 * 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;
import org.eclipse.draw2d.geometry.Rectangle;

/**
 * SchemeBorder allows the creation of borders based on
 * {@link SchemeBorder.Scheme Schemes}. A <i>Scheme</i> is a class whose only
 * purpose is to carry border specific information. SchemeBorder renders the
 * border based on the information given by the <i>Scheme</i> set to it.
 */
public class SchemeBorder extends AbstractBorder implements ColorConstants {

	/** The {@link SchemeBorder.Scheme} associated with this SchemeBorder **/
	protected Scheme scheme = null;

	/** Arrays of Colors, used for shadow or highlight effects **/
	protected static final Color DARKEST_DARKER[] = new Color[] {
			buttonDarkest, buttonDarker }, LIGHTER_DARKER[] = new Color[] {
			buttonLightest, buttonDarker }, DARKER_LIGHTER[] = new Color[] {
			buttonDarker, buttonLightest };

	/**
	 * Holds a set of information about a border, which can be changed to create
	 * a wide range of schemes. Provides support for border opacity, size,
	 * highlight side and shadow side colors.
	 */
	public static class Scheme {
		private Insets insets;
		private boolean isOpaque = false;

		/** Arrays of Colors, used for highlight and shadow effecsts */
		protected Color highlight[], shadow[];

		/**
		 * Constructs a default border Scheme with no border sides.
		 * 
		 * @since 2.0
		 */
		protected Scheme() {
		}

		/**
		 * Constructs a border Scheme with the specified highlight and shadow
		 * colors. The size of the border depends on the number of colors passed
		 * in for each parameter. Hightlight colors are used in the top and left
		 * sides of the border, and Shadow colors are used in the bottom and
		 * right sides of the border.
		 * 
		 * @param highlight
		 *            the hightlight colors
		 * @param shadow
		 *            the shadow colors
		 * @since 2.0
		 */
		public Scheme(Color[] highlight, Color[] shadow) {
			this.highlight = highlight;
			this.shadow = shadow;
			init();
		}

		/**
		 * Constructs a border scheme with the specified colors. The input
		 * colors serve as both highlight and shadow colors. The size of the
		 * border is the number of colors passed in as input. Hightlight colors
		 * are used in the top and left sides of the border, and Shadow colors
		 * are used in the bottom and right sides of the border.
		 * 
		 * @param colors
		 *            the colors to be used for the border
		 * @since 2.0
		 */
		public Scheme(Color[] colors) {
			highlight = shadow = colors;
			init();
		}

		/**
		 * Calculates and returns the Insets for this border Scheme. The
		 * calculations depend on the number of colors passed in as input.
		 * 
		 * @return the Insets used by this border
		 * @since 2.0
		 */
		protected Insets calculateInsets() {
			int tl = getHighlight().length;
			int br = getShadow().length;
			return new Insets(tl, tl, br, br);
		}

		/**
		 * Calculates and retuns the opaque state of this border scheme. Returns
		 * <code>false</code> if any of the border colors are <code>null</code>.
		 * This is done to prevent the appearance of underlying pixels since the
		 * border color is <code>null</code>.
		 * 
		 * @return <code>true</code> if this border is opaque
		 * @since 2.0
		 */
		protected boolean calculateOpaque() {
			Color colors[] = getHighlight();
			for (int i = 0; i < colors.length; i++)
				if (colors[i] == null)
					return false;
			colors = getShadow();
			for (int i = 0; i < colors.length; i++)
				if (colors[i] == null)
					return false;
			return true;
		}

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

		/**
		 * Returns the Insets required by this Scheme.
		 * 
		 * @return the Insets
		 * @since 2.0
		 */
		protected Insets getInsets() {
			return insets;
		}

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

		/**
		 * Calculates and initializes the properties of this border scheme.
		 * 
		 * @since 2.0
		 */
		protected void init() {
			insets = calculateInsets();
			isOpaque = calculateOpaque();
		}

		/**
		 * Returns whether this border should be opaque or not.
		 * 
		 * @return <code>true</code> if this border is opaque
		 * @since 2.0
		 */
		protected boolean isOpaque() {
			return isOpaque;
		}
	}

	/**
	 * Interface which defines some commonly used schemes for the border. These
	 * schemes can be given as input to the {@link SchemeBorder SchemeBorder} to
	 * generate appropriate borders.
	 */
	public static interface SCHEMES {

		/** Schemes used for shadow and highlight effects **/
		Scheme BUTTON_CONTRAST = new Scheme(new Color[] { button,
				buttonLightest }, DARKEST_DARKER), BUTTON_RAISED = new Scheme(
				new Color[] { buttonLightest }, DARKEST_DARKER),
				BUTTON_PRESSED = new Scheme(DARKEST_DARKER,
						new Color[] { buttonLightest }), RAISED = new Scheme(
						new Color[] { buttonLightest },
						new Color[] { buttonDarkest }), LOWERED = new Scheme(
						new Color[] { buttonDarkest },
						new Color[] { buttonLightest }), RIDGED = new Scheme(
						LIGHTER_DARKER, DARKER_LIGHTER), ETCHED = new Scheme(
						DARKER_LIGHTER, LIGHTER_DARKER);
	}

	/**
	 * Constructs a default SchemeBorder with no scheme defined.
	 * 
	 * @since 2.0
	 */
	protected SchemeBorder() {
	}

	/**
	 * Constructs a SchemeBorder with the Scheme given as input.
	 * 
	 * @param scheme
	 *            the Scheme to be used by this border
	 * @since 2.0
	 */
	public SchemeBorder(Scheme scheme) {
		setScheme(scheme);
	}

	/**
	 * @see Border#getInsets(IFigure)
	 */
	public Insets getInsets(IFigure figure) {
		return getScheme().getInsets();
	}

	/**
	 * Returns the scheme used by this border.
	 * 
	 * @return the Scheme used by this border
	 * @since 2.0
	 */
	protected Scheme getScheme() {
		return scheme;
	}

	/**
	 * Returns the opaque state of this border. Returns <code>true</code>
	 * indicating that this will fill in the area enclosed by the border.
	 * 
	 * @see Border#isOpaque()
	 */
	public boolean isOpaque() {
		return true;
	}

	/**
	 * Sets the Scheme for this border to the Scheme given as input.
	 * 
	 * @param scheme
	 *            the Scheme for this border
	 * @since 2.0
	 */
	protected void setScheme(Scheme scheme) {
		this.scheme = scheme;
	}

	/**
	 * @see Border#paint(IFigure, Graphics, Insets)
	 */
	public void paint(IFigure figure, Graphics g, Insets insets) {
		Color[] tl = scheme.getHighlight();
		Color[] br = scheme.getShadow();

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

	/**
	 * Paints the border using the information in the set Scheme and the inputs
	 * given. Side widths are determined by the number of colors in the Scheme
	 * for each side.
	 * 
	 * @param graphics
	 *            the graphics object
	 * @param fig
	 *            the figure this border belongs to
	 * @param insets
	 *            the insets
	 * @param tl
	 *            the highlight (top/left) colors
	 * @param br
	 *            the shadow (bottom/right) colors
	 */
	protected void paint(Graphics graphics, IFigure fig, Insets insets,
			Color[] tl, Color[] br) {
		graphics.setLineWidth(1);
		graphics.setLineStyle(Graphics.LINE_SOLID);
		graphics.setXORMode(false);

		Rectangle rect = getPaintRectangle(fig, insets);

		int top = rect.y;
		int left = rect.x;
		int bottom = rect.bottom() - 1;
		int right = rect.right() - 1;
		Color color;

		for (int i = 0; i < br.length; i++) {
			color = br[i];
			graphics.setForegroundColor(color);
			graphics.drawLine(right - i, bottom - i, right - i, top + i);
			graphics.drawLine(right - i, bottom - i, left + i, bottom - i);
		}

		right--;
		bottom--;

		for (int i = 0; i < tl.length; i++) {
			color = tl[i];
			graphics.setForegroundColor(color);
			graphics.drawLine(left + i, top + i, right - i, top + i);
			graphics.drawLine(left + i, top + i, left + i, bottom - i);
		}
	}

}