/*******************************************************************************
    * Copyright (c) 2011 Google, Inc.
    * 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:
    *    Google, Inc. - initial API and implementation
   *******************************************************************************/
  package org.eclipse.wb.swt;
  
  import java.io.FileInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.HashMap;
  import java.util.Map;
  
  import org.eclipse.swt.SWT;
  import org.eclipse.swt.graphics.Color;
  import org.eclipse.swt.graphics.Cursor;
  import org.eclipse.swt.graphics.Font;
  import org.eclipse.swt.graphics.FontData;
  import org.eclipse.swt.graphics.GC;
  import org.eclipse.swt.graphics.Image;
  import org.eclipse.swt.graphics.ImageData;
  import org.eclipse.swt.graphics.RGB;
  import org.eclipse.swt.graphics.Rectangle;
  import org.eclipse.swt.widgets.Display;
  
  /**
   * Utility class for managing OS resources associated with SWT controls such as colors, fonts, images, etc.
   * <p>
   * !!! IMPORTANT !!! Application code must explicitly invoke the <code>dispose()</code> method to release the
   * operating system resources managed by cached objects when those objects and OS resources are no longer
   * needed (e.g. on application shutdown)
   * <p>
   * This class may be freely distributed as part of any application or plugin.
   * <p>
   * @author scheglov_ke
   * @author Dan Rubel
   */
  public class SWTResourceManager {
  	////////////////////////////////////////////////////////////////////////////
  	//
  	// Color
  	//
  	////////////////////////////////////////////////////////////////////////////
  	private static Map<RGB, Color> m_colorMap = new HashMap<RGB, Color>();
  	/**
  	 * Returns the system {@link Color} matching the specific ID.
  	 * 
  	 * @param systemColorID
  	 *            the ID value for the color
  	 * @return the system {@link Color} matching the specific ID
  	 */
  	public static Color getColor(int systemColorID) {
  		Display display = Display.getCurrent();
  		return display.getSystemColor(systemColorID);
  	}
  	/**
  	 * Returns a {@link Color} given its red, green and blue component values.
  	 * 
  	 * @param r
  	 *            the red component of the color
  	 * @param g
  	 *            the green component of the color
  	 * @param b
  	 *            the blue component of the color
  	 * @return the {@link Color} matching the given red, green and blue component values
  	 */
  	public static Color getColor(int r, int g, int b) {
  		return getColor(new RGB(r, g, b));
  	}
  	/**
  	 * Returns a {@link Color} given its RGB value.
  	 * 
  	 * @param rgb
  	 *            the {@link RGB} value of the color
  	 * @return the {@link Color} matching the RGB value
  	 */
  	public static Color getColor(RGB rgb) {
  		Color color = m_colorMap.get(rgb);
  		if (color == null) {
  			Display display = Display.getCurrent();
  			color = new Color(display, rgb);
  			m_colorMap.put(rgb, color);
  		}
  		return color;
  	}
  	/**
  	 * Dispose of all the cached {@link Color}'s.
  	 */
  	public static void disposeColors() {
  		for (Color color : m_colorMap.values()) {
  			color.dispose();
  		}
  		m_colorMap.clear();
  	}
 	////////////////////////////////////////////////////////////////////////////
 	//
 	// Image
 	//
 	////////////////////////////////////////////////////////////////////////////
 	/**
 	 * Maps image paths to images.
 	 */
 	private static Map<String, Image> m_imageMap = new HashMap<String, Image>();
 	/**
 	 * Returns an {@link Image} encoded by the specified {@link InputStream}.
 	 * 
 	 * @param stream
 	 *            the {@link InputStream} encoding the image data
 	 * @return the {@link Image} encoded by the specified input stream
 	 */
 	protected static Image getImage(InputStream stream) throws IOException {
 		try {
 			Display display = Display.getCurrent();
 			ImageData data = new ImageData(stream);
 			if (data.transparentPixel > 0) {
 				return new Image(display, data, data.getTransparencyMask());
 			}
 			return new Image(display, data);
 		} finally {
 			stream.close();
 		}
 	}
 	/**
 	 * Returns an {@link Image} stored in the file at the specified path.
 	 * 
 	 * @param path
 	 *            the path to the image file
 	 * @return the {@link Image} stored in the file at the specified path
 	 */
 	public static Image getImage(String path) {
 		Image image = m_imageMap.get(path);
 		if (image == null) {
 			try {
 				image = getImage(new FileInputStream(path));
 				m_imageMap.put(path, image);
 			} catch (Exception e) {
 				image = getMissingImage();
 				m_imageMap.put(path, image);
 			}
 		}
 		return image;
 	}
 	/**
 	 * Returns an {@link Image} stored in the file at the specified path relative to the specified class.
 	 * 
 	 * @param clazz
 	 *            the {@link Class} relative to which to find the image
 	 * @param path
 	 *            the path to the image file, if starts with <code>'/'</code>
 	 * @return the {@link Image} stored in the file at the specified path
 	 */
 	public static Image getImage(Class<?> clazz, String path) {
 		String key = clazz.getName() + '|' + path;
 		Image image = m_imageMap.get(key);
 		if (image == null) {
 			try {
 				image = getImage(clazz.getResourceAsStream(path));
 				m_imageMap.put(key, image);
 			} catch (Exception e) {
 				image = getMissingImage();
 				m_imageMap.put(key, image);
 			}
 		}
 		return image;
 	}
 	private static final int MISSING_IMAGE_SIZE = 10;
 	/**
 	 * @return the small {@link Image} that can be used as placeholder for missing image.
 	 */
 	private static Image getMissingImage() {
 		Image image = new Image(Display.getCurrent(), MISSING_IMAGE_SIZE, MISSING_IMAGE_SIZE);
 		//
 		GC gc = new GC(image);
 		gc.setBackground(getColor(SWT.COLOR_RED));
 		gc.fillRectangle(0, 0, MISSING_IMAGE_SIZE, MISSING_IMAGE_SIZE);
 		gc.dispose();
 		//
 		return image;
 	}
 	/**
 	 * Style constant for placing decorator image in top left corner of base image.
 	 */
 	public static final int TOP_LEFT = 1;
 	/**
 	 * Style constant for placing decorator image in top right corner of base image.
 	 */
 	public static final int TOP_RIGHT = 2;
 	/**
 	 * Style constant for placing decorator image in bottom left corner of base image.
 	 */
 	public static final int BOTTOM_LEFT = 3;
 	/**
 	 * Style constant for placing decorator image in bottom right corner of base image.
 	 */
 	public static final int BOTTOM_RIGHT = 4;
 	/**
 	 * Internal value.
 	 */
 	protected static final int LAST_CORNER_KEY = 5;
 	/**
 	 * Maps images to decorated images.
 	 */
 	@SuppressWarnings("unchecked")
 	private static Map<Image, Map<Image, Image>>[] m_decoratedImageMap = new Map[LAST_CORNER_KEY];
 	/**
 	 * Returns an {@link Image} composed of a base image decorated by another image.
 	 * 
 	 * @param baseImage
 	 *            the base {@link Image} that should be decorated
 	 * @param decorator
 	 *            the {@link Image} to decorate the base image
 	 * @return {@link Image} The resulting decorated image
 	 */
 	public static Image decorateImage(Image baseImage, Image decorator) {
 		return decorateImage(baseImage, decorator, BOTTOM_RIGHT);
 	}
 	/**
 	 * Returns an {@link Image} composed of a base image decorated by another image.
 	 * 
 	 * @param baseImage
 	 *            the base {@link Image} that should be decorated
 	 * @param decorator
 	 *            the {@link Image} to decorate the base image
 	 * @param corner
 	 *            the corner to place decorator image
 	 * @return the resulting decorated {@link Image}
 	 */
 	public static Image decorateImage(final Image baseImage, final Image decorator, final int corner) {
 		if (corner <= 0 || corner >= LAST_CORNER_KEY) {
 			throw new IllegalArgumentException("Wrong decorate corner");
 		}
 		Map<Image, Map<Image, Image>> cornerDecoratedImageMap = m_decoratedImageMap[corner];
 		if (cornerDecoratedImageMap == null) {
 			cornerDecoratedImageMap = new HashMap<Image, Map<Image, Image>>();
 			m_decoratedImageMap[corner] = cornerDecoratedImageMap;
 		}
 		Map<Image, Image> decoratedMap = cornerDecoratedImageMap.get(baseImage);
 		if (decoratedMap == null) {
 			decoratedMap = new HashMap<Image, Image>();
 			cornerDecoratedImageMap.put(baseImage, decoratedMap);
 		}
 		//
 		Image result = decoratedMap.get(decorator);
 		if (result == null) {
 			Rectangle bib = baseImage.getBounds();
 			Rectangle dib = decorator.getBounds();
 			//
 			result = new Image(Display.getCurrent(), bib.width, bib.height);
 			//
 			GC gc = new GC(result);
 			gc.drawImage(baseImage, 0, 0);
 			if (corner == TOP_LEFT) {
 				gc.drawImage(decorator, 0, 0);
 			} else if (corner == TOP_RIGHT) {
 				gc.drawImage(decorator, bib.width - dib.width, 0);
 			} else if (corner == BOTTOM_LEFT) {
 				gc.drawImage(decorator, 0, bib.height - dib.height);
 			} else if (corner == BOTTOM_RIGHT) {
 				gc.drawImage(decorator, bib.width - dib.width, bib.height - dib.height);
 			}
 			gc.dispose();
 			//
 			decoratedMap.put(decorator, result);
 		}
 		return result;
 	}
 	/**
 	 * Dispose all of the cached {@link Image}'s.
 	 */
 	public static void disposeImages() {
 		// dispose loaded images
 		{
 			for (Image image : m_imageMap.values()) {
 				image.dispose();
 			}
 			m_imageMap.clear();
 		}
 		// dispose decorated images
 		for (int i = 0; i < m_decoratedImageMap.length; i++) {
 			Map<Image, Map<Image, Image>> cornerDecoratedImageMap = m_decoratedImageMap[i];
 			if (cornerDecoratedImageMap != null) {
 				for (Map<Image, Image> decoratedMap : cornerDecoratedImageMap.values()) {
 					for (Image image : decoratedMap.values()) {
 						image.dispose();
 					}
 					decoratedMap.clear();
 				}
 				cornerDecoratedImageMap.clear();
 			}
 		}
 	}
 	////////////////////////////////////////////////////////////////////////////
 	//
 	// Font
 	//
 	////////////////////////////////////////////////////////////////////////////
 	/**
 	 * Maps font names to fonts.
 	 */
 	private static Map<String, Font> m_fontMap = new HashMap<String, Font>();
 	/**
 	 * Maps fonts to their bold versions.
 	 */
 	private static Map<Font, Font> m_fontToBoldFontMap = new HashMap<Font, Font>();
 	/**
 	 * Returns a {@link Font} based on its name, height and style.
 	 * 
 	 * @param name
 	 *            the name of the font
 	 * @param height
 	 *            the height of the font
 	 * @param style
 	 *            the style of the font
 	 * @return {@link Font} The font matching the name, height and style
 	 */
 	public static Font getFont(String name, int height, int style) {
 		return getFont(name, height, style, false, false);
 	}
 	/**
 	 * Returns a {@link Font} based on its name, height and style. Windows-specific strikeout and underline
 	 * flags are also supported.
 	 * 
 	 * @param name
 	 *            the name of the font
 	 * @param size
 	 *            the size of the font
 	 * @param style
 	 *            the style of the font
 	 * @param strikeout
 	 *            the strikeout flag (warning: Windows only)
 	 * @param underline
 	 *            the underline flag (warning: Windows only)
 	 * @return {@link Font} The font matching the name, height, style, strikeout and underline
 	 */
 	public static Font getFont(String name, int size, int style, boolean strikeout, boolean underline) {
 		String fontName = name + '|' + size + '|' + style + '|' + strikeout + '|' + underline;
 		Font font = m_fontMap.get(fontName);
 		if (font == null) {
 			FontData fontData = new FontData(name, size, style);
 			if (strikeout || underline) {
 				try {
 					Class<?> logFontClass = Class.forName("org.eclipse.swt.internal.win32.LOGFONT"); //$NON-NLS-1$
 					Object logFont = FontData.class.getField("data").get(fontData); //$NON-NLS-1$
 					if (logFont != null && logFontClass != null) {
 						if (strikeout) {
 							logFontClass.getField("lfStrikeOut").set(logFont, Byte.valueOf((byte) 1)); //$NON-NLS-1$
 						}
 						if (underline) {
 							logFontClass.getField("lfUnderline").set(logFont, Byte.valueOf((byte) 1)); //$NON-NLS-1$
 						}
 					}
 				} catch (Throwable e) {
 					System.err.println("Unable to set underline or strikeout" + " (probably on a non-Windows platform). " + e); //$NON-NLS-1$ //$NON-NLS-2$
 				}
 			}
 			font = new Font(Display.getCurrent(), fontData);
 			m_fontMap.put(fontName, font);
 		}
 		return font;
 	}
 	/**
 	 * Returns a bold version of the given {@link Font}.
 	 * 
 	 * @param baseFont
 	 *            the {@link Font} for which a bold version is desired
 	 * @return the bold version of the given {@link Font}
 	 */
 	public static Font getBoldFont(Font baseFont) {
 		Font font = m_fontToBoldFontMap.get(baseFont);
 		if (font == null) {
 			FontData fontDatas[] = baseFont.getFontData();
 			FontData data = fontDatas[0];
 			font = new Font(Display.getCurrent(), data.getName(), data.getHeight(), SWT.BOLD);
 			m_fontToBoldFontMap.put(baseFont, font);
 		}
 		return font;
 	}
 	/**
 	 * Dispose all of the cached {@link Font}'s.
 	 */
 	public static void disposeFonts() {
 		// clear fonts
 		for (Font font : m_fontMap.values()) {
 			font.dispose();
 		}
 		m_fontMap.clear();
 		// clear bold fonts
 		for (Font font : m_fontToBoldFontMap.values()) {
 			font.dispose();
 		}
 		m_fontToBoldFontMap.clear();
 	}
 	////////////////////////////////////////////////////////////////////////////
 	//
 	// Cursor
 	//
 	////////////////////////////////////////////////////////////////////////////
 	/**
 	 * Maps IDs to cursors.
 	 */
 	private static Map<Integer, Cursor> m_idToCursorMap = new HashMap<Integer, Cursor>();
 	/**
 	 * Returns the system cursor matching the specific ID.
 	 * 
 	 * @param id
 	 *            int The ID value for the cursor
 	 * @return Cursor The system cursor matching the specific ID
 	 */
 	public static Cursor getCursor(int id) {
 		Integer key = Integer.valueOf(id);
 		Cursor cursor = m_idToCursorMap.get(key);
 		if (cursor == null) {
 			cursor = new Cursor(Display.getDefault(), id);
 			m_idToCursorMap.put(key, cursor);
 		}
 		return cursor;
 	}
 	/**
 	 * Dispose all of the cached cursors.
 	 */
 	public static void disposeCursors() {
 		for (Cursor cursor : m_idToCursorMap.values()) {
 			cursor.dispose();
 		}
 		m_idToCursorMap.clear();
 	}
 	////////////////////////////////////////////////////////////////////////////
 	//
 	// General
 	//
 	////////////////////////////////////////////////////////////////////////////
 	/**
 	 * Dispose of cached objects and their underlying OS resources. This should only be called when the cached
 	 * objects are no longer needed (e.g. on application shutdown).
 	 */
 	public static void dispose() {
 		disposeColors();
 		disposeImages();
 		disposeFonts();
 		disposeCursors();
 	}
 }