/*
    *  XNap - A P2P framework and client.
    *
    *  See the file AUTHORS for copyright information.
    *
    *  This program is free software; you can redistribute it and/or modify
    *  it under the terms of the GNU General Public License as published by
    *  the Free Software Foundation.
    *
   *  This program is distributed in the hope that it will be useful,
   *  but WITHOUT ANY WARRANTY; without even the implied warranty of
   *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *  GNU General Public License for more details.
   *
   *  You should have received a copy of the GNU General Public License
   *  along with this program; if not, write to the Free Software
   *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   */
  
  package org.xnap.gui.util;
  
  import java.awt.Component;
  import java.awt.Graphics;
  import java.awt.Image;
  import java.net.URL;
  
  import javax.swing.Icon;
  import javax.swing.ImageIcon;
  
  import org.xnap.action.AbstractXNapAction;
  import org.xnap.util.FileHelper;
  import org.xnap.util.Preferences;
  
  /***
   * This class provides methods to get icons in certain sizes. All icon
   * directories are searched.
   */
  public class IconHelper
  {
  
      //--- Constant(s) ---
  
      public static final String XNAP_ICON = AbstractXNapAction.XNAP_ICON;
  
      /***
       * List bigger sizes first. Scaling down looks nicer than scaling up.
       */
      private static final int[] ICON_SUBDIRS = {
  		32, 22, 16, 64, 48,
      };
  
  	/***
  	 * The default path to search for icons.
  	 */
      public static final String DEFAULT_ICON_PATH = "icons/";
  
      //--- Data field(s) ---
  
      private static Preferences prefs = Preferences.getInstance();
  	
  	/***
  	 * The path to search for icons.
  	 */
  	private static String iconPath = DEFAULT_ICON_PATH;
  
      //--- Constructor(s) ---
  
      //--- Method(s) ---
  
      /***
       * Returns an icon with <code>size</code> height and width. If no icon
       * named <code>filename</code> can be found and
       * <code>createEmptyIcon</code> is true, an empty icon is returned.
       *
       * <p>If the icon does not fit <code>size</code> it is scaled.
       */
      public static final Icon getIcon(String filename, int size, 
  									 boolean createEmptyIcon)
      {
  		if (filename == null) {
  			return createEmptyIcon ? new EmptyIcon(size) : null;
  		}
  
  		ImageIcon icon = getImage(iconPath, size, filename);
  		if (icon == null && !DEFAULT_ICON_PATH.equals(iconPath)) {
  			// try default path as a fallback
  			icon = getImage(DEFAULT_ICON_PATH, size, filename);
  		}
  
  		if (icon != null) {
  			if (icon.getIconWidth() != size || icon.getIconHeight() != size) {
  				// scale icon to fit size requirements
  				icon = new ImageIcon(icon.getImage().getScaledInstance
  									 (size, size, Image.SCALE_SMOOTH));
  			}
  
  			return icon;
  		}
  		else {
 			return createEmptyIcon ? new EmptyIcon(size) : null;
 		}
     }
 
     /***
      * @return never returns null
      * @see #getIcon(String, int, boolean)
      */
     public static final Icon getIcon(String filename, int size)
     {
 		return getIcon(filename, size, true);
     }
     
     /***
      * Searches {@link #iconPath} + {@link #ICON_PATH} for
      * <code>filename</code>. If filename is not found {@link
      * #ICON_PATH} is searched as a fallback.
      *
      * @return null, if <code>filename</code> does not exists.
      */
     public static final ImageIcon getImage(String filename)
     {
 		if (!prefs.getShowIcons()) {
 			return null;
 		}
 
 		URL url = FileHelper.getResource(iconPath + filename);
 		if (url == null && !DEFAULT_ICON_PATH.equals(iconPath)) {
 			// try default path as a fallback
 			url = FileHelper.getResource(DEFAULT_ICON_PATH + filename);
 		}
 		
 		return (url != null) ? new ImageIcon(url) : null;
     }
 
     public static final ImageIcon getImage
 		(String path, int size, String filename)
 	{
 		if (!prefs.getShowIcons()) {
 			return null;
 		}
 
 		URL url = FileHelper.getResource(path + size + "/" + filename);
 		if (url != null) {
 			return new ImageIcon(url);
 		}
 
 		// look for the icon in other subdirecotries
 		for (int i = 0; i < ICON_SUBDIRS.length; i++) {
 			url = FileHelper.getResource
 				(path + ICON_SUBDIRS[i] + "/" + filename);
 			if (url != null) {
 				return new ImageIcon(url);
 			}
 		}
 
 		return null;
 	}
 
     public static final Icon getEmptyIcon(int size)
     {
 		return new EmptyIcon(size);
     }	
 
     public static final Icon getListIcon(String filename)
     {
 		return getIcon(filename, 32, false);
     }
 
     public static final Icon getButtonIcon(String filename)
     {
 		return getIcon(filename, 16, false);
     }
 
     public static final Icon getMenuIcon(String filename)
     {
 		return getIcon(filename, 16);
     }
 
 	public static String getIconPath()
 	{
 		return iconPath;
 	}
 
 	public static Icon getScaledLogo(int height)
 	{
 		ImageIcon icon = IconHelper.getImage("xnap_logo.png");
 		return (icon != null)
 			? new ImageIcon(icon.getImage().getScaledInstance
 							(-1, height, Image.SCALE_SMOOTH))
 			: null;
 	}
 
     public static final Icon getStatusBarIcon(String filename)
     {
 		return getIcon(filename, 16, false);
     }
 
     public static final Icon getTabTitleIcon(String filename)
     {
 		return getIcon(filename, 16, false);
     }
 
     public static final Icon getTreeIcon(String filename)
     {
 		return getIcon(filename, 16, false);
     }
 
     public static final Icon getToolBarIcon(String filename)
     {
 		return getIcon(filename, 22);
     }
 
     public static final Icon getWizardIcon(String filename)
 	{
 		return getIcon(filename, 48, false);
 	}
 
 	/***
 	 * Sets the search path iconPath. Used for icon theming.
 	 */
 	public static void setIconPath(String iconPath)
 	{
 		if (iconPath == null) {
 			throw new NullPointerException();
 		}
 
 		IconHelper.iconPath = iconPath;
 	}
     
     /***
      * Provides an empty, transparent icon.
      */
     public static class EmptyIcon implements Icon
     {
 		private int size;
 
 		/***
 		 * Constructs an empty icon with a width and heigt of 
 		 * <code>size</code>.
 		 */
 		public EmptyIcon(int size)
 		{
 			this.size = size;
 		}
 	
 		public int getIconHeight() 
 		{
 			return size;
 		}
 	
 		public int getIconWidth() 
 		{
 			return size;
 		}
 	
 		public void paintIcon(Component c, Graphics g, int x, int y) 
 		{
 		}	
 	
     }
 
 }