package org.apache.turbine.services.ui;
   
   /*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache License, Version 2.0 (the
    * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   */
  
  import java.io.File;
  import java.io.FilenameFilter;
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.HashMap;
  import java.util.Properties;
  
  import org.apache.commons.configuration.Configuration;
  import org.apache.commons.io.filefilter.DirectoryFileFilter;
  import org.apache.commons.lang.StringUtils;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.turbine.Turbine;
  import org.apache.turbine.services.InitializationException;
  import org.apache.turbine.services.TurbineBaseService;
  import org.apache.turbine.services.pull.TurbinePull;
  import org.apache.turbine.services.servlet.TurbineServlet;
  import org.apache.turbine.util.ServerData;
  import org.apache.turbine.util.uri.DataURI;
  
  /***
   * The UI service provides for shared access to User Interface (skin) files,
   * as well as the ability for non-default skin files to inherit properties from 
   * a default skin.  Use TurbineUI to access skin properties from your screen 
   * classes and action code. UITool is provided as a pull tool for accessing 
   * skin properties from your templates. 
   *
   * @author <a href="mailto:jvanzyl@periapt.com">Jason van Zyl</a>
   * @author <a href="mailto:james_coltman@majorband.co.uk">James Coltman</a>
   * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
   * @author <a href="mailto:seade@backstagetech.com.au">Scott Eade</a>
   * @author <a href="thomas.vandahl@tewisoft.de">Thomas Vandahl</a>
   * @version $Id$
   * @see UIService
   * @see UITool
   */
  public class TurbineUIService
          extends TurbineBaseService
          implements UIService
  {
      /*** Logging. */
      private static Log log = LogFactory.getLog(TurbineUIService.class);
  
      /***
       * The location of the skins within the application resources directory.
       */
      private static final String SKINS_DIRECTORY = "/ui/skins";
  
      /***
       * The name of the directory where images are stored for this skin.
       */
      private static final String IMAGES_DIRECTORY = "/images";
  
      /***
       * Property tag for the default skin that is to be used for the web
       * application.
       */
      private static final String SKIN_PROPERTY = "tool.ui.skin";
  
      /***
       * Property tag for the image directory inside the skin that is to be used
       * for the web application.
       */
      private static final String IMAGEDIR_PROPERTY = "tool.ui.dir.image";
  
      /***
       * Property tag for the skin directory that is to be used for the web
       * application.
       */
      private static final String SKINDIR_PROPERTY = "tool.ui.dir.skin";
  
      /***
       * Property tag for the css file that is to be used for the web application.
       */
      private static final String CSS_PROPERTY = "tool.ui.css";
  
      /***
       * Property tag for indicating if relative links are wanted for the web
      * application.
      */
     private static final String RELATIVE_PROPERTY = "tool.ui.want.relative";
 
     /***
      * Default skin name. This name refers to a directory in the 
      * WEBAPP/resources/ui/skins directory. There is a file called skin.props
      * which contains the name/value pairs to be made available via the skin.
      */
     public static final String SKIN_PROPERTY_DEFAULT = "default";
 
     /***
      * The skins directory, qualified by the resources directory (which is
      * relative to the webapp context). This is used for constructing URIs and
      * for retrieving skin files.
      */
     private String skinsDirectory;
 
     /***
      * The file within the skin directory that contains the name/value pairs for
      * the skin.
      */
     private static final String SKIN_PROPS_FILE = "skin.props";
 
     /***
      * The file name for the skin style sheet.
      */
     private static final String DEFAULT_SKIN_CSS_FILE = "skin.css";
 
     /***
      * The directory within the skin directory that contains the skin images.
      */
     private String imagesDirectory;
 
     /***
      * The name of the css file within the skin directory.
      */
     private String cssFile;
 
     /***
      * The flag that determines if the links that are returned are are absolute
      * or relative.
      */
     private boolean wantRelative = false;
 
     /***
      * The skin Properties store.
      */
     private HashMap skins = new HashMap();
 
     /***
      * Refresh the service by clearing all skins.
      */
     public void refresh()
     {
         clearSkins();
     }
 
     /***
      * Refresh a particular skin by clearing it.
      * 
      * @param skinName the name of the skin to clear.
      */
     public void refresh(String skinName)
     {
         clearSkin(skinName);
     }
     
     /***
      * Retrieve the Properties for a specific skin.  If they are not yet loaded
      * they will be.  If the specified skin does not exist properties for the
      * default skin configured for the webapp will be returned and an error
      * level message will be written to the log.  If the webapp skin does not
      * exist the default skin will be used and id that doesn't exist an empty
      * Properties will be returned.
      * 
      * @param skinName the name of the skin whose properties are to be 
      * retrieved.
      * @return the Properties for the named skin or the properties for the 
      * default skin configured for the webapp if the named skin does not exist.
      */
     private Properties getSkinProperties(String skinName)
     {
         Properties skinProperties = (Properties) skins.get(skinName);
         return null != skinProperties ? skinProperties : loadSkin(skinName); 
     }
 
     /***
      * Retrieve a skin property from the named skin.  If the property is not 
      * defined in the named skin the value for the default skin will be 
      * provided.  If the named skin does not exist then the skin configured for 
      * the webapp will be used.  If the webapp skin does not exist the default
      * skin will be used.  If the default skin does not exist then 
      * <code>null</code> will be returned.
      * 
      * @param skinName the name of the skin to retrieve the property from.
      * @param key the key to retrieve from the skin.
      * @return the value of the property for the named skin (defaulting to the 
      * default skin), the webapp skin, the default skin or <code>null</code>,
      * depending on whether or not the property or skins exist.
      */
     public String get(String skinName, String key)
     {
         Properties skinProperties = getSkinProperties(skinName);
         return skinProperties.getProperty(key);
     }
 
     /***
      * Retrieve a skin property from the default skin for the webapp.  If the 
      * property is not defined in the webapp skin the value for the default skin 
      * will be provided.  If the webapp skin does not exist the default skin 
      * will be used.  If the default skin does not exist then <code>null</code> 
      * will be returned.
      * 
      * @param key the key to retrieve.
      * @return the value of the property for the webapp skin (defaulting to the 
      * default skin), the default skin or <code>null</code>, depending on 
      * whether or not the property or skins exist.
      */
     public String get(String key)
     {
         return get(getWebappSkinName(), key);
     }
 
     /***
      * Provide access to the list of available skin names.
      * 
      * @return the available skin names.
      */
     public String[] getSkinNames()
     {
         File skinsDir = new File(TurbineServlet.getRealPath(skinsDirectory));
         return skinsDir.list(DirectoryFileFilter.INSTANCE);
     }
 
     /***
      * Clear the map of stored skins. 
      */
     private void clearSkins()
     {
         synchronized (skins)
         {
             skins = new HashMap();
         }
         log.debug("All skins were cleared.");
     }
     
     /***
      * Clear a particular skin from the map of stored skins.
      * 
      * @param skinName the name of the skin to clear.
      */
     private void clearSkin(String skinName)
     {
         synchronized (skins)
         {
             if (!skinName.equals(SKIN_PROPERTY_DEFAULT))
             {
                 skins.remove(SKIN_PROPERTY_DEFAULT);
             }
             skins.remove(skinName);
         }
         log.debug("The skin \"" + skinName 
                 + "\" was cleared (will also clear \"default\" skin).");
     }
 
     /***
      * Load the specified skin.
      * 
      * @param skinName the name of the skin to load.
      * @return the Properties for the named skin if it exists, or the skin
      * configured for the web application if it does not exist, or the default
      * skin if that does not exist, or an empty Parameters object if even that 
      * cannot be found.
      */
     private synchronized Properties loadSkin(String skinName)
     {
         Properties defaultSkinProperties = null;
         
         if (!StringUtils.equals(skinName, SKIN_PROPERTY_DEFAULT))
         {
             defaultSkinProperties = getSkinProperties(SKIN_PROPERTY_DEFAULT);
         }
 
         // The following line is okay even for default.
         Properties skinProperties = new Properties(defaultSkinProperties);
         
         StringBuffer sb = new StringBuffer();
         sb.append('/').append(skinsDirectory);
         sb.append('/').append(skinName);
         sb.append('/').append(SKIN_PROPS_FILE);
         if (log.isDebugEnabled())
         {
             log.debug("Loading selected skin from: " + sb.toString());
         }
 
         try
         {
             // This will NPE if the directory associated with the skin does not
             // exist, but it is habdled correctly below.
             InputStream is = TurbineServlet.getResourceAsStream(sb.toString());
 
             skinProperties.load(is);
         }
         catch (Exception e)
         {
             log.error("Cannot load skin: " + skinName + ", from: "
                     + sb.toString(), e);
             if (!StringUtils.equals(skinName, getWebappSkinName()) 
                     && !StringUtils.equals(skinName, SKIN_PROPERTY_DEFAULT))
             {
                 log.error("Attempting to return the skin configured for " 
                         + "webapp instead of " + skinName);
                 return getSkinProperties(getWebappSkinName());
             }
             else if (!StringUtils.equals(skinName, SKIN_PROPERTY_DEFAULT))
             {
                 log.error("Return the default skin instead of " + skinName);
                 return skinProperties; // Already contains the default skin.
             }
             else
             {
                 log.error("No skins available - returning an empty Properties");
                 return new Properties();
             }
         }
         
         // Replace in skins HashMap
         synchronized (skins)
         {
             skins.put(skinName, skinProperties);
         }
         
         return skinProperties;
     }
 
     /***
      * Get the name of the default skin name for the web application from the 
      * TurbineResources.properties file. If the property is not present the 
      * name of the default skin will be returned.  Note that the web application
      * skin name may be something other than default, in which case its 
      * properties will default to the skin with the name "default".
      * 
      * @return the name of the default skin for the web application.
      */
     public String getWebappSkinName()
     {
         return Turbine.getConfiguration()
                 .getString(SKIN_PROPERTY, SKIN_PROPERTY_DEFAULT);
     }
 
     /***
      * Retrieve the URL for an image that is part of a skin. The images are 
      * stored in the WEBAPP/resources/ui/skins/[SKIN]/images directory.
      *
      * <p>Use this if for some reason your server name, server scheme, or server 
      * port change on a per request basis. I'm not sure if this would happen in 
      * a load balanced situation. I think in most cases the image(String image)
      * method would probably be enough, but I'm not absolutely positive.
      * 
      * @param skinName the name of the skin to retrieve the image from.
      * @param imageId the id of the image whose URL will be generated.
      * @param serverData the serverData to use as the basis for the URL.
      */
     public String image(String skinName, String imageId, ServerData serverData)
     {
         return getSkinResource(serverData, skinName, imagesDirectory, imageId);
     }
 
     /***
      * Retrieve the URL for an image that is part of a skin. The images are 
      * stored in the WEBAPP/resources/ui/skins/[SKIN]/images directory.
      * 
      * @param skinName the name of the skin to retrieve the image from.
      * @param imageId the id of the image whose URL will be generated.
      */
     public String image(String skinName, String imageId)
     {
         return image(skinName, imageId, Turbine.getDefaultServerData());
     }
 
     /***
      * Retrieve the URL for the style sheet that is part of a skin. The style is 
      * stored in the WEBAPP/resources/ui/skins/[SKIN] directory with the 
      * filename skin.css
      *
      * <p>Use this if for some reason your server name, server scheme, or server 
      * port change on a per request basis. I'm not sure if this would happen in 
      * a load balanced situation. I think in most cases the style() method would 
      * probably be enough, but I'm not absolutely positive.
      * 
      * @param skinName the name of the skin to retrieve the style sheet from.
      * @param serverData the serverData to use as the basis for the URL.
      */
     public String getStylecss(String skinName, ServerData serverData)
     {
         return getSkinResource(serverData, skinName, null, cssFile);
     }
 
     /***
      * Retrieve the URL for the style sheet that is part of a skin. The style is 
      * stored in the WEBAPP/resources/ui/skins/[SKIN] directory with the 
      * filename skin.css
      * 
      * @param skinName the name of the skin to retrieve the style sheet from.
      */
     public String getStylecss(String skinName)
     {
         return getStylecss(skinName, Turbine.getDefaultServerData());
     }
 
     /***
      * Retrieve the URL for a given script that is part of a skin. The script is
      * stored in the WEBAPP/resources/ui/skins/[SKIN] directory.
      *
      * <p>Use this if for some reason your server name, server scheme, or server 
      * port change on a per request basis. I'm not sure if this would happen in 
      * a load balanced situation. I think in most cases the style() method would 
      * probably be enough, but I'm not absolutely positive.
      *
      * @param skinName the name of the skin to retrieve the image from.
      * @param filename the name of the script file.
      * @param serverData the serverData to use as the basis for the URL.
      */
     public String getScript(String skinName, String filename,
             ServerData serverData)
     {
         return getSkinResource(serverData, skinName, null, filename);
     }
 
     /***
      * Retrieve the URL for a given script that is part of a skin. The script is
      * stored in the WEBAPP/resources/ui/skins/[SKIN] directory.
      *
      * @param skinName the name of the skin to retrieve the image from.
      * @param filename the name of the script file.
      */
     public String getScript(String skinName, String filename)
     {
         return getScript(skinName, filename, Turbine.getDefaultServerData());
     }
 
     private String stripSlashes(final String path)
     {
         if (StringUtils.isEmpty(path))
         {
             return "";
         }
 
         String ret = path;
         int len = ret.length() - 1;
 
         if (ret.charAt(len) == '/')
         {
             ret = ret.substring(0, len);
         }
 
         if (len > 0 && ret.charAt(0) == '/')
         {
             ret = ret.substring(1);
         }
 
         return ret;
     }
 
     /***
      * Construct the URL to the skin resource.
      *
      * @param serverData the serverData to use as the basis for the URL.
      * @param skinName the name of the skin.
      * @param subDir the sub-directory in which the resource resides or
      * <code>null</code> if it is in the root directory of the skin.
      * @param resourceName the name of the resource to be retrieved.
      * @return the path to the resource.
      */
     private String getSkinResource(ServerData serverData, String skinName,
             String subDir, String resourceName)
     {
         StringBuffer sb = new StringBuffer(skinsDirectory);
         sb.append("/").append(skinName);
         if (subDir != null)
         {
             sb.append("/").append(subDir);
         }
         sb.append("/").append(stripSlashes(resourceName));
 
         DataURI du = new DataURI(serverData);
         du.setScriptName(sb.toString());
         return wantRelative ? du.getRelativeLink() : du.getAbsoluteLink();
     }
 
     // ---- Service initilization ------------------------------------------
 
     /***
      * Initializes the service.
      */
     public void init() throws InitializationException
     {
         Configuration cfg = Turbine.getConfiguration();
 
         // Get the resources directory that is specified in the TR.props or 
         // default to "resources", relative to the webapp.
         StringBuffer sb = new StringBuffer();
         sb.append(stripSlashes(TurbinePull.getResourcesDirectory()));
         sb.append("/");
         sb.append(stripSlashes(
                 cfg.getString(SKINDIR_PROPERTY, SKINS_DIRECTORY)));
         skinsDirectory = sb.toString();
 
         imagesDirectory = stripSlashes(
                 cfg.getString(IMAGEDIR_PROPERTY, IMAGES_DIRECTORY));
         cssFile = cfg.getString(CSS_PROPERTY, DEFAULT_SKIN_CSS_FILE);
         wantRelative = cfg.getBoolean(RELATIVE_PROPERTY, false);
 
         setInit(true);
     }
 
     /***
      * Returns to uninitialized state.
      */
     public void shutdown()
     {
         clearSkins();
 
         setInit(false);
     }
 
 }