/**
    * This file Copyright (c) 2003-2012 Magnolia International
    * Ltd.  (http://www.magnolia-cms.com). All rights reserved.
    *
    *
    * This file is dual-licensed under both the Magnolia
    * Network Agreement and the GNU General Public License.
    * You may elect to use one or the other of these licenses.
    *
   * This file is distributed in the hope that it will be
   * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
   * implied warranty of MERCHANTABILITY or FITNESS FOR A
   * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
   * Redistribution, except as permitted by whichever of the GPL
   * or MNA you select, is prohibited.
   *
   * 1. For the GPL license (GPL), you can redistribute and/or
   * modify this file under the terms of the GNU General
   * Public License, Version 3, as published by the Free Software
   * Foundation.  You should have received a copy of the GNU
   * General Public License, Version 3 along with this program;
   * if not, write to the Free Software Foundation, Inc., 51
   * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * 2. For the Magnolia Network Agreement (MNA), this file
   * and the accompanying materials are made available under the
   * terms of the MNA which accompanies this distribution, and
   * is available at http://www.magnolia-cms.com/mna.html
   *
   * Any modifications to this file must keep this entire header
   * intact.
   *
   */
  package info.magnolia.freemarker;
  
  import java.beans.PropertyDescriptor;
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.FileNotFoundException;
  import java.io.InputStream;
  import java.io.UnsupportedEncodingException;
  import java.net.MalformedURLException;
  import java.net.URL;
  import java.net.URLClassLoader;
  import java.net.URLDecoder;
  import java.util.Enumeration;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Set;
  
  import javax.servlet.RequestDispatcher;
  import javax.servlet.Servlet;
  import javax.servlet.ServletContext;
  import javax.servlet.ServletException;
  
  import org.apache.commons.io.FileUtils;
  import org.apache.commons.lang.StringUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  
  /**
   * Wraps the servlet context expecially for freemarker taglib resolution. This will trick freemarker TaglibFactory class
   * to "see" all jars in classpath as if they were jars in /WEB-INF/lib
   * @author Danilo Ghirardelli
   */
  public class FreemarkerServletContextWrapper implements ServletContext {
  
      private ServletContext parentContext;
  
      /**
       * Logger.
       */
      private static Logger log = LoggerFactory.getLogger(FreemarkerServletContextWrapper.class);
  
      public FreemarkerServletContextWrapper(ServletContext parentServletContext) {
          // allow also a null parent context for unit tests
          this.parentContext = parentServletContext;
      }
  
      @Override
      public URL getResource(String path) throws MalformedURLException {
  
          URL result = parentContext.getResource(path);
          if (result == null) {
              // Trying the absolute path if the parent context fails.
              File file = new File(path);
              if ((file.exists()) && (file.isFile())) {
                  result = file.toURI().toURL();
              }
          }
          return result;
      }
  
      @Override
      public InputStream getResourceAsStream(String path) {
          InputStream is = parentContext.getResourceAsStream(path);
          if (is == null) {
              // Trying the absolute path if the parent context fails.
             File file = new File(path);
             if ((file.exists()) && (file.isFile())) {
                 try {
                     return new FileInputStream(file);
                 }
                 catch (FileNotFoundException e) {
                     // Ignore, file not found
                 }
             }
         }
         return is;
     }
 
     @Override
     @SuppressWarnings({"unchecked", "rawtypes"})
     public Set getResourcePaths(String path) {
         if (StringUtils.equals(path, "/WEB-INF/lib")) {
             log.debug("returning resources from classpath");
             // Just when asking libraries, pass the classpath ones.
             final Set<String> resources = new HashSet<String>();
             final ClassLoader cl = Thread.currentThread().getContextClassLoader();
             // if the classloader is an URLClassloader we have a better method for discovering resources
             // whis will also fetch files from jars outside WEB-INF/lib, useful during development
             if (cl instanceof URLClassLoader) {
                 final URLClassLoader urlClassLoader = (URLClassLoader) cl;
                 final URL[] urls = urlClassLoader.getURLs();
                 for (int j = 0; j < urls.length; j++) {
                     final File tofile = sanitizeToFile(urls[j]);
                     if (tofile.isDirectory()) {
                         for (File file : ((List<File>) FileUtils.listFiles(tofile, null, true))) {
                             resources.add(file.getAbsolutePath());
                         }
                     }
                     else {
                         resources.add(tofile.getAbsolutePath());
                     }
                 }
 
                 return resources;
             }
             try {
                 // be friendly to WAS developers too...
                 // in development mode under RAD 7.5 here we have an instance of com.ibm.ws.classloader.WsClassLoader
                 // and jars are NOT deployed to WEB-INF/lib by default, so they can't be found without this explicit
                 // check
                 //
                 // but since we don't want to depend on WAS stuff we just check if the cl exposes a "classPath" property
                 PropertyDescriptor pd = new PropertyDescriptor("classPath", cl.getClass());
                 if (pd != null && pd.getReadMethod() != null) {
                     String classpath = (String) pd.getReadMethod().invoke(cl, new Object[]{});
                     if (StringUtils.isNotBlank(classpath)) {
                         String[] paths = StringUtils.split(classpath, File.pathSeparator);
                         for (int j = 0; j < paths.length; j++) {
                             final File tofile = new File(paths[j]);
                             // there can be several missing (optional?) paths here...
                             if (tofile.exists()) {
                                 if (tofile.isDirectory()) {
                                     for (File file : ((List<File>) FileUtils.listFiles(tofile, null, true))) {
                                         resources.add(file.getAbsolutePath());
                                     }
                                 }
                                 else {
                                     resources.add(tofile.getAbsolutePath());
                                 }
                             }
                         }
                         return resources;
                     }
                 }
             }
             catch (Throwable e) {
                 // no, it's not a classloader we can handle in a special way
             }
             // no way, we have to assume a standard war structure and look in the WEB-INF/lib and WEB-INF/classes dirs
             // read the jars in the lib dir
         }
         return parentContext.getResourcePaths(path);
     }
 
     /**
      * Clean url and get the file.
      * @param url url to cleanup
      * @return file to url
      */
     private File sanitizeToFile(URL url) {
         try {
             String fileUrl = url.getFile();
             // needed because somehow the URLClassLoader has encoded URLs, and getFile does not decode them.
             fileUrl = URLDecoder.decode(fileUrl, "UTF-8");
             // needed for Resin - for some reason, its URLs are formed as jar:file:/absolutepath/foo/bar.jar instead of
             // using the :///abs.. notation
             fileUrl = StringUtils.removeStart(fileUrl, "file:");
             fileUrl = StringUtils.removeEnd(fileUrl, "!/");
             return new File(fileUrl);
         }
         catch (UnsupportedEncodingException e) {
             throw new RuntimeException(e);
         }
     }
 
     // Below here, just methods that redirects to the wrapped context.
     @Override
     public Object getAttribute(String name) {
         return parentContext.getAttribute(name);
     }
 
     @SuppressWarnings("rawtypes")
     @Override
     public Enumeration getAttributeNames() {
         return parentContext.getAttributeNames();
     }
 
     @Override
     public ServletContext getContext(String uripath) {
         return parentContext.getContext(uripath);
     }
 
     @Override
     public String getContextPath() {
         return parentContext.getContextPath();
     }
 
     @Override
     public String getInitParameter(String name) {
         return parentContext.getInitParameter(name);
     }
 
     @SuppressWarnings("rawtypes")
     @Override
     public Enumeration getInitParameterNames() {
         return parentContext.getInitParameterNames();
     }
 
     @Override
     public int getMajorVersion() {
         return parentContext.getMajorVersion();
     }
 
     @Override
     public String getMimeType(String file) {
         return parentContext.getMimeType(file);
     }
 
     @Override
     public int getMinorVersion() {
         return parentContext.getMinorVersion();
     }
 
     @Override
     public RequestDispatcher getNamedDispatcher(String name) {
         return parentContext.getNamedDispatcher(name);
     }
 
     @Override
     public String getRealPath(String path) {
         return parentContext.getRealPath(path);
     }
 
     @Override
     public RequestDispatcher getRequestDispatcher(String path) {
         return parentContext.getRequestDispatcher(path);
     }
 
     @Override
     public String getServerInfo() {
         return parentContext.getServerInfo();
     }
 
     @SuppressWarnings("deprecation")
     @Override
     public Servlet getServlet(String name) throws ServletException {
         return parentContext.getServlet(name);
     }
 
     @Override
     public String getServletContextName() {
         return parentContext.getServletContextName();
     }
 
     @SuppressWarnings({"rawtypes", "deprecation"})
     @Override
     public Enumeration getServletNames() {
         return parentContext.getServletNames();
     }
 
     @SuppressWarnings({"rawtypes", "deprecation"})
     @Override
     public Enumeration getServlets() {
         return parentContext.getServlets();
     }
 
     @Override
     public void log(String msg) {
         parentContext.log(msg);
     }
 
     @SuppressWarnings("deprecation")
     @Override
     public void log(Exception exception, String msg) {
         parentContext.log(exception, msg);
     }
 
     @Override
     public void log(String message, Throwable throwable) {
         parentContext.log(message, throwable);
     }
 
     @Override
     public void removeAttribute(String name) {
         parentContext.removeAttribute(name);
     }
 
     @Override
     public void setAttribute(String name, Object object) {
         parentContext.setAttribute(name, object);
     }
 }