/*

  * Copyright (c) 2003-2011, Simon Brown

  * All rights reserved.

  *

  * Redistribution and use in source and binary forms, with or without

  * modification, are permitted provided that the following conditions are met:

  *

  *   - Redistributions of source code must retain the above copyright

  *     notice, this list of conditions and the following disclaimer.

  *

  *   - Redistributions in binary form must reproduce the above copyright

  *     notice, this list of conditions and the following disclaimer in

  *     the documentation and/or other materials provided with the

  *     distribution.

  *

  *   - Neither the name of Pebble nor the names of its contributors may

  *     be used to endorse or promote products derived from this software

  *     without specific prior written permission.

  *

  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE

  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

  * POSSIBILITY OF SUCH DAMAGE.

  */

 package net.sourceforge.pebble.web.view;

 import org.apache.commons.io.IOUtils;

 import org.apache.commons.logging.Log;

 import org.apache.commons.logging.LogFactory;

 import javax.servlet.ServletContext;

 import java.io.*;

 import java.net.URISyntaxException;

 import java.util.Map;

 import java.util.concurrent.ConcurrentHashMap;

 /**

  * Maintains JSPs from plugins in the WAR directory

  *

  * @author James Roper

  */

 public class PluginResourceMaintainer {

   private static final Log log = LogFactory.getLog(PluginResourceMaintainer.class);

   public static final String PLUGINS_JSP = "plugins-jsp";

   public static final String WEB_INF_PLUGINS_JSP = "WEB-INF/plugins-jsp";

   private final static Map<String, Boolean> resourceStateCache = new ConcurrentHashMap<String, Boolean>();

   private final static Object lock = new Object();

   /**

    * Ensure that the given resource is deployed to somewhere where tomcat can serve it and is up to date, copying it

    * across if it's not

    *

    * @param classPathResource The classpath resource

    * @param deployLocation    The directory to deploy the resource to

    * @param sourceClass       A class that comes from the same JAR as the resource, for modification time checking

    * @param servletContext    The servlet context

    */

   public static void checkResource(String classPathResource, String deployLocation, Class sourceClass,

                               ServletContext servletContext) {

     String cacheKey = classPathResource + "|" + deployLocation;

     if (!resourceStateCache.containsKey(cacheKey)) {

       synchronized (lock) {

         if (!resourceStateCache.containsKey(cacheKey)) {

           String realPath = servletContext.getRealPath("/");

           if (realPath != null) {

             File deployTo;

             if (deployLocation != null) {

               deployTo = new File(realPath, deployLocation);

             } else {

               deployTo = new File(realPath);

             }

             String resourceName = classPathResource;

             if (classPathResource.contains("/")) {

               resourceName = classPathResource.substring(classPathResource.lastIndexOf("/") + 1);

             }

             File destResource = new File(deployTo, resourceName);

             if (destResource.exists()) {

               // Check if the resource has been updated

               try {

                 if (destResource.lastModified() < new File(sourceClass.getProtectionDomain().getCodeSource().getLocation()

                     .toURI()).lastModified()) {

                   // Update the resource

                   updateResource(destResource, classPathResource, sourceClass);

                 }

               } catch (URISyntaxException e) {

                 log.error("Bad code source", e);

               }

             } else {

               updateResource(destResource, classPathResource, sourceClass);

             }

           }

           resourceStateCache.put(cacheKey, true);

         }

       }

     }

   }

   /**

    * Ensure that the given classpath JSP is in the WEB-INF/plugins-jsp directory and up to date, copying it across if

    * it's not

    *

    * @param classPathJsp   The classpath JSP

    * @param viewClass      The class the JSP comes from, used to find the jar to do modification time based checking

    * @param servletContext The servlet context

    */

   public static void checkJsp(String classPathJsp, Class viewClass, ServletContext servletContext) {

     checkResource(classPathJsp, WEB_INF_PLUGINS_JSP, viewClass, servletContext);

   }

   private static void updateResource(File dest, String classpathResource, Class viewClass) {

     if (!dest.getParentFile().exists()) {

       //noinspection ResultOfMethodCallIgnored

       dest.getParentFile().mkdirs();

     }

     InputStream is = null;

     OutputStream os = null;

     try {

       os = new FileOutputStream(dest);

       is = viewClass.getClassLoader().getResourceAsStream(classpathResource);

       IOUtils.copy(is, os);

     } catch (IOException e) {

       log.error("Error copying resource (" + classpathResource + ") from classpath to " + dest.getAbsolutePath(), e);

     } finally {

       IOUtils.closeQuietly(is);

       IOUtils.closeQuietly(os);

     }

   }

 }