/*

  * $Id$

  *

  * 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.

  */

 package org.apache.tiles.request.locale;

 import java.io.File;

 import java.io.FileInputStream;

 import java.io.FileNotFoundException;

 import java.io.IOException;

 import java.io.InputStream;

 import java.net.JarURLConnection;

 import java.net.URI;

 import java.net.URISyntaxException;

 import java.net.URL;

 import java.net.URLConnection;

 import java.util.HashSet;

 import java.util.Locale;

 import java.util.Set;

 import org.slf4j.Logger;

 import org.slf4j.LoggerFactory;

 import static java.lang.System.getProperty;

 import static java.util.Collections.unmodifiableSet;

 /**

  * A {@link PostfixedApplicationResource} that can be accessed through a URL.

  *

  * @version $Rev$ $Date$

  */

 public class URLApplicationResource extends PostfixedApplicationResource {

     /**

      * System parameter to specify additional remote protocols. If a url has a remote protocol, then any

      * {@link IOException} will be thrown directly. If a url has a local protocol, then any {@link IOException}

      * will be caught and transformed into a {@link FileNotFoundException}.

      */

     static final String REMOTE_PROTOCOLS_PROPERTY = "tiles.remoteProtocols";

     private static final Logger LOG = LoggerFactory.getLogger(URLApplicationResource.class);

     private static final Set<String> REMOTE_PROTOCOLS;

     static {

         REMOTE_PROTOCOLS = initRemoteProtocols();

     }

     /**

      * Creates an unmodifiable set of <em>remote</em> protocols which are used in {@link URL} objects, see {@link URL#getProtocol()}.

      * A url with a remote protocol establishes a network connection when its {@link URL#openConnection()} is being called.

      * The set will always contain the built-in remote protocols below:

      * <ul>

      *  <li><a href="http://hg.openjdk.java.net/jdk8/jdk8/jdk/file/687fd7c7986d/src/share/classes/sun/net/www/protocol/ftp">ftp</a></li>

      *  <li><a href="http://hg.openjdk.java.net/jdk8/jdk8/jdk/file/687fd7c7986d/src/share/classes/sun/net/www/protocol/http">http</a></li>

      *  <li><a href="http://hg.openjdk.java.net/jdk8/jdk8/jdk/file/687fd7c7986d/src/share/classes/sun/net/www/protocol/https">https</a></li>

      *  <li><a href="http://hg.openjdk.java.net/jdk8/jdk8/jdk/file/687fd7c7986d/src/share/classes/sun/net/www/protocol/mailto">mailto</a></li>

      *  <li><a href="http://hg.openjdk.java.net/jdk8/jdk8/jdk/file/687fd7c7986d/src/share/classes/sun/net/www/protocol/netdoc">netdoc</a></li>

      * </ul>

      * It's possible, that your environment provides additional remote protocols because of following reasons:

      * <ul>

      *     <li>your application server adds more remote protocols, see its documentation for further details.</li>

      *     <li>your application supplies custom remote protocols trough its own {@link java.net.URLStreamHandlerFactory}

      *     (see following excellent <a href="https://stackoverflow.com/questions/26363573/registering-and-using-a-custom-java-net-url-protocol">explanation</a>

      *     for getting an idea how to do this)</li>

      * </ul>

      * If you need to use such extra remote protocols in Tiles, you may enhance the set via system property {@code tiles.remoteProtocols}. Suppose

      * you need to add your custom remote protocols "foo" and "bar". To do so, add following parameter to the command line (use ";" as separator):

      * <pre>

      *     -Dtiles.remoteProtocols=foo;bar

      * </pre>

      * The resulting set will then contain the built-in protocols plus "foo" and "bar".

      *

      * @return Unmodifiable set of remote protocols, never {@code null}

      */

     static Set<String> initRemoteProtocols() {

         Set<String> remoteProtocols = new HashSet<String>();

         remoteProtocols.add("ftp");

         remoteProtocols.add("http");

         remoteProtocols.add("https");

         remoteProtocols.add("mailto");

         remoteProtocols.add("netdoc");

         String protocolsProp = getProperty(REMOTE_PROTOCOLS_PROPERTY);

         if (protocolsProp != null) {

             for (String protocol : protocolsProp.split(";")) {

                 remoteProtocols.add(protocol.trim());

             }

         }

         return unmodifiableSet(remoteProtocols);

     }

     private static boolean isLocal(URL url) {

         return !REMOTE_PROTOCOLS.contains(url.getProtocol());

     }

     /** the URL where the contents can be found. */

     private final URL url;

     /** if the URL matches a file, this is the file. */

     private File file;

     /** if the URL points to a local resource */

     private final boolean local;

     /**

      * Creates a URLApplicationResource for the specified path that can be accessed through the specified URL.

      *

      * @param localePath the path including localization.

      * @param url the URL where the contents can be found.

      */

     public URLApplicationResource(String localePath, URL url) {

         super(localePath);

         this.url = url;

         if ("file".equals(url.getProtocol())) {

             file = getFile(url);

         }

         local = isLocal(url);

     }

     /**

      * Creates a URLApplicationResource for the specified path that can be accessed through the specified URL.

      *

      * @param path the path excluding localization.

      * @param locale the Locale.

      * @param url the URL where the contents can be found.

      */

     public URLApplicationResource(String path, Locale locale, URL url) {

         super(path, locale);

         this.url = url;

         if ("file".equals(url.getProtocol())) {

             file = getFile(url);

         }

         local = isLocal(url);

     }

     private URLConnection openConnection() throws IOException {

         try {

             return url.openConnection();

         } catch (IOException e) {

             // If the url points to a local resource but it cannot be

             // opened, then the resource actually does not exist. In this

             // case throw a FileNotFoundException

             if (local) {

                 FileNotFoundException fne = new FileNotFoundException(url.toString());

                 fne.initCause(e);

                 throw fne;

             }

             throw e;

         }

     }

     private static File getFile(URL url) {

         try {

             return new File(new URI(url.toExternalForm()).getSchemeSpecificPart());

         } catch (URISyntaxException e) {

             LOG.debug("Cannot translate URL to file name, expect a performance impact", e);

             return null;

         }

     }

     /** {@inheritDoc} */

     @Override

     public InputStream getInputStream() throws IOException {

         if (file != null) {

             return new FileInputStream(file);

         } else {

             return openConnection().getInputStream();

         }

     }

     /** {@inheritDoc} */

     @Override

     public long getLastModified() throws IOException {

         if (file != null) {

             return file.lastModified();

         } else {

             URLConnection connection = openConnection();

             if (connection instanceof JarURLConnection) {

                 return ((JarURLConnection) connection).getJarEntry().getTime();

             } else {

                 long result = connection.getLastModified();

                 return result;

             }

         }

     }

     /** {@inheritDoc} */

     @Override

     public String toString() {

         return "Resource " + getLocalePath() + " at " + url.toString();

     }

     protected URL getURL(){

         return url;

     }

     protected File getFile(){

         return file;

     }

 }