/*
    * 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.logging.log4j.core.util;
  
  import java.io.File;
  import java.io.IOException;
  import java.io.UnsupportedEncodingException;
  import java.net.MalformedURLException;
  import java.net.URI;
  import java.net.URL;
  import java.net.URLDecoder;
  import java.nio.charset.StandardCharsets;
  
  import org.apache.logging.log4j.Logger;
  import org.apache.logging.log4j.status.StatusLogger;
  
  /**
   * File utilities.
   */
  public final class FileUtils {
  
      /** Constant for the file URL protocol. */
      private static final String PROTOCOL_FILE = "file";
  
      private static final String JBOSS_FILE = "vfsfile";
  
      private static final Logger LOGGER = StatusLogger.getLogger();
  
      private FileUtils() {
      }
  
      /**
       * Tries to convert the specified URI to a file object. If this fails, <b>null</b> is returned.
       *
       * @param uri the URI
       * @return the resulting file object
       */
      public static File fileFromUri(URI uri) {
          // There MUST be a better way to do this. TODO Search other ASL projects...
          if (uri == null
                  || (uri.getScheme() != null && (!PROTOCOL_FILE.equals(uri.getScheme()) && !JBOSS_FILE.equals(uri
                          .getScheme())))) {
              return null;
          }
          if (uri.getScheme() == null) {
              File file = new File(uri.toString());
              if (file.exists()) {
                  return file;
              }
              try {
                  final String path = uri.getPath();
                  file = new File(path);
                  if (file.exists()) {
                      return file;
                  }
                  uri = new File(path).toURI();
              } catch (final Exception ex) {
                  LOGGER.warn("Invalid URI {}", uri);
                  return null;
              }
          }
          final String charsetName = StandardCharsets.UTF_8.name();
          try {
              String fileName = uri.toURL().getFile();
              if (new File(fileName).exists()) { // LOG4J2-466
                  return new File(fileName); // allow files with '+' char in name
              }
              fileName = URLDecoder.decode(fileName, charsetName);
              return new File(fileName);
          } catch (final MalformedURLException ex) {
              LOGGER.warn("Invalid URL {}", uri, ex);
          } catch (final UnsupportedEncodingException uee) {
              LOGGER.warn("Invalid encoding: {}", charsetName, uee);
          }
          return null;
      }
  
      public static boolean isFile(final URL url) {
          return url != null && (url.getProtocol().equals(PROTOCOL_FILE) || url.getProtocol().equals(JBOSS_FILE));
      }
  
      public static String getFileExtension(final File file) {
          final String fileName = file.getName();
          if (fileName.lastIndexOf(".") != -1 && fileName.lastIndexOf(".") != 0) {
              return fileName.substring(fileName.lastIndexOf(".") + 1);
         }
         return null;
     }
 
     /**
      * Asserts that the given directory exists and creates it if necessary.
      * 
      * @param dir the directory that shall exist
      * @param createDirectoryIfNotExisting specifies if the directory shall be created if it does not exist.
      * @throws java.io.IOException thrown if the directory could not be created.
      */
     public static void mkdir(final File dir, final boolean createDirectoryIfNotExisting) throws IOException {
         // commons io FileUtils.forceMkdir would be useful here, we just want to omit this dependency
         if (!dir.exists()) {
             if (!createDirectoryIfNotExisting) {
                 throw new IOException("The directory " + dir.getAbsolutePath() + " does not exist.");
             }
             if (!dir.mkdirs()) {
                 throw new IOException("Could not create directory " + dir.getAbsolutePath());
             }
         }
         if (!dir.isDirectory()) {
             throw new IOException("File " + dir + " exists and is not a directory. Unable to create directory.");
         }
     }
 }