/*

  * This file is part of dependency-check-core.

  *

  * Licensed 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.

  *

  * Copyright (c) 2012 Jeremy Long. All Rights Reserved.

  */

 package org.owasp.dependencycheck.utils;

 import org.slf4j.Logger;

 import org.slf4j.LoggerFactory;

 import java.io.File;

 import java.io.IOException;

 import java.util.UUID;

 /**

  * A collection of utilities for processing information about files.

  *

  * @author Jeremy Long

  */

 public final class FileUtils {

     /**

      * The logger.

      */

     private static final Logger LOGGER = LoggerFactory.getLogger(FileUtils.class);

     /**

      * Bit bucket for non-Windows systems

      */

     private static final String BIT_BUCKET_UNIX = "/dev/null";

     /**

      * Bit bucket for Windows systems (yes, only one 'L')

      */

     private static final String BIT_BUCKET_WIN = "NUL";

     /**

      * Private constructor for a utility class.

      */

     private FileUtils() {

     }

     /**

      * Returns the (lowercase) file extension for a specified file.

      *

      * @param fileName the file name to retrieve the file extension from.

      * @return the file extension.

      */

     public static String getFileExtension(String fileName) {

         String ret = null;

         final int pos = fileName.lastIndexOf(".");

         if (pos >= 0) {

             ret = fileName.substring(pos + 1, fileName.length()).toLowerCase();

         }

         return ret;

     }

     /**

      * Deletes a file. If the File is a directory it will recursively delete the contents.

      *

      * @param file the File to delete

      * @return true if the file was deleted successfully, otherwise false

      */

     public static boolean delete(File file) {

         boolean success = true;

         if (!org.apache.commons.io.FileUtils.deleteQuietly(file)) {

             success = false;

             LOGGER.debug("Failed to delete file: {}; attempting to delete on exit.", file.getPath());

             file.deleteOnExit();

         }

         return success;

     }

     /**

      * Generates a new temporary file name that is guaranteed to be unique.

      *

      * @param prefix the prefix for the file name to generate

      * @param extension the extension of the generated file name

      * @return a temporary File

      * @throws java.io.IOException thrown if the temporary folder could not be created

      */

     public static File getTempFile(String prefix, String extension) throws IOException {

         final File dir = Settings.getTempDirectory();

         final String tempFileName = String.format("%s%s.%s", prefix, UUID.randomUUID().toString(), extension);

         final File tempFile = new File(dir, tempFileName);

         if (tempFile.exists()) {

             return getTempFile(prefix, extension);

         }

         return tempFile;

     }

     /**

      * Return the bit bucket for the OS. '/dev/null' for Unix and 'NUL' for Windows

      *

      * @return a String containing the bit bucket

      */

     public static String getBitBucket() {

         if (System.getProperty("os.name").startsWith("Windows")) {

             return BIT_BUCKET_WIN;

         } else {

             return BIT_BUCKET_UNIX;

         }

     }

 }