/*

  * 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.any23.util;

 import java.io.BufferedInputStream;

 import java.io.BufferedOutputStream;

 import java.io.ByteArrayOutputStream;

 import java.io.File;

 import java.io.FileInputStream;

 import java.io.FileNotFoundException;

 import java.io.FileOutputStream;

 import java.io.FileWriter;

 import java.io.FilenameFilter;

 import java.io.IOException;

 import java.io.InputStream;

 import java.io.PrintWriter;

 import java.util.ArrayList;

 import java.util.List;

 /**

  * Utility class for handling files.

  *

  * @author Michele Mostarda (mostarda@fbk.eu)

  */

 public class FileUtils {

     /**

      * Moves a <code>target</code> file to a new <code>dest</code> location.

      *

      * @param target file to be moved.

      * @param dest   dest dir.

      * @return destination file.

      */

     public static File mv(File target, File dest) {

         if (!dest.isDirectory()) {

             throw new IllegalArgumentException("destination must be a directory.");

         }

         final File newFile = new File(dest, target.getName());

         boolean success = target.renameTo(newFile);

         if (!success) {

             throw new IllegalStateException(

                     String.format("Cannot move target file [%s] to destination [%s]", target, newFile)

             );

         }

         return newFile;

     }

     /**

      * Copies the content of the input stream within the given dest file.

      * The dest file must not exist.

      *

      * @param is

      * @param dest

      */

     public static void cp(InputStream is, File dest) {

         if (dest.exists()) {

             throw new IllegalArgumentException("Destination must not exist.");

         }

         BufferedInputStream bis = null;

         BufferedOutputStream bos = null;

         try {

             bis = new BufferedInputStream(is);

             FileOutputStream fos = new FileOutputStream(dest);

             bos = new BufferedOutputStream(fos);

             final byte[] buffer = new byte[1024 * 4];

             int read;

             while (true) {

                 read = bis.read(buffer);

                 if (read == -1) {

                     break;

                 }

                 bos.write(buffer, 0, read);

             }

         } catch (Exception e) {

             throw new RuntimeException("Error while copying stream into file.", e);

         } finally {

             StreamUtils.closeGracefully(bis);

             StreamUtils.closeGracefully(bos);

         }

     }

     /**

      * Copies a file <code>src</code> to the <code>dest</code>.

      *

      * @param src  source file.

      * @param dest destination file.

      * @throws java.io.FileNotFoundException if file cannot be copied or created.

      */

     public static void cp(File src, File dest) throws FileNotFoundException {

         FileInputStream fis = null;

         try {

             fis = new FileInputStream(src);

             cp(fis, dest);

         } finally {

             StreamUtils.closeGracefully(fis);

         }

     }

     /**

      * Dumps the given string within a file.

      *

      * @param f       file target.

      * @param content content to be dumped.

      * @throws IOException

      */

     public static void dumpContent(File f, String content) throws IOException {

         FileWriter fw = new FileWriter(f);

         try {

             fw.write(content);

         } finally {

             StreamUtils.closeGracefully(fw);

         }

     }

     /**

      * Dumps the stack trace of the given exception into the specified file.

      *

      * @param f file to generate dump.

      * @param t exception to be dumped.

      * @throws IOException

      */

     public static void dumpContent(File f, Throwable t) throws IOException {

         final ByteArrayOutputStream baos = new ByteArrayOutputStream();

         final PrintWriter pw = new PrintWriter(baos);

         t.printStackTrace(pw);

         pw.close();

         dumpContent(f, baos.toString());

     }

     /**

      * Reads a resource file and returns the content as a string.

      *

      * @param clazz    the class to use load the resource.

      * @param resource the resource to be load.

      * @return the string representing the file content.

      * @throws java.io.IOException

      */

     public static String readResourceContent(Class clazz, String resource) throws IOException {

         return StreamUtils.asString( clazz.getResourceAsStream(resource) );

     }

     /**

      * Reads a resource file and returns the content as a string.

      *

      * @param resource the resource to be load.

      * @return the string representing the file content.

      * @throws java.io.IOException

      */

     public static String readResourceContent(String resource) throws IOException {

         return readResourceContent(FileUtils.class, resource);

     }

     /**

      * Returns the content of a file a single string.

      *

      * @param f the file to read.

      * @return the content of file.

      * @throws IOException if an error occurs while locating or accessing the file.

      */

     public static String readFileContent(File f) throws IOException {

         FileInputStream fis = new FileInputStream(f);

         return StreamUtils.asString(fis, true);

     }

     /**

      * Returns all the lines of a file.

      *

      * @param f the file to read.

      * @return a not <code>null</code> array with not <code>null</code> line strings.

      * @throws IOException if an error occurs while locating or accessing the file.

      */

     public static String[] readFileLines(File f) throws IOException {

         FileInputStream fis = new FileInputStream(f);

         return StreamUtils.asLines(fis);

     }

     /**

      * Lists the content of a dir applying the specified filter.

      *

      * @param dir directory root.

      * @param filenameFilter filter to be applied.

      * @return list of matching files.

      */

     public static File[] listFilesRecursively(File dir, FilenameFilter filenameFilter) {

         if( ! dir.isDirectory() ) {

             throw new IllegalArgumentException(dir.getAbsolutePath() + " must be a directory.");

         }

         final List<File> result = new ArrayList<File>();

         visitFilesRecursively(dir, filenameFilter, result);

         return result.toArray( new File[result.size()] );

     }

     /**

      * Visits a directory recursively, applying the given filter and adding matches to the result list.

      *

      * @param dir directory to find.

      * @param filenameFilter filter to apply.

      * @param result result list.

      */

     private static void visitFilesRecursively(File dir, FilenameFilter filenameFilter, List<File> result) {

         for (File file : dir.listFiles()) {

             if (!file.isDirectory()) {

                 if (filenameFilter == null || filenameFilter.accept(dir, file.getName())) {

                     result.add(file);

                 }

             } else {

                 visitFilesRecursively(file, filenameFilter, result);

             }

         }

     }

     /**

      * Function class.

      */

     private FileUtils() {}

 }