/*
 * 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.tuscany.sca.contribution.service.util;

import java.io.File;
import java.io.FileFilter;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.net.URL;
import java.util.regex.Pattern;

public class FileHelper {
    /**
     * The extension separator character.
     */
    private static final char EXTENSION_SEPARATOR = '.';

    /**
     * The Unix separator character.
     */
    private static final char UNIX_SEPARATOR = '/';

    /**
     * The Windows separator character.
     */
    private static final char WINDOWS_SEPARATOR = '\\';

    /**
     * Returns the index of the last directory separator character.
     * <p>
     * This method will handle a file in either Unix or Windows format. The
     * position of the last forward or backslash is returned.
     * <p>
     * The output will be the same irrespective of the machine that the code is
     * running on.
     * 
     * @param filename the filename to find the last path separator in, null
     *            returns -1
     * @return the index of the last separator character, or -1 if there is no
     *         such character
     */
    public static int indexOfLastSeparator(String filename) {
        if (filename == null) {
            return -1;
        }
        int lastUnixPos = filename.lastIndexOf(UNIX_SEPARATOR);
        int lastWindowsPos = filename.lastIndexOf(WINDOWS_SEPARATOR);
        return Math.max(lastUnixPos, lastWindowsPos);
    }

    /**
     * Returns the index of the last extension separator character, which is a
     * dot.
     * <p>
     * This method also checks that there is no directory separator after the
     * last dot. To do this it uses {@link #indexOfLastSeparator(String)} which
     * will handle a file in either Unix or Windows format.
     * <p>
     * The output will be the same irrespective of the machine that the code is
     * running on.
     * 
     * @param filename the filename to find the last path separator in, null
     *            returns -1
     * @return the index of the last separator character, or -1 if there is no
     *         such character
     */
    public static int indexOfExtension(String filename) {
        if (filename == null) {
            return -1;
        }
        int extensionPos = filename.lastIndexOf(EXTENSION_SEPARATOR);
        int lastSeparator = indexOfLastSeparator(filename);
        return lastSeparator > extensionPos ? -1 : extensionPos;
    }

    /**
     * Gets the name minus the path from a full filename.
     * <p>
     * This method will handle a file in either Unix or Windows format. The text
     * after the last forward or backslash is returned.
     * 
     * <pre>
     * a/b/c.txt --&gt; c.txt
     * a.txt     --&gt; a.txt
     * a/b/c     --&gt; c
     * a/b/c/    --&gt; &quot;&quot;
     * </pre>
     * 
     * <p>
     * The output will be the same irrespective of the machine that the code is
     * running on.
     * 
     * @param fileName the filename to query, null returns null
     * @return the name of the file without the path, or an empty string if none
     *         exists
     */
    public static String getName(String fileName) {
        if (fileName == null) {
            return null;
        }
        int index = indexOfLastSeparator(fileName);
        return fileName.substring(index + 1);
    }

    /**
     * Gets the extension of a filename.
     * <p>
     * This method returns the textual part of the filename after the last dot.
     * There must be no directory separator after the dot.
     * 
     * <pre>
     * foo.txt      --&gt; &quot;txt&quot;
     * a/b/c.jpg    --&gt; &quot;jpg&quot;
     * a/b.txt/c    --&gt; &quot;&quot;
     * a/b/c        --&gt; &quot;&quot;
     * </pre>
     * 
     * <p>
     * The output will be the same irrespective of the machine that the code is
     * running on.
     * 
     * @param filename the filename to retrieve the extension of.
     * @return the extension of the file or an empty string if none exists.
     */
    public static String getExtension(String filename) {
        if (filename == null) {
            return null;
        }
        int index = indexOfExtension(filename);
        if (index == -1) {
            return "";
        } else {
            return filename.substring(index + 1);
        }
    }

    /**
     * Make a directory, including any necessary but nonexistent parent
     * directories. If there already exists a file with specified name or the
     * directory cannot be created then an exception is thrown.
     * 
     * @param directory directory to create, not null
     * @throws NullPointerException if the directory is null
     * @throws IOException if the directory cannot be created
     */
    public static void forceMkdir(File directory) throws IOException {
        if (directory.exists()) {
            if (directory.isFile()) {
                String message =
                    "File " + directory + " exists and is " + "not a directory. Unable to create directory.";
                throw new IOException(message);
            }
        } else {
            if (!directory.mkdirs()) {
                String message = "Unable to create directory " + directory;
                throw new IOException(message);
            }
        }
    }

    /**
     * Delete a file. If file is a directory, delete it and all sub-directories.
     * <p>
     * The difference between File.delete() and this method are:
     * <ul>
     * <li>A directory to be deleted does not have to be empty.</li>
     * <li>You get exceptions when a file or directory cannot be deleted.
     * (java.io.File methods returns a boolean)</li>
     * </ul>
     * 
     * @param file file or directory to delete, not null
     * @throws NullPointerException if the directory is null
     * @throws IOException in case deletion is unsuccessful
     */
    public static void forceDelete(File file) throws IOException {
        if (file.isDirectory()) {
            deleteDirectory(file);
        } else {
            if (!file.exists()) {
                throw new FileNotFoundException("File does not exist: " + file);
            }
            if (!file.delete()) {
                String message = "Unable to delete file: " + file;
                throw new IOException(message);
            }
        }
    }

    /**
     * Convert from a <code>URL</code> to a <code>File</code>.
     * <p>
     * From version 1.1 this method will decode the URL. Syntax such as
     * <code>file:///my%20docs/file.txt</code> will be correctly decoded to
     * <code>/my docs/file.txt</code>.
     * 
     * @param url the file URL to convert, null returns null
     * @return the equivalent <code>File</code> object, or <code>null</code>
     *         if the URL's protocol is not <code>file</code>
     * @throws IllegalArgumentException if the file is incorrectly encoded
     */
    public static File toFile(URL url) {
        if (url == null || !url.getProtocol().equals("file")) {
            return null;
        } else {
            String filename = url.getFile().replace('/', File.separatorChar);
            int pos = 0;
            while ((pos = filename.indexOf('%', pos)) >= 0) { // NOPMD
                if (pos + 2 < filename.length()) {
                    String hexStr = filename.substring(pos + 1, pos + 3);
                    char ch = (char)Integer.parseInt(hexStr, 16);
                    filename = filename.substring(0, pos) + ch + filename.substring(pos + 3);
                }
            }
            return new File(filename);
        }
    }

    public static FileFilter getFileFilter(String regExp, boolean ignoreCase) {
        return new RegExpFilter(regExp, ignoreCase);
    }

    /**
     * A regular-expression based resource filter
     */
    public static class RegExpFilter implements FileFilter {
        private Pattern pattern;

        public RegExpFilter(Pattern pattern) {
            this.pattern = pattern;
        }

        public RegExpFilter(String patternStr, boolean ignoreCase) {
            this.pattern = Pattern.compile(patternStr, ignoreCase ? Pattern.CASE_INSENSITIVE : 0);
        }

        public boolean accept(File file) {
            return pattern.matcher(file.getName()).matches();
        }

        /**
         * Convert wildcard into a regex pattern
         * 
         * @param str
         * @return
         */
        public static RegExpFilter getWildcardFilter(String str, boolean ignoreCase) {
            StringBuffer buffer = new StringBuffer();
            for (int i = 0; i < str.length(); i++) {
                char ch = str.charAt(i);
                if (ch == '?') {
                    buffer.append('.');
                } else if (ch == '*') {
                    buffer.append(".*");
                } else {
                    buffer.append(ch);
                }
            }
            return new RegExpFilter(buffer.toString(), ignoreCase);
        }

    }

    /**
     * Clean a directory without deleting it.
     * 
     * @param directory directory to clean
     * @throws IOException in case cleaning is unsuccessful
     */
    public static void cleanDirectory(File directory) throws IOException {
        if (!directory.exists()) {
            String message = directory + " does not exist";
            throw new IllegalArgumentException(message);
        }

        if (!directory.isDirectory()) {
            String message = directory + " is not a directory";
            throw new IllegalArgumentException(message);
        }

        File[] files = directory.listFiles();
        if (files == null) { // null if security restricted
            throw new IOException("Failed to list contents of " + directory);
        }

        IOException exception = null;
        for (int i = 0; i < files.length; i++) {
            File file = files[i];
            try {
                forceDelete(file);
            } catch (IOException ioe) {
                exception = ioe;
            }
        }

        if (null != exception) {
            throw exception;
        }
    }

    /**
     * Clean a directory without deleting it.
     * 
     * @param directory directory to clean, must not be <code>null</code>
     * @throws NullPointerException if the directory is <code>null</code>
     * @throws IOException in case cleaning is unsuccessful
     */
    private static void cleanDirectoryOnExit(File directory) throws IOException {
        if (!directory.exists()) {
            String message = directory + " does not exist";
            throw new IllegalArgumentException(message);
        }

        if (!directory.isDirectory()) {
            String message = directory + " is not a directory";
            throw new IllegalArgumentException(message);
        }

        File[] files = directory.listFiles();
        if (files == null) { // null if security restricted
            throw new IOException("Failed to list contents of " + directory);
        }

        IOException exception = null;
        for (int i = 0; i < files.length; i++) {
            File file = files[i];
            try {
                forceDeleteOnExit(file);
            } catch (IOException ioe) {
                exception = ioe;
            }
        }

        if (null != exception) {
            throw exception;
        }
    }

    /**
     * Copies a whole directory to a new location preserving the file dates.
     * <p>
     * This method copies the specified directory and all its child directories
     * and files to the specified destination. The destination is the new
     * location and name of the directory.
     * <p>
     * The destination directory is created if it does not exist. If the
     * destination directory did exist, then this method merges the source with
     * the destination, with the source taking precedence.
     * 
     * @param srcDir an existing directory to copy, must not be
     *            <code>null</code>
     * @param destDir the new directory, must not be <code>null</code>
     * @throws NullPointerException if source or destination is
     *             <code>null</code>
     * @throws IOException if source or destination is invalid
     * @throws IOException if an IO error occurs during copying
     * @since Commons IO 1.1
     */
    public static void copyDirectory(File srcDir, File destDir) throws IOException {
        copyDirectory(srcDir, destDir, true);
    }

    /**
     * Copies a whole directory to a new location.
     * <p>
     * This method copies the contents of the specified source directory to
     * within the specified destination directory.
     * <p>
     * The destination directory is created if it does not exist. If the
     * destination directory did exist, then this method merges the source with
     * the destination, with the source taking precedence.
     * 
     * @param srcDir an existing directory to copy, must not be
     *            <code>null</code>
     * @param destDir the new directory, must not be <code>null</code>
     * @param preserveFileDate true if the file date of the copy should be the
     *            same as the original
     * @throws NullPointerException if source or destination is
     *             <code>null</code>
     * @throws IOException if source or destination is invalid
     * @throws IOException if an IO error occurs during copying
     * @since Commons IO 1.1
     */
    public static void copyDirectory(File srcDir, File destDir, boolean preserveFileDate) throws IOException {
        if (srcDir == null) {
            throw new NullPointerException("Source must not be null");
        }
        if (destDir == null) {
            throw new NullPointerException("Destination must not be null");
        }
        if (!srcDir.exists()) {
            throw new FileNotFoundException("Source '" + srcDir + "' does not exist");
        }
        if (!srcDir.isDirectory()) {
            throw new IOException("Source '" + srcDir + "' exists but is not a directory");
        }
        if (srcDir.getCanonicalPath().equals(destDir.getCanonicalPath())) {
            throw new IOException("Source '" + srcDir + "' and destination '" + destDir + "' are the same");
        }
        doCopyDirectory(srcDir, destDir, preserveFileDate);
    }

    // -----------------------------------------------------------------------
    /**
     * Copies a directory to within another directory preserving the file dates.
     * <p>
     * This method copies the source directory and all its contents to a
     * directory of the same name in the specified destination directory.
     * <p>
     * The destination directory is created if it does not exist. If the
     * destination directory did exist, then this method merges the source with
     * the destination, with the source taking precedence.
     * 
     * @param srcDir an existing directory to copy, must not be
     *            <code>null</code>
     * @param destDir the directory to place the copy in, must not be
     *            <code>null</code>
     * @throws NullPointerException if source or destination is
     *             <code>null</code>
     * @throws IOException if source or destination is invalid
     * @throws IOException if an IO error occurs during copying
     * @since Commons IO 1.2
     */
    public static void copyDirectoryToDirectory(File srcDir, File destDir) throws IOException {
        if (srcDir == null) {
            throw new NullPointerException("Source must not be null");
        }
        if (!(srcDir.exists() && srcDir.isDirectory())) {
            throw new IllegalArgumentException("Source '" + destDir + "' is not a directory");
        }
        if (destDir == null) {
            throw new NullPointerException("Destination must not be null");
        }
        if (!(destDir.exists() && destDir.isDirectory())) {
            throw new IllegalArgumentException("Destination '" + destDir + "' is not a directory");
        }
        copyDirectory(srcDir, new File(destDir, srcDir.getName()), true);
    }

    /**
     * Copies a file to a new location preserving the file date.
     * <p>
     * This method copies the contents of the specified source file to the
     * specified destination file. The directory holding the destination file is
     * created if it does not exist. If the destination file exists, then this
     * method will overwrite it.
     * 
     * @param srcFile an existing file to copy, must not be <code>null</code>
     * @param destFile the new file, must not be <code>null</code>
     * @throws NullPointerException if source or destination is
     *             <code>null</code>
     * @throws IOException if source or destination is invalid
     * @throws IOException if an IO error occurs during copying
     * @see #copyFileToDirectory(File, File)
     */
    public static void copyFile(File srcFile, File destFile) throws IOException {
        copyFile(srcFile, destFile, true);
    }

    /**
     * Copies a file to a new location.
     * <p>
     * This method copies the contents of the specified source file to the
     * specified destination file. The directory holding the destination file is
     * created if it does not exist. If the destination file exists, then this
     * method will overwrite it.
     * 
     * @param srcFile an existing file to copy, must not be <code>null</code>
     * @param destFile the new file, must not be <code>null</code>
     * @param preserveFileDate true if the file date of the copy should be the
     *            same as the original
     * @throws NullPointerException if source or destination is
     *             <code>null</code>
     * @throws IOException if source or destination is invalid
     * @throws IOException if an IO error occurs during copying
     * @see #copyFileToDirectory(File, File, boolean)
     */
    public static void copyFile(File srcFile, File destFile, boolean preserveFileDate) throws IOException {
        if (srcFile == null) {
            throw new NullPointerException("Source must not be null");
        }
        if (destFile == null) {
            throw new NullPointerException("Destination must not be null");
        }
        if (!srcFile.exists()) {
            throw new FileNotFoundException("Source '" + srcFile + "' does not exist");
        }
        if (srcFile.isDirectory()) {
            throw new IOException("Source '" + srcFile + "' exists but is a directory");
        }
        if (srcFile.getCanonicalPath().equals(destFile.getCanonicalPath())) {
            throw new IOException("Source '" + srcFile + "' and destination '" + destFile + "' are the same");
        }
        if (!(destFile.getParentFile() != null && destFile.getParentFile().exists())) {
            if (!destFile.getParentFile().mkdirs()) { //NOPMD
                throw new IOException("Destination '" + destFile + "' directory cannot be created");
            }
        }
        if (!(destFile.exists() && destFile.canWrite())) {
            throw new IOException("Destination '" + destFile + "' exists but is read-only");
        }
        doCopyFile(srcFile, destFile, preserveFileDate);
    }

    // -----------------------------------------------------------------------
    /**
     * Copies a file to a directory preserving the file date.
     * <p>
     * This method copies the contents of the specified source file to a file of
     * the same name in the specified destination directory. The destination
     * directory is created if it does not exist. If the destination file
     * exists, then this method will overwrite it.
     * 
     * @param srcFile an existing file to copy, must not be <code>null</code>
     * @param destDir the directory to place the copy in, must not be
     *            <code>null</code>
     * @throws NullPointerException if source or destination is null
     * @throws IOException if source or destination is invalid
     * @throws IOException if an IO error occurs during copying
     * @see #copyFile(File, File, boolean)
     */
    public static void copyFileToDirectory(File srcFile, File destDir) throws IOException {
        copyFileToDirectory(srcFile, destDir, true);
    }

    /**
     * Copies a file to a directory optionally preserving the file date.
     * <p>
     * This method copies the contents of the specified source file to a file of
     * the same name in the specified destination directory. The destination
     * directory is created if it does not exist. If the destination file
     * exists, then this method will overwrite it.
     * 
     * @param srcFile an existing file to copy, must not be <code>null</code>
     * @param destDir the directory to place the copy in, must not be
     *            <code>null</code>
     * @param preserveFileDate true if the file date of the copy should be the
     *            same as the original
     * @throws NullPointerException if source or destination is
     *             <code>null</code>
     * @throws IOException if source or destination is invalid
     * @throws IOException if an IO error occurs during copying
     * @see #copyFile(File, File, boolean)
     * @since Commons IO 1.3
     */
    public static void copyFileToDirectory(File srcFile, File destDir, boolean preserveFileDate) throws IOException {
        if (destDir == null) {
            throw new NullPointerException("Destination must not be null");
        }
        if (!(destDir.exists() && destDir.isDirectory())) {
            throw new IllegalArgumentException("Destination '" + destDir + "' is not a directory");
        }
        copyFile(srcFile, new File(destDir, srcFile.getName()), preserveFileDate);
    }

    // -----------------------------------------------------------------------
    /**
     * Recursively delete a directory.
     * 
     * @param directory directory to delete
     * @throws IOException in case deletion is unsuccessful
     */
    public static void deleteDirectory(File directory) throws IOException {
        if (!directory.exists()) {
            return;
        }

        cleanDirectory(directory);
        if (!directory.delete()) {
            String message = "Unable to delete directory " + directory + ".";
            throw new IOException(message);
        }
    }

    /**
     * Recursively schedule directory for deletion on JVM exit.
     * 
     * @param directory directory to delete, must not be <code>null</code>
     * @throws NullPointerException if the directory is <code>null</code>
     * @throws IOException in case deletion is unsuccessful
     */
    private static void deleteDirectoryOnExit(File directory) throws IOException {
        if (!directory.exists()) {
            return;
        }

        cleanDirectoryOnExit(directory);
        directory.deleteOnExit();
    }

    /**
     * Internal copy directory method.
     * 
     * @param srcDir the validated source directory, must not be
     *            <code>null</code>
     * @param destDir the validated destination directory, must not be
     *            <code>null</code>
     * @param preserveFileDate whether to preserve the file date
     * @throws IOException if an error occurs
     * @since Commons IO 1.1
     */
    private static void doCopyDirectory(File srcDir, File destDir, boolean preserveFileDate) throws IOException {
        if (destDir.exists()) {
            if (!destDir.isDirectory()) {
                throw new IOException("Destination '" + destDir + "' exists but is not a directory");
            }
        } else {
            if (!destDir.mkdirs()) {
                throw new IOException("Destination '" + destDir + "' directory cannot be created");
            }
            if (preserveFileDate) {
                destDir.setLastModified(srcDir.lastModified());
            }
        }
        if (!destDir.canWrite()) {
            throw new IOException("Destination '" + destDir + "' cannot be written to");
        }
        // recurse
        File[] files = srcDir.listFiles();
        if (files == null) { // null if security restricted
            throw new IOException("Failed to list contents of " + srcDir);
        }
        for (int i = 0; i < files.length; i++) {
            File copiedFile = new File(destDir, files[i].getName());
            if (files[i].isDirectory()) {
                doCopyDirectory(files[i], copiedFile, preserveFileDate);
            } else {
                doCopyFile(files[i], copiedFile, preserveFileDate);
            }
        }
    }

    /**
     * Internal copy file method.
     * 
     * @param srcFile the validated source file, must not be <code>null</code>
     * @param destFile the validated destination file, must not be
     *            <code>null</code>
     * @param preserveFileDate whether to preserve the file date
     * @throws IOException if an error occurs
     */
    private static void doCopyFile(File srcFile, File destFile, boolean preserveFileDate) throws IOException {
        if (destFile.exists() && destFile.isDirectory()) {
            throw new IOException("Destination '" + destFile + "' exists but is a directory");
        }

        FileInputStream input = new FileInputStream(srcFile);
        try {
            FileOutputStream output = new FileOutputStream(destFile);
            try {
                IOHelper.copy(input, output);
            } finally {
                IOHelper.closeQuietly(output);
            }
        } finally {
            IOHelper.closeQuietly(input);
        }

        if (srcFile.length() != destFile.length()) {
            throw new IOException("Failed to copy full contents from '" + srcFile + "' to '" + destFile + "'");
        }
        if (preserveFileDate) {
            destFile.setLastModified(srcFile.lastModified());
        }
    }

    /**
     * Schedule a file to be deleted when JVM exits. If file is directory delete
     * it and all sub-directories.
     * 
     * @param file file or directory to delete, must not be <code>null</code>
     * @throws NullPointerException if the file is <code>null</code>
     * @throws IOException in case deletion is unsuccessful
     */
    public static void forceDeleteOnExit(File file) throws IOException {
        if (file.isDirectory()) {
            deleteDirectoryOnExit(file);
        } else {
            file.deleteOnExit();
        }
    }

}