/*
 * 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.");
        }
    }
}
