/*
 * 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.commons.net.ftp.parser;

import java.text.ParseException;

import org.apache.commons.net.ftp.FTPClientConfig;
import org.apache.commons.net.ftp.FTPFile;

/**
 * Implementation of FTPFileEntryParser and FTPFileListParser for OS2 Systems.
 *
 * @see org.apache.commons.net.ftp.FTPFileEntryParser FTPFileEntryParser (for usage instructions)
 */
public class OS2FTPEntryParser extends ConfigurableFTPFileEntryParserImpl

{

    private static final String DEFAULT_DATE_FORMAT = "MM-dd-yy HH:mm"; // 11-09-01 12:30
    /**
     * this is the regular expression used by this parser.
     */
    private static final String REGEX = "\\s*([0-9]+)\\s*" + "(\\s+|[A-Z]+)\\s*" + "(DIR|\\s+)\\s*" + "(\\S+)\\s+(\\S+)\\s+" /* date stuff */
            + "(\\S.*)";

    /**
     * The default constructor for a OS2FTPEntryParser object.
     *
     * @throws IllegalArgumentException Thrown if the regular expression is unparseable. Should not be seen under normal conditions. It it is seen, this is a
     *                                  sign that <code>REGEX</code> is not a valid regular expression.
     */
    public OS2FTPEntryParser() {
        this(null);
    }

    /**
     * This constructor allows the creation of an OS2FTPEntryParser object with something other than the default configuration.
     *
     * @param config The {@link FTPClientConfig configuration} object used to configure this parser.
     * @throws IllegalArgumentException Thrown if the regular expression is unparseable. Should not be seen under normal conditions. It it is seen, this is a
     *                                  sign that <code>REGEX</code> is not a valid regular expression.
     * @since 1.4
     */
    public OS2FTPEntryParser(final FTPClientConfig config) {
        super(REGEX);
        configure(config);
    }

    /**
     * Defines a default configuration to be used when this class is instantiated without a {@link FTPClientConfig FTPClientConfig} parameter being specified.
     *
     * @return the default configuration for this parser.
     */
    @Override
    protected FTPClientConfig getDefaultConfiguration() {
        return new FTPClientConfig(FTPClientConfig.SYST_OS2, DEFAULT_DATE_FORMAT, null);
    }

    /**
     * Parses a line of an OS2 FTP server file listing and converts it into a usable format in the form of an <code> FTPFile </code> instance. If the file
     * listing line doesn't describe a file, <code> null </code> is returned, otherwise a <code> FTPFile </code> instance representing the files in the
     * directory is returned.
     *
     * @param entry A line of text from the file listing
     * @return An FTPFile instance corresponding to the supplied entry
     */
    @Override
    public FTPFile parseFTPEntry(final String entry) {

        final FTPFile f = new FTPFile();
        if (matches(entry)) {
            final String size = group(1);
            final String attrib = group(2);
            final String dirString = group(3);
            final String datestr = group(4) + " " + group(5);
            final String name = group(6);
            try {
                f.setTimestamp(super.parseTimestamp(datestr));
            } catch (final ParseException e) {
                // intentionally do nothing
            }

            // is it a DIR or a file
            if (dirString.trim().equals("DIR") || attrib.trim().equals("DIR")) {
                f.setType(FTPFile.DIRECTORY_TYPE);
            } else {
                f.setType(FTPFile.FILE_TYPE);
            }

            // set the name
            f.setName(name.trim());

            // set the size
            f.setSize(Long.parseLong(size.trim()));

            return f;
        }
        return null;

    }

}
