/*
 * 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.maven.scm.util;

import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;

import org.codehaus.plexus.util.cli.StreamConsumer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @author <a href="mailto:evenisse@apache.org">Emmanuel Venisse</a>
 *
 */
public abstract class AbstractConsumer implements StreamConsumer {
    protected final Logger logger = LoggerFactory.getLogger(getClass());

    /**
     * Converts the date timestamp from the output into a date object.
     *
     * @param date TODO
     * @param userPattern TODO
     * @param defaultPattern TODO
     * @return A date representing the timestamp of the log entry.
     */
    protected Date parseDate(String date, String userPattern, String defaultPattern) {
        return parseDate(date, userPattern, defaultPattern, null);
    }

    /**
     * Converts the date timestamp from the output into a date object.
     *
     * @param date TODO
     * @param userPattern TODO
     * @param defaultPattern TODO
     * @param locale TODO
     * @return A date representing the timestamp of the log entry.
     */
    protected Date parseDate(String date, String userPattern, String defaultPattern, Locale locale) {
        DateFormat format;

        String patternUsed = null;
        Locale localeUsed = null;

        if (userPattern != null && !userPattern.isEmpty()) {
            if (locale != null) {
                format = new SimpleDateFormat(userPattern, locale);
                localeUsed = locale;
            } else {
                format = new SimpleDateFormat(userPattern);
                localeUsed = Locale.getDefault();
            }
            patternUsed = userPattern;
        } else {
            if (defaultPattern != null && !defaultPattern.isEmpty()) {
                if (locale != null) {
                    format = new SimpleDateFormat(defaultPattern, locale);
                    localeUsed = locale;
                } else {
                    format = new SimpleDateFormat(defaultPattern);
                    localeUsed = Locale.getDefault();
                }
                patternUsed = defaultPattern;
            } else {
                // Use the English short date pattern if no pattern is specified
                format = DateFormat.getDateInstance(DateFormat.SHORT, Locale.ENGLISH);
                patternUsed = "DateFormat.SHORT";
                localeUsed = Locale.ENGLISH;
            }
        }

        try {
            return format.parse(date);
        } catch (ParseException e) {
            if (logger.isWarnEnabled()) {
                logger.warn(
                        "skip ParseException: " + e.getMessage() + " during parsing date '" + date
                                + "' with pattern '" + patternUsed + "' and locale '"
                                + localeUsed + "'",
                        e);
            }

            return null;
        }
    }
}