/*
 * 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.provider.git.gitexe.command.update;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.maven.scm.util.AbstractConsumer;

/**
 * @author <a href="mailto:struberg@yahoo.de">Mark Struberg</a>
 */
public class GitLatestRevisionCommandConsumer extends AbstractConsumer {

    /**
     * The pattern used to match git log latest revision lines.
     */
    private static final Pattern LATESTREV_PATTERN = Pattern.compile("^commit \\s*(.*)");

    private String latestRevision;

    /**
     * {@inheritDoc}
     */
    public void consumeLine(String line) {
        if (logger.isDebugEnabled()) {
            logger.debug("GitLatestRevisionCommandConsumer consumeLine : " + line);
        }
        if (line == null || line.isEmpty()) {
            return;
        }

        processGetLatestRevision(line);
    }

    public String getLatestRevision() {
        return latestRevision;
    }

    /**
     * Process the current input line for the latest revision.
     *
     * @param line a line of text from the git log output
     */
    private void processGetLatestRevision(String line) {
        Matcher matcher = LATESTREV_PATTERN.matcher(line);
        if (matcher.matches()) {
            latestRevision = matcher.group(1);
        }
    }
}
