/*
 * 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;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

/**
 * @author <a href="mailto:evenisse@apache.org">Emmanuel Venisse</a>
 *
 */
public class GitConfigFileReader {
    private File configDirectory;

    public File getConfigDirectory() {
        if (configDirectory == null) {

            File confDir = new File(".git");

            if (confDir.exists()) {
                configDirectory = confDir;
            } else {
                confDir = new File(".");

                if (confDir.exists()) {
                    configDirectory = confDir;
                }
            }
        }

        return configDirectory;
    }

    public void setConfigDirectory(File configDirectory) {
        this.configDirectory = configDirectory;
    }

    public String getProperty(String group, String propertyName) {
        List<String> lines = getConfLines();

        boolean inGroup = false;
        for (Iterator<String> i = lines.iterator(); i.hasNext(); ) {
            String line = i.next().trim();

            if (!inGroup) {
                if (("[" + group + "]").equals(line)) {
                    inGroup = true;
                }
            } else {
                if (line.startsWith("[") && line.endsWith("]")) {
                    // a new group start
                    return null;
                }

                if (line.startsWith("#")) {
                    continue;
                }
                if (line.indexOf('=') < 0) {
                    continue;
                }

                String property = line.substring(0, line.indexOf('=')).trim();

                if (!property.equals(propertyName)) {
                    continue;
                }

                String value = line.substring(line.indexOf('=') + 1);
                return value.trim();
            }
        }

        return null;
    }

    /**
     * Load the git config file
     *
     * @return the list of all lines
     */
    private List<String> getConfLines() {
        List<String> lines = new ArrayList<>();

        try {
            if (getConfigDirectory().exists()) {
                try (BufferedReader reader =
                        new BufferedReader(new FileReader(new File(getConfigDirectory(), "config")))) {
                    String line;
                    while ((line = reader.readLine()) != null) {
                        if (!line.startsWith("#") && (line != null && !line.isEmpty())) {
                            lines.add(line);
                        }
                    }
                }
            }
        } catch (IOException e) {
            lines.clear();
        }

        return lines;
    }
}