/*
    * 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.isEmpty()) {
                             lines.add(line);
                         }
                     }
                 }
             }
         } catch (IOException e) {
             lines.clear();
         }
 
         return lines;
     }
 }