/*
    * Copyright 2013 University of Glasgow.
    *
    * Licensed 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 broadwick;
  
  import org.apache.commons.cli2.CommandLine;
  import org.apache.commons.cli2.Group;
  import org.apache.commons.cli2.Option;
  import org.apache.commons.cli2.builder.ArgumentBuilder;
  import org.apache.commons.cli2.builder.DefaultOptionBuilder;
  import org.apache.commons.cli2.builder.GroupBuilder;
  import org.apache.commons.cli2.commandline.Parser;
  import org.apache.commons.cli2.util.HelpFormatter;
  
  /**
   * Construct and read command line arguments. This class contains methods for extracting some of the main
   * options such as configuration file etc.
   */
  public class CliOptions {
  
      private Group options;
      private static final int LINEWIDTH = 120;
      private static final String SPACE = " ";
      private CommandLine cmdLine;
      private Option configFileOpt;
  
  
      /**
       * Construct and provide GNU-compatible Options. Read the command line extracting the arguments, this
       * additionally displays the help message if the command line is empty.
       *
       * @param args the command line arguments.
       */
      public CliOptions(final String[] args) {
          buildCommandLineArguments();
  
          final Parser parser = new Parser();
          parser.setGroup(options);
          final HelpFormatter hf = new HelpFormatter(SPACE, SPACE, SPACE, LINEWIDTH);
          parser.setHelpFormatter(hf);
          parser.setHelpTrigger("--help");
          cmdLine = parser.parseAndHelp(args);
  
          if (cmdLine == null) {
              hf.printHeader();
              throw new BroadwickException("Empty command line.");
          }
  
          validateCommandLineArguments();
      }
  
      /**
       * Construct and provide GNU-compatible Options.
       */
      private void buildCommandLineArguments() {
          final DefaultOptionBuilder oBuilder = new DefaultOptionBuilder();
          final GroupBuilder gbuilder = new GroupBuilder();
          final ArgumentBuilder abuilder = new ArgumentBuilder();
  
          final Option helpOpt = oBuilder.withLongName("help").withShortName("h").withRequired(false)
                  .withDescription("Print this message").create();
          final Option guiOpt = oBuilder.withLongName("gui").withShortName("x").withRequired(false)
                  .withDescription("Use a gui to configure and run a model").create();
          configFileOpt = oBuilder.withLongName("configFile").withShortName("c").withRequired(false)
                  .withArgument(abuilder.withName("input").withMinimum(1).withMaximum(1).create())
                  .withDescription("Use given configuration file").create();
          options = gbuilder.withName("Options")
                  .withOption(helpOpt)
                  .withOption(configFileOpt)
                  .withOption(guiOpt)
                  .create();
      }
  
      /**
       * Perform validation the command line arguments.
       */
      private void validateCommandLineArguments() {
          // nothing to validate (yet)
      }
  
      /**
       * Get the name of the configuration file specified on the command line.
       *
       * @return the name of the configuration file specified by either the -g or -c options. If neither
       *         option is specified then we return an empty string.
       */
      public final String getConfigurationFileName() {
         if (cmdLine.hasOption(configFileOpt)) {
             return (String) cmdLine.getValue(configFileOpt);
         } else {
             return "";
         }
     }
 
 }