/**
    * 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.commons.cli2.commandline;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Set;
  
  import org.apache.commons.cli2.CommandLine;
  import org.apache.commons.cli2.Option;
  import org.apache.commons.cli2.option.PropertyOption;
  
  /**
   * Manages a queue of default CommandLines. This CommandLine implementation is
   * backed by a queue of CommandLine instances which are queried in turn until a
   * suitable result is found.
   *
   * CommandLine instances can either be added to the back of the queue or can be
   * pushed in at a specific position.
   *
   * @see #appendCommandLine(CommandLine)
   * @see #insertCommandLine(int, CommandLine)
   */
  public class DefaultingCommandLine extends CommandLineImpl {
  
      /**
       * The list of default CommandLine instances
       */
      private final List commandLines = new ArrayList();
  
      /**
       * Adds a CommandLine instance to the back of the queue. The supplied
       * CommandLine will be used as defaults when all other CommandLines produce
       * no result
       *
       * @param commandLine
       *            the default values to use if all CommandLines
       */
      public void appendCommandLine(final CommandLine commandLine) {
          commandLines.add(commandLine);
      }
  
      /**
       * Adds a CommandLine instance to a specified position in the queue.
       *
       * @param index ths position at which to insert
       * @param commandLine the CommandLine to insert
       */
      public void insertCommandLine(
          final int index,
          final CommandLine commandLine) {
          commandLines.add(index, commandLine);
      }
  
      /**
       * Builds an iterator over the build in CommandLines.
       *
       * @return an unmodifiable iterator
       */
      public Iterator commandLines(){
          return Collections.unmodifiableList(commandLines).iterator();
      }
  
      public Option getOption(String trigger) {
          for (final Iterator i = commandLines.iterator(); i.hasNext();) {
              final CommandLine commandLine = (CommandLine)i.next();
              final Option actual = commandLine.getOption(trigger);
              if (actual != null) {
                  return actual;
              }
          }
          return null;
      }
  
      public List getOptions() {
          final List options = new ArrayList();
  
          final List temp = new ArrayList();
          for (final Iterator i = commandLines.iterator(); i.hasNext();) {
              final CommandLine commandLine = (CommandLine)i.next();
              temp.clear();
              temp.addAll(commandLine.getOptions());
             temp.removeAll(options);
             options.addAll(temp);
         }
 
         return Collections.unmodifiableList(options);
     }
 
     public Set getOptionTriggers() {
         final Set all = new HashSet();
         for (final Iterator i = commandLines.iterator(); i.hasNext();) {
             final CommandLine commandLine = (CommandLine)i.next();
             all.addAll(commandLine.getOptionTriggers());
         }
 
         return Collections.unmodifiableSet(all);
     }
 
     public boolean hasOption(Option option) {
         for (final Iterator i = commandLines.iterator(); i.hasNext();) {
             final CommandLine commandLine = (CommandLine)i.next();
             if (commandLine.hasOption(option)) {
                 return true;
             }
         }
         return false;
     }
 
     public List getValues(Option option, List defaultValues) {
         for (final Iterator i = commandLines.iterator(); i.hasNext();) {
             final CommandLine commandLine = (CommandLine)i.next();
             final List actual = commandLine.getValues(option);
             if (actual != null && !actual.isEmpty()) {
                 return actual;
             }
         }
         if(defaultValues==null){
             return Collections.EMPTY_LIST;
         }
         else{
             return defaultValues;
         }
     }
 
     public Boolean getSwitch(Option option, Boolean defaultValue) {
         for (final Iterator i = commandLines.iterator(); i.hasNext();) {
             final CommandLine commandLine = (CommandLine)i.next();
             final Boolean actual = commandLine.getSwitch(option);
             if (actual != null) {
                 return actual;
             }
         }
         return defaultValue;
     }
 
     public String getProperty(final String property) {
         return getProperty(new PropertyOption(), property);
     }
 
     public String getProperty(final Option option, String property, String defaultValue) {
         for (final Iterator i = commandLines.iterator(); i.hasNext();) {
             final CommandLine commandLine = (CommandLine)i.next();
             final String actual = commandLine.getProperty(option, property);
             if (actual != null) {
                 return actual;
             }
         }
         return defaultValue;
     }
 
     public Set getProperties(final Option option) {
         final Set all = new HashSet();
         for (final Iterator i = commandLines.iterator(); i.hasNext();) {
             final CommandLine commandLine = (CommandLine)i.next();
             all.addAll(commandLine.getProperties(option));
         }
         return Collections.unmodifiableSet(all);
     }
 
     public Set getProperties() {
         return getProperties(new PropertyOption());
     }
 }