/*
 * 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.jboss.forge.shell.console.jline.console.completer;

import java.util.Arrays;
import java.util.Collection;
import java.util.List;
import java.util.SortedSet;
import java.util.TreeSet;

/**
 * Completer for a set of strings.
 * 
 * @author <a href="mailto:jason@planet57.com">Jason Dillon</a>
 * @since 2.3
 */
public class StringsCompleter
         implements Completer
{
   private final SortedSet<String> strings = new TreeSet<String>();

   public StringsCompleter()
   {
      // empty
   }

   public StringsCompleter(final Collection<String> strings)
   {
      assert strings != null;
      getStrings().addAll(strings);
   }

   public StringsCompleter(final String... strings)
   {
      this(Arrays.asList(strings));
   }

   public Collection<String> getStrings()
   {
      return strings;
   }

   @Override
   public int complete(final String buffer, final int cursor, final List<CharSequence> candidates)
   {
      // buffer could be null
      assert candidates != null;

      if (buffer == null)
      {
         candidates.addAll(strings);
      }
      else
      {
         for (String match : strings.tailSet(buffer))
         {
            if (!match.startsWith(buffer))
            {
               break;
            }

            candidates.add(match);
         }
      }

      if (candidates.size() == 1)
      {
         candidates.set(0, candidates.get(0) + " ");
      }

      return candidates.isEmpty() ? -1 : 0;
   }
}