/*

  * Copyright (c) 2011 David Saff

  * Copyright (c) 2011 Christian Gruber

  * Copyright (c) 2012 Google, Inc.

  *

  * 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 org.truth0.subjects;

 import java.util.ArrayList;

 import java.util.Arrays;

 import java.util.Collection;

 import java.util.Collections;

 import java.util.HashSet;

 import java.util.List;

 import java.util.Set;

 /**

  * Utility methods used in Subject<T> implementors.

  *

  * @author Christian Gruber (cgruber@israfil.net)

  */

 final class SubjectUtils {

   static <T> List<T> accumulate(T only) {

     return new ArrayList<T>(Collections.singleton(only));

   }

   static <T> List<T> accumulate(T first, T second, T ... rest) {

     // rest should never be deliberately null, so assume that the caller passed null

     // in the third position but intended it to be the third element in the array of values.

     // Javac makes the opposite inference, so handle that here.

     List<T> items = new ArrayList<T>(2 + ((rest == null) ? 1 : rest.length));

     items.add(first);

     items.add(second);

     if (rest == null) {

       items.add(null);

     } else {

       items.addAll(Arrays.asList(rest));

     }

     return items;

   }

   static <T> int countOf(T t, Iterable<T> items) {

     int count = 0;

     for (T item : items) {

       if (t == null ? (item == null) : t.equals(item)) {

         count++;

       }

     }

     return count;

   }

   static <T> List<Object> countDuplicates(Collection<T> items) {

     Set<T> itemSet = new HashSet<T>(items);

     Object[] params = new Object[itemSet.size()];

     int n = 0;

     for (T item : itemSet) {

       int count = countOf(item, items);

       params[n++] = (count > 1) ? item + " [" + count + " copies]" : item;

     }

     return Arrays.asList(params);

   }

 }