/*
    * 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.math4.legacy.linear;
  
  import java.util.ConcurrentModificationException;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.Map;
  import java.util.NoSuchElementException;
  import java.util.Random;
  import java.util.Set;
  
  import org.apache.commons.numbers.core.Precision;
  import org.junit.Assert;
  import org.junit.Before;
  import org.junit.Test;
  
  
  /**
   * Test cases for the {@link OpenIntToDoubleHashMap}.
   */
  @SuppressWarnings("boxing")
  public class OpenIntToDoubleHashMapTest {
  
      private Map<Integer, Double> javaMap = new HashMap<>();
  
      @Before
      public void setUp() throws Exception {
          javaMap.put(50, 100.0);
          javaMap.put(75, 75.0);
          javaMap.put(25, 500.0);
          javaMap.put(Integer.MAX_VALUE, Double.MAX_VALUE);
          javaMap.put(0, -1.0);
          javaMap.put(1, 0.0);
          javaMap.put(33, -0.1);
          javaMap.put(23234234, -242343.0);
          javaMap.put(23321, Double.MIN_VALUE);
          javaMap.put(-4444, 332.0);
          javaMap.put(-1, -2323.0);
          javaMap.put(Integer.MIN_VALUE, 44.0);
  
          /* Add a few more to cause the table to rehash */
          javaMap.putAll(generate());
      }
  
      private Map<Integer, Double> generate() {
          Map<Integer, Double> map = new HashMap<>();
          Random r = new Random();
          for (int i = 0; i < 2000; ++i) {
              map.put(r.nextInt(), r.nextDouble());
          }
          return map;
      }
  
      private OpenIntToDoubleHashMap createFromJavaMap() {
          OpenIntToDoubleHashMap map = new OpenIntToDoubleHashMap();
          for (Map.Entry<Integer, Double> mapEntry : javaMap.entrySet()) {
              map.put(mapEntry.getKey(), mapEntry.getValue());
          }
          return map;
      }
  
      @Test
      public void testPutAndGetWith0ExpectedSize() {
          OpenIntToDoubleHashMap map = new OpenIntToDoubleHashMap(0);
          assertPutAndGet(map);
      }
  
      @Test
      public void testPutAndGetWithExpectedSize() {
          OpenIntToDoubleHashMap map = new OpenIntToDoubleHashMap(500);
          assertPutAndGet(map);
      }
  
      @Test
      public void testPutAndGet() {
          OpenIntToDoubleHashMap map = new OpenIntToDoubleHashMap();
          assertPutAndGet(map);
      }
  
      private void assertPutAndGet(OpenIntToDoubleHashMap map) {
          assertPutAndGet(map, 0, new HashSet<>());
      }
  
      private void assertPutAndGet(OpenIntToDoubleHashMap map, int mapSize,
             Set<Integer> keysInMap) {
         Assert.assertEquals(mapSize, map.size());
         for (Map.Entry<Integer, Double> mapEntry : javaMap.entrySet()) {
             map.put(mapEntry.getKey(), mapEntry.getValue());
             if (!keysInMap.contains(mapEntry.getKey())) {
                 ++mapSize;
             }
             Assert.assertEquals(mapSize, map.size());
             Assert.assertTrue(Precision.equals(mapEntry.getValue(), map.get(mapEntry.getKey()), 1));
         }
     }
 
     @Test
     public void testPutAbsentOnExisting() {
         OpenIntToDoubleHashMap map = createFromJavaMap();
         int size = javaMap.size();
         for (Map.Entry<Integer, Double> mapEntry : generateAbsent().entrySet()) {
             map.put(mapEntry.getKey(), mapEntry.getValue());
             Assert.assertEquals(++size, map.size());
             Assert.assertTrue(Precision.equals(mapEntry.getValue(), map.get(mapEntry.getKey()), 1));
         }
     }
 
     @Test
     public void testPutOnExisting() {
         OpenIntToDoubleHashMap map = createFromJavaMap();
         for (Map.Entry<Integer, Double> mapEntry : javaMap.entrySet()) {
             map.put(mapEntry.getKey(), mapEntry.getValue());
             Assert.assertEquals(javaMap.size(), map.size());
             Assert.assertTrue(Precision.equals(mapEntry.getValue(), map.get(mapEntry.getKey()), 1));
         }
     }
 
     @Test
     public void testGetAbsent() {
         Map<Integer, Double> generated = generateAbsent();
         OpenIntToDoubleHashMap map = createFromJavaMap();
 
         for (Map.Entry<Integer, Double> mapEntry : generated.entrySet()) {
             Assert.assertTrue(Double.isNaN(map.get(mapEntry.getKey())));
         }
     }
 
     @Test
     public void testGetFromEmpty() {
         OpenIntToDoubleHashMap map = new OpenIntToDoubleHashMap();
         Assert.assertTrue(Double.isNaN(map.get(5)));
         Assert.assertTrue(Double.isNaN(map.get(0)));
         Assert.assertTrue(Double.isNaN(map.get(50)));
     }
 
     @Test
     public void testRemove() {
         OpenIntToDoubleHashMap map = createFromJavaMap();
         int mapSize = javaMap.size();
         Assert.assertEquals(mapSize, map.size());
         for (Map.Entry<Integer, Double> mapEntry : javaMap.entrySet()) {
             map.remove(mapEntry.getKey());
             Assert.assertEquals(--mapSize, map.size());
             Assert.assertTrue(Double.isNaN(map.get(mapEntry.getKey())));
         }
 
         /* Ensure that put and get still work correctly after removals */
         assertPutAndGet(map);
     }
 
     /* This time only remove some entries */
     @Test
     public void testRemove2() {
         OpenIntToDoubleHashMap map = createFromJavaMap();
         int mapSize = javaMap.size();
         int count = 0;
         Set<Integer> keysInMap = new HashSet<>(javaMap.keySet());
         for (Map.Entry<Integer, Double> mapEntry : javaMap.entrySet()) {
             keysInMap.remove(mapEntry.getKey());
             map.remove(mapEntry.getKey());
             Assert.assertEquals(--mapSize, map.size());
             Assert.assertTrue(Double.isNaN(map.get(mapEntry.getKey())));
             if (count++ > 5) {
                 break;
             }
         }
 
         /* Ensure that put and get still work correctly after removals */
         assertPutAndGet(map, mapSize, keysInMap);
     }
 
     @Test
     public void testRemoveFromEmpty() {
         OpenIntToDoubleHashMap map = new OpenIntToDoubleHashMap();
         Assert.assertTrue(Double.isNaN(map.remove(50)));
     }
 
     @Test
     public void testRemoveAbsent() {
         Map<Integer, Double> generated = generateAbsent();
 
         OpenIntToDoubleHashMap map = createFromJavaMap();
         int mapSize = map.size();
 
         for (Map.Entry<Integer, Double> mapEntry : generated.entrySet()) {
             map.remove(mapEntry.getKey());
             Assert.assertEquals(mapSize, map.size());
             Assert.assertTrue(Double.isNaN(map.get(mapEntry.getKey())));
         }
     }
 
     /**
      * Returns a map with at least 100 elements where each element is absent from javaMap.
      */
     private Map<Integer, Double> generateAbsent() {
         Map<Integer, Double> generated = new HashMap<>();
         do {
             generated.putAll(generate());
             for (Integer key : javaMap.keySet()) {
                 generated.remove(key);
             }
         } while (generated.size() < 100);
         return generated;
     }
 
     @Test
     public void testCopy() {
         OpenIntToDoubleHashMap copy =
             new OpenIntToDoubleHashMap(createFromJavaMap());
         Assert.assertEquals(javaMap.size(), copy.size());
 
         for (Map.Entry<Integer, Double> mapEntry : javaMap.entrySet()) {
             Assert.assertTrue(Precision.equals(mapEntry.getValue(), copy.get(mapEntry.getKey()), 1));
         }
     }
 
     @Test
     public void testContainsKey() {
         OpenIntToDoubleHashMap map = createFromJavaMap();
         for (Map.Entry<Integer, Double> mapEntry : javaMap.entrySet()) {
             Assert.assertTrue(map.containsKey(mapEntry.getKey()));
         }
         for (Map.Entry<Integer, Double> mapEntry : generateAbsent().entrySet()) {
             Assert.assertFalse(map.containsKey(mapEntry.getKey()));
         }
         for (Map.Entry<Integer, Double> mapEntry : javaMap.entrySet()) {
             int key = mapEntry.getKey();
             Assert.assertTrue(map.containsKey(key));
             map.remove(key);
             Assert.assertFalse(map.containsKey(key));
         }
     }
 
     @Test
     public void testIterator() {
         OpenIntToDoubleHashMap map = createFromJavaMap();
         OpenIntToDoubleHashMap.Iterator iterator = map.iterator();
         for (int i = 0; i < map.size(); ++i) {
             Assert.assertTrue(iterator.hasNext());
             iterator.advance();
             int key = iterator.key();
             Assert.assertTrue(map.containsKey(key));
             Assert.assertEquals(javaMap.get(key), map.get(key), 0);
             Assert.assertEquals(javaMap.get(key), iterator.value(), 0);
             Assert.assertTrue(javaMap.containsKey(key));
         }
         Assert.assertFalse(iterator.hasNext());
         try {
             iterator.advance();
             Assert.fail("an exception should have been thrown");
         } catch (NoSuchElementException nsee) {
             // expected
         }
     }
 
     @Test
     public void testConcurrentModification() {
         OpenIntToDoubleHashMap map = createFromJavaMap();
         OpenIntToDoubleHashMap.Iterator iterator = map.iterator();
         map.put(3, 3);
         try {
             iterator.advance();
             Assert.fail("an exception should have been thrown");
         } catch (ConcurrentModificationException cme) {
             // expected
         }
     }
 
     /**
      * Regression test for a bug in findInsertionIndex where the hashing in the second probing
      * loop was inconsistent with the first causing duplicate keys after the right sequence
      * of puts and removes.
      */
     @Test
     public void testPutKeysWithCollisions() {
         OpenIntToDoubleHashMap map = new OpenIntToDoubleHashMap();
         int key1 = -1996012590;
         double value1 = 1.0;
         map.put(key1, value1);
         int key2 = 835099822;
         map.put(key2, value1);
         int key3 = 1008859686;
         map.put(key3, value1);
         Assert.assertTrue(Precision.equals(value1, map.get(key3), 1));
         Assert.assertEquals(3, map.size());
 
         map.remove(key2);
         double value2 = 2.0;
         map.put(key3, value2);
         Assert.assertTrue(Precision.equals(value2, map.get(key3), 1));
         Assert.assertEquals(2, map.size());
     }
 
     /**
      * Similar to testPutKeysWithCollisions() but exercises the codepaths in a slightly
      * different manner.
      */
     @Test
     public void testPutKeysWithCollision2() {
         OpenIntToDoubleHashMap map = new OpenIntToDoubleHashMap();
         int key1 = 837989881;
         double value1 = 1.0;
         map.put(key1, value1);
         int key2 = 476463321;
         map.put(key2, value1);
         Assert.assertEquals(2, map.size());
         Assert.assertTrue(Precision.equals(value1, map.get(key2), 1));
 
         map.remove(key1);
         double value2 = 2.0;
         map.put(key2, value2);
         Assert.assertEquals(1, map.size());
         Assert.assertTrue(Precision.equals(value2, map.get(key2), 1));
     }
 }