/*
    * 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
    *
    *      https://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.
   */
  
  /*
   * This is not the original file distributed by the Apache Software Foundation
   * It has been modified by the Hipparchus project
   */
  package org.hipparchus.util;
  
  import org.hipparchus.Field;
  import org.hipparchus.exception.MathIllegalStateException;
  import org.hipparchus.fraction.BigFraction;
  import org.hipparchus.fraction.BigFractionField;
  import org.hipparchus.fraction.Fraction;
  import org.hipparchus.fraction.FractionField;
  import org.junit.jupiter.api.BeforeEach;
  import org.junit.jupiter.api.Test;
  
  import java.util.ConcurrentModificationException;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.Map;
  import java.util.Map.Entry;
  import java.util.NoSuchElementException;
  import java.util.Random;
  import java.util.Set;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertFalse;
  import static org.junit.jupiter.api.Assertions.assertNotEquals;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  import static org.junit.jupiter.api.Assertions.fail;
  
  
  class OpenIntToFieldHashMapTest {
  
      private final Map<Integer, Fraction> javaMap = new HashMap<>();
      private final FractionField field = FractionField.getInstance();
  
      @BeforeEach
      void setUp() {
          javaMap.put(50, new Fraction(100.0));
          javaMap.put(75, new Fraction(75.0));
          javaMap.put(25, new Fraction(500.0));
          javaMap.put(Integer.MAX_VALUE, new Fraction(Integer.MAX_VALUE));
          javaMap.put(0, new Fraction(-1.0));
          javaMap.put(1, new Fraction(0.0));
          javaMap.put(33, new Fraction(-0.1));
          javaMap.put(23234234, new Fraction(-242343.0));
          javaMap.put(23321, new Fraction (Integer.MIN_VALUE));
          javaMap.put(-4444, new Fraction(332.0));
          javaMap.put(-1, new Fraction(-2323.0));
          javaMap.put(Integer.MIN_VALUE, new Fraction(44.0));
  
          /* Add a few more to cause the table to rehash */
          javaMap.putAll(generate());
  
      }
  
      private Map<Integer, Fraction> generate() {
          Map<Integer, Fraction> map = new HashMap<>();
          Random r = new Random();
          double dd;
          for (int i = 0; i < 2000; ++i) {
              dd = r.nextDouble();
              try {
                  map.put(r.nextInt(), new Fraction(dd));
              } catch (MathIllegalStateException e) {
                  throw new IllegalStateException("Invalid :" + dd, e);
              }
          }
          return map;
      }
  
      private OpenIntToFieldHashMap<Fraction> createFromJavaMap(Field<Fraction> field) {
          OpenIntToFieldHashMap<Fraction> map = new OpenIntToFieldHashMap<>(field);
          for (Map.Entry<Integer, Fraction> mapEntry : javaMap.entrySet()) {
              map.put(mapEntry.getKey(), mapEntry.getValue());
          }
          return map;
      }
  
      @Test
      void testPutAndGetWith0ExpectedSize() {
          OpenIntToFieldHashMap<Fraction> map = new OpenIntToFieldHashMap<>(field,0);
         customAssertPutAndGet(map);
     }
 
     @Test
     void testPutAndGetWithExpectedSize() {
         OpenIntToFieldHashMap<Fraction> map = new OpenIntToFieldHashMap<>(field,500);
         customAssertPutAndGet(map);
     }
 
     @Test
     void testPutAndGet() {
         OpenIntToFieldHashMap<Fraction> map = new OpenIntToFieldHashMap<>(field);
         customAssertPutAndGet(map);
     }
 
     private void customAssertPutAndGet(OpenIntToFieldHashMap<Fraction> map) {
         customAssertPutAndGet(map, 0, new HashSet<>());
     }
 
     private void customAssertPutAndGet(OpenIntToFieldHashMap<Fraction> map, int mapSize,
                                        Set<Integer> keysInMap) {
         assertEquals(mapSize, map.size());
         for (Map.Entry<Integer, Fraction> mapEntry : javaMap.entrySet()) {
             map.put(mapEntry.getKey(), mapEntry.getValue());
             if (!keysInMap.contains(mapEntry.getKey()))
                 ++mapSize;
             assertEquals(mapSize, map.size());
             assertEquals(mapEntry.getValue(), map.get(mapEntry.getKey()));
         }
     }
 
     @Test
     void testPutAbsentOnExisting() {
         OpenIntToFieldHashMap<Fraction> map = createFromJavaMap(field);
         int size = javaMap.size();
         for (Map.Entry<Integer, Fraction> mapEntry : generateAbsent().entrySet()) {
             map.put(mapEntry.getKey(), mapEntry.getValue());
             assertEquals(++size, map.size());
             assertEquals(mapEntry.getValue(), map.get(mapEntry.getKey()));
         }
     }
 
     @Test
     void testPutOnExisting() {
         OpenIntToFieldHashMap<Fraction> map = createFromJavaMap(field);
         for (Map.Entry<Integer, Fraction> mapEntry : javaMap.entrySet()) {
             map.put(mapEntry.getKey(), mapEntry.getValue());
             assertEquals(javaMap.size(), map.size());
             assertEquals(mapEntry.getValue(), map.get(mapEntry.getKey()));
         }
     }
 
     @Test
     void testGetAbsent() {
         Map<Integer, Fraction> generated = generateAbsent();
         OpenIntToFieldHashMap<Fraction> map = createFromJavaMap(field);
 
         for (Map.Entry<Integer, Fraction> mapEntry : generated.entrySet())
             assertEquals(field.getZero(), map.get(mapEntry.getKey()));
     }
 
     @Test
     void testGetFromEmpty() {
         OpenIntToFieldHashMap<Fraction> map = new OpenIntToFieldHashMap<>(field);
         assertEquals(field.getZero(), map.get(5));
         assertEquals(field.getZero(), map.get(0));
         assertEquals(field.getZero(), map.get(50));
     }
 
     @Test
     void testRemove() {
         OpenIntToFieldHashMap<Fraction> map = createFromJavaMap(field);
         int mapSize = javaMap.size();
         assertEquals(mapSize, map.size());
         for (Map.Entry<Integer, Fraction> mapEntry : javaMap.entrySet()) {
             map.remove(mapEntry.getKey());
             assertEquals(--mapSize, map.size());
             assertEquals(field.getZero(), map.get(mapEntry.getKey()));
         }
 
         /* Ensure that put and get still work correctly after removals */
         customAssertPutAndGet(map);
     }
 
     /* This time only remove some entries */
     @Test
     void testRemove2() {
         OpenIntToFieldHashMap<Fraction> map = createFromJavaMap(field);
         int mapSize = javaMap.size();
         int count = 0;
         Set<Integer> keysInMap = new HashSet<>(javaMap.keySet());
         for (Map.Entry<Integer, Fraction> mapEntry : javaMap.entrySet()) {
             keysInMap.remove(mapEntry.getKey());
             map.remove(mapEntry.getKey());
             assertEquals(--mapSize, map.size());
             assertEquals(field.getZero(), map.get(mapEntry.getKey()));
             if (count++ > 5)
                 break;
         }
 
         /* Ensure that put and get still work correctly after removals */
         customAssertPutAndGet(map, mapSize, keysInMap);
     }
 
     @Test
     void testRemoveFromEmpty() {
         OpenIntToFieldHashMap<Fraction> map = new OpenIntToFieldHashMap<>(field);
         assertEquals(field.getZero(), map.remove(50));
     }
 
     @Test
     void testRemoveAbsent() {
         Map<Integer, Fraction> generated = generateAbsent();
 
         OpenIntToFieldHashMap<Fraction> map = createFromJavaMap(field);
         int mapSize = map.size();
 
         for (Map.Entry<Integer, Fraction> mapEntry : generated.entrySet()) {
             map.remove(mapEntry.getKey());
             assertEquals(mapSize, map.size());
             assertEquals(field.getZero(), map.get(mapEntry.getKey()));
         }
     }
 
     /**
      * Returns a map with at least 100 elements where each element is absent from javaMap.
      */
     private Map<Integer, Fraction> generateAbsent() {
         Map<Integer, Fraction> generated = new HashMap<>();
         do {
             generated.putAll(generate());
             for (Integer key : javaMap.keySet())
                 generated.remove(key);
         } while (generated.size() < 100);
         return generated;
     }
 
     @Test
     void testCopy() {
         OpenIntToFieldHashMap<Fraction> copy =
             new OpenIntToFieldHashMap<>(createFromJavaMap(field));
         assertEquals(javaMap.size(), copy.size());
 
         for (Map.Entry<Integer, Fraction> mapEntry : javaMap.entrySet())
             assertEquals(mapEntry.getValue(), copy.get(mapEntry.getKey()));
     }
 
     @Test
     void testContainsKey() {
         OpenIntToFieldHashMap<Fraction> map = createFromJavaMap(field);
         for (Entry<Integer, Fraction> mapEntry : javaMap.entrySet()) {
             assertTrue(map.containsKey(mapEntry.getKey()));
         }
         for (Map.Entry<Integer, Fraction> mapEntry : generateAbsent().entrySet()) {
             assertFalse(map.containsKey(mapEntry.getKey()));
         }
         for (Entry<Integer, Fraction> mapEntry : javaMap.entrySet()) {
             int key = mapEntry.getKey();
             assertTrue(map.containsKey(key));
             map.remove(key);
             assertFalse(map.containsKey(key));
         }
     }
 
     @Test
     void testIterator() {
         OpenIntToFieldHashMap<Fraction> map = createFromJavaMap(field);
         OpenIntToFieldHashMap<Fraction>.Iterator iterator = map.iterator();
         for (int i = 0; i < map.size(); ++i) {
             assertTrue(iterator.hasNext());
             iterator.advance();
             int key = iterator.key();
             assertTrue(map.containsKey(key));
             assertEquals(javaMap.get(key), map.get(key));
             assertEquals(javaMap.get(key), iterator.value());
             assertTrue(javaMap.containsKey(key));
         }
         assertFalse(iterator.hasNext());
         try {
             iterator.advance();
             fail("an exception should have been thrown");
         } catch (NoSuchElementException nsee) {
             // expected
         }
     }
 
     @Test
     void testEquals() {
         OpenIntToFieldHashMap<Fraction> map1 = new OpenIntToFieldHashMap<>(FractionField.getInstance());
         map1.put(2,   new Fraction( 5, 2));
         map1.put(17,  new Fraction(-1, 2));
         map1.put(16,  Fraction.ZERO);
         assertEquals(map1, map1);
         OpenIntToFieldHashMap<Fraction> map2 = new OpenIntToFieldHashMap<>(FractionField.getInstance());
         map2.put(17, new Fraction(-1, 2));
         map2.put(2,  new Fraction( 5, 2));
         map2.put(16, new Fraction(0));
         assertEquals(map1, map2);
         map2.put(16,  new Fraction( 1, 4));
         assertNotEquals(map1, map2);
         map2.put(16,  Fraction.ZERO);
         assertEquals(map1, map2);
         OpenIntToFieldHashMap<BigFraction> map3 = new OpenIntToFieldHashMap<>(BigFractionField.getInstance());
         map3.put(2,   new BigFraction( 5, 2));
         map3.put(17,  new BigFraction(-1, 2));
         map3.put(16,  BigFraction.ZERO);
         assertNotEquals(map1, map3);
         assertNotEquals("", map1);
         assertNotEquals(null, map1);
     }
 
     @Test
     void testHashcode() {
         OpenIntToFieldHashMap<Fraction> map = new OpenIntToFieldHashMap<>(FractionField.getInstance());
         map.put(2,   new Fraction( 5, 2));
         map.put(17,  new Fraction(-1, 2));
         map.put(16,  Fraction.ZERO);
         assertEquals(-528348218, map.hashCode());
     }
 
     @Test
     void testConcurrentModification() {
         OpenIntToFieldHashMap<Fraction> map = createFromJavaMap(field);
         OpenIntToFieldHashMap<Fraction>.Iterator iterator = map.iterator();
         map.put(3, new Fraction(3));
         try {
             iterator.advance();
             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
     void testPutKeysWithCollisions() {
         OpenIntToFieldHashMap<Fraction> map = new OpenIntToFieldHashMap<>(field);
         int key1 = -1996012590;
         Fraction value1 = new Fraction(1);
         map.put(key1, value1);
         int key2 = 835099822;
         map.put(key2, value1);
         int key3 = 1008859686;
         map.put(key3, value1);
         assertEquals(value1, map.get(key3));
         assertEquals(3, map.size());
 
         map.remove(key2);
         Fraction value2 = new Fraction(2);
         map.put(key3, value2);
         assertEquals(value2, map.get(key3));
         assertEquals(2, map.size());
     }
 
     /**
      * Similar to testPutKeysWithCollisions() but exercises the codepaths in a slightly
      * different manner.
      */
     @Test
     void testPutKeysWithCollision2() {
         OpenIntToFieldHashMap<Fraction>map = new OpenIntToFieldHashMap<>(field);
         int key1 = 837989881;
         Fraction value1 = new Fraction(1);
         map.put(key1, value1);
         int key2 = 476463321;
         map.put(key2, value1);
         assertEquals(2, map.size());
         assertEquals(value1, map.get(key2));
 
         map.remove(key1);
         Fraction value2 = new Fraction(2);
         map.put(key2, value2);
         assertEquals(1, map.size());
         assertEquals(value2, map.get(key2));
     }
 
 
 }