/*
    * 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.
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  package org.apache.commons.numbers.primes;
  
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.List;
  
  import org.junit.jupiter.api.Assertions;
  import org.junit.jupiter.api.Test;
  
  class SmallPrimesTest {
  
      // Primes larger than the small PRIMES array in SmallPrimes
      private static final int[] LARGE_PRIME = {3673, 3677};
  
      @Test
      void smallTrialDivision_smallComposite() {
          final List<Integer> factors = new ArrayList<>();
          final int result = SmallPrimes.smallTrialDivision(3 * 7 * 23, factors);
          Assertions.assertEquals(1, result);
          Assertions.assertEquals(Arrays.asList(3, 7, 23), factors);
      }
  
      @Test
      void smallTrialDivision_repeatedFactors() {
          final List<Integer> factors = new ArrayList<>();
          final int result = SmallPrimes.smallTrialDivision(2 * 2 * 3 * 3 * 3, factors);
          Assertions.assertEquals(1, result);
          Assertions.assertEquals(Arrays.asList(2, 2, 3, 3, 3), factors);
      }
  
      @Test
      void smallTrialDivision_oneFactor() {
          final List<Integer> factors = new ArrayList<>();
          final int result = SmallPrimes.smallTrialDivision(59, factors);
          Assertions.assertEquals(1, result);
          Assertions.assertEquals(Collections.singletonList(59), factors);
      }
  
      @Test
      void smallTrialDivision_BoundaryPrimes() {
          final List<Integer> factors = new ArrayList<>();
          final int penultimatePrime = SmallPrimes.PRIMES[SmallPrimes.PRIMES.length - 2];
          final int result = SmallPrimes.smallTrialDivision(penultimatePrime * SmallPrimes.PRIMES_LAST, factors);
          Assertions.assertEquals(1, result);
          Assertions.assertEquals(Arrays.asList(penultimatePrime, SmallPrimes.PRIMES_LAST), factors);
      }
  
      @Test
      void smallTrialDivision_largeComposite() {
          final List<Integer> factors = new ArrayList<>();
          final int result = SmallPrimes.smallTrialDivision(2 * 5 * LARGE_PRIME[0], factors);
          Assertions.assertEquals(LARGE_PRIME[0], result);
          Assertions.assertEquals(Arrays.asList(2, 5), factors);
      }
  
      @Test
      void smallTrialDivision_noSmallPrimeFactors() {
          final List<Integer> factors = new ArrayList<>();
          final int result = SmallPrimes.smallTrialDivision(LARGE_PRIME[0] * LARGE_PRIME[1], factors);
          Assertions.assertEquals(LARGE_PRIME[0] * LARGE_PRIME[1], result);
          Assertions.assertEquals(Collections.<Integer>emptyList(), factors);
      }
  
      @Test
      void boundedTrialDivision_twoDifferentFactors() {
          final List<Integer> factors = new ArrayList<>();
          SmallPrimes.boundedTrialDivision(LARGE_PRIME[0] * LARGE_PRIME[1], Integer.MAX_VALUE, factors);
          Assertions.assertEquals(Arrays.asList(LARGE_PRIME[0], LARGE_PRIME[1]), factors);
      }
  
      @Test
      void boundedTrialDivision_square() {
          final List<Integer> factors = new ArrayList<>();
          SmallPrimes.boundedTrialDivision(LARGE_PRIME[0] * LARGE_PRIME[0], Integer.MAX_VALUE, factors);
          Assertions.assertEquals(Arrays.asList(LARGE_PRIME[0], LARGE_PRIME[0]), factors);
      }
  
      @Test
      void trialDivision_smallComposite() {
          final List<Integer> factors = SmallPrimes.trialDivision(5 * 11 * 29 * 103);
          Assertions.assertEquals(Arrays.asList(5, 11, 29, 103), factors);
      }
 
     @Test
     void trialDivision_repeatedFactors() {
         final List<Integer> factors = SmallPrimes.trialDivision(2 * 2 * 2 * 2 * 5 * 5);
         Assertions.assertEquals(Arrays.asList(2, 2, 2, 2, 5, 5), factors);
     }
 
     @Test
     void trialDivision_oneSmallFactor() {
         final List<Integer> factors = SmallPrimes.trialDivision(101);
         Assertions.assertEquals(Collections.singletonList(101), factors);
     }
 
     @Test
     void trialDivision_largeComposite() {
         final List<Integer> factors = SmallPrimes.trialDivision(2 * 3 * LARGE_PRIME[0]);
         Assertions.assertEquals(Arrays.asList(2, 3, LARGE_PRIME[0]), factors);
     }
 
     @Test
     void trialDivision_veryLargeComposite() {
         final List<Integer> factors = SmallPrimes.trialDivision(2 * LARGE_PRIME[0] * LARGE_PRIME[1]);
         Assertions.assertEquals(Arrays.asList(2, LARGE_PRIME[0], LARGE_PRIME[1]), factors);
     }
 
     @Test
     void millerRabinPrimeTest_primes() {
         for (final int n : PrimesTest.PRIMES) {
             if (n % 2 == 1) {
                 Assertions.assertTrue(SmallPrimes.millerRabinPrimeTest(n));
             }
         }
     }
 
     @Test
     void millerRabinPrimeTest_composites() {
         for (final int n : PrimesTest.NOT_PRIMES) {
             if (n % 2 == 1) {
                 Assertions.assertFalse(SmallPrimes.millerRabinPrimeTest(n));
             }
         }
     }
 }