/*
    * 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.statistics.distribution;
  
  import java.util.stream.Stream;
  import org.junit.jupiter.api.Assertions;
  import org.junit.jupiter.params.ParameterizedTest;
  import org.junit.jupiter.params.provider.Arguments;
  import org.junit.jupiter.params.provider.CsvSource;
  import org.junit.jupiter.params.provider.MethodSource;
  
  /**
   * Test cases for {@link TriangularDistribution}.
   * Extends {@link BaseContinuousDistributionTest}. See javadoc of that class for details.
   */
  class TriangularDistributionTest extends BaseContinuousDistributionTest {
      @Override
      ContinuousDistribution makeDistribution(Object... parameters) {
          final double lower = (Double) parameters[0];
          final double mode = (Double) parameters[1];
          final double upper = (Double) parameters[2];
          return TriangularDistribution.of(lower, mode, upper);
      }
  
  
      @Override
      Object[][] makeInvalidParameters() {
          return new Object[][] {
              {0.0, 0.0, 0.0},
              // 1.0, 2.0, 3 is OK - move points to incorrect locations
              {4.0, 2.0, 3.0},
              {3.0, 2.0, 3.0},
              {2.5, 2.0, 3.0},
              {1.0, 0.0, 3.0},
              {1.0, 4.0, 3.0},
              {1.0, 2.0, -1.0},
              {1.0, 2.0, 1.5},
          };
      }
  
      @Override
      String[] getParameterNames() {
          return new String[] {"SupportLowerBound", "Mode", "SupportUpperBound"};
      }
  
      @Override
      protected double getRelativeTolerance() {
          // Tolerance is 4.440892098500626E-15.
          return 20 * RELATIVE_EPS;
      }
  
      //-------------------- Additional test cases -------------------------------
  
      @ParameterizedTest
      @MethodSource
      void testAdditionalMoments(double a, double b, double c, double mean, double variance) {
          final TriangularDistribution dist = TriangularDistribution.of(a, b, c);
          testMoments(dist, mean, variance, DoubleTolerances.equals());
      }
  
      static Stream<Arguments> testAdditionalMoments() {
          return Stream.of(
              Arguments.of(0, 0.5, 1.0, 0.5, 1 / 24.0),
              Arguments.of(0, 1, 1, 2 / 3.0, 1 / 18.0),
              Arguments.of(-3, 2, 12, 3 + (2 / 3.0), 175 / 18.0)
          );
      }
  
      @ParameterizedTest
      @CsvSource({
          "1, 2, 3",
          "0.12, 3.45, 12.56",
      })
      void testAdditionalParameterAccessors(double lower, double mode, double upper) {
          final TriangularDistribution dist = TriangularDistribution.of(lower, mode, upper);
          Assertions.assertEquals(lower, dist.getSupportLowerBound());
          Assertions.assertEquals(mode, dist.getMode());
          Assertions.assertEquals(upper, dist.getSupportUpperBound());
      }
  }