/*
    * 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.analysis.integration.gauss;
  
  import org.hipparchus.analysis.UnivariateFunction;
  import org.hipparchus.analysis.function.Cos;
  import org.hipparchus.analysis.function.Inverse;
  import org.hipparchus.analysis.function.Log;
  import org.hipparchus.exception.LocalizedCoreFormats;
  import org.hipparchus.exception.MathIllegalArgumentException;
  import org.junit.jupiter.api.Test;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.fail;
  
  /**
   * Test of the {@link LegendreRuleFactory}.
   *
   */
  class LegendreTest {
      private static final GaussIntegratorFactory factory = new GaussIntegratorFactory();
  
      @Test
      void testTooLArgeNumberOfPoints() {
          try {
              factory.legendre(10000, 0, Math.PI / 2);
              fail("an exception should have been thrown");
          } catch (MathIllegalArgumentException miae) {
              assertEquals(LocalizedCoreFormats.NUMBER_TOO_LARGE, miae.getSpecifier());
              assertEquals(10000, ((Integer) miae.getParts()[0]).intValue());
              assertEquals(1000,  ((Integer) miae.getParts()[1]).intValue());
          }
      }
  
      @Test
      void testCos() {
          final UnivariateFunction cos = new Cos();
  
          final GaussIntegrator integrator = factory.legendre(7, 0, Math.PI / 2);
          final double s = integrator.integrate(cos);
          // System.out.println("s=" + s + " e=" + 1);
          assertEquals(1, s, Math.ulp(1d));
      }
  
  
      @Test
      void testInverse() {
          final UnivariateFunction inv = new Inverse();
          final UnivariateFunction log = new Log();
  
          final double lo = 12.34;
          final double hi = 456.78;
  
          final GaussIntegrator integrator = factory.legendre(60, lo, hi);
          final double s = integrator.integrate(inv);
          final double expected = log.value(hi) - log.value(lo);
          // System.out.println("s=" + s + " e=" + expected);
          assertEquals(expected, s, 1e-14);
      }
  }