/*
    * 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.exception.MathIllegalArgumentException;
  import org.junit.jupiter.api.Test;
  
  import java.util.NoSuchElementException;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertFalse;
  import static org.junit.jupiter.api.Assertions.assertThrows;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  import static org.junit.jupiter.api.Assertions.fail;
  
  /**
   * Test cases for the {@link MultidimensionalCounter} class.
   */
  class MultidimensionalCounterTest {
      @Test
      void testPreconditions() {
          MultidimensionalCounter c;
  
          try {
              c = new MultidimensionalCounter(0, 1);
              fail("MathIllegalArgumentException expected");
          } catch (MathIllegalArgumentException e) {
              // Expected.
          }
          try {
              c = new MultidimensionalCounter(2, 0);
              fail("MathIllegalArgumentException expected");
          } catch (MathIllegalArgumentException e) {
              // Expected.
          }
          try {
              c = new MultidimensionalCounter(-1, 1);
              fail("MathIllegalArgumentException expected");
          } catch (MathIllegalArgumentException e) {
              // Expected.
          }
  
          c = new MultidimensionalCounter(2, 3);
          try {
              c.getCount(1, 1, 1);
              fail("MathIllegalArgumentException expected");
          } catch (MathIllegalArgumentException e) {
              // Expected.
          }
          try {
              c.getCount(3, 1);
              fail("MathIllegalArgumentException expected");
          } catch (MathIllegalArgumentException e) {
              // Expected.
          }
          try {
              c.getCount(0, -1);
              fail("MathIllegalArgumentException expected");
          } catch (MathIllegalArgumentException e) {
              // Expected.
          }
          try {
              c.getCounts(-1);
              fail("MathIllegalArgumentException expected");
          } catch (MathIllegalArgumentException e) {
              // Expected.
          }
          try {
              c.getCounts(6);
              fail("MathIllegalArgumentException expected");
          } catch (MathIllegalArgumentException e) {
              // Expected.
          }
      }
  
      @Test
      void testIteratorPreconditions() {
          MultidimensionalCounter.Iterator iter = (new MultidimensionalCounter(2, 3)).iterator();
          try {
             iter.getCount(-1);
             fail("IndexOutOfBoundsException expected");
         } catch (IndexOutOfBoundsException e) {
             // Expected.
         }
         try {
             iter.getCount(2);
             fail("IndexOutOfBoundsException expected");
         } catch (IndexOutOfBoundsException e) {
             // Expected.
         }
     }
 
     @Test
     void testIterator() {
         final int dim1 = 3;
         final int dim2 = 4;
 
         final MultidimensionalCounter.Iterator iter
             = new MultidimensionalCounter(dim1, dim2).iterator();
 
         final int max = dim1 * dim2;
         for (int i = 0; i < max; i++) {
             assertTrue(iter.hasNext());
 
             // Should not throw.
             iter.next();
         }
 
         assertFalse(iter.hasNext());
     }
 
     @Test
     void testIteratorNoMoreElements() {
         assertThrows(NoSuchElementException.class, () -> {
             final MultidimensionalCounter.Iterator iter
                 = new MultidimensionalCounter(4, 2).iterator();
 
             while (iter.hasNext()) {
                 iter.next();
             }
 
             // No more elements: should throw.
             iter.next();
         });
     }
 
     @Test
     void testMulti2UniConversion() {
         final MultidimensionalCounter c = new MultidimensionalCounter(2, 4, 5);
         assertEquals(33, c.getCount(1, 2, 3));
     }
 
     @Test
     void testAccessors() {
         final int[] originalSize = new int[] {2, 6, 5};
         final MultidimensionalCounter c = new MultidimensionalCounter(originalSize);
         final int nDim = c.getDimension();
         assertEquals(nDim, originalSize.length);
 
         final int[] size = c.getSizes();
         for (int i = 0; i < nDim; i++) {
             assertEquals(originalSize[i], size[i]);
         }
     }
 
     @Test
     void testIterationConsistency() {
         final MultidimensionalCounter c = new MultidimensionalCounter(2, 3, 4);
         final int[][] expected = new int[][] {
             { 0, 0, 0 },
             { 0, 0, 1 },
             { 0, 0, 2 },
             { 0, 0, 3 },
             { 0, 1, 0 },
             { 0, 1, 1 },
             { 0, 1, 2 },
             { 0, 1, 3 },
             { 0, 2, 0 },
             { 0, 2, 1 },
             { 0, 2, 2 },
             { 0, 2, 3 },
             { 1, 0, 0 },
             { 1, 0, 1 },
             { 1, 0, 2 },
             { 1, 0, 3 },
             { 1, 1, 0 },
             { 1, 1, 1 },
             { 1, 1, 2 },
             { 1, 1, 3 },
             { 1, 2, 0 },
             { 1, 2, 1 },
             { 1, 2, 2 },
             { 1, 2, 3 }
         };
 
         final int totalSize = c.getSize();
         assertEquals(expected.length, totalSize);
 
         final int nDim = c.getDimension();
         final MultidimensionalCounter.Iterator iter = c.iterator();
         for (int i = 0; i < totalSize; i++) {
             if (!iter.hasNext()) {
                 fail("Too short");
             }
             final int uniDimIndex = iter.next().intValue();
             assertEquals(i, uniDimIndex, "Wrong iteration at " + i);
 
             for (int dimIndex = 0; dimIndex < nDim; dimIndex++) {
                 assertEquals(expected[i][dimIndex], iter.getCount(dimIndex), "Wrong multidimensional index for [" + i + "][" + dimIndex + "]");
             }
 
             assertEquals(c.getCount(expected[i]), uniDimIndex, "Wrong unidimensional index for [" + i + "]");
 
             final int[] indices = c.getCounts(uniDimIndex);
             for (int dimIndex = 0; dimIndex < nDim; dimIndex++) {
                 assertEquals(expected[i][dimIndex], indices[dimIndex], "Wrong multidimensional index for [" + i + "][" + dimIndex + "]");
             }
         }
 
         if (iter.hasNext()) {
             fail("Too long");
         }
     }
 }