/*
 * Copyright (C) 2017-2022 Sebastiano Vigna
 *
 * Licensed 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 it.unimi.dsi.fastutil.ints;

import static org.junit.Assert.assertArrayEquals;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertNotEquals;
import static org.junit.Assert.assertSame;
import static org.junit.Assert.assertTrue;

import org.junit.Test;

@SuppressWarnings("static-method")
public class IntImmutableListTest {

	@SuppressWarnings("unlikely-arg-type")
	@Test
	public void testEmptyListIsDifferentFromEmptySet() {
		assertFalse(IntLists.EMPTY_LIST.equals(IntSets.EMPTY_SET));
		assertFalse(IntSets.EMPTY_SET.equals(IntLists.EMPTY_LIST));
	}


	@Test
	public void testConstructors() {
		final int[] a = new int[] { 0, 1, 2 };
		assertEquals(IntArrayList.wrap(a), new IntImmutableList(a));
		assertEquals(IntArrayList.wrap(a), new IntImmutableList(a, 0, a.length));
	}

	@Test
	public void testOf() {
		final IntImmutableList l = IntImmutableList.of(0, 1, 2);
		assertEquals(IntArrayList.wrap(new int[] { 0, 1, 2 }), l);
		final int[] a = new int[] { 0, 1, 2 };
		assertEquals(IntArrayList.wrap(a), IntImmutableList.of(a));
	}

	@Test
	public void testOfEmpty() {
		final IntImmutableList l = IntImmutableList.of();
		assertTrue(l.isEmpty());
	}

	@Test
	public void testOfSingleton() {
		final IntImmutableList l = IntImmutableList.of(0);
		assertEquals(IntArrayList.wrap(new int[] { 0 }), l);
	}


	@Test
	public void testToList() {
		final IntImmutableList baseList = IntImmutableList.of(2, 380, 1297);
		// Also conveniently serves as a test of the intStream and spliterator.
		final IntImmutableList transformed = IntImmutableList.toList(baseList.intStream().map(i -> i + 40));
		assertEquals(IntImmutableList.of(42, 420, 1337), transformed);
	}

	@Test
	public void testToListWithExpectedSize() {
		final IntImmutableList baseList = IntImmutableList.toList(java.util.stream.IntStream.range(0, 100));
		IntImmutableList transformed = IntImmutableList.toListWithExpectedSize(baseList.intStream().map(i -> i + 40), 100);
		final IntImmutableList expectedList = IntImmutableList.toList(baseList.intStream().map(i -> i + 40));
		assertEquals(expectedList, transformed);

		// Test undersized below default capacity
		transformed = IntImmutableList.toListWithExpectedSize(baseList.intStream().map(i -> i + 40), 5);
		assertEquals(expectedList, transformed);

		// Test undersized above default capacity
		transformed = IntImmutableList.toListWithExpectedSize(baseList.intStream().map(i -> i + 40), 50);
		assertEquals(expectedList, transformed);

		// Test oversized
		transformed = IntImmutableList.toListWithExpectedSize(baseList.intStream().map(i -> i + 40), 50000);
		assertEquals(expectedList, transformed);
	}

	@Test
	public void testToListWithExpectedSize_parallel() {
		final IntImmutableList baseList = IntImmutableList.toList(java.util.stream.IntStream.range(0, 5000).parallel());
		IntImmutableList transformed = IntImmutableList.toListWithExpectedSize(baseList.intParallelStream().map(i -> i + 40), 5000);
		final IntImmutableList expectedList = IntImmutableList.toList(baseList.intParallelStream().map(i -> i + 40));
		assertEquals(expectedList, transformed);

		// Test undersized below default capacity
		transformed = IntImmutableList.toListWithExpectedSize(baseList.intParallelStream().map(i -> i + 40), 5);
		assertEquals(expectedList, transformed);

		// Test undersized above default capacity
		transformed = IntImmutableList.toListWithExpectedSize(baseList.intParallelStream().map(i -> i + 40), 50);
		assertEquals(expectedList, transformed);

		// Test oversized
		transformed = IntImmutableList.toListWithExpectedSize(baseList.intParallelStream().map(i -> i + 40), 50000);
		assertEquals(expectedList, transformed);
	}

	@Test
	public void testListIterator_testIteration() {
		final IntImmutableList l = IntImmutableList.of(0, 1, 2, 3);
		final IntListIterator li = l.listIterator(1);

		assertTrue(li.hasPrevious()); // We are at position 1
		assertTrue(li.hasNext());
		assertEquals(1, li.nextIndex());
		assertEquals(1, li.nextInt());
		assertEquals(2, li.nextIndex());
		assertEquals(2, li.nextInt());
		assertEquals(3, li.nextIndex());
		assertEquals(3, li.nextInt());
		assertEquals(4, li.nextIndex());
		assertFalse(li.hasNext());
		assertTrue(li.hasPrevious());

		assertEquals(3, li.previousIndex());
		assertEquals(3, li.previousInt());
		assertEquals(2, li.previousIndex());
		assertEquals(2, li.previousInt());
		assertEquals(1, li.previousIndex());
		assertEquals(1, li.previousInt());
		assertEquals(0, li.previousIndex());
		assertEquals(0, li.previousInt());
		assertEquals(-1, li.previousIndex());
		assertFalse(li.hasPrevious());
		assertTrue(li.hasNext());
	}

	@Test
	public void testListIterator_testSkipping() {
		final IntImmutableList l = IntImmutableList.of(0, 1, 2, 3, 4, 5);
		final IntListIterator li = l.listIterator(1);

		li.back(10);
		assertEquals(0, li.nextIndex());
		assertFalse(li.hasPrevious());
		assertTrue(li.hasNext());

		li.skip(10);
		assertEquals(6, li.nextIndex());
		assertTrue(li.hasPrevious());
		assertFalse(li.hasNext());

		li.back(3);
		assertEquals(3, li.nextIndex());

		li.skip(1);
		assertEquals(4, li.nextIndex());
	}

	@Test
	public void testListIterator_testForEachRemaining() {
		final IntImmutableList l = IntImmutableList.of(0, 1, 2, 3);
		final IntListIterator li = l.listIterator(1);
		final IntList consumer = new IntArrayList();
		li.forEachRemaining(consumer::add);
		assertEquals(consumer, IntList.of(1, 2, 3));
	}

	@Test
	public void testEquals_AnotherImmutableList() {
		final IntImmutableList baseList = IntImmutableList.of(2, 380, 1297);
		assertEquals(IntImmutableList.of(2, 380, 1297), baseList);
		assertNotEquals(IntImmutableList.of(42, 420, 1337), baseList);
	}

	@Test
	public void testEquals_Sublist() {
		final IntImmutableList l1 = IntImmutableList.of(0, 1, 2, 3);
		final IntImmutableList l2 = IntImmutableList.of(5, 0, 1, 2, 3, 4);
		final IntList sl2 = l2.subList(1, 5); // 0, 1, 2, 3
		assertEquals(l1, sl2);
		final IntList sl2b = l2.subList(0, 4); // 5, 0, 1, 2
		assertNotEquals(l1, sl2b);
	}

	@Test
	public void testEquals_OtherListImpl() {
		final IntImmutableList baseList = IntImmutableList.of(2, 380, 1297);
		assertEquals(IntArrayList.of(2, 380, 1297), baseList);
		assertNotEquals(IntArrayList.of(42, 420, 1337), baseList);
	}

	@Test
	public void testCompareTo_AnotherImmutableList() {
		final IntImmutableList baseList = IntImmutableList.of(2, 380, 1297);
		final IntImmutableList lessThenList = IntImmutableList.of(2, 365, 1297);
		final IntImmutableList greaterThenList = IntImmutableList.of(2, 380, 1300);
		final IntImmutableList lessBecauseItIsSmaller = IntImmutableList.of(2, 380);
		final IntImmutableList greaterBecauseItIsLarger = IntImmutableList.of(2, 380, 1297, 1);
		final IntImmutableList equalList = IntImmutableList.of(2, 380, 1297);
		assertTrue(baseList.compareTo(lessThenList) > 0);
		assertTrue(baseList.compareTo(greaterThenList) < 0);
		assertTrue(baseList.compareTo(lessBecauseItIsSmaller) > 0);
		assertTrue(baseList.compareTo(greaterBecauseItIsLarger) < 0);
		assertTrue(baseList.compareTo(equalList) == 0);
	}

	@Test
	public void testCompareTo_Sublist() {
		final IntImmutableList baseList = IntImmutableList.of(2, 380, 1297);
		final IntList lessThenList = IntImmutableList.of(2, 365, 1297, 1).subList(0, 3);
		final IntList greaterThenList = IntImmutableList.of(2, 380, 1300, 1).subList(0, 3);
		final IntList lessBecauseItIsSmaller = IntImmutableList.of(2, 380, 1).subList(0, 2);
		final IntList greaterBecauseItIsLarger = IntImmutableList.of(2, 380, 1297, 1, 1).subList(0, 4);
		final IntList equalList = IntImmutableList.of(2, 380, 1297, 1).subList(0, 3);
		assertTrue(baseList.compareTo(lessThenList) > 0);
		assertTrue(baseList.compareTo(greaterThenList) < 0);
		assertTrue(baseList.compareTo(lessBecauseItIsSmaller) > 0);
		assertTrue(baseList.compareTo(greaterBecauseItIsLarger) < 0);
		assertTrue(baseList.compareTo(equalList) == 0);
	}

	@Test
	public void testCompareTo_OtherListImpl() {
		final IntImmutableList baseList = IntImmutableList.of(2, 380, 1297);
		final IntArrayList lessThenList = IntArrayList.of(2, 365, 1297);
		final IntArrayList greaterThenList = IntArrayList.of(2, 380, 1300);
		final IntArrayList lessBecauseItIsSmaller = IntArrayList.of(2, 380);
		final IntArrayList greaterBecauseItIsLarger = IntArrayList.of(2, 380, 1297, 1);
		final IntArrayList equalList = IntArrayList.of(2, 380, 1297);
		assertTrue(baseList.compareTo(lessThenList) > 0);
		assertTrue(baseList.compareTo(greaterThenList) < 0);
		assertTrue(baseList.compareTo(lessBecauseItIsSmaller) > 0);
		assertTrue(baseList.compareTo(greaterBecauseItIsLarger) < 0);
		assertTrue(baseList.compareTo(equalList) == 0);
	}

	@Test
	public void testSpliteratorTrySplit() {
		final IntImmutableList baseList = IntImmutableList.of(0, 1, 2, 3, 72, 5, 6);
		final IntSpliterator willBeSuffix = baseList.spliterator();
		assertEquals(baseList.size(), willBeSuffix.getExactSizeIfKnown());
		// Rather non-intuitively for finite sequences (but makes perfect sense for infinite ones),
		// the spec demands the original spliterator becomes the suffix and the new Spliterator becomes the prefix.
		final IntSpliterator prefix = willBeSuffix.trySplit();
		// No assurance of where we split, but where ever it is it should be a perfect split into a prefix and suffix.
		final java.util.stream.IntStream suffixStream = java.util.stream.StreamSupport.intStream(willBeSuffix, false);
		final java.util.stream.IntStream prefixStream = java.util.stream.StreamSupport.intStream(prefix, false);

		final IntImmutableList prefixList = IntImmutableList.toList(prefixStream);
		final IntImmutableList suffixList = IntImmutableList.toList(suffixStream);
		assertEquals(baseList.size(), prefixList.size() + suffixList.size());
		assertEquals(baseList.subList(0, prefixList.size()), prefixList);
		assertEquals(baseList.subList(prefixList.size(), baseList.size()), suffixList);
		final IntArrayList recombinedList = new IntArrayList(baseList.size());
		recombinedList.addAll(prefixList);
		recombinedList.addAll(suffixList);
		assertEquals(baseList, recombinedList);
	}

	@Test
	public void testSubList_testEquals_ImmutableList() {
		final IntImmutableList l = IntImmutableList.of(0, 1, 2, 3);
		final IntList sl = l.subList(0, 3);
		assertEquals(IntImmutableList.of(0, 1, 2), sl);
		assertNotEquals(IntImmutableList.of(0, 1, 3), sl);
	}

	@Test
	public void testSubList_testEquals_Sublist() {
		final IntImmutableList l1 = IntImmutableList.of(0, 1, 2, 3);
		final IntImmutableList l2 = IntImmutableList.of(5, 0, 1, 2, 3, 4);
		final IntList sl1 = l1.subList(0, 3); // 0, 1, 2
		final IntList sl2 = l2.subList(1, 4); // 0, 1, 2
		assertEquals(sl1, sl2);
		final IntList sl3 = l2.subList(0, 3); // 5, 0, 1
		assertNotEquals(sl1, sl3);
	}

	@Test
	public void testSubList_testEquals_OtherListImpl() {
		final IntImmutableList l = IntImmutableList.of(0, 1, 2, 3);
		final IntList sl = l.subList(0, 3);
		assertEquals(IntArrayList.of(0, 1, 2), sl);
		assertNotEquals(IntArrayList.of(0, 1, 3), sl);
	}

	@Test
	public void testSubList_testToArray() {
		final IntImmutableList l = IntImmutableList.of(0, 1, 2, 3);
		final IntList sl = l.subList(0, 3);
		assertArrayEquals(new int[] { 0, 1, 2 }, sl.toIntArray());
	}

	@Test
	public void testSublistListIterator_testIteration() {
		final IntImmutableList l = IntImmutableList.of(0, 1, 2, 3, 4, 5);
		final IntList sl = l.subList(1, 4);
		final IntListIterator li = sl.listIterator(1);
		assertTrue(li.hasPrevious()); // We are at position 1
		assertTrue(li.hasNext());
		assertEquals(1, li.nextIndex());
		assertEquals(2, li.nextInt());
		assertEquals(2, li.nextIndex());
		assertEquals(3, li.nextInt());
		assertEquals(3, li.nextIndex());
		assertFalse(li.hasNext());
		assertTrue(li.hasPrevious());

		assertEquals(2, li.previousIndex());
		assertEquals(3, li.previousInt());
		assertEquals(1, li.previousIndex());
		assertEquals(2, li.previousInt());
		assertEquals(0, li.previousIndex());
		assertEquals(1, li.previousInt());
		assertEquals(-1, li.previousIndex());
		assertFalse(li.hasPrevious());
		assertTrue(li.hasNext());
	}

	@Test
	public void testSublistListIterator_testSkipping() {
		final IntImmutableList l = IntImmutableList.of(0, 1, 2, 3, 4, 5);
		final IntList sl = l.subList(1, 4);
		final IntListIterator li = sl.listIterator(1);

		li.back(10);
		assertEquals(0, li.nextIndex());
		assertFalse(li.hasPrevious());
		assertTrue(li.hasNext());

		li.skip(10);
		assertEquals(3, li.nextIndex());
		assertTrue(li.hasPrevious());
		assertFalse(li.hasNext());

		li.back(2);
		assertEquals(1, li.nextIndex());

		li.skip(1);
		assertEquals(2, li.nextIndex());
	}

	@Test
	public void testSublistListIterator_testForEachRemaining() {
		final IntImmutableList l = IntImmutableList.of(0, 1, 2, 3, 4, 5);
		final IntList sl = l.subList(1, 4);
		final IntListIterator li = sl.listIterator(1);
		final IntList consumer = new IntArrayList();
		li.forEachRemaining(consumer::add);
		assertEquals(consumer, IntList.of(2, 3));
	}

	@Test
	public void testSubList_testSubSubList() {
		final IntImmutableList l = IntImmutableList.of(0, 1, 2, 3, 4);
		final IntList sl = l.subList(1, 4);
		final IntList ssl = sl.subList(1, 2);
		assertEquals(IntImmutableList.of(1, 2, 3), sl);
		assertEquals(IntImmutableList.of(2), ssl);
	}

	@Test
	public void testSubList_testSpliteratorTrySplit() {
		final IntList baseList = IntImmutableList.of(0, 1, 2, 3, 72, 5, 6).subList(1, 5); // 1, 2, 3, 72, 5
		final IntSpliterator willBeSuffix = baseList.spliterator();
		assertEquals(baseList.size(), willBeSuffix.getExactSizeIfKnown());
		// Rather non-intuitively for finite sequences (but makes perfect sense for infinite ones),
		// the spec demands the original spliterator becomes the suffix and the new Spliterator becomes the prefix.
		final IntSpliterator prefix = willBeSuffix.trySplit();
		// No assurance of where we split, but where ever it is it should be a perfect split into a prefix and suffix.
		final java.util.stream.IntStream suffixStream = java.util.stream.StreamSupport.intStream(willBeSuffix, false);
		final java.util.stream.IntStream prefixStream = java.util.stream.StreamSupport.intStream(prefix, false);

		final IntImmutableList prefixList = IntImmutableList.toList(prefixStream);
		final IntImmutableList suffixList = IntImmutableList.toList(suffixStream);
		assertEquals(baseList.size(), prefixList.size() + suffixList.size());
		assertEquals(baseList.subList(0, prefixList.size()), prefixList);
		assertEquals(baseList.subList(prefixList.size(), baseList.size()), suffixList);
		final IntArrayList recombinedList = new IntArrayList(baseList.size());
		recombinedList.addAll(prefixList);
		recombinedList.addAll(suffixList);
		assertEquals(baseList, recombinedList);
	}

	@Test
	public void testSubList_testCompareTo_ImmutableList() {
		final IntList baseList = IntImmutableList.of(2, 380, 1297, 1).subList(0, 3);
		final IntImmutableList lessThenList = IntImmutableList.of(2, 365, 1297);
		final IntImmutableList greaterThenList = IntImmutableList.of(2, 380, 1300);
		final IntImmutableList lessBecauseItIsSmaller = IntImmutableList.of(2, 380);
		final IntImmutableList greaterBecauseItIsLarger = IntImmutableList.of(2, 380, 1297, 1);
		final IntImmutableList equalList = IntImmutableList.of(2, 380, 1297);
		assertTrue(baseList.compareTo(lessThenList) > 0);
		assertTrue(baseList.compareTo(greaterThenList) < 0);
		assertTrue(baseList.compareTo(lessBecauseItIsSmaller) > 0);
		assertTrue(baseList.compareTo(greaterBecauseItIsLarger) < 0);
		assertTrue(baseList.compareTo(equalList) == 0);
	}

	@Test
	public void testSubList_testCompareTo_Sublist() {
		final IntList baseList = IntImmutableList.of(2, 380, 1297, 1).subList(0, 3);
		final IntList lessThenList = IntImmutableList.of(2, 365, 1297, 1).subList(0, 3);
		final IntList greaterThenList = IntImmutableList.of(2, 380, 1300, 1).subList(0, 3);
		final IntList lessBecauseItIsSmaller = IntImmutableList.of(2, 380, 1).subList(0, 2);
		final IntList greaterBecauseItIsLarger = IntImmutableList.of(2, 380, 1297, 1, 1).subList(0, 4);
		final IntList equalList = IntImmutableList.of(2, 380, 1297, 1).subList(0, 3);
		assertTrue(baseList.compareTo(lessThenList) > 0);
		assertTrue(baseList.compareTo(greaterThenList) < 0);
		assertTrue(baseList.compareTo(lessBecauseItIsSmaller) > 0);
		assertTrue(baseList.compareTo(greaterBecauseItIsLarger) < 0);
		assertTrue(baseList.compareTo(equalList) == 0);
	}

	@Test
	public void testSubList_testCompareTo_OtherListImpl() {
		final IntList baseList = IntImmutableList.of(2, 380, 1297, 1).subList(0, 3);
		final IntArrayList lessThenList = IntArrayList.of(2, 365, 1297);
		final IntArrayList greaterThenList = IntArrayList.of(2, 380, 1300);
		final IntArrayList lessBecauseItIsSmaller = IntArrayList.of(2, 380);
		final IntArrayList greaterBecauseItIsLarger = IntArrayList.of(2, 380, 1297, 1);
		final IntArrayList equalList = IntArrayList.of(2, 380, 1297);
		assertTrue(baseList.compareTo(lessThenList) > 0);
		assertTrue(baseList.compareTo(greaterThenList) < 0);
		assertTrue(baseList.compareTo(lessBecauseItIsSmaller) > 0);
		assertTrue(baseList.compareTo(greaterBecauseItIsLarger) < 0);
		assertTrue(baseList.compareTo(equalList) == 0);
	}

	@Test
	public void testZeroLengthToArray() {
		assertSame(IntArrays.EMPTY_ARRAY, IntImmutableList.of().toIntArray());
	}

	@Test
	public void testOversizedToArray() {
		final IntImmutableList l = IntImmutableList.of(0, 1, 2, 3);
		assertArrayEquals(new int[]{0, 1, 2, 3, 0}, l.toArray(new int[5]));
	}
}