package org.lucares.collections;

import java.util.Random;
import java.util.stream.LongStream;

import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;

public class LongLongHashMapTest {
	@Test
	public void testPutRemove() {
		putGetRemove(1);
	}

	@Test
	public void testNullValue() {
		putGetRemove(0);
	}

	private void putGetRemove(final long key) {
		final LongLongHashMap map = new LongLongHashMap();

		final long valueA = 2L;
		final long valueB = 3L;

		// value does not exist
		Assertions.assertFalse(map.containsKey(key));
		Assertions.assertEquals(0, map.size());

		// add value and check it is in the map
		map.put(key, valueA);
		Assertions.assertTrue(map.containsKey(key));
		Assertions.assertEquals(valueA, map.get(key));
		Assertions.assertEquals(1, map.size());

		// overwrite value
		map.put(key, valueB);
		Assertions.assertEquals(valueB, map.get(key));
		Assertions.assertEquals(1, map.size());

		// remove value and check it is gone
		map.remove(key);
		Assertions.assertFalse(map.containsKey(key));
		Assertions.assertEquals(0, map.size());
	}

	@Test
	public void testComputeZeroKey() {
		final LongLongHashMap map = new LongLongHashMap();

		final long key = 1;
		map.compute(key, 6, l -> l + 1);
		Assertions.assertEquals(7, map.get(key), "initialValueIfAbsent is used when there is no mapping for the key");

		map.compute(key, 6, l -> l + 1);
		Assertions.assertEquals(8, map.get(key), "update function is called when 'zeroKey' is set");
	}

	@Test
	public void testCompute() {
		final LongLongHashMap map = new LongLongHashMap();
		final long key = 1;
		map.compute(key, 6, l -> l + 1);
		Assertions.assertEquals(7, map.get(key), "initialValueIfAbsent is used when there is no mapping for the key");

		map.compute(key, 6, l -> l + 1);
		Assertions.assertEquals(8, map.get(key), "update function is called when key is set");
	}

	@Test
	public void testGrowMap() {
		final LongLongHashMap map = new LongLongHashMap(4, 0.75);

		final int numEntries = 12;
		final Random rand = new Random(12345);
		final LongList entries = LongList.of(LongStream.generate(rand::nextLong).limit(numEntries).toArray());

		entries.stream().forEachOrdered(l -> {
			map.put(l, l);
		});
		entries.stream().forEachOrdered(l -> {
			Assertions.assertEquals(l, map.get(l));
		});
		Assertions.assertEquals(16, map.getCapacity(), "capacity after adding 12 entries must be a the smallest number "
				+ "that satisfies initialCapacity * 2^n >= entries/fillFactor");
	}

	@Test
	public void testMultipleValuesOnSamePosition() {
		final int initialCapacity = 20;
		final LongLongHashMap map = new LongLongHashMap(initialCapacity, 0.75);
		// find to values that yield the same 'spread' (position in the table)
		final LongList keysWithSameSpread = findKeysWithSameSpread(map);
		Assertions.assertTrue(keysWithSameSpread.size() > 5);

		keysWithSameSpread.stream().forEach(l -> map.put(l, l));
		Assertions.assertEquals(keysWithSameSpread.size(), map.size());
		keysWithSameSpread.stream().forEach(l -> Assertions.assertEquals(l, map.get(l)));
	}

	@Test
	public void testForEach() {
		final LongLongHashMap map = new LongLongHashMap();
		final Random rand = new Random(6789);
		final LongList entries = LongList.of(LongStream.generate(rand::nextLong).limit(15).toArray());

		entries.stream().forEachOrdered(l -> {
			map.put(l, 2 * l);
		});

		map.forEach((k, v) -> {
			Assertions.assertEquals(k * 2, v, "value is key*2");
			Assertions.assertTrue(entries.indexOf(k) >= 0, "value " + k + " in entries: " + entries);
		});
	}

	@Test
	public void testForEachOrdered() {
		final LongLongHashMap map = new LongLongHashMap();
		final Random rand = new Random(6789);
		final LongList entries = LongList.of(LongStream.generate(rand::nextLong).limit(15).toArray());

		entries.stream().forEachOrdered(l -> {
			map.put(l, 2 * l);
		});

		final LongList actualOrderOfKeys = new LongList();
		map.forEachOrdered((k, v) -> {
			Assertions.assertEquals(k * 2, v, "value is key*2");
			Assertions.assertTrue(entries.indexOf(k) >= 0, "value " + k + " in entries: " + entries);
			actualOrderOfKeys.add(k);
		});

		Assertions.assertTrue(actualOrderOfKeys.isSorted(), "keys are sorted");
		Assertions.assertEquals(LongList.intersection(actualOrderOfKeys, entries).size(), entries.size(),
				"all keys were visited");
		final LongList additionalKeys = new LongList(actualOrderOfKeys);
		additionalKeys.removeAll(entries);
		Assertions.assertEquals(additionalKeys, LongList.of(), "no additional keys were visited");
	}

	@Test
	public void testForEachOrderedOnlyNegativeValues() {
		final LongLongHashMap map = new LongLongHashMap();
		final LongList entries = LongList.of(LongStream.range(-20, -5).toArray());

		entries.stream().forEachOrdered(l -> {
			map.put(l, 2 * l);
		});

		final LongList actualOrderOfKeys = new LongList();
		map.forEachOrdered((k, v) -> {
			Assertions.assertEquals(k * 2, v, "value is key*2");
			Assertions.assertTrue(entries.indexOf(k) >= 0, "value " + k + " in entries: " + entries);
			actualOrderOfKeys.add(k);
		});

		Assertions.assertTrue(actualOrderOfKeys.isSorted(), "keys are sorted");
		Assertions.assertEquals(LongList.intersection(actualOrderOfKeys, entries).size(), entries.size(),
				"all keys were visited");
		final LongList additionalKeys = new LongList(actualOrderOfKeys);
		additionalKeys.removeAll(entries);
		Assertions.assertEquals(additionalKeys, LongList.of(), "no additional keys were visited");
	}

	@Test
	public void testForEachOrderedOnlyNegativeValues2() {
		final LongLongHashMap map = new LongLongHashMap();
		final LongList entries = LongList.of(LongStream.range(-20, -5).toArray());

		entries.stream().forEachOrdered(l -> {
			map.put(l, 2 * l);
		});

		final LongList actualOrderOfKeys = new LongList();
		map.forEachOrdered((k, v) -> {
			Assertions.assertEquals(k * 2, v, "value is key*2");
			Assertions.assertTrue(entries.indexOf(k) >= 0, "value " + k + " in entries: " + entries);
			actualOrderOfKeys.add(k);
		});

		Assertions.assertTrue(actualOrderOfKeys.isSorted(), "keys are sorted");
	}

	@Test
	public void testFindPositionOfFirstPositiveKey() {

		Assertions.assertEquals(-1, LongLongHashMap.findPosOfFirstPositiveKey(new long[] {}));
		Assertions.assertEquals(-1, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { 0 }));
		Assertions.assertEquals(0, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { 1 }));
		Assertions.assertEquals(1, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { 0, 1 }));
		Assertions.assertEquals(0, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { 1, 1 }));
		Assertions.assertEquals(2, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { -1, 0, 1 }));
		Assertions.assertEquals(0, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { 1, 1, 1, 1, 1, 1, 1, 1, 1 }));
		Assertions.assertEquals(0, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { 1, 1, 1, 1, 1, 1, 1, 1 }));
		Assertions.assertEquals(4,
				LongLongHashMap.findPosOfFirstPositiveKey(new long[] { -1, -1, -1, -1, 1, 1, 1, 1, 1 }));
		Assertions.assertEquals(4,
				LongLongHashMap.findPosOfFirstPositiveKey(new long[] { -1, -1, -1, -1, 1, 1, 1, 1 }));
		Assertions.assertEquals(3,
				LongLongHashMap.findPosOfFirstPositiveKey(new long[] { -1, -1, -1, 1, 1, 1, 1, 1, 1 }));
		Assertions.assertEquals(3, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { -1, -1, -1, 1, 1, 1, 1, 1 }));
		Assertions.assertEquals(-1, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { 0, 0, 0, 0, 0 }));
		Assertions.assertEquals(-1, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { 0, 0, 0, 0, 0, 0 }));
		Assertions.assertEquals(4, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { 0, 0, 0, 0, 1, 1, 1, 1 }));
		Assertions.assertEquals(5, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { 0, 0, 0, 0, 0, 1, 1, 1 }));
		Assertions.assertEquals(6, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { 0, 0, 0, 0, 0, 0, 1, 1 }));
		Assertions.assertEquals(4, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { 0, 0, 0, 0, 1, 1, 1 }));
		Assertions.assertEquals(5, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { 0, 0, 0, 0, 0, 1, 1 }));
		Assertions.assertEquals(6, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { 0, 0, 0, 0, 0, 0, 1 }));
		Assertions.assertEquals(4, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { -1, 0, 0, 0, 1, 1, 1 }));
		Assertions.assertEquals(5, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { -1, 0, 0, 0, 0, 1, 1 }));
		Assertions.assertEquals(6, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { -1, 0, 0, 0, 0, 0, 1 }));
	}

	private LongList findKeysWithSameSpread(final LongLongHashMap map) {
		final LongList result = new LongList();
		final int spread = map.spread(1);
		result.add(1);
		for (long l = 2; l < 10000; l++) {
			final int s = map.spread(l);
			if (s == spread) {
				result.add(l);
				if (result.size() > 10) {
					break;
				}
			}
		}

		return result;
	}
}