package it.cavallium.dbengine;

import static org.junit.jupiter.api.Assertions.assertEquals;

import io.net5.buffer.ByteBuf;
import it.cavallium.dbengine.database.disk.LLTempLMDBEnv;
import it.cavallium.dbengine.lucene.LMDBSortedCodec;
import it.cavallium.dbengine.lucene.LMDBPriorityQueue;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.function.Function;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;

public class TestLMDB {

	private LLTempLMDBEnv env;
	private LMDBPriorityQueue<Integer> queue;

	@BeforeEach
	public void beforeEach() throws IOException {
		this.env = new LLTempLMDBEnv();
		this.queue = new LMDBPriorityQueue<>(env, new LMDBSortedCodec<Integer>() {
			@Override
			public ByteBuf serialize(Function<Integer, ByteBuf> allocator, Integer data) {
				return allocator.apply(Integer.BYTES).writeInt(data).asReadOnly();
			}

			@Override
			public Integer deserialize(ByteBuf b) {
				return b.getInt(0);
			}

			@Override
			public int compare(Integer o1, Integer o2) {
				return Integer.compare(o1, o2);
			}

			@Override
			public int compareDirect(ByteBuf o1, ByteBuf o2) {
				return Integer.compare(o1.getInt(0), o2.getInt(0));
			}
		});
	}

	@Test
	public void testNoOp() {

	}

	@Test
	public void testEmptyTop() {
		Assertions.assertNull(queue.top());
	}

	@Test
	public void testAddSingle() {
		queue.add(2);
		Assertions.assertEquals(2, queue.top());
	}

	@Test
	public void testAddSame() {
		queue.add(2);
		queue.add(2);
		Assertions.assertEquals(2, queue.top());
		Assertions.assertEquals(2, queue.size());
	}

	@Test
	public void testAddMulti() {
		for (int i = 0; i < 1000; i++) {
			queue.add(i);
		}
		Assertions.assertEquals(0, queue.top());
	}

	@Test
	public void testAddMultiClear() {
		for (int i = 0; i < 1000; i++) {
			queue.add(i);
		}
		queue.clear();
		Assertions.assertNull(queue.top());
	}

	@Test
	public void testAddRemove() {
		queue.add(0);
		queue.remove(0);
		Assertions.assertNull(queue.top());
	}

	@Test
	public void testAddRemoveNonexistent() {
		queue.add(0);
		queue.remove(1);
		Assertions.assertEquals(0, queue.top());
	}

	@Test
	public void testAddMultiSameRemove() {
		queue.add(0);
		queue.add(0);
		queue.add(1);
		queue.remove(0);
		Assertions.assertEquals(2, queue.size());
		Assertions.assertEquals(0, queue.top());
	}

	@Test
	public void testAddMultiRemove() {
		for (int i = 0; i < 1000; i++) {
			queue.add(i);
		}
		queue.remove(0);
		Assertions.assertEquals(1, queue.top());
	}

	@Test
	public void testSort() {
		var sortedNumbers = new ArrayList<Integer>();
		for (int i = 0; i < 1000; i++) {
			sortedNumbers.add(i);
		}
		var shuffledNumbers = new ArrayList<>(sortedNumbers);
		Collections.shuffle(shuffledNumbers);
		for (Integer number : shuffledNumbers) {
			queue.add(number);
		}

		var newSortedNumbers = new ArrayList<>();
		Integer popped;
		while ((popped = queue.pop()) != null) {
			newSortedNumbers.add(popped);
		}

		Assertions.assertEquals(sortedNumbers, newSortedNumbers);
	}

	@AfterEach
	public void afterEach() throws IOException {
		queue.close();
		assertEquals(0, env.countUsedDbs());
		env.close();
	}
}