/* 
 * B-tree set test (Java)
 * 
 * Copyright (c) 2018 Project Nayuki. (MIT License)
 * https://www.nayuki.io/page/btree-set
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 * - The above copyright notice and this permission notice shall be included in
 *   all copies or substantial portions of the Software.
 * - The Software is provided "as is", without warranty of any kind, express or
 *   implied, including but not limited to the warranties of merchantability,
 *   fitness for a particular purpose and noninfringement. In no event shall the
 *   authors or copyright holders be liable for any claim, damages or other
 *   liability, whether in an action of contract, tort or otherwise, arising from,
 *   out of or in connection with the Software or the use or other dealings in the
 *   Software.
 */

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Random;
import java.util.Set;
import java.util.SortedSet;
import java.util.TreeSet;
import org.junit.Test;


public final class BTreeSetTest {
	
	@Test public void testSmallRandomly() {
		final int trials = 1000;
		final int operations = 100;
		final int range = 1000;
		
		for (int i = 0; i < trials; i++) {
			SortedSet<Integer> set0 = new TreeSet<>();
			BTreeSet<Integer> set1 = new BTreeSet<>(rand.nextInt(5) + 2);
			for (int j = 0; j < operations; j++) {
				// Add/remove a random value
				Integer val = rand.nextInt(range);
				if (rand.nextDouble() < 0.001) {
					set0.clear();
					set1.clear();
				} else if (rand.nextDouble() < 0.5)
					assertTrue(set0.add(val) == set1.add(val));
				else
					assertTrue(set0.remove(val) == set1.remove(val));
				set1.checkStructure();
				
				// Check size and check element membership over entire range
				assertTrue(set0.isEmpty() == set1.isEmpty());
				assertEquals(set0.size(), set1.size());
				if (!set0.isEmpty()) {
					assertEquals(set0.first(), set1.first());
					assertEquals(set0.last (), set1.last ());
				}
				for (int k = -4; k < range + 4; k++) {
					val = k;
					assertTrue(set0.contains(val) == set1.contains(val));
				}
			}
		}
	}
	
	
	@Test public void testInsertRandomly() {
		final int trials = 100;
		final int operations = 10_000;
		final int range = 100_000;
		final int checks = 10;
		
		for (int i = 0; i < trials; i++) {
			Set<Integer> set0 = new HashSet<>();
			BTreeSet<Integer> set1 = new BTreeSet<>(2);
			for (int j = 0; j < operations; j++) {
				// Add a random value
				Integer val = rand.nextInt(range);
				assertTrue(set0.add(val) == set1.add(val));
				if (rand.nextDouble() < 0.003)
					set1.checkStructure();
				
				// Check size and random element membership
				assertEquals(set0.size(), set1.size());
				for (int k = 0; k < checks; k++) {
					val = rand.nextInt(range);
					assertTrue(set0.contains(val) == set1.contains(val));
				}
			}
		}
	}
	
	
	@Test public void testLargeRandomly() {
		final int trials = 100;
		final int operations = 30_000;
		final int range = 100_000;
		final int checks = 10;
		
		for (int i = 0; i < trials; i++) {
			Set<Integer> set0 = new HashSet<>();
			BTreeSet<Integer> set1 = new BTreeSet<>(rand.nextInt(5) + 2);
			for (int j = 0; j < operations; j++) {
				// Add/remove a random value
				Integer val = rand.nextInt(range);
				if (rand.nextDouble() < 0.5)
					assertTrue(set0.add(val) == set1.add(val));
				else
					assertTrue(set0.remove(val) == set1.remove(val));
				if (rand.nextDouble() < 0.001)
					set1.checkStructure();
				
				// Check size and random element membership
				assertEquals(set0.size(), set1.size());
				for (int k = 0; k < checks; k++) {
					val = rand.nextInt(range);
					assertTrue(set0.contains(val) == set1.contains(val));
				}
			}
		}
	}
	
	
	@Test public void testRemoveAllRandomly() {
		final int trials = 100;
		final int limit = 10_000;
		final int range = 100_000;
		final int checks = 10;
		
		for (int i = 0; i < trials; i++) {
			// Create sets and add all values
			Set<Integer> set0 = new HashSet<>();
			BTreeSet<Integer> set1 = new BTreeSet<>(rand.nextInt(5) + 2);
			for (int j = 0; j < limit; j++) {
				Integer val = rand.nextInt(range);
				assertTrue(set0.add(val) == set1.add(val));
			}
			set1.checkStructure();
			
			// Remove each value in random order
			List<Integer> list = new ArrayList<>(set0);
			Collections.shuffle(list);
			for (Integer val : list) {
				assertTrue(set0.remove(val) == set1.remove(val));
				if (rand.nextDouble() < Math.max(1.0 / set1.size(), 0.001))
					set1.checkStructure();
				assertEquals(set0.size(), set1.size());
				for (int k = 0; k < checks; k++) {
					val = rand.nextInt(range);
					assertTrue(set0.contains(val) == set1.contains(val));
				}
			}
			assertTrue(set0.isEmpty() && set1.isEmpty());
		}
	}
	
	
	@Test public void testIteratorRandomly() {
		final int trials = 10_000;
		final int operations = 1000;
		final int range = 10_000;
		
		for (int i = 0; i < trials; i++) {
			// Create sets and add all values
			Set<Integer> set0 = new HashSet<>();
			BTreeSet<Integer> set1 = new BTreeSet<>(rand.nextInt(5) + 2);
			int numInsert = rand.nextInt(operations);
			for (int j = 0; j < numInsert; j++) {
				Integer val = rand.nextInt(range);
				assertTrue(set0.add(val) == set1.add(val));
			}
			assertEquals(set0, new HashSet<>(set1));
			
			// Remove a random subset
			List<Integer> list = new ArrayList<>(set0);
			Collections.shuffle(list);
			int numRemove = rand.nextInt(list.size() + 1);
			for (Integer val : list.subList(0, numRemove))
				assertTrue(set0.remove(val) == set1.remove(val));
			assertEquals(set0, new HashSet<>(set1));
		}
	}
	
	
	private static final Random rand = new Random();
	
}