import org.junit.Assert;
import org.junit.BeforeClass;
import org.junit.Test;

import java.util.*;


public class SimpleTest {

    private static Caching caching;

    @BeforeClass
    public static void init() {
        caching = new OptimalCaching();
    }

    @Test
    public void test1() {
        List<Integer> items = Arrays.asList(1, 2, 3, 1, 2, 3, 1, 2, 3);
        Set<Integer> cache = new HashSet<>(Arrays.asList(2, 3));
        List<Integer> evictions = caching.optimize(Collections.unmodifiableList(items), Collections.unmodifiableSet(cache));
        check(items, cache, evictions, 5);
    }

    @Test
    public void test2() {
        List<Integer> items = Arrays.asList(1, 2, 1, 2, 1, 2, 1, 2);
        Set<Integer> cache = new HashSet<>(Collections.singleton(1));
        List<Integer> evictions = caching.optimize(Collections.unmodifiableList(items), Collections.unmodifiableSet(cache));
        check(items, cache, evictions, 7);
    }

    @Test
    public void test3() {
        List<Integer> items = Arrays.asList(1, 2, 3, 2, 3, 1, 2);
        Set<Integer> cache = new HashSet<>(Arrays.asList(1, 2));
        List<Integer> evictions = caching.optimize(Collections.unmodifiableList(items), Collections.unmodifiableSet(cache));
        check(items, cache, evictions, 2);
    }

    @Test
    public void test4() {
        List<Integer> items = Arrays.asList(1, 2, 3, 4, 1, 4, 5, 1, 4, 2, 3);
        Set<Integer> cache = new HashSet<>(Arrays.asList(1, 2, 3));
        List<Integer> evictions = caching.optimize(Collections.unmodifiableList(items), Collections.unmodifiableSet(cache));
        check(items, cache, evictions, 4);
    }

    @Test
    public void test5() {
        List<Integer> items = Arrays.asList(1, 2, 1, 2);
        Set<Integer> cache = new HashSet<>(Arrays.asList(1, 2));
        List<Integer> evictions = caching.optimize(Collections.unmodifiableList(items), Collections.unmodifiableSet(cache));
        check(items, cache, evictions, 0);
    }

    static void check(List<Integer> items, Set<Integer> cache, List<Integer> evictions, int optimal) {
        Assert.assertEquals("Verkeerd aantal stappen.", items.size(), evictions.size());
        int count = 0;
        for (int i = 0; i < items.size(); i++) {
            Integer item = items.get(i);
            Integer evicted = evictions.get(i);
            if (evicted != null) {
                cache.remove(evicted);
                cache.add(items.get(i));
                count++;
            } else {
                Assert.assertTrue("Gevraagde item zit nog niet in cache.", cache.contains(items.get(i)));
            }
        }
        Assert.assertEquals("Aantal uitwijzingen is niet minimaal.", optimal, count);
    }
    
}