/*
 * Written by Doug Lea and Martin Buchholz with assistance from
 * members of JCP JSR-166 Expert Group and released to the public
 * domain, as explained at
 * http://creativecommons.org/publicdomain/zero/1.0/
 */

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ThreadLocalRandom;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicLong;
import java.util.function.BiFunction;

import junit.framework.Test;

/**
 * Contains tests applicable to all Map implementations.
 */
@SuppressWarnings("unchecked")
public class MapTest extends JSR166TestCase {
    final MapImplementation impl;

    /** Tests are parameterized by a Map implementation. */
    MapTest(MapImplementation impl, String methodName) {
        super(methodName);
        this.impl = impl;
    }

    public static Test testSuite(MapImplementation impl) {
        return newTestSuite(
            parameterizedTestSuite(MapTest.class,
                                   MapImplementation.class,
                                   impl));
    }

    public void testImplSanity() {
        final ThreadLocalRandom rnd = ThreadLocalRandom.current();
        {
            Map m = impl.emptyMap();
            assertTrue(m.isEmpty());
            mustEqual(0, m.size());
            Object k = impl.makeKey(rnd.nextInt());
            Object v = impl.makeValue(rnd.nextInt());
            m.put(k, v);
            assertFalse(m.isEmpty());
            mustEqual(1, m.size());
            assertTrue(m.containsKey(k));
            assertTrue(m.containsValue(v));
        }
        {
            Map m = impl.emptyMap();
            Object v = impl.makeValue(rnd.nextInt());
            if (impl.permitsNullKeys()) {
                m.put(null, v);
                assertTrue(m.containsKey(null));
                assertTrue(m.containsValue(v));
            } else {
                assertThrows(NullPointerException.class, () -> m.put(null, v));
            }
        }
        {
            Map m = impl.emptyMap();
            Object k = impl.makeKey(rnd.nextInt());
            if (impl.permitsNullValues()) {
                m.put(k, null);
                assertTrue(m.containsKey(k));
                assertTrue(m.containsValue(null));
            } else {
                assertThrows(NullPointerException.class, () -> m.put(k, null));
            }
        }
        {
            Map m = impl.emptyMap();
            Object k = impl.makeKey(rnd.nextInt());
            Object v1 = impl.makeValue(rnd.nextInt());
            Object v2 = impl.makeValue(rnd.nextInt());
            m.put(k, v1);
            if (impl.supportsSetValue()) {
                ((Map.Entry)(m.entrySet().iterator().next())).setValue(v2);
                assertSame(v2, m.get(k));
                assertTrue(m.containsKey(k));
                assertTrue(m.containsValue(v2));
                assertFalse(m.containsValue(v1));
            } else {
                assertThrows(UnsupportedOperationException.class,
                             () -> ((Map.Entry)(m.entrySet().iterator().next())).setValue(v2));
            }
        }
    }

    /**
     * Tests and extends the scenario reported in
     * https://bugs.openjdk.java.net/browse/JDK-8186171
     * HashMap: Entry.setValue may not work after Iterator.remove() called for previous entries
     * ant -Djsr166.tckTestClass=HashMapTest -Djsr166.methodFilter=testBug8186171 -Djsr166.runsPerTest=1000 tck
     */
    public void testBug8186171() {
        if (!impl.supportsSetValue()) return;
        if (!atLeastJava10()) return; // jdk9 is no longer maintained
        final ThreadLocalRandom rnd = ThreadLocalRandom.current();
        final boolean permitsNullValues = impl.permitsNullValues();
        final Object v1 = (permitsNullValues && rnd.nextBoolean())
            ? null : impl.makeValue(1);
        final Object v2 = (permitsNullValues && rnd.nextBoolean() && v1 != null)
            ? null : impl.makeValue(2);

        // If true, always lands in first bucket in hash tables.
        final boolean poorHash = rnd.nextBoolean();
        class Key implements Comparable<Key> {
            final int i;
            Key(int i) { this.i = i; }
            public int hashCode() { return poorHash ? 0 : super.hashCode(); }
            public int compareTo(Key x) {
                return Integer.compare(this.i, x.i);
            }
        }

        // Both HashMap and ConcurrentHashMap have:
        // TREEIFY_THRESHOLD = 8; UNTREEIFY_THRESHOLD = 6;
        final int size = rnd.nextInt(1, 25);

        List<Key> keys = new ArrayList<>();
        for (int i = size; i-->0; ) keys.add(new Key(i));
        Key keyToFrob = keys.get(rnd.nextInt(keys.size()));

        Map<Key, Object> m = impl.emptyMap();
        for (Key key : keys) m.put(key, v1);

        for (Iterator<Map.Entry<Key, Object>> it = m.entrySet().iterator();
             it.hasNext(); ) {
            Map.Entry<Key, Object> entry = it.next();
            if (entry.getKey() == keyToFrob)
                entry.setValue(v2); // does this have the expected effect?
            else
                it.remove();
        }

        assertFalse(m.containsValue(v1));
        assertTrue(m.containsValue(v2));
        assertTrue(m.containsKey(keyToFrob));
        mustEqual(1, m.size());
    }

    /**
     * "Missing" test found while investigating JDK-8210280.
     * ant -Djsr166.tckTestClass=HashMapTest -Djsr166.methodFilter=testBug8210280 -Djsr166.runsPerTest=1000000 tck
     */
    public void testBug8210280() {
        final ThreadLocalRandom rnd = ThreadLocalRandom.current();
        final int size1 = rnd.nextInt(32);
        final int size2 = rnd.nextInt(128);

        final Map m1 = impl.emptyMap();
        for (int i = 0; i < size1; i++) {
            int elt = rnd.nextInt(1024 * i, 1024 * (i + 1));
            assertNull(m1.put(impl.makeKey(elt), impl.makeValue(elt)));
        }

        final Map m2 = impl.emptyMap();
        for (int i = 0; i < size2; i++) {
            int elt = rnd.nextInt(Integer.MIN_VALUE + 1024 * i,
                                  Integer.MIN_VALUE + 1024 * (i + 1));
            assertNull(m2.put(impl.makeKey(elt), impl.makeValue(-elt)));
        }

        final Map m1Copy = impl.emptyMap();
        m1Copy.putAll(m1);

        m1.putAll(m2);

        for (Object elt : m2.keySet())
            mustEqual(m2.get(elt), m1.get(elt));
        for (Object elt : m1Copy.keySet())
            assertSame(m1Copy.get(elt), m1.get(elt));
        mustEqual(size1 + size2, m1.size());
    }

    /**
     * 8222930: ConcurrentSkipListMap.clone() shares size variable between original and clone
     */
    public void testClone() {
        final ThreadLocalRandom rnd = ThreadLocalRandom.current();
        final int size = rnd.nextInt(4);
        final Map map = impl.emptyMap();
        for (int i = 0; i < size; i++)
            map.put(impl.makeKey(i), impl.makeValue(i));
        final Map clone = cloneableClone(map);
        if (clone == null) return;      // not cloneable?

        mustEqual(size, map.size());
        mustEqual(size, clone.size());
        mustEqual(map.isEmpty(), clone.isEmpty());

        clone.put(impl.makeKey(-1), impl.makeValue(-1));
        mustEqual(size, map.size());
        mustEqual(size + 1, clone.size());

        clone.clear();
        mustEqual(size, map.size());
        mustEqual(0, clone.size());
        assertTrue(clone.isEmpty());
    }

    /**
     * Concurrent access by compute methods behaves as expected
     */
    public void testConcurrentAccess() throws Throwable {
        final Map map = impl.emptyMap();
        final long testDurationMillis = expensiveTests ? 1000 : 2;
        final int nTasks = impl.isConcurrent()
            ? ThreadLocalRandom.current().nextInt(1, 10)
            : 1;
        final AtomicBoolean done = new AtomicBoolean(false);
        final boolean remappingFunctionCalledAtMostOnce
            = impl.remappingFunctionCalledAtMostOnce();
        final List<CompletableFuture> futures = new ArrayList<>();
        final AtomicLong expectedSum = new AtomicLong(0);
        final Action[] tasks = {
            // repeatedly increment values using compute()
            () -> {
                long[] invocations = new long[2];
                ThreadLocalRandom rnd = ThreadLocalRandom.current();
                BiFunction<Object, Object, Object> incValue = (k, v) -> {
                    invocations[1]++;
                    int vi = (v == null) ? 1 : impl.valueToInt(v) + 1;
                    return impl.makeValue(vi);
                };
                while (!done.getAcquire()) {
                    invocations[0]++;
                    Object key = impl.makeKey(3 * rnd.nextInt(10));
                    map.compute(key, incValue);
                }
                if (remappingFunctionCalledAtMostOnce)
                    mustEqual(invocations[0], invocations[1]);
                expectedSum.getAndAdd(invocations[0]);
            },
            // repeatedly increment values using computeIfPresent()
            () -> {
                long[] invocations = new long[2];
                ThreadLocalRandom rnd = ThreadLocalRandom.current();
                BiFunction<Object, Object, Object> incValue = (k, v) -> {
                    invocations[1]++;
                    int vi = impl.valueToInt(v) + 1;
                    return impl.makeValue(vi);
                };
                while (!done.getAcquire()) {
                    Object key = impl.makeKey(3 * rnd.nextInt(10));
                    if (map.computeIfPresent(key, incValue) != null)
                        invocations[0]++;
                }
                if (remappingFunctionCalledAtMostOnce)
                    mustEqual(invocations[0], invocations[1]);
                expectedSum.getAndAdd(invocations[0]);
            },
        };
        for (int i = nTasks; i--> 0; ) {
            Action task = chooseRandomly(tasks);
            futures.add(CompletableFuture.runAsync(checkedRunnable(task)));
        }
        Thread.sleep(testDurationMillis);
        done.setRelease(true);
        for (var future : futures)
            checkTimedGet(future, null);

        long sum = map.values().stream().mapToLong(x -> (int) x).sum();
        mustEqual(expectedSum.get(), sum);
    }

//     public void testFailsIntentionallyForDebugging() {
//         fail(impl.klazz().getSimpleName());
//     }
}