/*

 * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

import org.testng.annotations.Test;

import java.util.concurrent.CountDownLatch;

import java.util.concurrent.CyclicBarrier;

import java.util.concurrent.atomic.AtomicReference;

import static org.testng.Assert.assertEquals;

import static org.testng.Assert.assertFalse;

import static org.testng.Assert.assertTrue;

public class DemandTest {

    @Test

    public void test01() {

        assertTrue(new Demand().isFulfilled());

    }

    @Test

    public void test011() {

        Demand d = new Demand();

        d.increase(3);

        d.decreaseAndGet(3);

        assertTrue(d.isFulfilled());

    }

    @Test

    public void test02() {

        Demand d = new Demand();

        d.increase(1);

        assertFalse(d.isFulfilled());

    }

    @Test

    public void test03() {

        Demand d = new Demand();

        d.increase(3);

        assertEquals(d.decreaseAndGet(3), 3);

    }

    @Test

    public void test04() {

        Demand d = new Demand();

        d.increase(3);

        assertEquals(d.decreaseAndGet(5), 3);

    }

    @Test

    public void test05() {

        Demand d = new Demand();

        d.increase(7);

        assertEquals(d.decreaseAndGet(4), 4);

    }

    @Test

    public void test06() {

        Demand d = new Demand();

        assertEquals(d.decreaseAndGet(3), 0);

    }

    @Test(expectedExceptions = IllegalArgumentException.class)

    public void test07() {

        Demand d = new Demand();

        d.increase(0);

    }

    @Test(expectedExceptions = IllegalArgumentException.class)

    public void test08() {

        Demand d = new Demand();

        d.increase(-1);

    }

    @Test(expectedExceptions = IllegalArgumentException.class)

    public void test09() {

        Demand d = new Demand();

        d.increase(10);

        d.decreaseAndGet(0);

    }

    @Test(expectedExceptions = IllegalArgumentException.class)

    public void test10() {

        Demand d = new Demand();

        d.increase(13);

        d.decreaseAndGet(-3);

    }

    @Test

    public void test11() {

        Demand d = new Demand();

        d.increase(1);

        assertTrue(d.tryDecrement());

    }

    @Test

    public void test12() {

        Demand d = new Demand();

        d.increase(2);

        assertTrue(d.tryDecrement());

    }

    @Test

    public void test14() {

        Demand d = new Demand();

        assertFalse(d.tryDecrement());

    }

    @Test

    public void test141() {

        Demand d = new Demand();

        d.increase(Long.MAX_VALUE);

        assertFalse(d.isFulfilled());

    }

    @Test

    public void test142() {

        Demand d = new Demand();

        d.increase(Long.MAX_VALUE);

        d.increase(1);

        assertFalse(d.isFulfilled());

    }

    @Test

    public void test143() {

        Demand d = new Demand();

        d.increase(Long.MAX_VALUE);

        d.increase(1);

        assertFalse(d.isFulfilled());

    }

    @Test

    public void test144() {

        Demand d = new Demand();

        d.increase(Long.MAX_VALUE);

        d.increase(Long.MAX_VALUE);

        d.decreaseAndGet(3);

        d.decreaseAndGet(5);

        assertFalse(d.isFulfilled());

    }

    @Test

    public void test145() {

        Demand d = new Demand();

        d.increase(Long.MAX_VALUE);

        d.decreaseAndGet(Long.MAX_VALUE);

        assertTrue(d.isFulfilled());

    }

    @Test(invocationCount = 32)

    public void test15() throws InterruptedException {

        int N = Math.max(2, Runtime.getRuntime().availableProcessors() + 1);

        int M = ((N + 1) * N) / 2; // 1 + 2 + 3 + ... N

        Demand d = new Demand();

        d.increase(M);

        CyclicBarrier start = new CyclicBarrier(N);

        CountDownLatch stop = new CountDownLatch(N);

        AtomicReference<Throwable> error = new AtomicReference<>();

        for (int i = 0; i < N; i++) {

            int j = i + 1;

            new Thread(() -> {

                try {

                    start.await();

                } catch (Exception e) {

                    error.compareAndSet(null, e);

                }

                try {

                    assertEquals(d.decreaseAndGet(j), j);

                } catch (Throwable t) {

                    error.compareAndSet(null, t);

                } finally {

                    stop.countDown();

                }

            }).start();

        }

        stop.await();

        assertTrue(d.isFulfilled());

        assertEquals(error.get(), null);

    }

}