/*
 * SPDX-License-Identifier: Apache-2.0
 *
 * The OpenSearch Contributors require contributions made to
 * this file be licensed under the Apache-2.0 license or a
 * compatible open source license.
 */

/*
 * Licensed to Elasticsearch under one or more contributor
 * license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright
 * ownership. Elasticsearch licenses this file to you under
 * the Apache License, Version 2.0 (the "License"); you may
 * not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

/*
 * Modifications Copyright OpenSearch Contributors. See
 * GitHub history for details.
 */

package org.opensearch.common.util.concurrent;

import org.opensearch.test.OpenSearchTestCase;

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.atomic.AtomicInteger;

public class RunOnceTests extends OpenSearchTestCase {

    public void testRunOnce() {
        final AtomicInteger counter = new AtomicInteger(0);
        final RunOnce runOnce = new RunOnce(counter::incrementAndGet);
        assertFalse(runOnce.hasRun());

        runOnce.run();
        assertTrue(runOnce.hasRun());
        assertEquals(1, counter.get());

        runOnce.run();
        assertTrue(runOnce.hasRun());
        assertEquals(1, counter.get());
    }

    public void testRunOnceConcurrently() throws InterruptedException {
        final AtomicInteger counter = new AtomicInteger(0);
        final RunOnce runOnce = new RunOnce(counter::incrementAndGet);

        final Thread[] threads = new Thread[between(3, 10)];
        final CountDownLatch latch = new CountDownLatch(1 + threads.length);
        for (int i = 0; i < threads.length; i++) {
            threads[i] = new Thread(() -> {
                latch.countDown();
                try {
                    latch.await();
                } catch (InterruptedException e) {
                    throw new RuntimeException(e);
                }
                runOnce.run();
            });
            threads[i].start();
        }

        latch.countDown();
        for (Thread thread : threads) {
            thread.join();
        }
        assertTrue(runOnce.hasRun());
        assertEquals(1, counter.get());
    }

    public void testRunOnceWithAbstractRunnable() {
        final AtomicInteger onRun = new AtomicInteger(0);
        final AtomicInteger onFailure = new AtomicInteger(0);
        final AtomicInteger onAfter = new AtomicInteger(0);

        final RunOnce runOnce = new RunOnce(new AbstractRunnable() {
            @Override
            protected void doRun() throws Exception {
                onRun.incrementAndGet();
                throw new RuntimeException("failure");
            }

            @Override
            public void onFailure(Exception e) {
                onFailure.incrementAndGet();
            }

            @Override
            public void onAfter() {
                onAfter.incrementAndGet();
            }
        });

        final int iterations = randomIntBetween(1, 10);
        for (int i = 0; i < iterations; i++) {
            runOnce.run();
            assertEquals(1, onRun.get());
            assertEquals(1, onFailure.get());
            assertEquals(1, onAfter.get());
            assertTrue(runOnce.hasRun());
        }
    }
}