/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF 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.
 */

package org.apache.flink.streaming.runtime.operators;

import org.apache.flink.api.common.functions.MapFunction;
import org.apache.flink.api.common.typeinfo.BasicTypeInfo;
import org.apache.flink.streaming.api.graph.StreamConfig;
import org.apache.flink.streaming.api.operators.StreamMap;
import org.apache.flink.streaming.runtime.tasks.OneInputStreamTask;
import org.apache.flink.streaming.runtime.tasks.OneInputStreamTaskTestHarness;
import org.apache.flink.streaming.runtime.tasks.StreamTask;
import org.apache.flink.streaming.runtime.tasks.ProcessingTimeService;
import org.apache.flink.streaming.runtime.tasks.ProcessingTimeCallback;

import org.junit.Test;

import java.util.concurrent.atomic.AtomicReference;

import static org.junit.Assert.*;

/**
 * Tests for the timer service of {@link org.apache.flink.streaming.runtime.tasks.StreamTask}.
 */
@SuppressWarnings("serial")
public class StreamTaskTimerTest {

	@Test
	public void testOpenCloseAndTimestamps() throws Exception {
		final OneInputStreamTask<String, String> mapTask = new OneInputStreamTask<>();

		final OneInputStreamTaskTestHarness<String, String> testHarness = new OneInputStreamTaskTestHarness<>(
				mapTask, BasicTypeInfo.STRING_TYPE_INFO, BasicTypeInfo.STRING_TYPE_INFO);
		testHarness.setupOutputForSingletonOperatorChain();

		StreamConfig streamConfig = testHarness.getStreamConfig();

		StreamMap<String, String> mapOperator = new StreamMap<>(new DummyMapFunction<String>());
		streamConfig.setStreamOperator(mapOperator);

		testHarness.invoke();
		testHarness.waitForTaskRunning();

		// first one spawns thread
		mapTask.getProcessingTimeService().registerTimer(System.currentTimeMillis(), new ProcessingTimeCallback() {
			@Override
			public void onProcessingTime(long timestamp) {
			}
		});

		assertEquals(1, StreamTask.TRIGGER_THREAD_GROUP.activeCount());


		testHarness.endInput();
		testHarness.waitForTaskCompletion();

		// thread needs to die in time
		long deadline = System.currentTimeMillis() + 4000;
		while (StreamTask.TRIGGER_THREAD_GROUP.activeCount() > 0 && System.currentTimeMillis() < deadline) {
			Thread.sleep(10);
		}

		assertEquals("Trigger timer thread did not properly shut down",
				0, StreamTask.TRIGGER_THREAD_GROUP.activeCount());
	}

	@Test
	public void checkScheduledTimestampe() {
		try {
			final OneInputStreamTask<String, String> mapTask = new OneInputStreamTask<>();
			final OneInputStreamTaskTestHarness<String, String> testHarness = new OneInputStreamTaskTestHarness<>(mapTask, BasicTypeInfo.STRING_TYPE_INFO, BasicTypeInfo.STRING_TYPE_INFO);
			testHarness.setupOutputForSingletonOperatorChain();

			StreamConfig streamConfig = testHarness.getStreamConfig();
			StreamMap<String, String> mapOperator = new StreamMap<>(new DummyMapFunction<String>());
			streamConfig.setStreamOperator(mapOperator);

			testHarness.invoke();
			testHarness.waitForTaskRunning();

			final AtomicReference<Throwable> errorRef = new AtomicReference<>();

			final long t1 = System.currentTimeMillis();
			final long t2 = System.currentTimeMillis() - 200;
			final long t3 = System.currentTimeMillis() + 100;
			final long t4 = System.currentTimeMillis() + 200;

			ProcessingTimeService timeService = mapTask.getProcessingTimeService();
			timeService.registerTimer(t1, new ValidatingProcessingTimeCallback(errorRef, t1, 0));
			timeService.registerTimer(t2, new ValidatingProcessingTimeCallback(errorRef, t2, 1));
			timeService.registerTimer(t3, new ValidatingProcessingTimeCallback(errorRef, t3, 2));
			timeService.registerTimer(t4, new ValidatingProcessingTimeCallback(errorRef, t4, 3));

			long deadline = System.currentTimeMillis() + 20000;
			while (errorRef.get() == null &&
					ValidatingProcessingTimeCallback.numInSequence < 4 &&
					System.currentTimeMillis() < deadline)
			{
				Thread.sleep(100);
			}

			// handle errors
			if (errorRef.get() != null) {
				errorRef.get().printStackTrace();
				fail(errorRef.get().getMessage());
			}

			assertEquals(4, ValidatingProcessingTimeCallback.numInSequence);

			testHarness.endInput();
			testHarness.waitForTaskCompletion();

			// wait until the trigger thread is shut down. otherwise, the other tests may become unstable
			deadline = System.currentTimeMillis() + 4000;
			while (StreamTask.TRIGGER_THREAD_GROUP.activeCount() > 0 && System.currentTimeMillis() < deadline) {
				Thread.sleep(10);
			}

			assertEquals("Trigger timer thread did not properly shut down",
					0, StreamTask.TRIGGER_THREAD_GROUP.activeCount());
		}
		catch (Exception e) {
			e.printStackTrace();
			fail(e.getMessage());
		}
	}

	private static class ValidatingProcessingTimeCallback implements ProcessingTimeCallback {

		static int numInSequence;

		private final AtomicReference<Throwable> errorRef;

		private final long expectedTimestamp;
		private final int expectedInSequence;

		private ValidatingProcessingTimeCallback(AtomicReference<Throwable> errorRef, long expectedTimestamp, int expectedInSequence) {
			this.errorRef = errorRef;
			this.expectedTimestamp = expectedTimestamp;
			this.expectedInSequence = expectedInSequence;
		}

		@Override
		public void onProcessingTime(long timestamp) {
			try {
				assertEquals(expectedTimestamp, timestamp);
				assertEquals(expectedInSequence, numInSequence);
				numInSequence++;
			}
			catch (Throwable t) {
				errorRef.compareAndSet(null, t);
			}
		}
	}

	// ------------------------------------------------------------------------

	public static class DummyMapFunction<T> implements MapFunction<T, T> {
		@Override
		public T map(T value) {
			return value;
		}
	}
}