/*
 * 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.runtime.checkpoint.savepoint;

import org.apache.flink.core.memory.ByteArrayInputStreamWithPos;
import org.apache.flink.core.memory.ByteArrayOutputStreamWithPos;
import org.apache.flink.core.memory.DataInputViewStreamWrapper;
import org.apache.flink.core.memory.DataOutputViewStreamWrapper;
import org.apache.flink.runtime.checkpoint.MasterState;
import org.apache.flink.runtime.checkpoint.OperatorState;
import org.junit.Test;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.Random;

import static org.junit.Assert.assertEquals;

/**
 * Various tests for the version 2 format serializer of a checkpoint. 
 */
public class SavepointV2SerializerTest {

	@Test
	public void testCheckpointWithNoState() throws Exception {
		final Random rnd = new Random();

		for (int i = 0; i < 100; ++i) {
			final long checkpointId = rnd.nextLong() & 0x7fffffffffffffffL;
			final Collection<OperatorState> taskStates = Collections.emptyList();
			final Collection<MasterState> masterStates = Collections.emptyList();

			testCheckpointSerialization(checkpointId, taskStates, masterStates);
		}
	}

	@Test
	public void testCheckpointWithOnlyMasterState() throws Exception {
		final Random rnd = new Random();
		final int maxNumMasterStates = 5;

		for (int i = 0; i < 100; ++i) {
			final long checkpointId = rnd.nextLong() & 0x7fffffffffffffffL;

			final Collection<OperatorState> operatorStates = Collections.emptyList();

			final int numMasterStates = rnd.nextInt(maxNumMasterStates) + 1;
			final Collection<MasterState> masterStates = 
					CheckpointTestUtils.createRandomMasterStates(rnd, numMasterStates);

			testCheckpointSerialization(checkpointId, operatorStates, masterStates);
		}
	}

	@Test
	public void testCheckpointWithOnlyTaskState() throws Exception {
		final Random rnd = new Random();
		final int maxTaskStates = 20;
		final int maxNumSubtasks = 20;

		for (int i = 0; i < 100; ++i) {
			final long checkpointId = rnd.nextLong() & 0x7fffffffffffffffL;

			final int numTasks = rnd.nextInt(maxTaskStates) + 1;
			final int numSubtasks = rnd.nextInt(maxNumSubtasks) + 1;
			final Collection<OperatorState> taskStates = 
					CheckpointTestUtils.createOperatorStates(rnd, numTasks, numSubtasks);

			final Collection<MasterState> masterStates = Collections.emptyList();

			testCheckpointSerialization(checkpointId, taskStates, masterStates);
		}
	}

	@Test
	public void testCheckpointWithMasterAndTaskState() throws Exception {
		final Random rnd = new Random();

		final int maxNumMasterStates = 5;
		final int maxTaskStates = 20;
		final int maxNumSubtasks = 20;

		for (int i = 0; i < 100; ++i) {
			final long checkpointId = rnd.nextLong() & 0x7fffffffffffffffL;

			final int numTasks = rnd.nextInt(maxTaskStates) + 1;
			final int numSubtasks = rnd.nextInt(maxNumSubtasks) + 1;
			final Collection<OperatorState> taskStates =
					CheckpointTestUtils.createOperatorStates(rnd, numTasks, numSubtasks);

			final int numMasterStates = rnd.nextInt(maxNumMasterStates) + 1;
			final Collection<MasterState> masterStates =
					CheckpointTestUtils.createRandomMasterStates(rnd, numMasterStates);

			testCheckpointSerialization(checkpointId, taskStates, masterStates);
		}
	}

	private void testCheckpointSerialization(
			long checkpointId,
			Collection<OperatorState> operatorStates,
			Collection<MasterState> masterStates) throws IOException {

		SavepointV2Serializer serializer = SavepointV2Serializer.INSTANCE;

		ByteArrayOutputStreamWithPos baos = new ByteArrayOutputStreamWithPos();
		DataOutputStream out = new DataOutputViewStreamWrapper(baos);

		serializer.serialize(new SavepointV2(checkpointId, operatorStates, masterStates), out);
		out.close();

		byte[] bytes = baos.toByteArray();

		DataInputStream in = new DataInputViewStreamWrapper(new ByteArrayInputStreamWithPos(bytes));
		SavepointV2 deserialized = serializer.deserialize(in, getClass().getClassLoader());

		assertEquals(checkpointId, deserialized.getCheckpointId());
		assertEquals(operatorStates, deserialized.getOperatorStates());

		assertEquals(masterStates.size(), deserialized.getMasterStates().size());
		for (Iterator<MasterState> a = masterStates.iterator(), b = deserialized.getMasterStates().iterator();
				a.hasNext();)
		{
			CheckpointTestUtils.assertMasterStateEquality(a.next(), b.next());
		}
	}
}