/*
 * 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.test.runtime;

import org.apache.flink.api.common.ExecutionConfig;
import org.apache.flink.api.common.JobID;
import org.apache.flink.api.common.restartstrategy.RestartStrategies;
import org.apache.flink.client.program.MiniClusterClient;
import org.apache.flink.configuration.CheckpointingOptions;
import org.apache.flink.configuration.Configuration;
import org.apache.flink.configuration.JobManagerOptions;
import org.apache.flink.configuration.MemorySize;
import org.apache.flink.configuration.RestOptions;
import org.apache.flink.configuration.TaskManagerOptions;
import org.apache.flink.runtime.execution.Environment;
import org.apache.flink.runtime.io.network.partition.ResultPartitionType;
import org.apache.flink.runtime.jobgraph.DistributionPattern;
import org.apache.flink.runtime.jobgraph.JobGraph;
import org.apache.flink.runtime.jobgraph.JobGraphBuilder;
import org.apache.flink.runtime.jobgraph.JobVertex;
import org.apache.flink.runtime.jobgraph.tasks.AbstractInvokable;
import org.apache.flink.runtime.jobmanager.scheduler.SlotSharingGroup;
import org.apache.flink.runtime.jobmaster.JobResult;
import org.apache.flink.runtime.minicluster.MiniCluster;
import org.apache.flink.runtime.minicluster.MiniClusterConfiguration;
import org.apache.flink.runtime.testtasks.NoOpInvokable;
import org.apache.flink.util.FlinkException;
import org.apache.flink.util.TestLogger;

import org.junit.Test;

import javax.annotation.Nonnull;

import java.io.IOException;
import java.util.Arrays;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.atomic.AtomicBoolean;

import static org.apache.flink.configuration.JobManagerOptions.EXECUTION_FAILOVER_STRATEGY;
import static org.hamcrest.Matchers.is;
import static org.junit.Assert.assertThat;

/** IT case for testing Flink's scheduling strategies. */
public class SchedulingITCase extends TestLogger {

    /** Tests that if local recovery is disabled we won't spread out tasks when recovering. */
    @Test
    public void testDisablingLocalRecovery() throws Exception {
        final Configuration configuration = new Configuration();
        configuration.setBoolean(CheckpointingOptions.LOCAL_RECOVERY, false);

        executeSchedulingTest(configuration);
    }

    /**
     * Tests that if local recovery is enabled we won't spread out tasks when recovering for global
     * failover.
     */
    @Test
    public void testLocalRecoveryFull() throws Exception {
        testLocalRecoveryInternal("full");
    }

    /**
     * Tests that if local recovery is enabled we won't spread out tasks when recovering for
     * regional failover.
     */
    @Test
    public void testLocalRecoveryRegion() throws Exception {
        testLocalRecoveryInternal("region");
    }

    private void testLocalRecoveryInternal(String failoverStrategyValue) throws Exception {
        final Configuration configuration = new Configuration();
        configuration.setBoolean(CheckpointingOptions.LOCAL_RECOVERY, true);
        configuration.setString(EXECUTION_FAILOVER_STRATEGY.key(), failoverStrategyValue);

        executeSchedulingTest(configuration);
    }

    private void executeSchedulingTest(Configuration configuration) throws Exception {
        configuration.setString(RestOptions.BIND_PORT, "0");

        final long slotIdleTimeout = 50L;
        configuration.setLong(JobManagerOptions.SLOT_IDLE_TIMEOUT, slotIdleTimeout);

        configuration.set(TaskManagerOptions.TOTAL_FLINK_MEMORY, MemorySize.parse("1g"));

        final int parallelism = 4;
        final MiniClusterConfiguration miniClusterConfiguration =
                new MiniClusterConfiguration.Builder()
                        .setConfiguration(configuration)
                        .setNumTaskManagers(parallelism)
                        .setNumSlotsPerTaskManager(1)
                        .build();

        try (MiniCluster miniCluster = new MiniCluster(miniClusterConfiguration)) {
            miniCluster.start();

            MiniClusterClient miniClusterClient = new MiniClusterClient(configuration, miniCluster);

            JobGraph jobGraph = createJobGraph(slotIdleTimeout << 1, parallelism);

            // wait for the submission to succeed
            JobID jobID = miniClusterClient.submitJob(jobGraph).get();

            CompletableFuture<JobResult> resultFuture = miniClusterClient.requestJobResult(jobID);

            JobResult jobResult = resultFuture.get();

            assertThat(jobResult.getSerializedThrowable().isPresent(), is(false));
        }
    }

    @Nonnull
    private JobGraph createJobGraph(long delay, int parallelism) throws IOException {
        SlotSharingGroup slotSharingGroup = new SlotSharingGroup();

        final JobVertex source = new JobVertex("source");
        source.setInvokableClass(OneTimeFailingInvokable.class);
        source.setParallelism(parallelism);
        source.setSlotSharingGroup(slotSharingGroup);

        final JobVertex sink = new JobVertex("sink");
        sink.setInvokableClass(NoOpInvokable.class);
        sink.setParallelism(parallelism);
        sink.setSlotSharingGroup(slotSharingGroup);

        sink.connectNewDataSetAsInput(
                source, DistributionPattern.POINTWISE, ResultPartitionType.PIPELINED);

        ExecutionConfig executionConfig = new ExecutionConfig();
        executionConfig.setRestartStrategy(RestartStrategies.fixedDelayRestart(1, delay));

        return JobGraphBuilder.newStreamingJobGraphBuilder()
                .addJobVertices(Arrays.asList(source, sink))
                .setExecutionConfig(executionConfig)
                .build();
    }

    /** Invokable which fails exactly once (one sub task of it). */
    public static final class OneTimeFailingInvokable extends AbstractInvokable {

        private static final AtomicBoolean hasFailed = new AtomicBoolean(false);

        /**
         * Create an Invokable task and set its environment.
         *
         * @param environment The environment assigned to this invokable.
         */
        public OneTimeFailingInvokable(Environment environment) {
            super(environment);
        }

        @Override
        public void invoke() throws Exception {
            if (hasFailed.compareAndSet(false, true)) {
                throw new FlinkException("One time failure.");
            }
        }
    }
}