/*
 * 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.benchmark;

import org.apache.flink.api.common.functions.MapFunction;
import org.apache.flink.benchmark.operators.RecordSource;
import org.apache.flink.benchmark.operators.RecordSource.Record;
import org.apache.flink.configuration.ConfigConstants;
import org.apache.flink.configuration.Configuration;
import org.apache.flink.configuration.MemorySize;
import org.apache.flink.configuration.TaskManagerOptions;
import org.apache.flink.streaming.api.datastream.DataStreamSource;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.api.functions.sink.SinkFunction;

import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.OperationsPerInvocation;
import org.openjdk.jmh.annotations.OutputTimeUnit;
import org.openjdk.jmh.annotations.Param;
import org.openjdk.jmh.annotations.Setup;
import org.openjdk.jmh.runner.Runner;
import org.openjdk.jmh.runner.RunnerException;
import org.openjdk.jmh.runner.options.Options;
import org.openjdk.jmh.runner.options.OptionsBuilder;
import org.openjdk.jmh.runner.options.VerboseMode;

import java.io.IOException;
import java.time.Duration;

import static java.util.concurrent.TimeUnit.SECONDS;
import static org.apache.flink.api.common.eventtime.WatermarkStrategy.noWatermarks;

/**
 * The benchmark for measuring the time taken to finish the configured number of unaligned
 * checkpoints.
 */
@OutputTimeUnit(SECONDS)
@OperationsPerInvocation(UnalignedCheckpointTimeBenchmark.NUM_FINISHED_CHECKPOINTS)
public class UnalignedCheckpointTimeBenchmark extends BenchmarkBase {
    public static final int NUM_FINISHED_CHECKPOINTS = 10;
    private static final int NUM_VERTICES = 3;
    private static final int PARALLELISM = 4;
    private static final long CHECKPOINT_INTERVAL_MS = 10;

    public static void main(String[] args) throws RunnerException {
        Options options =
                new OptionsBuilder()
                        .verbosity(VerboseMode.NORMAL)
                        .include(UnalignedCheckpointTimeBenchmark.class.getCanonicalName())
                        .build();

        new Runner(options).run();
    }

    @Benchmark
    public void unalignedCheckpoint(UnalignedCheckpointEnvironmentContext context)
            throws Exception {
        StreamExecutionEnvironment env = context.env;
        DataStreamSource<Record> source =
                env.fromSource(
                        new RecordSource(NUM_FINISHED_CHECKPOINTS),
                        noWatermarks(),
                        RecordSource.class.getName());

        source.slotSharingGroup("source")
                .rebalance()
                .map((MapFunction<Record, Record>) value -> value)
                .slotSharingGroup("map")
                .rebalance()
                .addSink(new SlowDiscardSink<>())
                .slotSharingGroup("sink");

        env.execute();
    }

    public static class UnalignedCheckpointEnvironmentContext extends FlinkEnvironmentContext {

        @Param({"0", "1", "ALIGNED"})
        public String timeout = "0";

        public void setUp() throws IOException {
            super.setUp();

            env.setParallelism(parallelism);
            env.enableCheckpointing(CHECKPOINT_INTERVAL_MS);
            if ("ALIGNED".equals(timeout)) {
                env.getCheckpointConfig().enableUnalignedCheckpoints(false);
            } else {
                env.getCheckpointConfig().enableUnalignedCheckpoints(true);
                env.getCheckpointConfig()
                        .setAlignmentTimeout(Duration.ofMillis(Integer.parseInt(timeout)));
            }
        }

        protected Configuration createConfiguration() {
            Configuration conf = super.createConfiguration();
            conf.setInteger(TaskManagerOptions.NUM_TASK_SLOTS, 1);
            conf.set(TaskManagerOptions.MEMORY_SEGMENT_SIZE, new MemorySize(1024 * 4));
            conf.setInteger(ConfigConstants.LOCAL_NUMBER_TASK_MANAGER, NUM_VERTICES * PARALLELISM);
            return conf;
        }
    }

    /**
     * The custom sink for processing records slowly to cause accumulate in-flight buffers even back
     * pressure.
     */
    public static class SlowDiscardSink<T> implements SinkFunction<T> {

        @Override
        public void invoke(T value, Context context) throws Exception {
            Thread.sleep(1);
        }
    }
}