/*
 * 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.misc;

import org.apache.flink.api.common.JobExecutionResult;
import org.apache.flink.api.common.accumulators.LongCounter;
import org.apache.flink.api.common.functions.MapFunction;
import org.apache.flink.api.common.functions.OpenContext;
import org.apache.flink.api.common.functions.RichFlatMapFunction;
import org.apache.flink.api.common.serialization.SimpleStringEncoder;
import org.apache.flink.connector.file.sink.FileSink;
import org.apache.flink.core.fs.Path;
import org.apache.flink.runtime.client.JobExecutionException;
import org.apache.flink.runtime.testutils.MiniClusterResourceConfiguration;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.api.functions.sink.v2.DiscardingSink;
import org.apache.flink.test.util.MiniClusterWithClientResource;
import org.apache.flink.util.Collector;
import org.apache.flink.util.TestLogger;

import org.junit.ClassRule;
import org.junit.Test;

import static org.apache.flink.util.ExceptionUtils.findThrowable;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
import static org.junit.Assert.fail;

/**
 * Tests for the system behavior in multiple corner cases - when null records are passed through the
 * system. - when disjoint dataflows are executed - when accumulators are used chained after a
 * non-udf operator.
 *
 * <p>The tests are bundled into one class to reuse the same test cluster. This speeds up test
 * execution, as the majority of the test time goes usually into starting/stopping the test cluster.
 */
@SuppressWarnings("serial")
public class MiscellaneousIssuesITCase extends TestLogger {

    @ClassRule
    public static final MiniClusterWithClientResource MINI_CLUSTER_RESOURCE =
            new MiniClusterWithClientResource(
                    new MiniClusterResourceConfiguration.Builder()
                            .setNumberTaskManagers(2)
                            .setNumberSlotsPerTaskManager(3)
                            .build());

    @Test
    public void testNullValues() throws Exception {
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        env.setParallelism(1);

        DataStream<String> data =
                env.fromData("hallo")
                        .map(
                                new MapFunction<String, String>() {
                                    @Override
                                    public String map(String value) throws Exception {
                                        return null;
                                    }
                                });
        data.sinkTo(
                FileSink.forRowFormat(new Path("/tmp/myTest"), new SimpleStringEncoder<String>())
                        .build());

        try {
            env.execute();
            fail("this should fail due to null values.");
        } catch (JobExecutionException e) {
            assertTrue(findThrowable(e, NullPointerException.class).isPresent());
        }
    }

    @Test
    public void testDisjointDataflows() throws Exception {
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        env.setParallelism(5);

        // generate two different flows
        env.fromSequence(1, 10).sinkTo(new DiscardingSink<>());
        env.fromSequence(1, 10).sinkTo(new DiscardingSink<>());
    }

    @Test
    public void testAccumulatorsAfterNoOp() throws Exception {

        final String accName = "test_accumulator";

        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        env.setParallelism(6);

        env.fromSequence(1, 1000000)
                .rebalance()
                .flatMap(
                        new RichFlatMapFunction<Long, Long>() {

                            private LongCounter counter;

                            @Override
                            public void open(OpenContext openContext) {
                                counter = getRuntimeContext().getLongCounter(accName);
                            }

                            @Override
                            public void flatMap(Long value, Collector<Long> out) {
                                counter.add(1L);
                            }
                        })
                .sinkTo(new DiscardingSink<>());

        JobExecutionResult result = env.execute();

        assertEquals(1000000L, result.getAllAccumulatorResults().get(accName));
    }
}
