/*
 * 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.checkpointing.utils;

import org.apache.flink.api.common.JobID;
import org.apache.flink.api.common.JobStatus;
import org.apache.flink.api.common.time.Deadline;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.client.program.ClusterClient;
import org.apache.flink.configuration.CheckpointingOptions;
import org.apache.flink.configuration.ConfigConstants;
import org.apache.flink.configuration.Configuration;
import org.apache.flink.configuration.HeartbeatManagerOptions;
import org.apache.flink.configuration.MemorySize;
import org.apache.flink.configuration.StateBackendOptions;
import org.apache.flink.configuration.TaskManagerOptions;
import org.apache.flink.runtime.jobgraph.JobGraph;
import org.apache.flink.runtime.jobgraph.SavepointRestoreSettings;
import org.apache.flink.runtime.testutils.MiniClusterResourceConfiguration;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.test.util.MiniClusterWithClientResource;
import org.apache.flink.test.util.TestBaseUtils;

import org.apache.commons.io.FileUtils;
import org.junit.ClassRule;
import org.junit.Rule;
import org.junit.rules.TemporaryFolder;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.File;
import java.net.URI;
import java.net.URL;
import java.time.Duration;
import java.util.Map;
import java.util.UUID;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.TimeUnit;

import static org.junit.Assert.assertNotEquals;
import static org.junit.Assert.fail;

/** Test savepoint migration. */
public abstract class SavepointMigrationTestBase extends TestBaseUtils {

    @ClassRule public static final TemporaryFolder TEMP_FOLDER = new TemporaryFolder();

    @Rule public final MiniClusterWithClientResource miniClusterResource;

    private static final Logger LOG = LoggerFactory.getLogger(SavepointMigrationTestBase.class);

    protected static final int DEFAULT_PARALLELISM = 4;

    protected static String getResourceFilename(String filename) {
        ClassLoader cl = SavepointMigrationTestBase.class.getClassLoader();
        URL resource = cl.getResource(filename);
        if (resource == null) {
            throw new NullPointerException("Missing snapshot resource.");
        }
        return resource.getFile();
    }

    protected SavepointMigrationTestBase() throws Exception {
        miniClusterResource =
                new MiniClusterWithClientResource(
                        new MiniClusterResourceConfiguration.Builder()
                                .setConfiguration(getConfiguration())
                                .setNumberTaskManagers(1)
                                .setNumberSlotsPerTaskManager(DEFAULT_PARALLELISM)
                                .build());
    }

    private Configuration getConfiguration() throws Exception {
        // Flink configuration
        final Configuration config = new Configuration();

        config.setInteger(ConfigConstants.LOCAL_NUMBER_TASK_MANAGER, 1);
        config.setInteger(TaskManagerOptions.NUM_TASK_SLOTS, DEFAULT_PARALLELISM);

        UUID id = UUID.randomUUID();
        final File checkpointDir = TEMP_FOLDER.newFolder("checkpoints_" + id).getAbsoluteFile();
        final File savepointDir = TEMP_FOLDER.newFolder("savepoints_" + id).getAbsoluteFile();

        if (!checkpointDir.exists() || !savepointDir.exists()) {
            throw new Exception("Test setup failed: failed to create (temporary) directories.");
        }

        LOG.info("Created temporary checkpoint directory: " + checkpointDir + ".");
        LOG.info("Created savepoint directory: " + savepointDir + ".");

        config.setString(StateBackendOptions.STATE_BACKEND, "memory");
        config.setString(
                CheckpointingOptions.CHECKPOINTS_DIRECTORY, checkpointDir.toURI().toString());
        config.set(CheckpointingOptions.FS_SMALL_FILE_THRESHOLD, MemorySize.ZERO);
        config.setString(CheckpointingOptions.SAVEPOINT_DIRECTORY, savepointDir.toURI().toString());
        config.setLong(HeartbeatManagerOptions.HEARTBEAT_INTERVAL, 300L);

        return config;
    }

    @SafeVarargs
    protected final void executeAndSavepoint(
            StreamExecutionEnvironment env,
            String savepointPath,
            Tuple2<String, Integer>... expectedAccumulators)
            throws Exception {

        final Deadline deadLine = Deadline.fromNow(Duration.ofMinutes(5));

        ClusterClient<?> client = miniClusterResource.getClusterClient();

        // Submit the job
        JobGraph jobGraph = env.getStreamGraph().getJobGraph();

        JobID jobID = client.submitJob(jobGraph).get();

        LOG.info("Submitted job {} and waiting...", jobID);

        boolean done = false;
        while (deadLine.hasTimeLeft()) {
            Thread.sleep(100);
            Map<String, Object> accumulators = client.getAccumulators(jobID).get();

            boolean allDone = true;
            for (Tuple2<String, Integer> acc : expectedAccumulators) {
                Object accumOpt = accumulators.get(acc.f0);
                if (accumOpt == null) {
                    allDone = false;
                    break;
                }

                Integer numFinished = (Integer) accumOpt;
                if (!numFinished.equals(acc.f1)) {
                    allDone = false;
                    break;
                }
            }
            if (allDone) {
                done = true;
                break;
            }
        }

        if (!done) {
            fail("Did not see the expected accumulator results within time limit.");
        }

        LOG.info("Triggering savepoint.");

        CompletableFuture<String> savepointPathFuture = client.triggerSavepoint(jobID, null);

        String jobmanagerSavepointPath =
                savepointPathFuture.get(deadLine.timeLeft().toMillis(), TimeUnit.MILLISECONDS);

        File jobManagerSavepoint = new File(new URI(jobmanagerSavepointPath).getPath());
        // savepoints were changed to be directories in Flink 1.3
        if (jobManagerSavepoint.isDirectory()) {
            FileUtils.moveDirectory(jobManagerSavepoint, new File(savepointPath));
        } else {
            FileUtils.moveFile(jobManagerSavepoint, new File(savepointPath));
        }
    }

    @SafeVarargs
    protected final void restoreAndExecute(
            StreamExecutionEnvironment env,
            String savepointPath,
            Tuple2<String, Integer>... expectedAccumulators)
            throws Exception {

        final Deadline deadLine = Deadline.fromNow(Duration.ofMinutes(5));

        ClusterClient<?> client = miniClusterResource.getClusterClient();

        // Submit the job
        JobGraph jobGraph = env.getStreamGraph().getJobGraph();

        jobGraph.setSavepointRestoreSettings(SavepointRestoreSettings.forPath(savepointPath));

        JobID jobID = client.submitJob(jobGraph).get();

        boolean done = false;
        while (deadLine.hasTimeLeft()) {

            // try and get a job result, this will fail if the job already failed. Use this
            // to get out of this loop

            try {
                CompletableFuture<JobStatus> jobStatusFuture = client.getJobStatus(jobID);

                JobStatus jobStatus = jobStatusFuture.get(5, TimeUnit.SECONDS);

                if (jobStatus == JobStatus.FAILED) {
                    LOG.warn(
                            "Job reached status failed",
                            client.requestJobResult(jobID)
                                    .get()
                                    .getSerializedThrowable()
                                    .get()
                                    .deserializeError(ClassLoader.getSystemClassLoader()));
                }
                assertNotEquals(JobStatus.FAILED, jobStatus);
            } catch (Exception e) {
                fail("Could not connect to job: " + e);
            }

            Thread.sleep(100);
            Map<String, Object> accumulators = client.getAccumulators(jobID).get();

            boolean allDone = true;
            for (Tuple2<String, Integer> acc : expectedAccumulators) {
                Object numFinished = accumulators.get(acc.f0);
                if (numFinished == null) {
                    allDone = false;
                    break;
                }
                if (!numFinished.equals(acc.f1)) {
                    allDone = false;
                    break;
                }
            }

            if (allDone) {
                done = true;
                break;
            }
        }

        if (!done) {
            fail("Did not see the expected accumulator results within time limit.");
        }
    }
}