/*
 * 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.ignite.internal.processors.localtask;

import java.util.List;
import java.util.Map;
import java.util.concurrent.atomic.AtomicReference;
import org.apache.ignite.IgniteCheckedException;
import org.apache.ignite.IgniteException;
import org.apache.ignite.configuration.DataRegionConfiguration;
import org.apache.ignite.configuration.DataStorageConfiguration;
import org.apache.ignite.configuration.IgniteConfiguration;
import org.apache.ignite.failure.StopNodeFailureHandler;
import org.apache.ignite.internal.IgniteEx;
import org.apache.ignite.internal.IgniteInternalFuture;
import org.apache.ignite.internal.processors.cache.persistence.checkpoint.CheckpointListener;
import org.apache.ignite.internal.processors.cache.persistence.checkpoint.CheckpointWorkflow;
import org.apache.ignite.internal.processors.cache.persistence.metastorage.pendingtask.DurableBackgroundTask;
import org.apache.ignite.internal.processors.cache.persistence.metastorage.pendingtask.DurableBackgroundTaskResult;
import org.apache.ignite.internal.processors.localtask.DurableBackgroundTaskState.State;
import org.apache.ignite.internal.util.future.GridFutureAdapter;
import org.apache.ignite.testframework.junits.common.GridCommonAbstractTest;
import org.jetbrains.annotations.Nullable;
import org.junit.Test;

import static org.apache.ignite.cluster.ClusterState.ACTIVE;
import static org.apache.ignite.cluster.ClusterState.INACTIVE;
import static org.apache.ignite.internal.processors.cache.persistence.metastorage.pendingtask.DurableBackgroundTaskResult.complete;
import static org.apache.ignite.internal.processors.cache.persistence.metastorage.pendingtask.DurableBackgroundTaskResult.restart;
import static org.apache.ignite.internal.processors.localtask.DurableBackgroundTaskState.State.COMPLETED;
import static org.apache.ignite.internal.processors.localtask.DurableBackgroundTaskState.State.INIT;
import static org.apache.ignite.internal.processors.localtask.DurableBackgroundTaskState.State.STARTED;
import static org.apache.ignite.internal.processors.localtask.DurableBackgroundTasksProcessor.metaStorageKey;
import static org.apache.ignite.testframework.GridTestUtils.assertThrows;
import static org.apache.ignite.testframework.GridTestUtils.getFieldValue;
import static org.apache.ignite.testframework.GridTestUtils.runAsync;

/**
 * Class for testing the {@link DurableBackgroundTasksProcessor}.
 */
public class DurableBackgroundTasksProcessorSelfTest extends GridCommonAbstractTest {
    /** {@inheritDoc} */
    @Override protected void beforeTest() throws Exception {
        super.beforeTest();

        stopAllGrids();
        cleanPersistenceDir();
    }

    /** {@inheritDoc} */
    @Override protected void afterTest() throws Exception {
        super.afterTest();

        stopAllGrids();
        cleanPersistenceDir();
    }

    /** {@inheritDoc} */
    @Override protected IgniteConfiguration getConfiguration(String igniteInstanceName) throws Exception {
        return super.getConfiguration(igniteInstanceName)
            .setFailureHandler(new StopNodeFailureHandler())
            .setDataStorageConfiguration(
                new DataStorageConfiguration()
                    .setDefaultDataRegionConfiguration(new DataRegionConfiguration().setPersistenceEnabled(true))
            );
    }

    /**
     * Checking the correctness of work (without saving to the MetaStorage) of the task in normal mode.
     *
     * @throws Exception If failed.
     */
    @Test
    public void testSimpleTaskExecutionWithoutMetaStorage() throws Exception {
        checkSimpleTaskExecute(false);
    }

    /**
     * Checking the correctness of work (with saving to the MetaStorage) of the task in normal mode.
     *
     * @throws Exception If failed.
     */
    @Test
    public void testSimpleTaskExecutionWithMetaStorage() throws Exception {
        checkSimpleTaskExecute(true);
    }

    /**
     * Checking the correctness of restarting the task without MetaStorage.
     *
     * @throws Exception If failed.
     */
    @Test
    public void testRestartTaskExecutionWithoutMetaStorage() throws Exception {
        checkRestartTaskExecute(false);
    }

    /**
     * Checking the correctness of restarting the task with MetaStorage.
     *
     * @throws Exception If failed.
     */
    @Test
    public void testRestartTaskExecutionWithMetaStorage() throws Exception {
        checkRestartTaskExecute(true);
    }

    /**
     * Checking the correctness of cancelling the task.
     *
     * @throws Exception If failed.
     */
    @Test
    public void testCancelTaskExecution() throws Exception {
        IgniteEx n = startGrid(0);
        n.cluster().state(ACTIVE);

        SimpleTask t = new SimpleTask("t");
        IgniteInternalFuture<Void> execAsyncFut = execAsync(n, t, false);

        t.onExecFut.get(getTestTimeout());
        checkStateAndMetaStorage(n, t, STARTED, false, false);
        assertFalse(execAsyncFut.isDone());

        n.cluster().state(INACTIVE);

        t.onExecFut.get(getTestTimeout());
        t.taskFut.onDone(complete(null));

        execAsyncFut.get(getTestTimeout());
    }

    /**
     * Check that the task can be started on the node if it joined after the cluster activation.
     *
     * @throws Exception If failed.
     */
    @Test
    public void testTaskStartOnNodeJoinedAfterActivation() throws Exception {
        IgniteEx n = startGrid(0);
        startGrid(1);

        n.cluster().state(ACTIVE);

        stopGrid(1);
        n = startGrid(1);

        SimpleTask t = new SimpleTask("t");
        execAsync(n, t, true);

        t.onExecFut.get(getTestTimeout());
        checkStateAndMetaStorage(n, t, STARTED, true, false);

        stopGrid(1);
        n = startGrid(1);

        checkStateAndMetaStorage(n, t, STARTED, true, false);

        n.cluster().state(INACTIVE);

        stopGrid(1);
        n = startGrid(1);

        checkStateAndMetaStorage(n, t, INIT, true, false);
    }

    /**
     * Check that the task will be restarted after restarting the node.
     *
     * @throws Exception If failed.
     */
    @Test
    public void testRestartTaskAfterRestartNode() throws Exception {
        IgniteEx n = startGrid(0);
        n.cluster().state(ACTIVE);

        SimpleTask t = new SimpleTask("t");
        execAsync(n, t, true);

        t.onExecFut.get(getTestTimeout());
        checkStateAndMetaStorage(n, t, STARTED, true, false);
        t.taskFut.onDone(restart(null));

        stopAllGrids();

        n = startGrid(0);
        n.cluster().state(ACTIVE);

        t = ((SimpleTask)tasks(n).get(t.name()).task());

        t.onExecFut.get(getTestTimeout());
        checkStateAndMetaStorage(n, t, STARTED, true, false);
        t.taskFut.onDone(complete(null));
    }

    /**
     * Checks that stopping the node does not fail the node when deleting tasks.
     *
     * @throws Exception If failed.
     */
    @Test
    public void testNotFailNodeWhenNodeStoppindAndDeleteTasks() throws Exception {
        IgniteEx n = startGrid(0);

        ObservingCheckpointListener observingCpLsnr = new ObservingCheckpointListener();
        dbMgr(n).addCheckpointListener(observingCpLsnr);

        n.cluster().state(ACTIVE);

        CheckpointWorkflow cpWorkflow = checkpointWorkflow(n);
        List<CheckpointListener> cpLs = cpWorkflow.getRelevantCheckpointListeners(dbMgr(n).checkpointedDataRegions());

        assertTrue(cpLs.contains(observingCpLsnr));
        assertTrue(cpLs.contains(durableBackgroundTask(n)));
        assertTrue(cpLs.indexOf(observingCpLsnr) < cpLs.indexOf(durableBackgroundTask(n)));

        SimpleTask simpleTask = new SimpleTask("t");
        IgniteInternalFuture<Void> taskFut = durableBackgroundTask(n).executeAsync(simpleTask, true);

        simpleTask.onExecFut.get(getTestTimeout());

        GridFutureAdapter<Void> startStopFut = new GridFutureAdapter<>();
        GridFutureAdapter<Void> finishStopFut = new GridFutureAdapter<>();

        observingCpLsnr.repeatOnMarkCheckpointBeginConsumer = true;
        observingCpLsnr.onMarkCheckpointBeginConsumer = ctx -> {
            if (n.context().isStopping()) {
                startStopFut.onDone();

                finishStopFut.get(getTestTimeout());

                observingCpLsnr.repeatOnMarkCheckpointBeginConsumer = false;
            }
        };

        IgniteInternalFuture<Void> stopFut = runAsync(() -> stopAllGrids(false));

        startStopFut.get(getTestTimeout());

        simpleTask.taskFut.onDone(DurableBackgroundTaskResult.complete(null));
        taskFut.get(getTestTimeout());

        finishStopFut.onDone();

        stopFut.get(getTestTimeout());
        assertNull(n.context().failure().failureContext());

        assertThrows(log, () -> durableBackgroundTask(n).executeAsync(simpleTask, true), IgniteException.class, null);
    }

    /**
     * Check that the task will not be deleted from the MetaStorage if it was restarted.
     *
     * @throws Exception If failed.
     */
    @Test
    public void testDontDeleteTaskIfItsRestart() throws Exception {
        IgniteEx n = startGrid(0);

        ObservingCheckpointListener observingCpLsnr = new ObservingCheckpointListener();
        dbMgr(n).addCheckpointListener(observingCpLsnr);

        n.cluster().state(ACTIVE);

        CheckpointWorkflow cpWorkflow = checkpointWorkflow(n);
        List<CheckpointListener> cpLs = cpWorkflow.getRelevantCheckpointListeners(dbMgr(n).checkpointedDataRegions());

        assertTrue(cpLs.contains(observingCpLsnr));
        assertTrue(cpLs.contains(durableBackgroundTask(n)));
        assertTrue(cpLs.indexOf(observingCpLsnr) < cpLs.indexOf(durableBackgroundTask(n)));

        SimpleTask simpleTask0 = new SimpleTask("t");
        IgniteInternalFuture<Void> taskFut = durableBackgroundTask(n).executeAsync(simpleTask0, true);

        simpleTask0.onExecFut.get(getTestTimeout());

        forceCheckpoint();
        dbMgr(n).enableCheckpoints(false).get(getTestTimeout());

        simpleTask0.taskFut.onDone(DurableBackgroundTaskResult.complete(null));
        taskFut.get(getTestTimeout());

        SimpleTask simpleTask1 = new SimpleTask("t");
        AtomicReference<IgniteInternalFuture<Void>> taskFutRef = new AtomicReference<>();

        observingCpLsnr.afterCheckpointEndConsumer =
            ctx -> taskFutRef.set(durableBackgroundTask(n).executeAsync(simpleTask1, true));

        dbMgr(n).enableCheckpoints(true).get(getTestTimeout());
        forceCheckpoint();

        assertNotNull(metaStorageOperation(n, ms -> ms.read(metaStorageKey(simpleTask0))));

        simpleTask1.onExecFut.get(getTestTimeout());
        simpleTask1.taskFut.onDone(DurableBackgroundTaskResult.complete(null));
        taskFutRef.get().get(getTestTimeout());

        forceCheckpoint();
        assertNull(metaStorageOperation(n, ms -> ms.read(metaStorageKey(simpleTask1))));
    }

    /**
     * Checking the correctness of using the {@link DurableBackgroundTask#convertAfterRestoreIfNeeded}.
     *
     * @throws Exception If failed.
     */
    @Test
    public void testConvertAfterRestoreIfNeeded() throws Exception {
        IgniteEx n = startGrid(0);
        n.cluster().state(ACTIVE);

        String taskName0 = "test-task0";
        String taskName1 = "test-task1";

        ConvertibleTask t0 = new ConvertibleTask(taskName0);
        SimpleTask t1 = new SimpleTask(taskName1);

        SimpleTask t2 = (SimpleTask)t0.convertAfterRestoreIfNeeded();
        assertEquals("converted-task-" + taskName0, t2.name());

        assertNotNull(n.context().durableBackgroundTask().executeAsync(t0, true));
        assertNotNull(n.context().durableBackgroundTask().executeAsync(t1, true));

        assertEquals(2, tasks(n).size());

        checkStateAndMetaStorage(n, t0, STARTED, true, false);
        checkStateAndMetaStorage(n, t1, STARTED, true, false);

        stopGrid(0);

        n = startGrid(0);

        assertEquals(3, tasks(n).size());

        checkStateAndMetaStorage(n, t0, COMPLETED, true, true, false);
        checkStateAndMetaStorage(n, t1, INIT, true, false, false);

        n.cluster().state(ACTIVE);

        checkStateAndMetaStorage(n, t2, STARTED, true, false, true);
    }

    /**
     * Check that the task will be restarted correctly.
     *
     * @param save Save to MetaStorage.
     * @throws Exception If failed.
     */
    private void checkRestartTaskExecute(boolean save) throws Exception {
        IgniteEx n = startGrid(0);
        n.cluster().state(ACTIVE);

        SimpleTask t = new SimpleTask("t");
        IgniteInternalFuture<Void> execAsyncFut = execAsync(n, t, save);

        t.onExecFut.get(getTestTimeout());
        checkStateAndMetaStorage(n, t, STARTED, save, false);
        assertFalse(execAsyncFut.isDone());

        if (save) {
            ObservingCheckpointListener checkpointLsnr = new ObservingCheckpointListener();
            dbMgr(n).addCheckpointListener(checkpointLsnr);

            forceCheckpoint();
            dbMgr(n).enableCheckpoints(false).get(getTestTimeout());

            t.taskFut.onDone(restart(null));
            checkStateAndMetaStorage(n, t, INIT, true, false);
            assertFalse(execAsyncFut.isDone());

            GridFutureAdapter<Void> onMarkCheckpointBeginFut = checkpointLsnr.onMarkCheckpointBeginAsync(ctx -> {
                checkStateAndMetaStorage(n, t, INIT, true, false);
                assertFalse(toRmv(n).containsKey(t.name()));
            });

            dbMgr(n).enableCheckpoints(true).get(getTestTimeout());
            onMarkCheckpointBeginFut.get(getTestTimeout());
        }
        else {
            t.taskFut.onDone(restart(null));
            checkStateAndMetaStorage(n, t, INIT, false, false);
            assertFalse(execAsyncFut.isDone());
        }

        t.reset();

        n.cluster().state(INACTIVE);
        n.cluster().state(ACTIVE);

        t.onExecFut.get(getTestTimeout());
        checkStateAndMetaStorage(n, t, STARTED, save, false);
        assertFalse(execAsyncFut.isDone());

        t.taskFut.onDone(complete(null));
        execAsyncFut.get(getTestTimeout());
    }

    /**
     * Checking that the task will be processed correctly in the normal mode.
     *
     * @param save Save to MetaStorage.
     * @throws Exception If failed.
     */
    private void checkSimpleTaskExecute(boolean save) throws Exception {
        IgniteEx n = startGrid(0);

        SimpleTask t = new SimpleTask("t");
        IgniteInternalFuture<Void> execAsyncFut = execAsync(n, t, save);

        checkStateAndMetaStorage(n, t, INIT, save, false);

        checkExecuteSameTask(n, t);
        checkStateAndMetaStorage(n, t, INIT, save, false);

        assertFalse(t.onExecFut.isDone());
        assertFalse(execAsyncFut.isDone());

        n.cluster().state(ACTIVE);

        t.onExecFut.get(getTestTimeout());

        checkStateAndMetaStorage(n, t, STARTED, save, false);
        assertFalse(execAsyncFut.isDone());

        if (save) {
            forceCheckpoint();
            dbMgr(n).enableCheckpoints(false).get(getTestTimeout());

            t.taskFut.onDone(complete(null));
            execAsyncFut.get(getTestTimeout());

            checkStateAndMetaStorage(n, t, COMPLETED, true, true);

            ObservingCheckpointListener checkpointLsnr = new ObservingCheckpointListener();

            GridFutureAdapter<Void> onMarkCheckpointBeginFut = checkpointLsnr.onMarkCheckpointBeginAsync(
                ctx -> {
                    checkStateAndMetaStorage(n, t, null, true, false);
                    assertTrue(toRmv(n).containsKey(t.name()));
                }
            );

            GridFutureAdapter<Void> afterCheckpointEndFut = checkpointLsnr.afterCheckpointEndAsync(
                ctx -> {
                    checkStateAndMetaStorage(n, t, null, false, false);
                    assertFalse(toRmv(n).containsKey(t.name()));
                }
            );

            dbMgr(n).addCheckpointListener(checkpointLsnr);
            dbMgr(n).enableCheckpoints(true).get(getTestTimeout());

            onMarkCheckpointBeginFut.get(getTestTimeout());
            afterCheckpointEndFut.get(getTestTimeout());
        }
        else {
            t.taskFut.onDone(complete(null));
            execAsyncFut.get(getTestTimeout());

            checkStateAndMetaStorage(n, t, null, false, false);
        }
    }

    /**
     * Checking that until the task is completed it is impossible to add a
     * task with the same {@link DurableBackgroundTask#name name}.
     *
     * @param n Node.
     * @param t Task.
     */
    private void checkExecuteSameTask(IgniteEx n, DurableBackgroundTask t) {
        assertThrows(log, () -> execAsync(n, t, false), IllegalArgumentException.class, null);
        assertThrows(log, () -> execAsync(n, t, true), IllegalArgumentException.class, null);
        assertThrows(log, () -> execAsync(n, new SimpleTask(t.name()), false), IllegalArgumentException.class, null);
        assertThrows(log, () -> execAsync(n, new SimpleTask(t.name()), true), IllegalArgumentException.class, null);
    }

    /**
     * Checking the internal {@link DurableBackgroundTaskState state} of the task and storage in the MetaStorage.
     *
     * @param n Node.
     * @param t Task.
     * @param expState Expected state of the task, {@code null} means that the task should not be.
     * @param expSaved Task is expected to be stored in MetaStorage.
     * @param expDone Expect completion of the futures task.
     * @throws IgniteCheckedException If failed.
     */
    private void checkStateAndMetaStorage(
        IgniteEx n,
        DurableBackgroundTask<?> t,
        @Nullable State expState,
        boolean expSaved,
        boolean expDone
    ) throws IgniteCheckedException {
        checkStateAndMetaStorage(n, t, expState, expSaved, expDone, null);
    }

    /**
     * Checking the internal {@link DurableBackgroundTaskState state} of the task and storage in the MetaStorage.
     *
     * @param n Node.
     * @param t Task.
     * @param expState Expected state of the task, {@code null} means that the task should not be.
     * @param expSaved Task is expected to be stored in MetaStorage.
     * @param expDone Expect completion of the futures task.
     * @param expConverted Expected value of the {@link DurableBackgroundTaskState#converted()},
     *      {@code null} if no validation is required.
     * @throws IgniteCheckedException If failed.
     */
    private void checkStateAndMetaStorage(
        IgniteEx n,
        DurableBackgroundTask<?> t,
        @Nullable State expState,
        boolean expSaved,
        boolean expDone,
        @Nullable Boolean expConverted
    ) throws IgniteCheckedException {
        DurableBackgroundTaskState<?> taskState = tasks(n).get(t.name());

        if (expState == null)
            assertNull(taskState);
        else {
            assertEquals(expState, taskState.state());
            assertEquals(expSaved, taskState.saved());
            assertEquals(expDone, taskState.outFuture().isDone());

            if (expConverted != null)
                assertEquals(expConverted.booleanValue(), taskState.converted());
        }

        DurableBackgroundTask<?> ser =
            (DurableBackgroundTask<?>)metaStorageOperation(n, ms -> ms.read(metaStorageKey(t)));

        if (expSaved) {
            assertEquals(t.name(), ser.name());

            assertTrue(t.getClass().isInstance(ser));
        }
        else
            assertNull(ser);
    }

    /**
     * Asynchronous execution of a durable background task.
     *
     * @param n Node.
     * @param t Task.
     * @param save Save task to MetaStorage.
     * @return Task future.
     */
    private <R> IgniteInternalFuture<R> execAsync(IgniteEx n, DurableBackgroundTask<R> t, boolean save) {
        return durableBackgroundTask(n).executeAsync(t, save);
    }

    /**
     * Getting {@code DurableBackgroundTasksProcessor#toRmv}.
     *
     * @param n Node.
     * @return Map of tasks that will be removed from the MetaStorage.
     */
    private Map<String, DurableBackgroundTask<?>> toRmv(IgniteEx n) {
        return getFieldValue(durableBackgroundTask(n), "toRmv");
    }

    /**
     * Getting {@code DurableBackgroundTasksProcessor#tasks}.
     *
     * @param n Node.
     * @return Task states map.
     */
    private Map<String, DurableBackgroundTaskState<?>> tasks(IgniteEx n) {
        return getFieldValue(durableBackgroundTask(n), "tasks");
    }

    /**
     * Getting durable background task processor.
     *
     * @param n Node.
     * @return Durable background task processor.
     */
    private DurableBackgroundTasksProcessor durableBackgroundTask(IgniteEx n) {
        return n.context().durableBackgroundTask();
    }

    /**
     * Getting {@code CheckpointManager#checkpointWorkflow}.
     *
     * @param n Node.
     * @return Checkpoint workflow.
     */
    private CheckpointWorkflow checkpointWorkflow(IgniteEx n) {
        return getFieldValue(dbMgr(n), "checkpointManager", "checkpointWorkflow");
    }
}