/*
 * 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.streaming.api.operators;

import org.apache.flink.api.common.JobID;
import org.apache.flink.api.common.state.KeyedStateStore;
import org.apache.flink.api.common.typeutils.base.IntSerializer;
import org.apache.flink.core.fs.CloseableRegistry;
import org.apache.flink.core.fs.FSDataInputStream;
import org.apache.flink.core.memory.ByteArrayOutputStreamWithPos;
import org.apache.flink.core.memory.DataInputView;
import org.apache.flink.core.memory.DataInputViewStreamWrapper;
import org.apache.flink.core.memory.DataOutputView;
import org.apache.flink.core.memory.DataOutputViewStreamWrapper;
import org.apache.flink.metrics.groups.UnregisteredMetricsGroup;
import org.apache.flink.runtime.checkpoint.JobManagerTaskRestore;
import org.apache.flink.runtime.checkpoint.OperatorSubtaskState;
import org.apache.flink.runtime.checkpoint.StateObjectCollection;
import org.apache.flink.runtime.checkpoint.SubTaskInitializationMetricsBuilder;
import org.apache.flink.runtime.checkpoint.TaskStateSnapshot;
import org.apache.flink.runtime.jobgraph.OperatorID;
import org.apache.flink.runtime.metrics.groups.TaskIOMetricGroup;
import org.apache.flink.runtime.operators.testutils.DummyEnvironment;
import org.apache.flink.runtime.state.CheckpointableKeyedStateBackend;
import org.apache.flink.runtime.state.DefaultOperatorStateBackend;
import org.apache.flink.runtime.state.KeyGroupRange;
import org.apache.flink.runtime.state.KeyGroupRangeOffsets;
import org.apache.flink.runtime.state.KeyGroupStatePartitionStreamProvider;
import org.apache.flink.runtime.state.KeyGroupsStateHandle;
import org.apache.flink.runtime.state.KeyedStateHandle;
import org.apache.flink.runtime.state.OperatorStateHandle;
import org.apache.flink.runtime.state.OperatorStreamStateHandle;
import org.apache.flink.runtime.state.StateBackend;
import org.apache.flink.runtime.state.StateInitializationContextImpl;
import org.apache.flink.runtime.state.StatePartitionStreamProvider;
import org.apache.flink.runtime.state.TaskExecutorStateChangelogStoragesManager;
import org.apache.flink.runtime.state.TaskStateManager;
import org.apache.flink.runtime.state.TaskStateManagerImpl;
import org.apache.flink.runtime.state.TestTaskLocalStateStore;
import org.apache.flink.runtime.state.changelog.inmemory.InMemoryStateChangelogStorage;
import org.apache.flink.runtime.state.memory.ByteStreamStateHandle;
import org.apache.flink.runtime.state.memory.MemoryStateBackend;
import org.apache.flink.runtime.state.ttl.TtlTimeProvider;
import org.apache.flink.runtime.taskmanager.CheckpointResponder;
import org.apache.flink.runtime.util.LongArrayList;
import org.apache.flink.streaming.runtime.tasks.ProcessingTimeService;
import org.apache.flink.streaming.runtime.tasks.StreamTaskCancellationContext;
import org.apache.flink.util.clock.SystemClock;

import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.OptionalLong;
import java.util.Set;

import static org.apache.flink.runtime.executiongraph.ExecutionGraphTestUtils.createExecutionAttemptId;
import static org.assertj.core.api.Assertions.assertThat;
import static org.assertj.core.api.Assertions.fail;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.when;

/** Tests for {@link StateInitializationContextImpl}. */
class StateInitializationContextImplTest {

    static final int NUM_HANDLES = 10;

    private StateInitializationContextImpl initializationContext;
    private CloseableRegistry closableRegistry;

    private int writtenKeyGroups;
    private Set<Integer> writtenOperatorStates;

    @BeforeEach
    void setUp() throws Exception {

        this.writtenKeyGroups = 0;
        this.writtenOperatorStates = new HashSet<>();

        this.closableRegistry = new CloseableRegistry();

        ByteArrayOutputStreamWithPos out = new ByteArrayOutputStreamWithPos(64);

        List<KeyedStateHandle> keyedStateHandles = new ArrayList<>(NUM_HANDLES);
        int prev = 0;
        for (int i = 0; i < NUM_HANDLES; ++i) {
            out.reset();
            int size = i % 4;
            int end = prev + size;
            DataOutputView dov = new DataOutputViewStreamWrapper(out);
            KeyGroupRangeOffsets offsets =
                    new KeyGroupRangeOffsets(
                            i == 9
                                    ? KeyGroupRange.EMPTY_KEY_GROUP_RANGE
                                    : new KeyGroupRange(prev, end));
            prev = end + 1;
            for (int kg : offsets.getKeyGroupRange()) {
                offsets.setKeyGroupOffset(kg, out.getPosition());
                dov.writeInt(kg);
                ++writtenKeyGroups;
            }

            KeyedStateHandle handle =
                    new KeyGroupsStateHandle(
                            offsets,
                            new ByteStateHandleCloseChecking("kg-" + i, out.toByteArray()));

            keyedStateHandles.add(handle);
        }

        List<OperatorStateHandle> operatorStateHandles = new ArrayList<>(NUM_HANDLES);

        for (int i = 0; i < NUM_HANDLES; ++i) {
            int size = i % 4;
            out.reset();
            DataOutputView dov = new DataOutputViewStreamWrapper(out);
            LongArrayList offsets = new LongArrayList(size);
            for (int s = 0; s < size; ++s) {
                offsets.add(out.getPosition());
                int val = i * NUM_HANDLES + s;
                dov.writeInt(val);
                writtenOperatorStates.add(val);
            }

            Map<String, OperatorStateHandle.StateMetaInfo> offsetsMap = new HashMap<>();
            offsetsMap.put(
                    DefaultOperatorStateBackend.DEFAULT_OPERATOR_STATE_NAME,
                    new OperatorStateHandle.StateMetaInfo(
                            offsets.toArray(), OperatorStateHandle.Mode.SPLIT_DISTRIBUTE));
            OperatorStateHandle operatorStateHandle =
                    new OperatorStreamStateHandle(
                            offsetsMap,
                            new ByteStateHandleCloseChecking("os-" + i, out.toByteArray()));
            operatorStateHandles.add(operatorStateHandle);
        }

        OperatorSubtaskState operatorSubtaskState =
                OperatorSubtaskState.builder()
                        .setRawOperatorState(new StateObjectCollection<>(operatorStateHandles))
                        .setRawKeyedState(new StateObjectCollection<>(keyedStateHandles))
                        .build();

        OperatorID operatorID = new OperatorID();
        TaskStateSnapshot taskStateSnapshot = new TaskStateSnapshot();
        taskStateSnapshot.putSubtaskStateByOperatorID(operatorID, operatorSubtaskState);

        JobManagerTaskRestore jobManagerTaskRestore =
                new JobManagerTaskRestore(0L, taskStateSnapshot);

        TaskStateManager manager =
                new TaskStateManagerImpl(
                        new JobID(),
                        createExecutionAttemptId(),
                        new TestTaskLocalStateStore(),
                        null,
                        new InMemoryStateChangelogStorage(),
                        new TaskExecutorStateChangelogStoragesManager(),
                        jobManagerTaskRestore,
                        mock(CheckpointResponder.class));

        DummyEnvironment environment = new DummyEnvironment("test", 1, 0, prev);

        environment.setTaskStateManager(manager);

        StateBackend stateBackend = new MemoryStateBackend(1024);
        StreamTaskStateInitializer streamTaskStateManager =
                new StreamTaskStateInitializerImpl(
                        environment,
                        stateBackend,
                        new SubTaskInitializationMetricsBuilder(
                                SystemClock.getInstance().absoluteTimeMillis()),
                        TtlTimeProvider.DEFAULT,
                        new InternalTimeServiceManager.Provider() {
                            @Override
                            public <K> InternalTimeServiceManager<K> create(
                                    TaskIOMetricGroup taskIOMetricGroup,
                                    CheckpointableKeyedStateBackend<K> keyedStatedBackend,
                                    ClassLoader userClassloader,
                                    KeyContext keyContext,
                                    ProcessingTimeService processingTimeService,
                                    Iterable<KeyGroupStatePartitionStreamProvider> rawKeyedStates,
                                    StreamTaskCancellationContext cancellationContext)
                                    throws Exception {
                                // We do not initialize a timer service manager here, because it
                                // would already consume the raw keyed
                                // state as part of initialization. For the purpose of this test, we
                                // want an unconsumed raw keyed
                                // stream.
                                return null;
                            }
                        },
                        StreamTaskCancellationContext.alwaysRunning());

        AbstractStreamOperator<?> mockOperator = mock(AbstractStreamOperator.class);
        when(mockOperator.getOperatorID()).thenReturn(operatorID);

        StreamOperatorStateContext stateContext =
                streamTaskStateManager.streamOperatorStateContext(
                        operatorID,
                        "TestOperatorClass",
                        mock(ProcessingTimeService.class),
                        mockOperator,
                        // notice that this essentially disables the previous test of the keyed
                        // stream because it was and is always
                        // consumed by the timer service.
                        IntSerializer.INSTANCE,
                        closableRegistry,
                        new UnregisteredMetricsGroup(),
                        1.0,
                        false);

        OptionalLong restoredCheckpointId = stateContext.getRestoredCheckpointId();
        this.initializationContext =
                new StateInitializationContextImpl(
                        restoredCheckpointId.isPresent() ? restoredCheckpointId.getAsLong() : null,
                        stateContext.operatorStateBackend(),
                        mock(KeyedStateStore.class),
                        stateContext.rawKeyedStateInputs(),
                        stateContext.rawOperatorStateInputs());
    }

    @Test
    void getOperatorStateStreams() throws Exception {

        int i = 0;
        int s = 0;
        for (StatePartitionStreamProvider streamProvider :
                initializationContext.getRawOperatorStateInputs()) {
            if (0 == i % 4) {
                ++i;
            }
            assertThat(streamProvider).isNotNull();
            try (InputStream is = streamProvider.getStream()) {
                DataInputView div = new DataInputViewStreamWrapper(is);

                int val = div.readInt();
                assertThat(val).isEqualTo(i * NUM_HANDLES + s);
            }

            ++s;
            if (s == i % 4) {
                s = 0;
                ++i;
            }
        }
    }

    @Test
    void getKeyedStateStreams() throws Exception {

        int readKeyGroupCount = 0;

        for (KeyGroupStatePartitionStreamProvider stateStreamProvider :
                initializationContext.getRawKeyedStateInputs()) {

            assertThat(stateStreamProvider).isNotNull();

            try (InputStream is = stateStreamProvider.getStream()) {
                DataInputView div = new DataInputViewStreamWrapper(is);
                int val = div.readInt();
                ++readKeyGroupCount;
                assertThat(val).isEqualTo(stateStreamProvider.getKeyGroupId());
            }
        }

        assertThat(readKeyGroupCount).isEqualTo(writtenKeyGroups);
    }

    @Test
    void getOperatorStateStore() throws Exception {

        Set<Integer> readStatesCount = new HashSet<>();

        for (StatePartitionStreamProvider statePartitionStreamProvider :
                initializationContext.getRawOperatorStateInputs()) {

            assertThat(statePartitionStreamProvider).isNotNull();

            try (InputStream is = statePartitionStreamProvider.getStream()) {
                DataInputView div = new DataInputViewStreamWrapper(is);
                assertThat(readStatesCount.add(div.readInt())).isTrue();
            }
        }

        assertThat(readStatesCount).isEqualTo(writtenOperatorStates);
    }

    @Test
    void close() throws Exception {

        int count = 0;
        int stopCount = NUM_HANDLES / 2;
        boolean isClosed = false;

        try {
            for (KeyGroupStatePartitionStreamProvider stateStreamProvider :
                    initializationContext.getRawKeyedStateInputs()) {
                assertThat(stateStreamProvider).isNotNull();

                if (count == stopCount) {
                    closableRegistry.close();
                    isClosed = true;
                }

                try (InputStream is = stateStreamProvider.getStream()) {
                    DataInputView div = new DataInputViewStreamWrapper(is);
                    try {
                        int val = div.readInt();
                        assertThat(val).isEqualTo(stateStreamProvider.getKeyGroupId());
                        assertThat(isClosed).as("Close was ignored: stream").isFalse();
                        ++count;
                    } catch (IOException ioex) {
                        if (!isClosed) {
                            throw ioex;
                        }
                    }
                }
            }
            fail("Close was ignored: registry");
        } catch (IOException iex) {
            assertThat(isClosed).isTrue();
            assertThat(count).isEqualTo(stopCount);
        }
    }

    static final class ByteStateHandleCloseChecking extends ByteStreamStateHandle {

        private static final long serialVersionUID = -6201941296931334140L;

        public ByteStateHandleCloseChecking(String handleName, byte[] data) {
            super(handleName, data);
        }

        @Override
        public FSDataInputStream openInputStream() throws IOException {
            final FSDataInputStream original = super.openInputStream();

            return new FSDataInputStream() {

                private boolean closed = false;

                @Override
                public void seek(long desired) throws IOException {
                    original.seek(desired);
                }

                @Override
                public long getPos() throws IOException {
                    return original.getPos();
                }

                @Override
                public int read() throws IOException {
                    if (closed) {
                        throw new IOException("Stream closed");
                    }
                    return original.read();
                }

                @Override
                public void close() throws IOException {
                    original.close();
                    this.closed = true;
                }
            };
        }
    }
}
