/*
 * 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.table.planner.plan.nodes.exec.stream;

import org.apache.flink.FlinkVersion;
import org.apache.flink.api.dag.Transformation;
import org.apache.flink.configuration.ReadableConfig;
import org.apache.flink.table.data.RowData;
import org.apache.flink.table.planner.codegen.CodeGeneratorContext;
import org.apache.flink.table.planner.codegen.agg.AggsHandlerCodeGenerator;
import org.apache.flink.table.planner.delegation.PlannerBase;
import org.apache.flink.table.planner.plan.nodes.exec.ExecEdge;
import org.apache.flink.table.planner.plan.nodes.exec.ExecNode;
import org.apache.flink.table.planner.plan.nodes.exec.ExecNodeConfig;
import org.apache.flink.table.planner.plan.nodes.exec.ExecNodeContext;
import org.apache.flink.table.planner.plan.nodes.exec.ExecNodeMetadata;
import org.apache.flink.table.planner.plan.nodes.exec.InputProperty;
import org.apache.flink.table.planner.plan.nodes.exec.utils.ExecNodeUtil;
import org.apache.flink.table.planner.plan.utils.AggregateInfoList;
import org.apache.flink.table.planner.plan.utils.AggregateUtil;
import org.apache.flink.table.planner.plan.utils.KeySelectorUtil;
import org.apache.flink.table.planner.utils.JavaScalaConversionUtil;
import org.apache.flink.table.runtime.generated.GeneratedAggsHandleFunction;
import org.apache.flink.table.runtime.keyselector.RowDataKeySelector;
import org.apache.flink.table.runtime.operators.aggregate.MiniBatchLocalGroupAggFunction;
import org.apache.flink.table.runtime.operators.bundle.MapBundleOperator;
import org.apache.flink.table.runtime.typeutils.InternalTypeInfo;
import org.apache.flink.table.types.logical.RowType;

import org.apache.flink.shaded.jackson2.com.fasterxml.jackson.annotation.JsonCreator;
import org.apache.flink.shaded.jackson2.com.fasterxml.jackson.annotation.JsonProperty;

import org.apache.calcite.rel.core.AggregateCall;

import java.util.Arrays;
import java.util.Collections;
import java.util.List;

import static org.apache.flink.util.Preconditions.checkArgument;
import static org.apache.flink.util.Preconditions.checkNotNull;

/** Stream {@link ExecNode} for unbounded local group aggregate. */
@ExecNodeMetadata(
        name = "stream-exec-local-group-aggregate",
        version = 1,
        consumedOptions = {
            "table.exec.mini-batch.enabled",
            "table.exec.mini-batch.size",
        },
        producedTransformations =
                StreamExecLocalGroupAggregate.LOCAL_GROUP_AGGREGATE_TRANSFORMATION,
        minPlanVersion = FlinkVersion.v1_15,
        minStateVersion = FlinkVersion.v1_15)
public class StreamExecLocalGroupAggregate extends StreamExecAggregateBase {

    public static final String LOCAL_GROUP_AGGREGATE_TRANSFORMATION = "local-group-aggregate";

    @JsonProperty(FIELD_NAME_GROUPING)
    private final int[] grouping;

    @JsonProperty(FIELD_NAME_AGG_CALLS)
    private final AggregateCall[] aggCalls;

    /** Each element indicates whether the corresponding agg call needs `retract` method. */
    @JsonProperty(FIELD_NAME_AGG_CALL_NEED_RETRACTIONS)
    private final boolean[] aggCallNeedRetractions;

    /** Whether this node consumes retraction messages. */
    @JsonProperty(FIELD_NAME_NEED_RETRACTION)
    private final boolean needRetraction;

    public StreamExecLocalGroupAggregate(
            ReadableConfig tableConfig,
            int[] grouping,
            AggregateCall[] aggCalls,
            boolean[] aggCallNeedRetractions,
            boolean needRetraction,
            InputProperty inputProperty,
            RowType outputType,
            String description) {
        this(
                ExecNodeContext.newNodeId(),
                ExecNodeContext.newContext(StreamExecLocalGroupAggregate.class),
                ExecNodeContext.newPersistedConfig(
                        StreamExecLocalGroupAggregate.class, tableConfig),
                grouping,
                aggCalls,
                aggCallNeedRetractions,
                needRetraction,
                Collections.singletonList(inputProperty),
                outputType,
                description);
    }

    @JsonCreator
    public StreamExecLocalGroupAggregate(
            @JsonProperty(FIELD_NAME_ID) int id,
            @JsonProperty(FIELD_NAME_TYPE) ExecNodeContext context,
            @JsonProperty(FIELD_NAME_CONFIGURATION) ReadableConfig persistedConfig,
            @JsonProperty(FIELD_NAME_GROUPING) int[] grouping,
            @JsonProperty(FIELD_NAME_AGG_CALLS) AggregateCall[] aggCalls,
            @JsonProperty(FIELD_NAME_AGG_CALL_NEED_RETRACTIONS) boolean[] aggCallNeedRetractions,
            @JsonProperty(FIELD_NAME_NEED_RETRACTION) boolean needRetraction,
            @JsonProperty(FIELD_NAME_INPUT_PROPERTIES) List<InputProperty> inputProperties,
            @JsonProperty(FIELD_NAME_OUTPUT_TYPE) RowType outputType,
            @JsonProperty(FIELD_NAME_DESCRIPTION) String description) {
        super(id, context, persistedConfig, inputProperties, outputType, description);
        this.grouping = checkNotNull(grouping);
        this.aggCalls = checkNotNull(aggCalls);
        this.aggCallNeedRetractions = checkNotNull(aggCallNeedRetractions);
        checkArgument(aggCalls.length == aggCallNeedRetractions.length);
        this.needRetraction = needRetraction;
    }

    @SuppressWarnings("unchecked")
    @Override
    protected Transformation<RowData> translateToPlanInternal(
            PlannerBase planner, ExecNodeConfig config) {
        final ExecEdge inputEdge = getInputEdges().get(0);
        final Transformation<RowData> inputTransform =
                (Transformation<RowData>) inputEdge.translateToPlan(planner);
        final RowType inputRowType = (RowType) inputEdge.getOutputType();

        final AggsHandlerCodeGenerator generator =
                new AggsHandlerCodeGenerator(
                        new CodeGeneratorContext(
                                config, planner.getFlinkContext().getClassLoader()),
                        planner.createRelBuilder(),
                        JavaScalaConversionUtil.toScala(inputRowType.getChildren()),
                        // the local aggregate result will be buffered, so need copy
                        true);
        generator.needAccumulate().needMerge(0, true, null);
        if (needRetraction) {
            generator.needRetract();
        }

        final AggregateInfoList aggInfoList =
                AggregateUtil.transformToStreamAggregateInfoList(
                        planner.getTypeFactory(),
                        inputRowType,
                        JavaScalaConversionUtil.toScala(Arrays.asList(aggCalls)),
                        aggCallNeedRetractions,
                        needRetraction,
                        false, // isStateBackendDataViews
                        true); // needDistinctInfo
        final GeneratedAggsHandleFunction aggsHandler =
                generator.generateAggsHandler("GroupAggsHandler", aggInfoList);
        final MiniBatchLocalGroupAggFunction aggFunction =
                new MiniBatchLocalGroupAggFunction(aggsHandler);

        final RowDataKeySelector selector =
                KeySelectorUtil.getRowDataSelector(
                        planner.getFlinkContext().getClassLoader(),
                        grouping,
                        (InternalTypeInfo<RowData>) inputTransform.getOutputType());

        final MapBundleOperator<RowData, RowData, RowData, RowData> operator =
                new MapBundleOperator<>(
                        aggFunction, AggregateUtil.createMiniBatchTrigger(config), selector);

        return ExecNodeUtil.createOneInputTransformation(
                inputTransform,
                createTransformationMeta(LOCAL_GROUP_AGGREGATE_TRANSFORMATION, config),
                operator,
                InternalTypeInfo.of(getOutputType()),
                inputTransform.getParallelism(),
                false);
    }
}
