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   * Licensed to the Apache Software Foundation (ASF) under one
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   * 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,
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   * See the License for the specific language governing permissions and
   * limitations under the License.
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  package org.apache.beam.sdk.extensions.sql.impl.rel;
  
  import static org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.base.Preconditions.checkArgument;
  
  import java.util.List;
  import java.util.Map;
  import org.apache.beam.sdk.extensions.sql.impl.BeamCalciteTable;
  import org.apache.beam.sdk.extensions.sql.impl.BeamTableStatistics;
  import org.apache.beam.sdk.extensions.sql.impl.planner.BeamCostModel;
  import org.apache.beam.sdk.extensions.sql.impl.planner.BeamRelMetadataQuery;
  import org.apache.beam.sdk.extensions.sql.impl.planner.NodeStats;
  import org.apache.beam.sdk.extensions.sql.meta.BeamSqlTable;
  import org.apache.beam.sdk.extensions.sql.meta.BeamSqlTableFilter;
  import org.apache.beam.sdk.transforms.PTransform;
  import org.apache.beam.sdk.values.PCollection;
  import org.apache.beam.sdk.values.PCollectionList;
  import org.apache.beam.sdk.values.Row;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.plan.RelOptCluster;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.plan.RelOptCost;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.plan.RelOptPlanner;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.plan.RelOptTable;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.plan.RelTraitSet;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.prepare.RelOptTableImpl;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.rel.core.TableScan;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.rel.metadata.RelMetadataQuery;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.rel.type.RelDataType;
  
  /** BeamRelNode to replace a {@code TableScan} node. */
  public class BeamIOSourceRel extends TableScan implements BeamRelNode {
    public static final double CONSTANT_WINDOW_SIZE = 10d;
    private final BeamSqlTable beamTable;
    private final BeamCalciteTable calciteTable;
    private final Map<String, String> pipelineOptions;
  
    public BeamIOSourceRel(
        RelOptCluster cluster,
        RelTraitSet traitSet,
        RelOptTable table,
        BeamSqlTable beamTable,
        Map<String, String> pipelineOptions,
        BeamCalciteTable calciteTable) {
      super(cluster, traitSet, table);
      this.beamTable = beamTable;
      this.calciteTable = calciteTable;
      this.pipelineOptions = pipelineOptions;
    }
  
    public BeamPushDownIOSourceRel createPushDownRel(
        RelDataType newType, List<String> usedFields, BeamSqlTableFilter tableFilters) {
      RelOptTable relOptTable =
          newType == null ? table : ((RelOptTableImpl) getTable()).copy(newType);
  
      return new BeamPushDownIOSourceRel(
          getCluster(),
          traitSet,
          relOptTable,
          beamTable,
          usedFields,
          tableFilters,
          pipelineOptions,
          calciteTable);
    }
  
    @Override
    public double estimateRowCount(RelMetadataQuery mq) {
      BeamTableStatistics rowCountStatistics = calciteTable.getStatistic();
      if (beamTable.isBounded() == PCollection.IsBounded.BOUNDED) {
        return rowCountStatistics.getRowCount();
      } else {
        return rowCountStatistics.getRate();
      }
    }
  
    @Override
    public NodeStats estimateNodeStats(BeamRelMetadataQuery mq) {
      BeamTableStatistics rowCountStatistics = calciteTable.getStatistic();
      double window =
          (beamTable.isBounded() == PCollection.IsBounded.BOUNDED)
              ? rowCountStatistics.getRowCount()
              : CONSTANT_WINDOW_SIZE;
      return NodeStats.create(rowCountStatistics.getRowCount(), rowCountStatistics.getRate(), window);
    }
  
    @Override
    public PCollection.IsBounded isBounded() {
      return beamTable.isBounded();
    }
  
    @Override
    public PTransform<PCollectionList<Row>, PCollection<Row>> buildPTransform() {
      return new Transform();
    }
  
    private class Transform extends PTransform<PCollectionList<Row>, PCollection<Row>> {
  
      @Override
      public PCollection<Row> expand(PCollectionList<Row> input) {
        checkArgument(
            input.size() == 0,
            "Should not have received input for %s: %s",
            BeamIOSourceRel.class.getSimpleName(),
            input);
  
        return beamTable.buildIOReader(input.getPipeline().begin());
      }
    }
  
    @Override
    public RelOptCost computeSelfCost(RelOptPlanner planner, RelMetadataQuery mq) {
      // We should technically avoid this function. This happens if we are in JDBC path or the
      // costFactory is not set correctly.
      double rowCount = this.estimateRowCount(mq);
      return planner.getCostFactory().makeCost(rowCount, rowCount, rowCount);
    }
  
    @Override
    public BeamCostModel beamComputeSelfCost(RelOptPlanner planner, BeamRelMetadataQuery mq) {
      NodeStats estimates = BeamSqlRelUtils.getNodeStats(this, mq);
      return BeamCostModel.FACTORY.makeCost(estimates.getRowCount(), estimates.getRate());
    }
  
    public BeamSqlTable getBeamSqlTable() {
      return beamTable;
    }
  
    @Override
    public Map<String, String> getPipelineOptions() {
      return pipelineOptions;
    }
  }
  