content: /*
   * 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.beam.sdk.extensions.sql.meta.provider.bigquery;
  
  import java.io.IOException;
  import java.io.Serializable;
  import java.math.BigInteger;
  import java.util.Arrays;
  import java.util.List;
  import java.util.function.IntFunction;
  import java.util.stream.Collectors;
  import org.apache.beam.sdk.extensions.sql.impl.BeamTableStatistics;
  import org.apache.beam.sdk.extensions.sql.meta.BeamSqlTableFilter;
  import org.apache.beam.sdk.extensions.sql.meta.DefaultTableFilter;
  import org.apache.beam.sdk.extensions.sql.meta.ProjectSupport;
  import org.apache.beam.sdk.extensions.sql.meta.SchemaBaseBeamTable;
  import org.apache.beam.sdk.extensions.sql.meta.Table;
  import org.apache.beam.sdk.io.gcp.bigquery.BigQueryHelpers;
  import org.apache.beam.sdk.io.gcp.bigquery.BigQueryIO;
  import org.apache.beam.sdk.io.gcp.bigquery.BigQueryIO.TypedRead;
  import org.apache.beam.sdk.io.gcp.bigquery.BigQueryIO.TypedRead.Method;
  import org.apache.beam.sdk.io.gcp.bigquery.BigQueryIO.Write.WriteDisposition;
  import org.apache.beam.sdk.io.gcp.bigquery.BigQueryOptions;
  import org.apache.beam.sdk.io.gcp.bigquery.BigQueryUtils;
  import org.apache.beam.sdk.io.gcp.bigquery.BigQueryUtils.ConversionOptions;
  import org.apache.beam.sdk.options.PipelineOptions;
  import org.apache.beam.sdk.schemas.FieldAccessDescriptor;
  import org.apache.beam.sdk.schemas.Schema;
  import org.apache.beam.sdk.schemas.SchemaCoder;
  import org.apache.beam.sdk.schemas.utils.SelectHelpers;
  import org.apache.beam.sdk.values.PBegin;
  import org.apache.beam.sdk.values.PCollection;
  import org.apache.beam.sdk.values.POutput;
  import org.apache.beam.sdk.values.Row;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.rel.rel2sql.SqlImplementor;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.rex.RexNode;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.sql.SqlIdentifier;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.sql.SqlNode;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.sql.fun.SqlStdOperatorTable;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.sql.parser.SqlParserPos;
  import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.annotations.VisibleForTesting;
  import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.collect.ImmutableList;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * {@code BigQueryTable} represent a BigQuery table as a target. This provider does not currently
   * support being a source.
   */
  @SuppressWarnings({
    "rawtypes", // TODO(https://github.com/apache/beam/issues/20447)
    "nullness" // TODO(https://github.com/apache/beam/issues/20497)
  })
  class BigQueryTable extends SchemaBaseBeamTable implements Serializable {
    @VisibleForTesting static final String METHOD_PROPERTY = "method";
    @VisibleForTesting static final String WRITE_DISPOSITION_PROPERTY = "writeDisposition";
    @VisibleForTesting final String bqLocation;
    private final ConversionOptions conversionOptions;
    private BeamTableStatistics rowCountStatistics = null;
    private static final Logger LOG = LoggerFactory.getLogger(BigQueryTable.class);
    @VisibleForTesting final Method method;
    @VisibleForTesting final WriteDisposition writeDisposition;
  
    BigQueryTable(Table table, BigQueryUtils.ConversionOptions options) {
      super(table.getSchema());
      this.conversionOptions = options;
      this.bqLocation = table.getLocation();
  
      if (table.getProperties().has(METHOD_PROPERTY)) {
        List<String> validMethods =
            Arrays.stream(Method.values()).map(Enum::toString).collect(Collectors.toList());
        // toUpperCase should make it case-insensitive
        String selectedMethod = table.getProperties().get(METHOD_PROPERTY).asText().toUpperCase();
  
        if (validMethods.contains(selectedMethod)) {
          method = Method.valueOf(selectedMethod);
        } else {
          throw new InvalidPropertyException(
              "Invalid method "
                  + "'"
                  + selectedMethod
                  + "'. "
                  + "Supported methods are: "
                  + validMethods.toString()
                  + ".");
        }
      } else {
        method = Method.DIRECT_READ;
      }
  
      LOG.info("BigQuery method is set to: {}", method);
  
      if (table.getProperties().has(WRITE_DISPOSITION_PROPERTY)) {
        List<String> validWriteDispositions =
            Arrays.stream(WriteDisposition.values()).map(Enum::toString).collect(Collectors.toList());
        // toUpperCase should make it case-insensitive
        String selectedWriteDisposition =
            table.getProperties().get(WRITE_DISPOSITION_PROPERTY).asText().toUpperCase();
  
        if (validWriteDispositions.contains(selectedWriteDisposition)) {
          writeDisposition = WriteDisposition.valueOf(selectedWriteDisposition);
        } else {
          throw new InvalidPropertyException(
              "Invalid write disposition "
                  + "'"
                  + selectedWriteDisposition
                  + "'. "
                  + "Supported write dispositions are: "
                  + validWriteDispositions.toString()
                  + ".");
        }
      } else {
        writeDisposition = WriteDisposition.WRITE_EMPTY;
      }
  
      LOG.info("BigQuery writeDisposition is set to: {}", writeDisposition);
    }
  
    @Override
    public BeamTableStatistics getTableStatistics(PipelineOptions options) {
  
      if (rowCountStatistics == null) {
        rowCountStatistics = getRowCountFromBQ(options, bqLocation);
      }
  
      return rowCountStatistics;
    }
  
    @Override
    public PCollection.IsBounded isBounded() {
      return PCollection.IsBounded.BOUNDED;
    }
  
    @Override
    public PCollection<Row> buildIOReader(PBegin begin) {
      return begin.apply("Read Input BQ Rows", getBigQueryTypedRead(getSchema()));
    }
  
    @Override
    public PCollection<Row> buildIOReader(
        PBegin begin, BeamSqlTableFilter filters, List<String> fieldNames) {
      if (!method.equals(Method.DIRECT_READ)) {
        LOG.info("Predicate/project push-down only available for `DIRECT_READ` method, skipping.");
        return buildIOReader(begin);
      }
  
      final FieldAccessDescriptor resolved =
          FieldAccessDescriptor.withFieldNames(fieldNames).resolve(getSchema());
      final Schema newSchema = SelectHelpers.getOutputSchema(getSchema(), resolved);
  
      TypedRead<Row> typedRead = getBigQueryTypedRead(newSchema);
  
      if (!(filters instanceof DefaultTableFilter)) {
        BigQueryFilter bigQueryFilter = (BigQueryFilter) filters;
        if (!bigQueryFilter.getSupported().isEmpty()) {
          String rowRestriction = generateRowRestrictions(getSchema(), bigQueryFilter.getSupported());
          if (!rowRestriction.isEmpty()) {
            LOG.info("Pushing down the following filter: {}", rowRestriction);
            typedRead = typedRead.withRowRestriction(rowRestriction);
          }
        }
      }
  
      if (!fieldNames.isEmpty()) {
        typedRead = typedRead.withSelectedFields(fieldNames);
      }
  
      return begin.apply("Read Input BQ Rows with push-down", typedRead);
    }
  
    @Override
    public POutput buildIOWriter(PCollection<Row> input) {
      return input.apply(
          BigQueryIO.<Row>write()
              .withSchema(BigQueryUtils.toTableSchema(getSchema()))
              .withFormatFunction(BigQueryUtils.toTableRow())
              .withWriteDisposition(writeDisposition)
              .to(bqLocation));
    }
  
    @Override
    public ProjectSupport supportsProjects() {
      return method.equals(Method.DIRECT_READ)
          ? ProjectSupport.WITHOUT_FIELD_REORDERING
          : ProjectSupport.NONE;
    }
  
    @Override
    public BeamSqlTableFilter constructFilter(List<RexNode> filter) {
      if (method.equals(Method.DIRECT_READ)) {
        return new BigQueryFilter(filter);
      }
  
      return super.constructFilter(filter);
    }
  
    private String generateRowRestrictions(Schema schema, List<RexNode> supported) {
      assert !supported.isEmpty();
      final IntFunction<SqlNode> field =
          i -> new SqlIdentifier(schema.getField(i).getName(), SqlParserPos.ZERO);
  
      // TODO: BigQuerySqlDialectWithTypeTranslation can be replaced with BigQuerySqlDialect after
      // updating vendor Calcite version.
      SqlImplementor.Context context = new BeamSqlUnparseContext(field);
  
      // Create a single SqlNode from a list of RexNodes
      SqlNode andSqlNode = null;
      for (RexNode node : supported) {
        SqlNode sqlNode = context.toSql(null, node);
        if (andSqlNode == null) {
          andSqlNode = sqlNode;
          continue;
        }
        // AND operator must have exactly 2 operands.
        andSqlNode =
            SqlStdOperatorTable.AND.createCall(
                SqlParserPos.ZERO, ImmutableList.of(andSqlNode, sqlNode));
      }
  
      return andSqlNode.toSqlString(BeamBigQuerySqlDialect.DEFAULT).getSql();
    }
  
    private TypedRead<Row> getBigQueryTypedRead(Schema schema) {
      return BigQueryIO.read(
              record -> BigQueryUtils.toBeamRow(record.getRecord(), schema, conversionOptions))
          .withMethod(method)
          .from(bqLocation)
          .withCoder(SchemaCoder.of(schema));
    }
  
    private static BeamTableStatistics getRowCountFromBQ(PipelineOptions o, String bqLocation) {
      try {
        BigInteger rowCount =
            BigQueryHelpers.getNumRows(
                o.as(BigQueryOptions.class), BigQueryHelpers.parseTableSpec(bqLocation));
  
        if (rowCount == null) {
          return BeamTableStatistics.BOUNDED_UNKNOWN;
        }
  
        return BeamTableStatistics.createBoundedTableStatistics(rowCount.doubleValue());
  
      } catch (IOException | InterruptedException e) {
        LOG.warn("Could not get the row count for the table " + bqLocation, e);
      }
  
      return BeamTableStatistics.BOUNDED_UNKNOWN;
    }
  
    public static class InvalidPropertyException extends UnsupportedOperationException {
      private InvalidPropertyException(String s) {
        super(s);
      }
    }
  }
  