/*
 * 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.stream.Collectors;
import org.apache.beam.sdk.annotations.Experimental;
import org.apache.beam.sdk.extensions.sql.impl.BeamTableStatistics;
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.Method;
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.SchemaCoder;
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_20_0.com.google.common.annotations.VisibleForTesting;
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.
 */
@Experimental
class BigQueryTable extends SchemaBaseBeamTable implements Serializable {
  @VisibleForTesting static final String METHOD_PROPERTY = "method";
  @VisibleForTesting final String bqLocation;
  private final ConversionOptions conversionOptions;
  private BeamTableStatistics rowCountStatistics = null;
  private static final Logger LOGGER = LoggerFactory.getLogger(BigQueryTable.class);
  @VisibleForTesting final Method method;

  BigQueryTable(Table table, BigQueryUtils.ConversionOptions options) {
    super(table.getSchema());
    this.conversionOptions = options;
    this.bqLocation = table.getLocation();

    if (table.getProperties().containsKey(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().getString(METHOD_PROPERTY).toUpperCase();

      if (validMethods.contains(selectedMethod)) {
        method = Method.valueOf(selectedMethod);
      } else {
        InvalidPropertyException e =
            new InvalidPropertyException(
                "Invalid method "
                    + "'"
                    + selectedMethod
                    + "'. "
                    + "Supported methods are: "
                    + validMethods.toString()
                    + ".");

        throw e;
      }
    } else {
      method = Method.DEFAULT;
    }

    LOGGER.info("BigQuery method is set to: " + method.toString());
  }

  @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",
            BigQueryIO.read(
                    record ->
                        BigQueryUtils.toBeamRow(record.getRecord(), getSchema(), conversionOptions))
                .withMethod(method)
                .from(bqLocation)
                .withCoder(SchemaCoder.of(getSchema())))
        .setRowSchema(getSchema());
  }

  @Override
  public POutput buildIOWriter(PCollection<Row> input) {
    return input.apply(
        BigQueryIO.<Row>write()
            .withSchema(BigQueryUtils.toTableSchema(getSchema()))
            .withFormatFunction(BigQueryUtils.toTableRow())
            .to(bqLocation));
  }

  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) {
      LOGGER.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);
    }
  }
}