/*
 * 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.io.gcp.bigquery;

import static org.apache.beam.sdk.io.gcp.bigquery.BigQueryHelpers.createJobIdToken;
import static org.apache.beam.sdk.io.gcp.bigquery.BigQueryHelpers.createTempTableReference;
import static org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.Preconditions.checkArgument;

import com.google.api.services.bigquery.model.EncryptionConfiguration;
import com.google.api.services.bigquery.model.Job;
import com.google.api.services.bigquery.model.JobConfigurationQuery;
import com.google.api.services.bigquery.model.JobReference;
import com.google.api.services.bigquery.model.JobStatistics;
import com.google.api.services.bigquery.model.Table;
import com.google.api.services.bigquery.model.TableReference;
import java.io.IOException;
import java.util.List;
import java.util.Optional;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicReference;
import javax.annotation.Nullable;
import org.apache.beam.sdk.io.gcp.bigquery.BigQueryHelpers.Status;
import org.apache.beam.sdk.io.gcp.bigquery.BigQueryIO.TypedRead.QueryPriority;
import org.apache.beam.sdk.io.gcp.bigquery.BigQueryServices.DatasetService;
import org.apache.beam.sdk.io.gcp.bigquery.BigQueryServices.JobService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Helper object for executing query jobs in BigQuery.
 *
 * <p>This object is not serializable, and its state can be safely discarded across serialization
 * boundaries for any associated source objects.
 */
class BigQueryQueryHelper {

  private static final Integer JOB_POLL_MAX_RETRIES = Integer.MAX_VALUE;

  private static final Logger LOG = LoggerFactory.getLogger(BigQueryQueryHelper.class);

  public static JobStatistics dryRunQueryIfNeeded(
      BigQueryServices bqServices,
      BigQueryOptions options,
      AtomicReference<JobStatistics> dryRunJobStats,
      String query,
      Boolean flattenResults,
      Boolean useLegacySql,
      @Nullable String location)
      throws InterruptedException, IOException {
    if (dryRunJobStats.get() == null) {
      JobStatistics jobStatistics =
          bqServices
              .getJobService(options)
              .dryRunQuery(
                  options.getProject(),
                  createBasicQueryConfig(query, flattenResults, useLegacySql),
                  location);
      dryRunJobStats.compareAndSet(null, jobStatistics);
    }

    return dryRunJobStats.get();
  }

  public static TableReference executeQuery(
      BigQueryServices bqServices,
      BigQueryOptions options,
      AtomicReference<JobStatistics> dryRunJobStats,
      String stepUuid,
      String query,
      Boolean flattenResults,
      Boolean useLegacySql,
      QueryPriority priority,
      @Nullable String location,
      @Nullable String queryTempDatasetId,
      @Nullable String kmsKey)
      throws InterruptedException, IOException {
    // Step 1: Find the effective location of the query.
    String effectiveLocation = location;
    DatasetService tableService = bqServices.getDatasetService(options);
    if (effectiveLocation == null) {
      List<TableReference> referencedTables =
          dryRunQueryIfNeeded(
                  bqServices,
                  options,
                  dryRunJobStats,
                  query,
                  flattenResults,
                  useLegacySql,
                  location)
              .getQuery()
              .getReferencedTables();
      if (referencedTables != null && !referencedTables.isEmpty()) {
        TableReference referencedTable = referencedTables.get(0);
        effectiveLocation = tableService.getTable(referencedTable).getLocation();
      }
    }

    // Step 2: Create a temporary dataset in the query location only if the user has not specified a
    // temp dataset.
    String jobIdToken = createJobIdToken(options.getJobName(), stepUuid);
    Optional<String> queryTempDatasetOpt = Optional.ofNullable(queryTempDatasetId);
    TableReference queryResultTable =
        createTempTableReference(options.getProject(), jobIdToken, queryTempDatasetOpt);

    boolean beamToCreateTempDataset = !queryTempDatasetOpt.isPresent();
    // Create dataset only if it has not been set by the user
    if (beamToCreateTempDataset) {
      LOG.info("Creating temporary dataset {} for query results", queryResultTable.getDatasetId());

      tableService.createDataset(
          queryResultTable.getProjectId(),
          queryResultTable.getDatasetId(),
          effectiveLocation,
          "Temporary tables for query results of job " + options.getJobName(),
          TimeUnit.DAYS.toMillis(1));
    } else { // If the user specified a temp dataset, check that the destination table does not
      // exist
      Table destTable = tableService.getTable(queryResultTable);
      checkArgument(
          destTable == null,
          "Refusing to write on existing table {} in the specified temp dataset {}",
          queryResultTable.getTableId(),
          queryResultTable.getDatasetId());
    }

    // Step 3: Execute the query. Generate a transient (random) query job ID, because this code may
    // be retried after the temporary dataset and table have been deleted by a previous attempt --
    // in that case, we want to regenerate the temporary dataset and table, and we'll need a fresh
    // query ID to do that.
    String queryJobId = jobIdToken + "-query-" + BigQueryHelpers.randomUUIDString();
    LOG.info(
        "Exporting query results into temporary table {} using job {}",
        queryResultTable,
        queryJobId);

    JobReference jobReference =
        new JobReference()
            .setProjectId(options.getProject())
            .setLocation(effectiveLocation)
            .setJobId(queryJobId);

    JobConfigurationQuery queryConfiguration =
        createBasicQueryConfig(query, flattenResults, useLegacySql)
            .setAllowLargeResults(true)
            .setDestinationTable(queryResultTable)
            .setCreateDisposition("CREATE_IF_NEEDED")
            .setWriteDisposition("WRITE_TRUNCATE")
            .setPriority(priority.name());

    if (kmsKey != null) {
      queryConfiguration.setDestinationEncryptionConfiguration(
          new EncryptionConfiguration().setKmsKeyName(kmsKey));
    }

    JobService jobService = bqServices.getJobService(options);
    jobService.startQueryJob(jobReference, queryConfiguration);
    Job job = jobService.pollJob(jobReference, JOB_POLL_MAX_RETRIES);
    if (BigQueryHelpers.parseStatus(job) != Status.SUCCEEDED) {
      throw new IOException(
          String.format(
              "Query job %s failed, status: %s",
              queryJobId, BigQueryHelpers.statusToPrettyString(job.getStatus())));
    }

    LOG.info("Query job {} completed", queryJobId);
    return queryResultTable;
  }

  private static JobConfigurationQuery createBasicQueryConfig(
      String query, Boolean flattenResults, Boolean useLegacySql) {
    return new JobConfigurationQuery()
        .setQuery(query)
        .setFlattenResults(flattenResults)
        .setUseLegacySql(useLegacySql);
  }
}
