/*
 * 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;

import static org.apache.beam.sdk.extensions.sql.utils.RowAsserts.matchesScalar;

import java.util.List;
import org.apache.beam.sdk.schemas.Schema;
import org.apache.beam.sdk.testing.PAssert;
import org.apache.beam.sdk.testing.TestPipeline;
import org.apache.beam.sdk.transforms.Create;
import org.apache.beam.sdk.transforms.SerializableFunctions;
import org.apache.beam.sdk.values.PCollection;
import org.apache.beam.sdk.values.Row;
import org.junit.Before;
import org.junit.Rule;
import org.junit.Test;

/** Integration tests for {@code COVAR_POP} and {@code COVAR_SAMP}. */
public class BeamSqlDslAggregationCovarianceTest {

  private static final double PRECISION = 1e-7;

  @Rule public TestPipeline pipeline = TestPipeline.create();

  private PCollection<Row> boundedInput;

  @Before
  public void setUp() {
    Schema schema =
        Schema.builder()
            .addDoubleField("f_double1")
            .addDoubleField("f_double2")
            .addDoubleField("f_double3")
            .addInt32Field("f_int1")
            .addInt32Field("f_int2")
            .addInt32Field("f_int3")
            .build();

    List<Row> rowsInTableB =
        TestUtils.RowsBuilder.of(schema)
            .addRows(
                3.0, 1.0, 1.0, 3, 1, 0, 4.0, 2.0, 2.0, 4, 2, 0, 5.0, 3.0, 1.0, 5, 3, 0, 6.0, 4.0,
                2.0, 6, 4, 0, 8.0, 4.0, 1.0, 8, 4, 0)
            .getRows();

    boundedInput =
        pipeline.apply(
            Create.of(rowsInTableB)
                .withSchema(
                    schema, SerializableFunctions.identity(), SerializableFunctions.identity()));
  }

  @Test
  public void testPopulationVarianceDouble() {
    String sql = "SELECT COVAR_POP(f_double1, f_double2) FROM PCOLLECTION GROUP BY f_int3";

    PAssert.that(boundedInput.apply(SqlTransform.query(sql)))
        .satisfies(matchesScalar(1.84, PRECISION));

    pipeline.run().waitUntilFinish();
  }

  @Test
  public void testPopulationVarianceInt() {
    String sql = "SELECT COVAR_POP(f_int1, f_int2) FROM PCOLLECTION GROUP BY f_int3";

    PAssert.that(boundedInput.apply(SqlTransform.query(sql))).satisfies(matchesScalar(1));

    pipeline.run().waitUntilFinish();
  }

  @Test
  public void testSampleVarianceDouble() {
    String sql = "SELECT COVAR_SAMP(f_double1, f_double2) FROM PCOLLECTION GROUP BY f_int3";

    PAssert.that(boundedInput.apply(SqlTransform.query(sql)))
        .satisfies(matchesScalar(2.3, PRECISION));

    pipeline.run().waitUntilFinish();
  }

  @Test
  public void testSampleVarianceInt() {
    String sql = "SELECT COVAR_SAMP(f_int1, f_int2) FROM PCOLLECTION GROUP BY f_int3";

    PAssert.that(boundedInput.apply(SqlTransform.query(sql))).satisfies(matchesScalar(2));

    pipeline.run().waitUntilFinish();
  }
}