/*
 * 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.impl.rule;

import static org.apache.beam.sdk.extensions.sql.meta.provider.test.TestTableProvider.PUSH_DOWN_OPTION;
import static org.hamcrest.MatcherAssert.assertThat;
import static org.hamcrest.collection.IsIterableContainingInAnyOrder.containsInAnyOrder;
import static org.hamcrest.core.IsInstanceOf.instanceOf;

import org.apache.beam.sdk.extensions.sql.TableUtils;
import org.apache.beam.sdk.extensions.sql.impl.BeamSqlEnv;
import org.apache.beam.sdk.extensions.sql.impl.rel.BeamAggregationRel;
import org.apache.beam.sdk.extensions.sql.impl.rel.BeamCalcRel;
import org.apache.beam.sdk.extensions.sql.impl.rel.BeamIOSourceRel;
import org.apache.beam.sdk.extensions.sql.impl.rel.BeamPushDownIOSourceRel;
import org.apache.beam.sdk.extensions.sql.impl.rel.BeamRelNode;
import org.apache.beam.sdk.extensions.sql.meta.Table;
import org.apache.beam.sdk.extensions.sql.meta.provider.test.TestTableProvider;
import org.apache.beam.sdk.extensions.sql.meta.provider.test.TestTableProvider.PushDownOptions;
import org.apache.beam.sdk.schemas.Schema;
import org.apache.beam.sdk.testing.TestPipeline;
import org.apache.beam.sdk.values.Row;
import org.junit.Before;
import org.junit.Rule;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

@RunWith(JUnit4.class)
public class BeamAggregateProjectMergeRuleTest {
  private static final Schema BASIC_SCHEMA =
      Schema.builder()
          .addInt32Field("unused1")
          .addInt32Field("id")
          .addStringField("name")
          .addInt32Field("unused2")
          .build();
  private BeamSqlEnv sqlEnv;

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

  @Before
  public void buildUp() {
    TestTableProvider tableProvider = new TestTableProvider();
    Table projectTable = getTable("TEST_PROJECT", PushDownOptions.PROJECT);
    Table filterTable = getTable("TEST_FILTER", PushDownOptions.FILTER);
    Table noneTable = getTable("TEST_NONE", PushDownOptions.NONE);

    tableProvider.createTable(projectTable);
    tableProvider.createTable(filterTable);
    tableProvider.createTable(noneTable);

    // Rules are cost based, need rows to optimize!
    tableProvider.addRows(
        "TEST_PROJECT", Row.withSchema(BASIC_SCHEMA).addValues(1, 2, "3", 4).build());
    tableProvider.addRows(
        "TEST_FILTER", Row.withSchema(BASIC_SCHEMA).addValues(1, 2, "3", 4).build());
    tableProvider.addRows(
        "TEST_NONE", Row.withSchema(BASIC_SCHEMA).addValues(1, 2, "3", 4).build());

    sqlEnv = BeamSqlEnv.inMemory(tableProvider);
  }

  @Test
  public void testBeamAggregateProjectMergeRule_withProjectTable() {
    // When an IO supports project push-down, Projects should be merged with an IO.
    String sqlQuery = "select SUM(id) as id_sum from TEST_PROJECT group by name";
    BeamRelNode beamRel = sqlEnv.parseQuery(sqlQuery);

    BeamAggregationRel aggregate = (BeamAggregationRel) beamRel.getInput(0);
    BeamIOSourceRel ioSourceRel = (BeamIOSourceRel) aggregate.getInput();

    // Make sure project push-down took place.
    assertThat(ioSourceRel, instanceOf(BeamPushDownIOSourceRel.class));
    assertThat(ioSourceRel.getRowType().getFieldNames(), containsInAnyOrder("name", "id"));
  }

  @Test
  public void testBeamAggregateProjectMergeRule_withProjectTable_withPredicate() {
    // When an IO supports project push-down, Projects should be merged with an IO.
    String sqlQuery = "select SUM(id) as id_sum from TEST_PROJECT where unused1=1 group by name";
    BeamRelNode beamRel = sqlEnv.parseQuery(sqlQuery);

    BeamAggregationRel aggregate = (BeamAggregationRel) beamRel.getInput(0);
    BeamCalcRel calc = (BeamCalcRel) aggregate.getInput();
    BeamIOSourceRel ioSourceRel = (BeamIOSourceRel) calc.getInput();

    // Make sure project push-down took place.
    assertThat(ioSourceRel, instanceOf(BeamPushDownIOSourceRel.class));
    assertThat(
        ioSourceRel.getRowType().getFieldNames(), containsInAnyOrder("name", "id", "unused1"));
  }

  @Test
  public void testBeamAggregateProjectMergeRule_withFilterTable() {
    // When an IO does not supports project push-down, Projects should be merged with an aggregate.
    String sqlQuery = "select SUM(id) as id_sum from TEST_FILTER group by name";
    BeamRelNode beamRel = sqlEnv.parseQuery(sqlQuery);

    BeamAggregationRel aggregate = (BeamAggregationRel) beamRel.getInput(0);
    BeamIOSourceRel ioSourceRel = (BeamIOSourceRel) aggregate.getInput();

    // Make sure project merged with an aggregate.
    assertThat(aggregate.getRowType().getFieldNames(), containsInAnyOrder("id_sum", "name"));

    // IO projects al fields.
    assertThat(ioSourceRel, instanceOf(BeamIOSourceRel.class));
    assertThat(
        ioSourceRel.getRowType().getFieldNames(),
        containsInAnyOrder("unused1", "name", "id", "unused2"));
  }

  @Test
  public void testBeamAggregateProjectMergeRule_withNoneTable() {
    // When an IO does not supports project push-down, Projects should be merged with an aggregate.
    String sqlQuery = "select SUM(id) as id_sum from TEST_NONE group by name";
    BeamRelNode beamRel = sqlEnv.parseQuery(sqlQuery);

    BeamAggregationRel aggregate = (BeamAggregationRel) beamRel.getInput(0);
    BeamIOSourceRel ioSourceRel = (BeamIOSourceRel) aggregate.getInput();

    // Make sure project merged with an aggregate.
    assertThat(aggregate.getRowType().getFieldNames(), containsInAnyOrder("id_sum", "name"));

    // IO projects al fields.
    assertThat(ioSourceRel, instanceOf(BeamIOSourceRel.class));
    assertThat(
        ioSourceRel.getRowType().getFieldNames(),
        containsInAnyOrder("unused1", "name", "id", "unused2"));
  }

  private static Table getTable(String name, PushDownOptions options) {
    return Table.builder()
        .name(name)
        .comment(name + " table")
        .schema(BASIC_SCHEMA)
        .properties(
            TableUtils.parseProperties(
                "{ " + PUSH_DOWN_OPTION + ": " + "\"" + options.toString() + "\" }"))
        .type("test")
        .build();
  }
}
