/*
 * 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.phoenix.end2end;

import static org.apache.phoenix.util.TestUtil.TEST_PROPERTIES;
import static org.junit.Assert.*;

import java.sql.*;
import java.util.Properties;
import org.apache.phoenix.compile.ExplainPlan;
import org.apache.phoenix.compile.ExplainPlanAttributes;
import org.apache.phoenix.jdbc.PhoenixPreparedStatement;
import org.apache.phoenix.schema.ColumnNotFoundException;
import org.apache.phoenix.util.PropertiesUtil;
import org.junit.Before;
import org.junit.Test;
import org.junit.experimental.categories.Category;

@Category(ParallelStatsDisabledTest.class)
public class CountDistinctApproximateHyperLogLogIT extends ParallelStatsDisabledIT {
  private String tableName;

  @Before
  public void generateTableNames() {
    tableName = "T_" + generateUniqueName();
  }

  @Test(expected = ColumnNotFoundException.class)
  public void testDistinctCountException() throws Exception {
    String query = "SELECT APPROX_COUNT_DISTINCT(x) FROM " + tableName;
    Properties props = PropertiesUtil.deepCopy(TEST_PROPERTIES);

    try (Connection conn = DriverManager.getConnection(getUrl(), props);
      PreparedStatement statement = conn.prepareStatement(query);) {
      prepareTableWithValues(conn, 100);
      ResultSet rs = statement.executeQuery();
    }
  }

  @Test
  public void testDistinctCountOnConstant() throws Exception {
    String query = "SELECT APPROX_COUNT_DISTINCT(20) FROM " + tableName;
    Properties props = PropertiesUtil.deepCopy(TEST_PROPERTIES);

    try (Connection conn = DriverManager.getConnection(getUrl(), props);
      PreparedStatement statement = conn.prepareStatement(query);) {
      prepareTableWithValues(conn, 100);
      ResultSet rs = statement.executeQuery();

      assertTrue(rs.next());
      assertEquals(1, rs.getLong(1));
      assertFalse(rs.next());
    }
  }

  @Test
  public void testDistinctCountOnSingleColumn() throws Exception {
    String query = "SELECT APPROX_COUNT_DISTINCT(i2) FROM " + tableName;
    Properties props = PropertiesUtil.deepCopy(TEST_PROPERTIES);

    try (Connection conn = DriverManager.getConnection(getUrl(), props);
      PreparedStatement statement = conn.prepareStatement(query);) {
      prepareTableWithValues(conn, 100);
      ResultSet rs = statement.executeQuery();

      assertTrue(rs.next());
      assertEquals(10, rs.getLong(1));
      assertFalse(rs.next());
    }
  }

  @Test
  public void testDistinctCountOnMutlipleColumns() throws Exception {
    String query = "SELECT APPROX_COUNT_DISTINCT(i1||i2) FROM " + tableName;
    Properties props = PropertiesUtil.deepCopy(TEST_PROPERTIES);

    try (Connection conn = DriverManager.getConnection(getUrl(), props);
      PreparedStatement statement = conn.prepareStatement(query);) {
      prepareTableWithValues(conn, 100);

      ResultSet rs = statement.executeQuery();

      assertTrue(rs.next());
      assertEquals(100, rs.getLong(1));
      assertFalse(rs.next());
    }
  }

  @Test
  public void testDistinctCountOnjoining() throws Exception {
    String query = "SELECT APPROX_COUNT_DISTINCT(a.i1||a.i2||b.i2) FROM " + tableName + " a, "
      + tableName + " b where a.i1=b.i1 and a.i2 = b.i2";
    Properties props = PropertiesUtil.deepCopy(TEST_PROPERTIES);

    try (Connection conn = DriverManager.getConnection(getUrl(), props);
      PreparedStatement statement = conn.prepareStatement(query);) {
      prepareTableWithValues(conn, 100);
      ResultSet rs = statement.executeQuery();

      assertTrue(rs.next());
      assertEquals(100, rs.getLong(1));
      assertFalse(rs.next());
    }
  }

  @Test
  public void testDistinctCountPlanExplain() throws Exception {
    Properties props = PropertiesUtil.deepCopy(TEST_PROPERTIES);
    String query = "SELECT APPROX_COUNT_DISTINCT(i1||i2) FROM " + tableName;
    try (Connection conn = DriverManager.getConnection(getUrl(), props)) {
      prepareTableWithValues(conn, 100);
      ExplainPlan plan = conn.prepareStatement(query).unwrap(PhoenixPreparedStatement.class)
        .optimizeQuery().getExplainPlan();
      ExplainPlanAttributes explainPlanAttributes = plan.getPlanStepsAsAttributes();
      assertEquals(tableName, explainPlanAttributes.getTableName());
      assertEquals("PARALLEL 1-WAY", explainPlanAttributes.getIteratorTypeAndScanSize());
      assertEquals("FULL SCAN ", explainPlanAttributes.getExplainScanType());
      assertEquals("SERVER FILTER BY FIRST KEY ONLY", explainPlanAttributes.getServerWhereFilter());
      assertEquals("SERVER AGGREGATE INTO SINGLE ROW", explainPlanAttributes.getServerAggregate());
    }
  }

  /**
   * Prepare tables with stats updated. format of first table such as i1, i2 1, 10 2, 20 3, 30 ...
   */
  final private void prepareTableWithValues(final Connection conn, final int nRows)
    throws Exception {
    conn.createStatement()
      .execute("create table " + tableName + "\n" + "   (i1 integer not null, i2 integer not null\n"
        + "    CONSTRAINT pk PRIMARY KEY (i1,i2))");

    final PreparedStatement stmt =
      conn.prepareStatement("upsert into " + tableName + " VALUES (?, ?)");
    for (int i = 0; i < nRows; i++) {
      stmt.setInt(1, i);
      stmt.setInt(2, (i * 10) % 100);
      stmt.execute();
    }
    conn.commit();
  }
}
