/*
 * SonarQube
 * Copyright (C) 2009-2017 SonarSource SA
 * mailto:info AT sonarsource DOT com
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 3 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
package org.sonar.db;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.NoSuchElementException;
import org.junit.Rule;
import org.junit.Test;
import org.sonar.api.utils.System2;

import static org.assertj.core.api.Assertions.assertThat;
import static org.junit.Assert.fail;


public class ResultSetIteratorTest {

  @Rule
  public CoreDbTester dbTester = CoreDbTester.createForSchema(ResultSetIteratorTest.class, "schema.sql");

  @Test
  public void create_iterator_from_statement() throws Exception {
    dbTester.prepareDbUnit(getClass(), "feed.xml");

    try (Connection connection = dbTester.openConnection()) {
      PreparedStatement stmt = connection.prepareStatement("select * from issues order by id");
      FirstIntColumnIterator iterator = new FirstIntColumnIterator(stmt);

      assertThat(iterator.hasNext()).isTrue();

      // calling multiple times hasNext() is ok
      assertThat(iterator.hasNext()).isTrue();

      assertThat(iterator.next()).isEqualTo(10);
      assertThat(iterator.hasNext()).isTrue();
      assertThat(iterator.next()).isEqualTo(20);

      // call next() without calling hasNext()
      assertThat(iterator.next()).isEqualTo(30);
      assertThat(iterator.hasNext()).isFalse();

      try {
        iterator.next();
        fail();
      } catch (NoSuchElementException e) {
        // ok
      }

      iterator.close();
      // statement is closed by ResultSetIterator
      assertThat(stmt.isClosed()).isTrue();
    }
  }

  @Test
  public void iterate_empty_list() throws Exception {
    dbTester.prepareDbUnit(getClass(), "feed.xml");

    try (Connection connection = dbTester.openConnection()) {
      PreparedStatement stmt = connection.prepareStatement("select * from issues where id < 0");
      FirstIntColumnIterator iterator = new FirstIntColumnIterator(stmt);

      assertThat(iterator.hasNext()).isFalse();
    }
  }

  @Test
  public void create_iterator_from_result_set() throws Exception {
    dbTester.prepareDbUnit(getClass(), "feed.xml");

    try (Connection connection = dbTester.openConnection()) {
      PreparedStatement stmt = connection.prepareStatement("select * from issues order by id");
      ResultSet rs = stmt.executeQuery();
      FirstIntColumnIterator iterator = new FirstIntColumnIterator(rs);

      assertThat(iterator.next()).isEqualTo(10);
      assertThat(iterator.next()).isEqualTo(20);
      assertThat(iterator.next()).isEqualTo(30);

      iterator.close();
      assertThat(rs.isClosed()).isTrue();
      stmt.close();
    }
  }

  @Test
  public void remove_row_is_not_supported() throws Exception {
    try (Connection connection = dbTester.openConnection()) {
      PreparedStatement stmt = connection.prepareStatement("select * from issues order by id");
      FirstIntColumnIterator iterator = new FirstIntColumnIterator(stmt);

      try {
        iterator.remove();
        fail();
      } catch (UnsupportedOperationException ok) {
        // ok
      }

      iterator.close();
    }
  }

  @Test
  public void fail_to_read_row() throws Exception {
    dbTester.prepareDbUnit(getClass(), "feed.xml");

    try (Connection connection = dbTester.openConnection()) {
      PreparedStatement stmt = connection.prepareStatement("select * from issues order by id");
      FailIterator iterator = new FailIterator(stmt);

      assertThat(iterator.hasNext()).isTrue();
      try {
        iterator.next();
        fail();
      } catch (IllegalStateException e) {
        assertThat(e.getCause()).isInstanceOf(SQLException.class);
      }
      iterator.close();
    }
  }

  private static class FirstIntColumnIterator extends ResultSetIterator<Integer> {

    public FirstIntColumnIterator(PreparedStatement stmt) throws SQLException {
      super(stmt);
    }

    public FirstIntColumnIterator(ResultSet rs) {
      super(rs);
    }

    @Override
    protected Integer read(ResultSet rs) throws SQLException {
      return rs.getInt(1);
    }
  }

  private static class FailIterator extends ResultSetIterator<Integer> {

    public FailIterator(PreparedStatement stmt) throws SQLException {
      super(stmt);
    }

    @Override
    protected Integer read(ResultSet rs) throws SQLException {
      // column does not exist
      return rs.getInt(1234);
    }
  }
}