/**
 * 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.sqoop.mapreduce.db;

import java.sql.SQLException;
import java.util.List;

import org.junit.Test;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.fail;

/**
 * Test that the IntegerSplitter generates sane splits.
 */
public class TestIntegerSplitter {
  private long [] toLongArray(List<Long> in) {
    long [] out = new long[in.size()];
    for (int i = 0; i < in.size(); i++) {
      out[i] = in.get(i).longValue();
    }

    return out;
  }

  public String formatLongArray(long [] ar) {
    StringBuilder sb = new StringBuilder();
    sb.append("[");
    boolean first = true;
    for (long val : ar) {
      if (!first) {
        sb.append(", ");
      }

      sb.append(Long.toString(val));
      first = false;
    }

    sb.append("]");
    return sb.toString();
  }

  public void assertLongArrayEquals(long [] expected, long [] actual) {
    for (int i = 0; i < expected.length; i++) {
      try {
        assertEquals("Failure at position " + i + "; got " + actual[i]
            + " instead of " + expected[i]
            + "; actual array is " + formatLongArray(actual),
            expected[i], actual[i]);
      } catch (ArrayIndexOutOfBoundsException oob) {
        fail("Expected array with " + expected.length
            + " elements; got " + actual.length
            + ". Actual array is " + formatLongArray(actual));
      }
    }

    if (actual.length > expected.length) {
      fail("Actual array has " + actual.length
          + " elements; expected " + expected.length
          + ". Actual array is " + formatLongArray(actual));
    }
  }

  @Test
  public void testEvenSplits() throws SQLException {
    List<Long> splits = new IntegerSplitter().split(10,-1, 0, 100);
    long [] expected = { 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, };
    assertLongArrayEquals(expected, toLongArray(splits));
  }

  @Test
  public void testOddSplits() throws SQLException {
    List<Long> splits = new IntegerSplitter().split(10,-1, 0, 95);
    long [] expected = { 0, 10, 20, 30, 40, 50, 59, 68, 77, 86, 95, };
    assertLongArrayEquals(expected, toLongArray(splits));
  }

  @Test
  public void testSingletonSplit() throws SQLException {
    List<Long> splits = new IntegerSplitter().split(1,-1, 5, 5);
    long [] expected = { 5, 5 };
    assertLongArrayEquals(expected, toLongArray(splits));
  }

  @Test
  public void testSingletonSplit2() throws SQLException {
    // Same test, but overly-high numSplits
    List<Long> splits = new IntegerSplitter().split(5,-1, 5, 5);
    long [] expected = { 5, 5 };
    assertLongArrayEquals(expected, toLongArray(splits));
  }

  @Test
  public void testTooManySplits() throws SQLException {
    List<Long> splits = new IntegerSplitter().split(5,-1, 3, 5);
    long [] expected = { 3, 4, 5, 5};
    assertLongArrayEquals(expected, toLongArray(splits));
  }

  @Test
  public void testExactSplitsAsInterval() throws SQLException {
    List<Long> splits = new IntegerSplitter().split(5,-1, 1, 5);
    long [] expected = { 1, 2, 3, 4, 5, 5};
    assertLongArrayEquals(expected, toLongArray(splits));
  }

  /**
   * This tests verifies that overflows do not happen due to the splitting
   * algorithm.
   *
   * @throws SQLException
   */
  @Test
  public void testBigIntSplits() throws SQLException {
    List<Long> splits = new IntegerSplitter().split(4,-1, 14,
        7863696997872966707L);
    assertEquals(splits.size(), 5);
  }

  @Test
  public void testEvenSplitsWithLimit() throws SQLException {
    List<Long> splits = new IntegerSplitter().split(5, 10, 0, 100);
    long [] expected = { 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 };
    assertLongArrayEquals(expected, toLongArray(splits));
  }

  @Test
  public void testOddSplitsWithLimit() throws SQLException {
    List<Long> splits = new IntegerSplitter().split(5, 10, 0, 95);
    long [] expected = { 0, 10, 20, 30, 40, 50, 59, 68, 77, 86, 95};
    assertLongArrayEquals(expected, toLongArray(splits));
  }

  @Test
  public void testSplitWithBiggerLimit() throws SQLException {
    List<Long> splits = new IntegerSplitter().split(10, 15, 0, 100);
    long [] expected = {0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100};
    assertLongArrayEquals(expected, toLongArray(splits));
  }

  @Test
  public void testFractionalSplitWithLimit() throws SQLException {
    List<Long> splits = new IntegerSplitter().split(5, 1, 1, 10);
    long [] expected = {1,2, 3, 4, 5, 6, 7, 8, 9, 10, 10};
    assertLongArrayEquals(expected, toLongArray(splits));
  }
}