/*
 * Copyright 2019, Verizon Media.
 * Licensed under the terms of the Apache License 2.0. See LICENSE file at the project root for terms.
 */

package com.yahoo.sketches.pig.kll;

import org.apache.pig.Accumulator;
import org.apache.pig.EvalFunc;
import org.apache.pig.data.BagFactory;
import org.apache.pig.data.DataBag;
import org.apache.pig.data.DataByteArray;
import org.apache.pig.data.Tuple;
import org.apache.pig.data.TupleFactory;
import org.testng.Assert;
import org.testng.annotations.Test;

import com.yahoo.memory.Memory;
import com.yahoo.sketches.kll.KllFloatsSketch;

public class UnionSketchTest {
  private static final TupleFactory TUPLE_FACTORY = TupleFactory.getInstance();
  private static final BagFactory BAG_FACTORY = BagFactory.getInstance();

  @Test
  public void execNullInputTuple() throws Exception {
    final EvalFunc<DataByteArray> func = new UnionSketch();
    final DataByteArray result = func.exec(null);
    final KllFloatsSketch sketch = getSketch(result);
    Assert.assertTrue(sketch.isEmpty());
  }

  @Test
  public void execEmptyInputTuple() throws Exception {
    final EvalFunc<DataByteArray> func = new UnionSketch();
    final DataByteArray result = func.exec(TUPLE_FACTORY.newTuple());
    final KllFloatsSketch sketch = getSketch(result);
    Assert.assertTrue(sketch.isEmpty());
  }

  @Test
  public void execEmptyBag() throws Exception {
    final EvalFunc<DataByteArray> func = new UnionSketch();
    final DataByteArray result = func.exec(TUPLE_FACTORY.newTuple(BAG_FACTORY.newDefaultBag()));
    final KllFloatsSketch sketch = getSketch(result);
    Assert.assertTrue(sketch.isEmpty());
  }

  @Test
  public void execNormalCase() throws Exception {
    final EvalFunc<DataByteArray> func = new UnionSketch();
    final DataBag bag = BAG_FACTORY.newDefaultBag();
    final KllFloatsSketch inputSketch = new KllFloatsSketch();
    inputSketch.update(1);
    bag.add(TUPLE_FACTORY.newTuple(new DataByteArray(inputSketch.toByteArray())));
    final DataByteArray result = func.exec(TUPLE_FACTORY.newTuple(bag));
    final KllFloatsSketch sketch = getSketch(result);
    Assert.assertFalse(sketch.isEmpty());
    Assert.assertEquals(sketch.getN(), 1);
  }

  @Test
  public void accumulator() throws Exception {
    final Accumulator<DataByteArray> func = new UnionSketch();

    // no input yet
    DataByteArray result = func.getValue();
    KllFloatsSketch sketch = getSketch(result);
    Assert.assertTrue(sketch.isEmpty());

    // null input tuple
    func.accumulate(null);
    result = func.getValue();
    sketch = getSketch(result);
    Assert.assertTrue(sketch.isEmpty());

    // empty input tuple
    func.accumulate(TUPLE_FACTORY.newTuple());
    result = func.getValue();
    sketch = getSketch(result);
    Assert.assertTrue(sketch.isEmpty());

    // empty bag
    func.accumulate(TUPLE_FACTORY.newTuple(BAG_FACTORY.newDefaultBag()));
    result = func.getValue();
    sketch = getSketch(result);
    Assert.assertTrue(sketch.isEmpty());

    // normal case
    final DataBag bag = BAG_FACTORY.newDefaultBag();
    final KllFloatsSketch inputSketch = new KllFloatsSketch();
    inputSketch.update(1);
    bag.add(TUPLE_FACTORY.newTuple(new DataByteArray(inputSketch.toByteArray())));
    func.accumulate(TUPLE_FACTORY.newTuple(bag));
    func.accumulate(TUPLE_FACTORY.newTuple(bag));
    result = func.getValue();
    sketch = getSketch(result);
    Assert.assertFalse(sketch.isEmpty());
    Assert.assertEquals(sketch.getN(), 2);

    // cleanup
    func.cleanup();
    result = func.getValue();
    sketch = getSketch(result);
    Assert.assertTrue(sketch.isEmpty());
  }

  @Test
  public void accumulatorCustomK() throws Exception {
    final Accumulator<DataByteArray> func = new UnionSketch("400");
    final KllFloatsSketch sketch = getSketch(func.getValue());
    Assert.assertEquals(sketch.getK(), 400);
  }

  @Test
  public void algebraicInitial() throws Exception {
    @SuppressWarnings("unchecked")
    final EvalFunc<Tuple> func =
        (EvalFunc<Tuple>) Class.forName(new UnionSketch().getInitial())
        .getConstructor(String.class).newInstance("400");
    final DataBag bag = BAG_FACTORY.newDefaultBag();
    bag.add(TUPLE_FACTORY.newTuple());
    final Tuple resultTuple = func.exec(TUPLE_FACTORY.newTuple(bag));
    Assert.assertNotNull(resultTuple);
    Assert.assertEquals(resultTuple.size(), 1);
    Assert.assertTrue(resultTuple.get(0) instanceof DataBag);
    Assert.assertEquals(((DataBag) resultTuple.get(0)).size(), 1);
  }

  @Test
  public void algebraicIntermediateNullInputTupleCustomK() throws Exception {
    @SuppressWarnings("unchecked")
    final EvalFunc<Tuple> func =
        (EvalFunc<Tuple>) Class.forName(new UnionSketch().getIntermed())
        .getConstructor(String.class).newInstance("400");
    final Tuple resultTuple = func.exec(null);
    final KllFloatsSketch sketch = getSketch(resultTuple);
    Assert.assertTrue(sketch.isEmpty());
    Assert.assertEquals(sketch.getK(), 400);
  }

  @Test
  public void algebraicIntermediateEmptyInputTuple() throws Exception {
    @SuppressWarnings("unchecked")
    final EvalFunc<Tuple> func =
        (EvalFunc<Tuple>) Class.forName(new UnionSketch().getIntermed()).newInstance();
    final Tuple resultTuple = func.exec(TUPLE_FACTORY.newTuple());
    final KllFloatsSketch sketch = getSketch(resultTuple);
    Assert.assertTrue(sketch.isEmpty());
  }

  @Test
  public void algebraicIntermediateNormalCase() throws Exception {
    @SuppressWarnings("unchecked")
    final EvalFunc<Tuple> func =
        (EvalFunc<Tuple>) Class.forName(new UnionSketch().getIntermed()).newInstance();
    final DataBag bag = BAG_FACTORY.newDefaultBag();

    { // this is to simulate an output from Initial
      final DataBag innerBag = BAG_FACTORY.newDefaultBag();
      final KllFloatsSketch qs = new KllFloatsSketch();
      qs.update(1);
      innerBag.add(TUPLE_FACTORY.newTuple(new DataByteArray(qs.toByteArray())));
      bag.add(TUPLE_FACTORY.newTuple(innerBag));
    }

    { // this is to simulate an output from a prior call of Intermediate
      final KllFloatsSketch qs = new KllFloatsSketch();
      qs.update(2);
      bag.add(TUPLE_FACTORY.newTuple(new DataByteArray(qs.toByteArray())));
    }

    final Tuple resultTuple = func.exec(TUPLE_FACTORY.newTuple(bag));
    final KllFloatsSketch sketch = getSketch(resultTuple);
    Assert.assertFalse(sketch.isEmpty());
    Assert.assertEquals(sketch.getN(), 2);
  }

  @Test(expectedExceptions = IllegalArgumentException.class)
  public void algebraicIntermediateWrongType() throws Exception {
    @SuppressWarnings("unchecked")
    final EvalFunc<Tuple> func =
        (EvalFunc<Tuple>) Class.forName(new UnionSketch().getIntermed()).newInstance();
    final DataBag bag = BAG_FACTORY.newDefaultBag();

    // this bag must have tuples with either bags or data byte arrays
    bag.add(TUPLE_FACTORY.newTuple(1.0));
    func.exec(TUPLE_FACTORY.newTuple(bag));
  }

  @Test
  public void algebraicFinalNullInputTupleCustomK() throws Exception {
    @SuppressWarnings("unchecked")
    final EvalFunc<DataByteArray> func =
        (EvalFunc<DataByteArray>) Class.forName(new UnionSketch().getFinal())
        .getConstructor(String.class).newInstance("400");
    final DataByteArray result = func.exec(null);
    final KllFloatsSketch sketch = getSketch(result);
    Assert.assertTrue(sketch.isEmpty());
    Assert.assertEquals(sketch.getK(), 400);
  }

  @Test
  public void algebraicFinalEmptyInputTuple() throws Exception {
    @SuppressWarnings("unchecked")
    final EvalFunc<DataByteArray> func =
        (EvalFunc<DataByteArray>) Class.forName(new UnionSketch().getFinal()).newInstance();
    final DataByteArray result = func.exec(TUPLE_FACTORY.newTuple());
    final KllFloatsSketch sketch = getSketch(result);
    Assert.assertTrue(sketch.isEmpty());
  }

  @Test
  public void algebraicFinalNormalCase() throws Exception {
    @SuppressWarnings("unchecked")
    final EvalFunc<DataByteArray> func =
        (EvalFunc<DataByteArray>) Class.forName(new UnionSketch().getFinal()).newInstance();
    final DataBag bag = BAG_FACTORY.newDefaultBag();

    { // this is to simulate an output from Initial
      final DataBag innerBag = BAG_FACTORY.newDefaultBag();
      final KllFloatsSketch qs = new KllFloatsSketch();
      qs.update(1);
      innerBag.add(TUPLE_FACTORY.newTuple(new DataByteArray(qs.toByteArray())));
      bag.add(TUPLE_FACTORY.newTuple(innerBag));
    }

    { // this is to simulate an output from a prior call of Intermediate
      final KllFloatsSketch qs = new KllFloatsSketch();
      qs.update(2);
      bag.add(TUPLE_FACTORY.newTuple(new DataByteArray(qs.toByteArray())));
    }

    final DataByteArray result = func.exec(TUPLE_FACTORY.newTuple(bag));
    final KllFloatsSketch sketch = getSketch(result);
    Assert.assertFalse(sketch.isEmpty());
    Assert.assertEquals(sketch.getN(), 2);
  }

  @Test(expectedExceptions = IllegalArgumentException.class)
  public void algebraicIntermediateFinalWrongType() throws Exception {
    @SuppressWarnings("unchecked")
    final EvalFunc<DataByteArray> func =
        (EvalFunc<DataByteArray>) Class.forName(new UnionSketch().getFinal()).newInstance();
    DataBag bag = BAG_FACTORY.newDefaultBag();

    // this bag must have tuples with either bags or data byte arrays
    bag.add(TUPLE_FACTORY.newTuple(1.0));
    func.exec(TUPLE_FACTORY.newTuple(bag));
  }

  // end of tests

  private static KllFloatsSketch getSketch(final Tuple tuple) throws Exception {
    Assert.assertNotNull(tuple);
    Assert.assertEquals(tuple.size(), 1);
    final DataByteArray bytes = (DataByteArray) tuple.get(0);
    return getSketch(bytes);
  }

  private static KllFloatsSketch getSketch(final DataByteArray bytes) throws Exception {
    Assert.assertTrue(bytes.size() > 0);
    return KllFloatsSketch.heapify(Memory.wrap(bytes.get()));
  }

}