/*
 * 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 opennlp.tools.chunker;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.charset.StandardCharsets;

import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;

import opennlp.tools.cmdline.chunker.ChunkEvaluationErrorListener;
import opennlp.tools.formats.ResourceAsStreamFactory;
import opennlp.tools.util.PlainTextByLineStream;
import opennlp.tools.util.eval.FMeasure;

/**
 * Tests for {@link ChunkerEvaluator}.
 */
public class ChunkerEvaluatorTest {

  private static final double DELTA = 1.0E-9d;

  /**
   * Checks the evaluator results against the results got using the conlleval,
   * available at <a href="https://www.cnts.ua.ac.be/conll2000/chunking/output.html">
   *   https://www.cnts.ua.ac.be/conll2000/chunking/output.html</a>.
   * <p>
   * The {@code output.txt} file has only 3 sentences, but can be replaced by the one
   * available at the conll2000 site to validate using a bigger sample.
   */
  @Test
  void testEvaluator() throws IOException {
    ResourceAsStreamFactory inPredicted = new ResourceAsStreamFactory(
        getClass(), "/opennlp/tools/chunker/output.txt");
    ResourceAsStreamFactory inExpected = new ResourceAsStreamFactory(getClass(),
        "/opennlp/tools/chunker/output.txt");

    DummyChunkSampleStream predictedSample = new DummyChunkSampleStream(
        new PlainTextByLineStream(inPredicted, StandardCharsets.UTF_8), true);

    DummyChunkSampleStream expectedSample = new DummyChunkSampleStream(
        new PlainTextByLineStream(inExpected, StandardCharsets.UTF_8), false);

    Chunker dummyChunker = new DummyChunker(predictedSample);

    OutputStream stream = new ByteArrayOutputStream();
    ChunkerEvaluationMonitor listener = new ChunkEvaluationErrorListener(stream);
    ChunkerEvaluator evaluator = new ChunkerEvaluator(dummyChunker, listener);

    evaluator.evaluate(expectedSample);

    FMeasure fm = evaluator.getFMeasure();

    Assertions.assertEquals(0.8d, fm.getPrecisionScore(), DELTA);
    Assertions.assertEquals(0.875d, fm.getRecallScore(), DELTA);

    Assertions.assertNotSame(0, stream.toString().length());
  }

  @Test
  void testEvaluatorNoError() throws IOException {
    ResourceAsStreamFactory inPredicted = new ResourceAsStreamFactory(
        getClass(), "/opennlp/tools/chunker/output.txt");
    ResourceAsStreamFactory inExpected = new ResourceAsStreamFactory(getClass(),
        "/opennlp/tools/chunker/output.txt");

    DummyChunkSampleStream predictedSample = new DummyChunkSampleStream(
        new PlainTextByLineStream(inPredicted, StandardCharsets.UTF_8), true);

    DummyChunkSampleStream expectedSample = new DummyChunkSampleStream(
        new PlainTextByLineStream(inExpected, StandardCharsets.UTF_8), true);

    Chunker dummyChunker = new DummyChunker(predictedSample);

    OutputStream stream = new ByteArrayOutputStream();
    ChunkerEvaluationMonitor listener = new ChunkEvaluationErrorListener(
        stream);
    ChunkerEvaluator evaluator = new ChunkerEvaluator(dummyChunker, listener);

    evaluator.evaluate(expectedSample);

    FMeasure fm = evaluator.getFMeasure();

    Assertions.assertEquals(1d, fm.getPrecisionScore(), DELTA);
    Assertions.assertEquals(1d, fm.getRecallScore(), DELTA);

    Assertions.assertEquals(0, stream.toString().length());
  }

}
