/*
 * 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.postag;

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

import org.junit.Assert;
import org.junit.Test;

import opennlp.tools.formats.ResourceAsStreamFactory;
import opennlp.tools.util.InputStreamFactory;
import opennlp.tools.util.InsufficientTrainingDataException;
import opennlp.tools.util.ObjectStream;
import opennlp.tools.util.PlainTextByLineStream;
import opennlp.tools.util.TrainingParameters;
import opennlp.tools.util.model.ModelType;

/**
 * Tests for the {@link POSTaggerME} class.
 */
public class POSTaggerMETest {

  private static ObjectStream<POSSample> createSampleStream() throws IOException {
    InputStreamFactory in = new ResourceAsStreamFactory(POSTaggerMETest.class,
        "/opennlp/tools/postag/AnnotatedSentences.txt");

    return new WordTagSampleStream(new PlainTextByLineStream(in, StandardCharsets.UTF_8));
  }

  /**
   * Trains a POSModel from the annotated test data.
   *
   * @return {@link POSModel}
   */
  public static POSModel trainPOSModel(ModelType type) throws IOException {
    TrainingParameters params = new TrainingParameters();
    params.put(TrainingParameters.ALGORITHM_PARAM, type.toString());
    params.put(TrainingParameters.ITERATIONS_PARAM, 100);
    params.put(TrainingParameters.CUTOFF_PARAM, 5);

    return POSTaggerME.train("eng", createSampleStream(), params,
        new POSTaggerFactory());
  }

  @Test
  public void testPOSTagger() throws IOException {
    POSModel posModel = trainPOSModel(ModelType.MAXENT);

    POSTagger tagger = new POSTaggerME(posModel);

    String[] tags = tagger.tag(new String[] {
        "The",
        "driver",
        "got",
        "badly",
        "injured",
        "."});

    Assert.assertEquals(6, tags.length);
    Assert.assertEquals("DT", tags[0]);
    Assert.assertEquals("NN", tags[1]);
    Assert.assertEquals("VBD", tags[2]);
    Assert.assertEquals("RB", tags[3]);
    Assert.assertEquals("VBN", tags[4]);
    Assert.assertEquals(".", tags[5]);
  }

  @Test
  public void testBuildNGramDictionary() throws IOException {
    ObjectStream<POSSample> samples = createSampleStream();
    POSTaggerME.buildNGramDictionary(samples, 0);
  }
  
  @Test(expected = InsufficientTrainingDataException.class)
  public void insufficientTestData() throws IOException {

    InputStreamFactory in = new ResourceAsStreamFactory(POSTaggerMETest.class,
        "/opennlp/tools/postag/AnnotatedSentencesInsufficient.txt");

    ObjectStream<POSSample> stream = new WordTagSampleStream(
        new PlainTextByLineStream(in, StandardCharsets.UTF_8));
 
    TrainingParameters params = new TrainingParameters();
    params.put(TrainingParameters.ALGORITHM_PARAM, ModelType.MAXENT.name());
    params.put(TrainingParameters.ITERATIONS_PARAM, 100);
    params.put(TrainingParameters.CUTOFF_PARAM, 5);

    POSTaggerME.train("eng", stream, params, new POSTaggerFactory());

  }
  
}
