/*
 * 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.sentdetect;

import java.io.IOException;
import java.util.Locale;

import org.junit.jupiter.api.BeforeAll;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.ValueSource;

import opennlp.tools.dictionary.Dictionary;

import static org.junit.jupiter.api.Assertions.assertAll;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.assertTrue;
import static org.junit.jupiter.api.Assertions.fail;

/**
 * Tests for the {@link SentenceDetectorME} class.
 * <p>
 * Verifies OPENNLP-793 in combination with OPENNLP-570.
 * <p>
 * In this context, well-known known German (de_DE) abbreviations must be respected,
 * so that words abbreviated with one or more '.' characters do not
 * result in incorrect sentence boundaries.
 * <p>
 * See:
 * <a href="https://issues.apache.org/jira/projects/OPENNLP/issues/OPENNLP-793">OPENNLP-793</a>
 * <a href="https://issues.apache.org/jira/projects/OPENNLP/issues/OPENNLP-570">OPENNLP-570</a>
 */
public class SentenceDetectorMEGermanTest extends AbstractSentenceDetectorTest {

  private static final char[] EOS_CHARS = {'.', '?', '!'};
  private static Dictionary abbreviationDict;
  private SentenceModel sentdetectModel;

  // SUT
  private SentenceDetectorME sentenceDetector;

  @BeforeAll
  static void loadResources() throws IOException {
    abbreviationDict = loadAbbDictionary(Locale.GERMAN);
  }

  private void prepareResources(boolean useTokenEnd) {
    try {
      SentenceDetectorFactory factory = new SentenceDetectorFactory(
          "deu", useTokenEnd, abbreviationDict, EOS_CHARS);
      sentdetectModel = train(factory, Locale.GERMAN);

      assertAll(
          () -> assertNotNull(sentdetectModel),
          () -> assertEquals("deu", sentdetectModel.getLanguage())
      );
      sentenceDetector = new SentenceDetectorME(sentdetectModel);
    } catch (IOException ex) {
      fail("Couldn't train the SentenceModel using test data. Exception: " + ex.getMessage());
    }
  }

  // Example taken from 'Sentences_DE.txt'
  @Test
  void testSentDetectWithInlineAbbreviationsEx1() {
    prepareResources(true);

    final String sent1 = "Ein Traum, zu dessen Bildung eine besonders starke Verdichtung beigetragen, " +
        "wird für diese Untersuchung das günstigste Material sein.";
    // Here we have two abbreviations "S. = Seite" and "ff. = folgende (Plural)"
    final String sent2 = "Ich wähle den auf S. 183 ff. mitgeteilten Traum von der botanischen Monographie.";

    String sampleSentences = sent1 + " " + sent2;
    String[] sents = sentenceDetector.sentDetect(sampleSentences);
    double[] probs = sentenceDetector.probs();

    assertAll(
        () -> assertEquals(2, sents.length),
        () -> assertEquals(sent1, sents[0]),
        () -> assertEquals(sent2, sents[1]),
        () -> assertEquals(2, probs.length));
  }

  // Reduced example taken from 'Sentences_DE.txt'
  @Test
  void testSentDetectWithInlineAbbreviationsEx2() {
    prepareResources(true);

    // Here we have three abbreviations: "S. = Seite", "vgl. = vergleiche", and "f. = folgende (Singular)"
    final String sent1 = "Die farbige Tafel, die ich aufschlage, " +
        "geht (vgl. die Analyse S. 185 f.) auf ein neues Thema ein.";

    String[] sents = sentenceDetector.sentDetect(sent1);
    double[] probs = sentenceDetector.probs();

    assertAll(
        () -> assertEquals(1, sents.length),
        () -> assertEquals(sent1, sents[0]),
        () -> assertEquals(1, probs.length));
  }

  // Modified example deduced from 'Sentences_DE.txt'
  @Test
  void testSentDetectWithInlineAbbreviationsEx3() {
    prepareResources(true);

    // Here we have two abbreviations "z. B. = zum Beispiel" and "S. = Seite"
    final String sent1 = "Die farbige Tafel, die ich aufschlage, " +
        "geht (z. B. die Analyse S. 185) auf ein neues Thema ein.";

    String[] sents = sentenceDetector.sentDetect(sent1);
    double[] probs = sentenceDetector.probs();

    assertAll(
        () -> assertEquals(1, sents.length),
        () -> assertEquals(sent1, sents[0]),
        () -> assertEquals(1, probs.length));
  }

  @Test
  void testSentDetectWithUseTokenEndFalse() {
    prepareResources(false);

    final String sent1 = "Träume sind eine Verbindung von Gedanken.";
    final String sent2 = "Verschiedene Gedanken sind während der Traumformation aktiv.";

    //There is no blank space before start of the second sentence.
    String[] sents = sentenceDetector.sentDetect(sent1 + sent2);
    double[] probs = sentenceDetector.probs();

    assertAll(
        () -> assertEquals(2, sents.length),
        () -> assertEquals(sent1, sents[0]),
        () -> assertEquals(sent2, sents[1]),
        () -> assertEquals(2, probs.length));
  }

  /*
   * A reproducer and test for OPENNLP-1781.
   */
  @Test
  void testSentDetectWithSingleLetterAbbreviationsAtSentenceStart() {
    prepareResources(true);

    final String sent1 = "S. Träume sind eine Verbindung von Gedanken.";

    final String[] sents = sentenceDetector.sentDetect(sent1);
    final double[] probs = sentenceDetector.probs();

    assertAll(
        () -> assertEquals(1, sents.length),
        () -> assertEquals(sent1, sents[0]),
        () -> assertEquals(1, probs.length));
  }

  /*
   * A reproducer and test for OPENNLP-1809.
   */
  @Test
  void testSentDetectWithMultiLetterAbbreviationsAtSentenceStart() {
    prepareResources(true);

    final String sent1 = "Bek. Problem: Schlafmangel.";
    final String sent2 = "Über die letzten Tage hinweg war sie zunehmend müde.";

    String sampleSentences = sent1 + " " + sent2;
    String[] sents = sentenceDetector.sentDetect(sampleSentences);
    double[] probs = sentenceDetector.probs();

    assertAll(
        () -> assertEquals(2, sents.length),
        () -> assertEquals(sent1, sents[0]),
        () -> assertEquals(sent2, sents[1]),
        () -> assertEquals(2, probs.length));
  }

  // Edge case: The same abbreviation appears twice in a single sentence segment.
  @Test
  void testSentDetectWithDuplicateAbbreviationInSameSegment() {
    prepareResources(true);
    final String sent1 = "Lt. Vertrag und lt. Bescheid gelten andere Bedingungen.";
    String[] sents = sentenceDetector.sentDetect(sent1);
    double[] probs = sentenceDetector.probs();
    assertAll(
        () -> assertEquals(1, sents.length),
        () -> assertEquals(sent1, sents[0]),
        () -> assertEquals(1, probs.length));
  }

  /**
   * Edge case: Multi-letter abbreviation at the start of a non-first sentence
   * with {@code useTokenEnd = false} (no space between sentences).
   */
  @Test
  void testSentDetectWithMultiLetterAbbreviationAtNonFirstSentenceStart() {
    prepareResources(false);
    final String sent1 = "Träume sind eine Verbindung von Gedanken.";
    final String sent2 = "Bek. Problem: Schlafmangel.";
    // No space between sentences (useTokenEnd=false supports this)
    String sampleSentences = sent1 + sent2;
    String[] sents = sentenceDetector.sentDetect(sampleSentences);
    double[] probs = sentenceDetector.probs();
    assertAll(
        () -> assertEquals(2, sents.length),
        () -> assertEquals(sent1, sents[0]),
        () -> assertEquals(sent2, sents[1]),
        () -> assertEquals(2, probs.length));
  }

  /*
   * A reproducer and test for OPENNLP-1767.
   * It checks that sentence detection with common abbreviations works correctly,
   * that is, tokens such as "lt.", "f.", "S." (page), "ca.", or "ugs." do not cause
   * mis-matches when it accidentally overlaps at the end of a sentence.
   */
  @ParameterizedTest
  @ValueSource(strings = {
      "Die Frage wurde gestellt. Sie wurde beantwortet.",
      "Der Auto stand schief. Wer hat es dort geparkt?",
      "Es lag am DBMS. Die Performance muss verbessert werden.",
      "Siehe Buch S. 17f. Dort ist es zu finden.",
      "S. Buch S. 17f. Dort ist es zu finden.", // OPENNLP-1781
      "Sie trank einen Mocca. Er schmeckte ihr!",
      "Der Anker hängt zu Beginn des Bugs. Es ist vertaut.",
      "Das Verfahren testet auf HIV. Es ist präzise."
  })
  void testSentDetectWithOverlappingAbbreviationAtSentenceEnd(String input) {
    prepareResources(true);
    String[] sents = sentenceDetector.sentDetect(input);
    assertAll(
        () -> assertNotNull(sents),
        () -> assertEquals(2, sents.length),
        () -> assertTrue(Character.isUpperCase(sents[0].charAt(0))),
        () -> assertTrue(Character.isUpperCase(sents[1].charAt(0)))
    );
  }
}
