code: package zemberek.core.turkish.hyphenation;
  
  
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.HashSet;
  import java.util.List;
  import zemberek.core.logging.Log;
  import zemberek.core.text.TextIO;
  import zemberek.core.turkish.TurkishAlphabet;
  
  /**
   * This syllable service is designed for extracting syllable information from Turkish words.
   * Algorithm cannot parse words like "tren", "spor", "sfinks", "angstrom", "mavimtrak", "stetoskop"
   * etc.
   */
  public class TurkishSyllableExtractor implements SyllableExtractor {
  
    private final TurkishAlphabet alphabet = TurkishAlphabet.INSTANCE;
  
    // STRICT extractor cannot parse words ending two consonants. Such as `kart`, `yoğurt`
    public static TurkishSyllableExtractor STRICT = new TurkishSyllableExtractor(true);
  
    // DEFAULT extractor allows parsing words like "kitapt -> ki-tapt"
    public static TurkishSyllableExtractor DEFAULT = new TurkishSyllableExtractor(false);
  
    public final boolean strict;
  
    private static HashSet<String> acceptedSyllablePrefixes;
  
    static {
      acceptedSyllablePrefixes = new HashSet<>();
      try {
        acceptedSyllablePrefixes.addAll(TextIO.loadLinesFromResource(
            "zemberek/core/syllable/accepted-syllable-prefixes"));
      } catch (IOException e) {
        Log.warn("Cannot find accepted syllable prefixes.");
      }
    }
  
    private TurkishSyllableExtractor(boolean strict) {
      this.strict = strict;
    }
  
    public List<String> getSyllables(String str) {
      int[] boundaries = syllableBoundaries(str);
      List<String> result = new ArrayList<>();
      for (int i = 0; i < boundaries.length - 1; i++) {
        int boundary = boundaries[i];
        result.add(str.substring(boundary, boundaries[i + 1]));
      }
      if (boundaries.length > 0) {
        result.add(str.substring(boundaries[boundaries.length - 1]));
      }
      return result;
    }
  
    public int[] syllableBoundaries(String str) {
      final int size = str.length();
      char[] chr = str.toCharArray();
      int[] boundaryIndexes = new int[size];
      int lastIndex = size;
      int index = 0;
      while (lastIndex > 0) {
        int letterCount = letterCountForLastSyllable(chr, lastIndex);
        if (letterCount == -1) {
          return new int[0];
        }
        boundaryIndexes[index++] = lastIndex - letterCount;
        lastIndex -= letterCount;
      }
      int[] result = new int[index];
      for (int i = 0; i < index; i++) {
        result[i] = boundaryIndexes[index - i - 1];
      }
      return result;
    }
  
  
    private boolean isVowel(char c) {
      return alphabet.isVowel(c);
    }
  
    private int letterCountForLastSyllable(char[] chr, int endIndex) {
  
      if (endIndex == 0) {
        return -1;
      }
  
      if (isVowel(chr[endIndex - 1])) {
        if (endIndex == 1) {
          return 1;
        }
        if (isVowel(chr[endIndex - 2])) {
          return 1;
        }
        if (endIndex == 2) {
          return 2;
        }
        if (!isVowel(chr[endIndex - 3]) && endIndex == 3) {
          return 3;
        }
        return 2;
      } else {
        if (endIndex == 1) {
          return -1;
        }
        if (isVowel(chr[endIndex - 2])) {
          if (endIndex == 2 || isVowel(chr[endIndex - 3])) {
            return 2;
          }
          if (endIndex == 3 || isVowel(chr[endIndex - 4])) {
            return 3;
          }
          // If the word is 4 letters and rules above passed, we assume this cannot be parsed.
          // That is why words like tren, strateji, krank, angstrom cannot be parsed.
          if (endIndex == 4) {
            return -1;
          }
          if (!isVowel(chr[endIndex - 5])) {
            return 3;
          }
          return 3;
        } else {
          if (strict && !isVowel(chr[endIndex - 2])) {
            return -1;
          }
          if (endIndex == 2 || !isVowel(chr[endIndex - 3])) {
            return -1;
          }
          if (endIndex > 3 && !isVowel(chr[endIndex - 4])) {
            return 4;
          }
          return 3;
        }
      }
    }
  }