const consonants = [
  'β',
  'γ',
  'δ',
  'ζ',
  'θ',
  'κ',
  'λ',
  'μ',
  'ν',
  'ξ',
  'π',
  'ρ',
  'ς',
  'σ',
  'τ',
  'φ',
  'χ',
  'ψ',
];
const consonantClustersPronouncedTogether = [
  'βλ',
  'βρ',
  'γλ',
  'γν',
  'γρ',
  'δρ',
  'θλ',
  'θρ',
  'θν',
  'κλ',
  'κρ',
  'κτ',
  'μν',
  'πλ',
  'πν',
  'πρ',
  'πτ',
  'σκ',
  'σκλ',
  'σμ',
  'σπ',
  'σπλ',
  'στ',
  'στρ',
  'σφ',
  'σθ',
  'σχ',
  'τρ',
  'φθ',
  'φλ',
  'φρ',
  'χρ',
  'χθ',
];

const longVowels = ['η', 'ω', 'ᾳ'];
const shortVowels = ['α', 'ε', 'ι', 'ο', 'υ'];
const vowels = longVowels.concat(shortVowels);

const longDiphthongs = ['ει', 'ηυ', 'ου', 'ευ', 'αι', 'υι'];
const shortDiphthongsWhenFinal = ['αυ', 'οι'];
const diphthongs = longDiphthongs.concat(shortDiphthongsWhenFinal);

function isLongVowel(character: string) {
  return longVowels.indexOf(character) !== -1;
}

export function isLongSyllable(syllable: string) {
  const vowelsOnly = syllable.split('').filter(isVowel).join('');
  if (vowelsOnly.length === 2) {
    return isDiphthong(vowelsOnly);
  }
  return isLongVowel(vowelsOnly);
}

function isVowel(character = '') {
  return vowels.indexOf(character.normalize('NFD')[0] || '') !== -1;
}

function beginsWithVowel(characters: string) {
  return isVowel(characters[0]);
}

function isConsonant(character: string) {
  return !isVowel(character);
}

function isDiphthong(characters: string) {
  return diphthongs.indexOf(characters) !== -1;
}

function beginsWithConsonant(characters: string) {
  return isConsonant(characters[0] || '');
}

function beginsWithDiphthong(characters: string) {
  return diphthongs.indexOf(withoutAccents(characters).substr(0, 2)) !== -1;
}

function beginsWithConsonantClusterPronouncedTogether(characters: string) {
  const charactersLowerCased = characters.toLowerCase();
  for (let x = 0; x < consonantClustersPronouncedTogether.length; x++) {
    const tmp = consonantClustersPronouncedTogether[x] || '';
    if (charactersLowerCased.indexOf(tmp) === 0) {
      return characters.substr(0, tmp.length);
    }
  }
  return null;
}

function endsWithShortDiphthong(characters: string) {
  return (
    shortDiphthongsWhenFinal.indexOf(
      characters.substr(characters.length - 2),
    ) !== -1
  );
}

function isSingleConsonant(characters: string) {
  return characters.length === 1 && isConsonant(characters[0] || '');
}

function beginsWithSingleConsonantFollowedByVowel(characters: string) {
  return isConsonant(characters[0] || '') && isVowel(characters[1]);
}

function beginsWithVowelFollowedByVowel(characters: string) {
  return isVowel(characters[0]) && isVowel(characters[1]);
}

function beginsWithDoubleConsonant(characters: string) {
  return (
    characters.length > 1 &&
    isConsonant(characters[0] || '') &&
    isConsonant(characters[1] || '')
  );
}

function withoutAccent(character: string) {
  return character.normalize('NFD')[0];
}

function withoutAccents(characters: string) {
  return characters.split('').map(withoutAccent).join('');
}

function removePunctuation(characters: string) {
  return characters.replace(/[,.·;]/g, '');
}

function removeNumbers(characters: string) {
  return clean(characters).replace(/[1234567890]/g, '');
}

// function lengthen(vowel: string) {}

// function connectAndLengthen(part1: string, part2: string) {}

function clean(characters: string) {
  return (
    characters
      //remove newlines
      .replace(/(\r\n|\n|\r)/gm, '')
      // remove multiple spaces as well
      .replace(/ +(?= )/g, '')
  );
}

export {
  consonants,
  consonantClustersPronouncedTogether,
  isVowel,
  isLongVowel,
  isConsonant,
  withoutAccents,
  removeNumbers,
  removePunctuation,
  isSingleConsonant,
  beginsWithVowel,
  beginsWithDiphthong,
  beginsWithConsonant,
  beginsWithVowelFollowedByVowel,
  beginsWithSingleConsonantFollowedByVowel,
  beginsWithDoubleConsonant,
  beginsWithConsonantClusterPronouncedTogether,
  endsWithShortDiphthong,
};