numerica/packages/core/src/utils/common/latinPowers.ts

import {BLANK_DIGIT, createBlankDigits, deconstructNumeric, Group, groupDigits, normalizeNumeric} from '../numeric';
import BigNumber from 'bignumber.js';

interface Config {
  hundredsLatinNames: string[],
  onesLatinNames: string[],
  onesSpecialLatinNames: string[],
  tensLatinNames: string[],
  illion: string,
  illionth: string,
  illiard?: string,
  illiardth?: string,
  millia: string,
}

const getLatinPowerGroupDigitsName = (latinRaw: string, special: boolean, config: Config) => {
  const digits = latinRaw.padStart(3, BLANK_DIGIT);
  const [hundreds, tens, ones] = digits.split('').map(s => Number(s));
  const names = [];

  if (hundreds > 0) {
    names.push(config.hundredsLatinNames[hundreds]);
    names.push(config.onesLatinNames[ones]);
    names.push(config.tensLatinNames[tens]);
  } else {
    if (tens > 0) {
      names.push(config.onesLatinNames[ones]);
      names.push(config.tensLatinNames[tens]);
    } else {
      if (special) {
        names.push(config.onesSpecialLatinNames[ones]);
      } else if (ones > 1) {
        names.push(config.onesLatinNames[ones]);
      }
    }
  }
  return names.join('');
};

const getLatinPowerSuffix = (latinRaw: string, isOdd: boolean, special: boolean, ordinal: boolean, config: Config) => {
  const digits = latinRaw.padStart(3, BLANK_DIGIT);
  const [hundreds, tens, ones] = digits.split('').map(s => Number(s));
  const suffix = isOdd ? (ordinal ? config.illiardth : config.illiard) : (ordinal ? config.illionth : config.illion);

  if (hundreds > 0) {
    if (tens !== 1) {
      return 't' + suffix;
    }
    return suffix;
  }
  if (tens > 0) {
    switch (tens) {
    case 1:
      return suffix;
    default:
      break;
    }
    return 't' + suffix;
  }
  switch (ones) {
  case 1:
  case 2:
  case 3:
  case 4:
    return special ? suffix : 't' + suffix;
  case 5:
  case 6:
  case 7:
    return 't' + suffix;
  case 8:
  case 9:
    return suffix;
  default:
    break;
  }
  return '';
};

const getLatinPowerGroupName = (g: Group, config: Config) => {
  const [digits, index] = g;
  if (index.lt(1)) {
    return getLatinPowerGroupDigitsName(digits, index.eq(0), config);
  }
  let milliaSuffix = '';
  for (let i = new BigNumber(0); i.lt(index); i = i.plus(1)) {
    milliaSuffix += config.millia;
  }
  return [getLatinPowerGroupDigitsName(digits, index.eq(0), config), milliaSuffix].join('');
};

const getLatinPowerName = (latinRaw: BigNumber, isOdd: boolean, ordinal: boolean, config: Config) => {
  const x = normalizeNumeric(latinRaw);
  const {significandDigits, exponent} = deconstructNumeric(x);
  const blankDigits = createBlankDigits(3);
  const groups = groupDigits(significandDigits, exponent, 3);

  if (groups.length === 1) {
    return [
      getLatinPowerGroupName(groups[0], config),
      getLatinPowerSuffix(groups[0][0], isOdd, true, ordinal, config),
    ].join('');
  }

  const visibleGroups = groups.filter(([digits]) => digits !== blankDigits);
  const [lastVisibleGroup] = visibleGroups.slice(-1);
  return [
    ...visibleGroups.map(g => getLatinPowerGroupName(g, config)),
    getLatinPowerSuffix(lastVisibleGroup[0], isOdd, lastVisibleGroup[1].eq(0), ordinal, config),
  ].join('');
};

export default getLatinPowerName;