// 국립국어원 표준 한글 -> 영문 로마자 변환 유틸
const CHO = ['g', 'kk', 'n', 'd', 'tt', 'r', 'm', 'b', 'pp', 's', 'ss', '', 'j', 'jj', 'ch', 'k', 't', 'p', 'h'];
const JUNG = ['a', 'ae', 'ya', 'yae', 'eo', 'e', 'yeo', 'ye', 'o', 'wa', 'wae', 'oe', 'yo', 'u', 'wo', 'we', 'wi', 'yu', 'eu', 'ui', 'i'];
const JONG = ['', 'k', 'k', 'ks', 'n', 'nj', 'nh', 't', 'l', 'lg', 'lm', 'lb', 'ls', 'lt', 'lp', 'lh', 'm', 'p', 'bs', 's', 'ss', 'ng', 'j', 'ch', 'k', 't', 'p', 'h'];

export function hangulToRoman(str) {
  if (!str) return '';
  let res = '';
  for (let i = 0; i < str.length; i++) {
    const code = str.charCodeAt(i);
    if (code >= 0xac00 && code <= 0xd7a3) {
      const syl = code - 0xac00;
      const c = Math.floor(syl / 588);
      const j = Math.floor((syl % 588) / 28);
      const jg = syl % 28;
      res += CHO[c] + JUNG[j] + JONG[jg];
    } else if (/[a-zA-Z0-9]/.test(str[i])) {
      res += str[i].toLowerCase();
    }
  }
  return res;
}

export function toDongSlug(dongName) {
  const clean = dongName.trim();
  if (clean.endsWith('동')) {
    const base = hangulToRoman(clean.slice(0, -1));
    return `${base}-dong`;
  }
  if (clean.endsWith('읍')) {
    const base = hangulToRoman(clean.slice(0, -1));
    return `${base}-eup`;
  }
  if (clean.endsWith('면')) {
    const base = hangulToRoman(clean.slice(0, -1));
    return `${base}-myeon`;
  }
  if (clean.endsWith('가')) {
    const base = hangulToRoman(clean.slice(0, -1));
    return `${base}-ga`;
  }
  if (clean.endsWith('로')) {
    const base = hangulToRoman(clean.slice(0, -1));
    return `${base}-ro`;
  }
  return hangulToRoman(clean);
}

export function toSigunguSlug(sigunguName) {
  const parts = sigunguName.trim().split(' ');
  return parts.map(p => {
    if (p.endsWith('구')) return `${hangulToRoman(p.slice(0, -1))}-gu`;
    if (p.endsWith('시')) return `${hangulToRoman(p.slice(0, -1))}-si`;
    if (p.endsWith('군')) return `${hangulToRoman(p.slice(0, -1))}-gun`;
    return hangulToRoman(p);
  }).join('-');
}