/**
 * Latin → Elder Futhark transliteration for the "Runic browser
 * names" display option. Each letter maps to a single rune chosen
 * for phonetic or visual fit; letters without a clean Futhark
 * match (Q, X, Y) fall back to multi-rune combinations or the
 * closest phoneme. Runes have no case, so the mapping is
 * case-insensitive and the input is lowercased before lookup.
 *
 * Tested on the installed browser list — every name remains
 * readable (each glyph is distinct, lengths comparable to the
 * Latin original):
 *   Brave           → ᛒᚱᚨᚹᛖ
 *   Chrome          → ᚲᚺᚱᛟᛗᛖ
 *   DuckDuckGo      → ᛞᚢᚲᚲᛞᚢᚲᚲᚷᛟ
 *   Firefox         → ᚠᛁᚱᛖᚠᛟᚲᛋ
 *   Firefox Nightly → ᚠᛁᚱᛖᚠᛟᚲᛋ ᚾᛁᚷᚺᛏᛚᛁ
 *   Helium          → ᚺᛖᛚᛁᚢᛗ
 *   IronFox         → ᛁᚱᛟᚾᚠᛟᚲᛋ
 *   Tor Browser     → ᛏᛟᚱ ᛒᚱᛟᚹᛋᛖᚱ
 *   Vanadium        → ᚹᚨᚾᚨᛞᛁᚢᛗ
 */
const LATIN_TO_RUNE: Record<string, string> = {
  a: 'ᚨ', b: 'ᛒ', c: 'ᚲ', d: 'ᛞ', e: 'ᛖ', f: 'ᚠ', g: 'ᚷ', h: 'ᚺ',
  i: 'ᛁ', j: 'ᛃ', k: 'ᚲ', l: 'ᛚ', m: 'ᛗ', n: 'ᚾ', o: 'ᛟ', p: 'ᛈ',
  q: 'ᚲᚹ', r: 'ᚱ', s: 'ᛋ', t: 'ᛏ', u: 'ᚢ', v: 'ᚹ', w: 'ᚹ',
  x: 'ᚲᛋ', y: 'ᛁ', z: 'ᛉ',
};

/**
 * Transliterates a Latin-letter string to Elder Futhark runes.
 * Non-letter characters (spaces, punctuation, digits) pass through
 * unchanged.
 */
export function transliterateToRunes(input: string): string {
  let out = '';
  for (const ch of input) {
    const lower = ch.toLowerCase();
    out += LATIN_TO_RUNE[lower] ?? ch;
  }
  return out;
}

/**
 * Convenience wrapper used by display components: returns the
 * runic transliteration when the runic-names toggle is on,
 * otherwise the original string verbatim.
 */
export function formatRunicName(name: string, runic: boolean): string {
  return runic ? transliterateToRunes(name) : name;
}