const M = new Map<string, string>([
  ["\u3041", "\u30a1"],
  ["\u3042", "\u30a2"],
  ["\u3043", "\u30a3"],
  ["\u3044", "\u30a4"],
  ["\u3045", "\u30a5"],
  ["\u3046", "\u30a6"],
  ["\u3047", "\u30a7"],
  ["\u3048", "\u30a8"],
  ["\u3049", "\u30a9"],
  ["\u304a", "\u30aa"],
  ["\u304b", "\u30ab"],
  ["\u304c", "\u30ac"],
  ["\u304d", "\u30ad"],
  ["\u304e", "\u30ae"],
  ["\u304f", "\u30af"],
  ["\u3050", "\u30b0"],
  ["\u3051", "\u30b1"],
  ["\u3052", "\u30b2"],
  ["\u3053", "\u30b3"],
  ["\u3054", "\u30b4"],
  ["\u3055", "\u30b5"],
  ["\u3056", "\u30b6"],
  ["\u3057", "\u30b7"],
  ["\u3058", "\u30b8"],
  ["\u3059", "\u30b9"],
  ["\u305a", "\u30ba"],
  ["\u305b", "\u30bb"],
  ["\u305c", "\u30bc"],
  ["\u305d", "\u30bd"],
  ["\u305e", "\u30be"],
  ["\u305f", "\u30bf"],
  ["\u3060", "\u30c0"],
  ["\u3061", "\u30c1"],
  ["\u3062", "\u30c2"],
  ["\u3063", "\u30c3"],
  ["\u3064", "\u30c4"],
  ["\u3065", "\u30c5"],
  ["\u3066", "\u30c6"],
  ["\u3067", "\u30c7"],
  ["\u3068", "\u30c8"],
  ["\u3069", "\u30c9"],
  ["\u306a", "\u30ca"],
  ["\u306b", "\u30cb"],
  ["\u306c", "\u30cc"],
  ["\u306d", "\u30cd"],
  ["\u306e", "\u30ce"],
  ["\u306f", "\u30cf"],
  ["\u3070", "\u30d0"],
  ["\u3071", "\u30d1"],
  ["\u3072", "\u30d2"],
  ["\u3073", "\u30d3"],
  ["\u3074", "\u30d4"],
  ["\u3075", "\u30d5"],
  ["\u3076", "\u30d6"],
  ["\u3077", "\u30d7"],
  ["\u3078", "\u30d8"],
  ["\u3079", "\u30d9"],
  ["\u307a", "\u30da"],
  ["\u307b", "\u30db"],
  ["\u307c", "\u30dc"],
  ["\u307d", "\u30dd"],
  ["\u307e", "\u30de"],
  ["\u307f", "\u30df"],
  ["\u3080", "\u30e0"],
  ["\u3081", "\u30e1"],
  ["\u3082", "\u30e2"],
  ["\u3083", "\u30e3"],
  ["\u3084", "\u30e4"],
  ["\u3085", "\u30e5"],
  ["\u3086", "\u30e6"],
  ["\u3087", "\u30e7"],
  ["\u3088", "\u30e8"],
  ["\u3089", "\u30e9"],
  ["\u308a", "\u30ea"],
  ["\u308b", "\u30eb"],
  ["\u308c", "\u30ec"],
  ["\u308d", "\u30ed"],
  ["\u308e", "\u30ee"],
  ["\u308f", "\u30ef"],
  ["\u308f\u3099", "\u30f7"],
  ["\u3090", "\u30f0"],
  ["\u3090\u3099", "\u30f8"],
  ["\u3091", "\u30f1"],
  ["\u3091\u3099", "\u30f9"],
  ["\u3092", "\u30f2"],
  ["\u3092\u3099", "\u30fa"],
  ["\u3093", "\u30f3"],
  ["\u3094", "\u30f4"],
  ["\u3095", "\u30f5"],
  ["\u3096", "\u30f6"],
  ["\u309d", "\u30fd"],
  ["\u309e", "\u30fe"],
  ["\uff61", "\u3002"],
  ["\uff62", "\u300c"],
  ["\uff63", "\u300d"],
  ["\uff64", "\u3001"],
  ["\uff65", "\u30fb"],
  ["\uff66", "\u30f2"],
  ["\uff66\uff9e", "\u30fa"],
  ["\uff67", "\u30a1"],
  ["\uff68", "\u30a3"],
  ["\uff69", "\u30a5"],
  ["\uff6a", "\u30a7"],
  ["\uff6b", "\u30a9"],
  ["\uff6c", "\u30e3"],
  ["\uff6d", "\u30e5"],
  ["\uff6e", "\u30e7"],
  ["\uff6f", "\u30c3"],
  ["\uff70", "\u30fc"],
  ["\uff71", "\u30a2"],
  ["\uff72", "\u30a4"],
  ["\uff73", "\u30a6"],
  ["\uff73\uff9e", "\u30f4"],
  ["\uff74", "\u30a8"],
  ["\uff75", "\u30aa"],
  ["\uff76", "\u30ab"],
  ["\uff76\uff9e", "\u30ac"],
  ["\uff77", "\u30ad"],
  ["\uff77\uff9e", "\u30ae"],
  ["\uff78", "\u30af"],
  ["\uff78\uff9e", "\u30b0"],
  ["\uff79", "\u30b1"],
  ["\uff79\uff9e", "\u30b2"],
  ["\uff7a", "\u30b3"],
  ["\uff7a\uff9e", "\u30b4"],
  ["\uff7b", "\u30b5"],
  ["\uff7b\uff9e", "\u30b6"],
  ["\uff7c", "\u30b7"],
  ["\uff7c\uff9e", "\u30b8"],
  ["\uff7d", "\u30b9"],
  ["\uff7d\uff9e", "\u30ba"],
  ["\uff7e", "\u30bb"],
  ["\uff7e\uff9e", "\u30bc"],
  ["\uff7f", "\u30bd"],
  ["\uff7f\uff9e", "\u30be"],
  ["\uff80", "\u30bf"],
  ["\uff80\uff9e", "\u30c0"],
  ["\uff81", "\u30c1"],
  ["\uff81\uff9e", "\u30c2"],
  ["\uff82", "\u30c4"],
  ["\uff82\uff9e", "\u30c5"],
  ["\uff83", "\u30c6"],
  ["\uff83\uff9e", "\u30c7"],
  ["\uff84", "\u30c8"],
  ["\uff84\uff9e", "\u30c9"],
  ["\uff85", "\u30ca"],
  ["\uff86", "\u30cb"],
  ["\uff87", "\u30cc"],
  ["\uff88", "\u30cd"],
  ["\uff89", "\u30ce"],
  ["\uff8a", "\u30cf"],
  ["\uff8a\uff9e", "\u30d0"],
  ["\uff8a\uff9f", "\u30d1"],
  ["\uff8b", "\u30d2"],
  ["\uff8b\uff9e", "\u30d3"],
  ["\uff8b\uff9f", "\u30d4"],
  ["\uff8c", "\u30d5"],
  ["\uff8c\uff9e", "\u30d6"],
  ["\uff8c\uff9f", "\u30d7"],
  ["\uff8d", "\u30d8"],
  ["\uff8d\uff9e", "\u30d9"],
  ["\uff8d\uff9f", "\u30da"],
  ["\uff8e", "\u30db"],
  ["\uff8e\uff9e", "\u30dc"],
  ["\uff8e\uff9f", "\u30dd"],
  ["\uff8f", "\u30de"],
  ["\uff90", "\u30df"],
  ["\uff91", "\u30e0"],
  ["\uff92", "\u30e1"],
  ["\uff93", "\u30e2"],
  ["\uff94", "\u30e4"],
  ["\uff95", "\u30e6"],
  ["\uff96", "\u30e8"],
  ["\uff97", "\u30e9"],
  ["\uff98", "\u30ea"],
  ["\uff99", "\u30eb"],
  ["\uff9a", "\u30ec"],
  ["\uff9b", "\u30ed"],
  ["\uff9c", "\u30ef"],
  ["\uff9c\uff9e", "\u30f7"],
  ["\uff9d", "\u30f3"],
  ["\uff9e", "\u309b"],
  ["\uff9f", "\u309c"],
]);

export function toFullwidthKatakana(str: string): string;
export function toFullwidthKatakana(str: null): null;
export function toFullwidthKatakana(str: undefined): undefined;
export function toFullwidthKatakana(value: string | null | undefined) {
  if (!value) {
    return value;
  }

  const array = [];
  let start = 0;
  for (let i = 0; i < value.length; i++) {
    const c = value.charAt(i);
    if (i + 1 < value.length) {
      const c2 = value.charAt(i + 1);
      if (
        c2 === "\u3099" ||
        c2 === "\u309A" ||
        c2 === "\uFF9E" ||
        c2 === "\uFF9F"
      ) {
        const m = M.get(c + c2);
        if (m != null) {
          if (start < i) {
            array.push(value.substring(start, i));
          }
          array.push(m);
          i++;
          start = i + 1;
          continue;
        }
      }
    }

    const m = M.get(c);
    if (m != null) {
      if (start < i) {
        array.push(value.substring(start, i));
      }
      array.push(m);
      start = i + 1;
    }
  }
  if (start < value.length) {
    array.push(value.substring(start));
  }
  return array.join("");
}