/**
 * 续作 / 章节 / Part 序号(ID-2):`Chapter III`、`Part Two`、`Vol. 2`、`第3章`、`第三章`、`Ⅲ`。
 * 只认显式关键词或罗马数字符号,不把片名末尾的普通数字当序号(`Blade Runner 2049`、`Apollo 13`)。
 * 季号不在这里(季由解析器单独给出)。
 */
import { cnToInt } from "../release-parser/cn-number.ts";

const WORD_NUM: Record<string, number> = {
  one: 1,
  two: 2,
  three: 3,
  four: 4,
  five: 5,
  six: 6,
  seven: 7,
  eight: 8,
  nine: 9,
  ten: 10,
  first: 1,
  second: 2,
  third: 3,
  fourth: 4,
  final: -1,
};
const ROMAN: Record<string, number> = { i: 1, ii: 2, iii: 3, iv: 4, v: 5, vi: 6, vii: 7, viii: 8, ix: 9, x: 10 };
const ROMAN_CHAR: Record<string, number> = {
  Ⅰ: 1,
  Ⅱ: 2,
  Ⅲ: 3,
  Ⅳ: 4,
  Ⅴ: 5,
  Ⅵ: 6,
  Ⅶ: 7,
  Ⅷ: 8,
  Ⅸ: 9,
  Ⅹ: 10,
};

function toNum(tok: string): number | undefined {
  const t = tok.toLowerCase();
  if (/^\d{1,2}$/.test(t)) return Number(t);
  if (t in ROMAN) return ROMAN[t];
  if (t in WORD_NUM) return WORD_NUM[t]! > 0 ? WORD_NUM[t] : undefined;
  return undefined;
}

export function sequelNumbers(title: string): number[] {
  if (!title) return [];
  const out = new Set<number>();
  const s = title.replace(/[ⅠⅡⅢⅣⅤⅥⅦⅧⅨⅩ]/g, (c) => ` ${ROMAN_CHAR[c]} `);
  for (const m of s.matchAll(/\b(?:chapter|part|vol(?:ume)?)\b\.?\s*[:：-]?\s*([0-9]{1,2}|[ivx]{1,4}|[a-z]+)\b/giu)) {
    const n = toNum(m[1]!);
    if (n !== undefined) out.add(n);
  }
  for (const m of s.matchAll(/第\s*([0-9]{1,2}|[一二三四五六七八九十]{1,3})\s*章/gu)) {
    const n = /^\d+$/.test(m[1]!) ? Number(m[1]) : cnToInt(m[1]!);
    if (n !== undefined) out.add(n);
  }
  return [...out];
}