export interface makePageInit {
  section: string;
  gyazo: string;
  text: string;
  /** ページ番号 */
  pageNum: number;
  prevSection?: string;
  nextSection?: string;
}
export const makePage = (init: makePageInit): { title: string; lines: string[]; } => {
  const {
    section,
    gyazo,
    text,
    pageNum,
    prevSection,
    nextSection,
  } = init;
  const title = `${format(section)} ${pageNum}`;
  const prevTitle = prevSection ? `${format(prevSection)} ${pageNum - 1}` : undefined;
  const nextTitle = nextSection ? `${format(nextSection)} ${pageNum + 1}` : undefined;
  
  return {
    title,
    lines: [
      title,
      ...format(text).split("\n"),
      "",
      `<=${
        prevTitle ? `[${prevTitle}]` : ""
      }|${
        nextTitle ? `[${nextTitle}]` : ""
      }=>`,
      "",
      `[${gyazo}]`,
      `[${section}]`,
    ],
  };
}

const format = (text: string): string =>
  text
    .replace(/\s+$/, "") // 末尾の余計な空白を消す
    .replace(/^(\s*)・/, "$1 ") // ・を箇条書きに変える
    .replace(
      /[Ａ-Ｚａ-ｚ０-９]/g,
      (s) => String.fromCharCode(s.charCodeAt(0) - 0xFEE0),
    ) // 全角英数を半角に直す
    .replace(/\s?\[/g, "［") // リンク記法をescapeする
    .replace(/\s?\[/g, "［")
    .replace(/(\d+)．\s*/g, "$1. ") // 番号付き箇条書きにする
    .replaceAll("．", "。") // 句読点を変換する
    .replaceAll("，", "、");