// EPUB pieces shared by fetch-novel.js (new books) and update-novels.js (appends).
import { load } from 'cheerio';
import { stripPromo } from './clean-chapter.js';

export const esc = s =>
  String(s ?? '').replace(
    /[&<>"]/g,
    c => ({ '&': '&amp;', '<': '&lt;', '>': '&gt;', '"': '&quot;' })[c],
  );

// Chapter HTML is tag soup; re-serialise it as well-formed XHTML without
// scripts, remote resources (an EPUB must be self-contained) or promo lines.
export const toXhtml = html => {
  const $ = load(html, null, false);
  $('script, style, iframe, link, meta, img, video, audio, source').remove();
  stripPromo($);
  return $.xml();
};

export const page = (title, body) => `<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" xmlns:epub="http://www.idpf.org/2007/ops" lang="en" xml:lang="en">
<head><meta charset="UTF-8"/><title>${esc(title)}</title></head>
<body>${body}</body>
</html>`;

export const chapterPage = (title, body) =>
  page(title, `<h2>${esc(title)}</h2>\n${body}`);