// Build-time helpers shared by the pages that redraw a rendered Markdown list: Neighbors' plat map and the Tool shed.

/** A rendered list item that opens with a link and a colon: `<a href="…">Name</a>: the rest`. */
export const ITEM = /^<a href="([^"]+)">([\s\S]+?)<\/a>:\s*([\s\S]*)$/;

/** An HTML fragment as plain text, for names and labels. */
export const text = (html) => html.replace(/<[^>]*>/g, '').replace(/&amp;/g, '&').trim();

/** A phrase without its surrounding space and trailing full stop. */
export const trimStop = (s) => s.trim().replace(/\.$/, '').trim();

/** "https://www.ribbonfarm.com/" → "ribbonfarm.com". */
export function address(href) {
  try {
    return new URL(href).hostname.replace(/^www\./, '');
  } catch {
    return '';
  }
}

/** A small, stable hash, so art drawn from a name stays put from build to build. */
export function hash(s) {
  let h = 2166136261;
  for (const c of s) h = Math.imul(h ^ c.codePointAt(0), 16777619) >>> 0;
  return h;
}

/**
 * The first `<ul>` in a rendered body, or with `heading` the one straight after the `<h2>` of that title:
 * where it starts and ends, and its `<li>` bodies. Null when there's no such list.
 * @param {string} html
 * @param {string} [heading]
 * @returns {{ start: number, end: number, items: string[] } | null}
 */
export function findList(html, heading) {
  const before = heading == null ? '' : `<h2[^>]*>${heading}</h2>\\s*`;
  const m = html.match(new RegExp(`(${before})<ul>\\s*([\\s\\S]*?)\\s*</ul>`));
  if (!m || m.index == null) return null;
  const items = m[2].split(/<\/li>\s*/).filter((s) => s.trim()).map((s) => s.replace(/^<li>/, ''));
  return { start: m.index + m[1].length, end: m.index + m[0].length, items };
}