/**
 * Regenerate `TODO.md` — the index over `todo/`.
 *
 * The index is the one file everybody reads, so it is the one most able to lie. It is generated rather
 * than maintained: `bun run todo:index` after any change to `todo/`, and it cannot drift from the tree
 * it describes.
 */
import { readFileSync, readdirSync, writeFileSync, statSync } from 'node:fs';
import { join } from 'node:path';

const ROOT = new URL('..', import.meta.url).pathname;
const OUT = join(ROOT, 'todo');

export type Item = {
  id: string;
  title: string;
  theme: string;
  status: string;
  created: string;
  order: number;
  file: string;
};

/** Minimal frontmatter reader — `key: value`, values optionally JSON-quoted. No YAML dependency. */
export function frontmatter(text: string): Record<string, string> {
  const end = text.indexOf('\n---', 4);
  if (!text.startsWith('---') || end === -1) return {};
  const out: Record<string, string> = {};
  for (const line of text.slice(4, end).split('\n')) {
    const m = line.match(/^([a-z_]+):\s*(.*)$/);
    if (!m || !m[1]) continue;
    const raw = (m[2] ?? '').trim();
    out[m[1]] = raw.startsWith('"') ? (JSON.parse(raw) as string) : raw;
  }
  return out;
}

export function readTree(): { themes: { theme: string; heading: string; items: Item[] }[] } {
  const themes = readdirSync(OUT)
    .filter((d) => statSync(join(OUT, d)).isDirectory())
    .sort()
    .map((theme) => {
      const files = readdirSync(join(OUT, theme)).filter((f) => f.endsWith('.md'));
      const meta = frontmatter(readFileSync(join(OUT, theme, '_index.md'), 'utf8'));
      const items = files
        .filter((f) => f !== '_index.md')
        .map((f) => {
          const fm = frontmatter(readFileSync(join(OUT, theme, f), 'utf8'));
          return {
            id: fm.id ?? `${theme}/${f.replace(/\.md$/, '')}`,
            title: fm.title ?? f,
            theme,
            status: fm.status ?? 'open',
            created: fm.created ?? '',
            order: Number(fm.order ?? 0),
            file: `todo/${theme}/${f}`,
          };
        })
        .sort((a, b) => a.order - b.order);
      return { theme, heading: meta.heading ?? theme, items };
    });
  return { themes };
}

const HEADER = `# TODO — the index

Deferred work. **The items live in \`todo/\`, one file each**, grouped by theme; this file is the map
over them and is GENERATED — run \`bun run todo:index\` after any change rather than editing it here.
Format and the two-way-sync contract: \`todo/README.md\`.

**Context, corrected 2026-08-07.** This list used to open by saying Officer was "collapsing from
multi-tenant / open-source-ready to a **single-user platform**", and told you to treat multi-tenant
indirection as accidental complexity. **That direction was reversed.** The permission model shipped on
2026-08-07 to serve a real goal — deploy to the company server, onboard people, give each one their own
Gitea account through the platform. Per-user scoping is now a requirement, and the items that proposed
deleting it have been removed rather than left to mislead the next reader.

What did NOT reverse: \`execution\` permissions (terminal, chat, tasks, files, desktop, browser) run as
the owner's OS user and can never be granted. Indirection there really is accidental complexity.
`;

function render(): string {
  const { themes } = readTree();
  const open = themes.reduce((n, t) => n + t.items.filter((i) => i.status !== 'done').length, 0);
  const done = themes.reduce((n, t) => n + t.items.filter((i) => i.status === 'done').length, 0);

  const rows = themes
    .filter((t) => t.items.length)
    .map((t) => {
      const o = t.items.filter((i) => i.status !== 'done').length;
      const d = t.items.length - o;
      return `| [${t.heading}](todo/${t.theme}/) | ${o} | ${d} |`;
    });

  const recent = themes
    .flatMap((t) => t.items)
    .filter((i) => i.status !== 'done')
    .sort((a, b) => b.created.localeCompare(a.created))
    .slice(0, 10)
    .map((i) => `- \`${i.created}\` **${i.title}** — [${i.id}](${i.file})`);

  // A theme holding only prose has no row above, and an entry nobody can see is the failure mode this
  // whole split risks. List them explicitly rather than letting them age out of view.
  const notes = themes.filter((t) => !t.items.length).map((t) => `- [${t.heading}](todo/${t.theme}/_index.md)`);

  return [
    HEADER,
    `## Themes\n`,
    `**${open} open, ${done} closed**, across ${rows.length} themes.\n`,
    `| Theme | Open | Closed |`,
    `| --- | --- | --- |`,
    ...rows,
    ``,
    `## Records — no items, kept for the reasoning\n`,
    ...notes,
    ``,
    `## Newest ten\n`,
    ...recent,
    ``,
  ].join('\n');
}

if (import.meta.main) {
  writeFileSync(join(ROOT, 'TODO.md'), render());
  console.log('TODO.md regenerated');
}