import type { DatabaseSync } from "node:sqlite";

// Backfills the `start` parameter on stored YouTube embed URLs.
//
// `rich_content.embedUrl` is computed once, at dump creation, and previously
// dropped the timestamp carried by the source URL (`?t=1265`, `?t=1h2m3s`), so
// those videos always opened at 0:00 in the global player. The provider now
// translates `t`/`start` into the `start` param the iframe player honours; this
// migration applies the same translation to rows written before that fix.
//
// Purely local — it re-derives the param from the already-stored source URL and
// makes no network calls. Self-contained (no imports from api/services) so it
// stays reproducible even if the provider's parsing evolves later.
//
// Idempotent: rows whose embed URL already carries a `start` are skipped, so a
// fresh database built from schema.sql is simply a no-op.

/** Parse `t`/`start` — plain seconds, `90s`, or `1h2m3s` / `20m5s`. */
function extractStartSeconds(url: string): number | null {
  let raw: string | null;
  try {
    const u = new URL(url);
    raw = u.searchParams.get("t") ?? u.searchParams.get("start");
  } catch {
    return null;
  }
  if (!raw) return null;

  if (/^\d+$/.test(raw)) return Number(raw);

  const hms = /^(?:(\d+)h)?(?:(\d+)m)?(?:(\d+)s)?$/i.exec(raw);
  if (!hms || (!hms[1] && !hms[2] && !hms[3])) return null;
  return Number(hms[1] ?? 0) * 3600 + Number(hms[2] ?? 0) * 60 +
    Number(hms[3] ?? 0);
}

export function up(db: DatabaseSync): void {
  const rows = db.prepare(
    `SELECT id, url, rich_content FROM dumps
      WHERE kind = 'url' AND url IS NOT NULL AND rich_content IS NOT NULL;`,
  ).all() as { id: string; url: string; rich_content: string }[];

  const update = db.prepare(
    `UPDATE dumps SET rich_content = ? WHERE id = ?;`,
  );

  let patched = 0;
  for (const row of rows) {
    let rich: { type?: string; embedUrl?: string };
    try {
      rich = JSON.parse(row.rich_content);
    } catch {
      continue; // malformed payload — leave it untouched
    }
    if (rich.type !== "youtube" || !rich.embedUrl) continue;

    const start = extractStartSeconds(row.url);
    if (!start) continue;

    let embed: URL;
    try {
      embed = new URL(rich.embedUrl);
    } catch {
      continue;
    }
    if (embed.searchParams.has("start")) continue;

    embed.searchParams.set("start", String(start));
    update.run(JSON.stringify({ ...rich, embedUrl: embed.toString() }), row.id);
    patched++;
  }

  if (patched > 0) {
    console.log(`[migrate] 0010: added start offset to ${patched} embed(s)`);
  }
}