// Optional leased piano jobs; the heavy model always lives in a separate worker.
import { randomUUID, timingSafeEqual } from 'node:crypto';
import { createRequire } from 'node:module';
import { existsSync } from 'node:fs';
import { db as sql } from './db.js';
const { normalizeNotes } = createRequire(import.meta.url)(
  existsSync(new URL('../frontend/piano-core.js', import.meta.url))
    ? '../frontend/piano-core.js'
    : './public/piano-core.js',
);
const ID = /^(?:[\w-]{11}|upl_[a-f0-9]{12})$/;
const LEASE = 120000;
const sourceKey = (row) =>
  String(row?.sha256 || row?.gen || row?.path || row?.created_at || 'original');
export function registerPianoRoutes(
  app,
  { db, adminAuth, enabled = false, workerToken = '', now = Date.now },
) {
  enabled = enabled && workerToken.length >= 24;
  const ready = sql.execute(`CREATE TABLE IF NOT EXISTS piano_jobs (
    video_id TEXT PRIMARY KEY,status TEXT NOT NULL,source_key TEXT NOT NULL,notes TEXT,error TEXT,
    attempts INTEGER NOT NULL DEFAULT 0,lease_token TEXT,lease_until INTEGER NOT NULL DEFAULT 0,
    created_at INTEGER NOT NULL,updated_at INTEGER NOT NULL)`);
  const source = async (id) =>
    id.startsWith('upl_')
      ? db.getUpload(id)
      : db.getMedia(id).then((row) => (row?.status === 'ready' ? row : null));
  const get = async (id) =>
    (await sql.execute({ sql: 'SELECT * FROM piano_jobs WHERE video_id=?', args: [id] })).rows[0];
  const publicJob = (row) =>
    row
      ? {
          videoId: row.video_id,
          status: row.status,
          error: row.error,
          notes: row.notes ? JSON.parse(row.notes) : null,
          updatedAt: Number(row.updated_at),
        }
      : null;
  async function workerAuth(c, next) {
    const token = (c.req.header('authorization') || '').replace(/^Bearer\s+/i, '');
    const a = Buffer.from(token),
      b = Buffer.from(workerToken);
    if (!enabled || a.length !== b.length || !timingSafeEqual(a, b))
      return c.json({ ok: false, error: 'Unauthorized worker' }, 401);
    await ready;
    return next();
  }
  app.get('/api/media/:id/piano', async (c) => {
    await ready;
    const id = c.req.param('id');
    if (!ID.test(id)) return c.json({ ok: false, error: 'Invalid video id' }, 400);
    const row = await get(id),
      media = await source(id);
    const stale = row && media && sourceKey(media) !== row.source_key;
    return c.json(
      {
        ok: true,
        enabled,
        job: stale
          ? {
              videoId: id,
              status: 'stale',
              notes: null,
              error: 'The source changed. Transcribe it again.',
            }
          : publicJob(row),
      },
      200,
      { 'Cache-Control': 'no-store' },
    );
  });
  app.post('/api/media/:id/piano', adminAuth, async (c) => {
    await ready;
    if (!enabled) return c.json({ ok: false, error: 'The optional piano worker is off.' }, 503);
    const id = c.req.param('id');
    if (!ID.test(id)) return c.json({ ok: false, error: 'Invalid video id' }, 400);
    const media = await source(id);
    if (!media) return c.json({ ok: false, error: 'Save this song on the server first.' }, 409);
    if (Number(media.duration) > 900)
      return c.json({ ok: false, error: 'Piano jobs are limited to 15 minutes.' }, 422);
    const old = await get(id);
    if (
      old &&
      ['queued', 'running', 'ready'].includes(old.status) &&
      old.source_key === sourceKey(media)
    )
      return c.json({ ok: true, job: publicJob(old) });
    const active = Number(
      (await sql.execute("SELECT COUNT(*) n FROM piano_jobs WHERE status IN ('queued','running')"))
        .rows[0].n,
    );
    if (active >= 10) return c.json({ ok: false, error: 'Piano queue is full.' }, 429);
    await sql.execute({
      sql: `INSERT INTO piano_jobs(video_id,status,source_key,created_at,updated_at) SELECT ?,'queued',?,?,? WHERE (SELECT COUNT(*) FROM piano_jobs WHERE status IN ('queued','running'))<10
      ON CONFLICT(video_id) DO UPDATE SET status='queued',source_key=excluded.source_key,notes=NULL,error=NULL,attempts=0,lease_token=NULL,lease_until=0,updated_at=excluded.updated_at`,
      args: [id, sourceKey(media), now(), now()],
    });
    const queued = await get(id);
    if (
      !queued ||
      !['queued', 'running'].includes(queued.status) ||
      queued.source_key !== sourceKey(media)
    )
      return c.json({ ok: false, error: 'Piano queue is full.' }, 429);
    return c.json({ ok: true, job: publicJob(queued) }, 202);
  });
  app.post('/api/piano-worker/claim', workerAuth, async (c) => {
    const time = now();
    await sql.execute({
      sql: "UPDATE piano_jobs SET status='failed',error='Worker stopped repeatedly',updated_at=? WHERE status='running' AND lease_until<? AND attempts>=3",
      args: [time, time],
    });
    const row = (
      await sql.execute({
        sql: `UPDATE piano_jobs SET status='running',attempts=attempts+1,lease_token=?,lease_until=?,updated_at=?
      WHERE video_id=(SELECT video_id FROM piano_jobs WHERE (status='queued' OR (status='running' AND lease_until<?)) AND attempts<3 ORDER BY created_at LIMIT 1) RETURNING *`,
        args: [randomUUID(), time + LEASE, time, time],
      })
    ).rows[0];
    return c.json({
      ok: true,
      job: row
        ? {
            ...publicJob(row),
            lease: row.lease_token,
            audioPath: row.video_id.startsWith('upl_')
              ? `/api/uploads/${row.video_id}`
              : `/api/media/${row.video_id}?a=1`,
          }
        : null,
    });
  });
  app.post('/api/piano-worker/:id', workerAuth, async (c) => {
    const id = c.req.param('id');
    if (!ID.test(id)) return c.json({ ok: false, error: 'Invalid video id' }, 400);
    const text = await c.req.text();
    if (text.length > 4 * 1048576) return c.json({ ok: false, error: 'Result too large' }, 413);
    let body;
    try {
      body = JSON.parse(text);
    } catch {
      return c.json({ ok: false, error: 'Invalid JSON' }, 400);
    }
    const row = await get(id);
    if (
      !row ||
      row.status !== 'running' ||
      row.lease_token !== body.lease ||
      Number(row.lease_until) < now()
    )
      return c.json({ ok: false, error: 'Job lease expired' }, 409);
    if (body.action === 'heartbeat') {
      await sql.execute({
        sql: 'UPDATE piano_jobs SET lease_until=?,updated_at=? WHERE video_id=? AND lease_token=?',
        args: [now() + LEASE, now(), id, body.lease],
      });
      return c.json({ ok: true });
    }
    let notes = null,
      status = 'failed';
    if (body.action === 'complete') {
      try {
        notes = normalizeNotes(body.notes);
      } catch (error) {
        return c.json({ ok: false, error: error.message }, 422);
      }
      status = 'ready';
    } else if (body.action !== 'fail')
      return c.json({ ok: false, error: 'Unknown worker action' }, 400);
    await sql.execute({
      sql: 'UPDATE piano_jobs SET status=?,notes=?,error=?,updated_at=?,lease_token=NULL,lease_until=0 WHERE video_id=? AND lease_token=?',
      args: [
        status,
        notes ? JSON.stringify(notes) : null,
        status === 'failed' ? String(body.error || 'Transcription failed').slice(0, 500) : null,
        now(),
        id,
        body.lease,
      ],
    });
    return c.json({ ok: true });
  });
  return { ready };
}