import express from 'express';
import {
  SESSION_COOKIE,
  SESSION_MAX_AGE_MS,
  createLoginLimiter,
  createToken,
  pinMatches,
  readCookie,
  verifyToken,
} from './auth.js';
import { HttpError, badRequest } from './http-error.js';

export function createApp({ config, secret, store, queue }) {
  const app = express();
  app.disable('x-powered-by');
  app.set('trust proxy', true);

  const limiter = createLoginLimiter();
  const isAuthenticated = (req) =>
    verifyToken(secret, config.pin, readCookie(req, SESSION_COOKIE));

  app.get('/healthz', (req, res) => res.json({ ok: true }));

  app.use('/api', express.json({ limit: '100kb' }));

  app.get('/api/session', (req, res) => {
    res.json({ authenticated: isAuthenticated(req), pinConfigured: Boolean(config.pin) });
  });

  app.post('/api/login', (req, res) => {
    if (limiter.isBlocked()) {
      return res.status(429).json({ error: 'Zu viele Fehlversuche. Bitte später erneut versuchen.' });
    }
    if (!pinMatches(config.pin, req.body?.pin)) {
      limiter.recordFailure();
      return res.status(401).json({ error: 'PIN falsch.' });
    }
    limiter.reset();
    res.cookie(SESSION_COOKIE, createToken(secret, config.pin), {
      httpOnly: true,
      sameSite: 'lax',
      secure: req.secure,
      maxAge: SESSION_MAX_AGE_MS,
      path: '/',
    });
    res.json({ authenticated: true });
  });

  app.post('/api/logout', (req, res) => {
    res.clearCookie(SESSION_COOKIE, { path: '/' });
    res.json({ authenticated: false });
  });

  app.use('/api', (req, res, next) => {
    if (!isAuthenticated(req)) return res.status(401).json({ error: 'Nicht angemeldet.' });
    next();
  });

  const route = (handler) => (req, res, next) => Promise.resolve(handler(req, res)).catch(next);
  const present = (project) => ({ ...project, render: queue.describe(project) });

  app.get('/api/projects', route(async (req, res) => {
    res.json(await store.list());
  }));

  app.post('/api/projects', route(async (req, res) => {
    res.status(201).json(present(await store.create(req.body ?? {})));
  }));

  app.get('/api/projects/:id', route(async (req, res) => {
    res.json(present(await store.get(req.params.id)));
  }));

  app.delete('/api/projects/:id', route(async (req, res) => {
    if (queue.isRunning(req.params.id)) queue.cancel(req.params.id);
    await store.remove(req.params.id);
    res.status(204).end();
  }));

  const readOffset = (req) => {
    const offset = Number(req.query.offset);
    if (!Number.isSafeInteger(offset) || offset < 0) throw badRequest('Ungültiger Offset.');
    return offset;
  };

  app.patch('/api/projects/:id/settings', route(async (req, res) => {
    res.json(present(await store.updateSettings(req.params.id, req.body)));
  }));

  app.put('/api/projects/:id/clips/:index', route(async (req, res) => {
    const target = { type: 'clip', index: req.params.index };
    res.json(await store.appendChunk(req.params.id, target, readOffset(req), req));
  }));

  app.get('/api/projects/:id/clips/:index/file', route(async (req, res) => {
    const project = await store.get(req.params.id);
    res.sendFile(store.readyPath(project, { type: 'clip', index: req.params.index }));
  }));

  app.post('/api/projects/:id/assets/:slot', route(async (req, res) => {
    res.status(201).json(present(await store.createAsset(req.params.id, req.params.slot, req.body)));
  }));

  app.put('/api/projects/:id/assets/:slot', route(async (req, res) => {
    const target = { type: 'asset', slot: req.params.slot };
    res.json(await store.appendChunk(req.params.id, target, readOffset(req), req));
  }));

  app.delete('/api/projects/:id/assets/:slot', route(async (req, res) => {
    res.json(present(await store.removeAsset(req.params.id, req.params.slot)));
  }));

  app.get('/api/projects/:id/assets/:slot/file', route(async (req, res) => {
    const project = await store.get(req.params.id);
    res.sendFile(store.readyPath(project, { type: 'asset', slot: req.params.slot }));
  }));

  app.post('/api/projects/:id/render', route(async (req, res) => {
    await queue.start(req.params.id);
    res.status(202).json(present(await store.get(req.params.id)));
  }));

  app.delete('/api/projects/:id/render', route(async (req, res) => {
    queue.cancel(req.params.id);
    res.status(202).json(present(await store.get(req.params.id)));
  }));

  // ?download=1 speichert die Datei, sonst Wiedergabe im Browser
  app.get('/api/projects/:id/output', route(async (req, res) => {
    const project = await store.get(req.params.id);
    const file = await queue.outputPath(project);
    if (req.query.download === undefined) return res.sendFile(file);
    const { from, to } = project.range;
    res.download(file, from && to ? `FuerDieCuts_${from}_bis_${to}.mp4` : 'FuerDieCuts.mp4');
  }));

  app.use('/api', (req, res) => res.status(404).json({ error: 'Nicht gefunden.' }));

  // eslint-disable-next-line no-unused-vars -- Express erkennt Fehlerbehandler an vier Parametern
  app.use((error, req, res, next) => {
    if (error instanceof HttpError) {
      return res.status(error.status).json({ error: error.message, ...error.details });
    }
    // Fehler aus express.json (kaputtes oder zu großes JSON)
    if (error.status >= 400 && error.status < 500) {
      return res.status(error.status).json({ error: 'Ungültige Anfrage.' });
    }
    // Der Browser hat den Upload abgebrochen; der Stand bleibt gültig.
    if (error.code === 'ERR_STREAM_PREMATURE_CLOSE') return;
    console.error(error);
    if (!res.headersSent) res.status(500).json({ error: 'Interner Fehler.' });
  });

  return app;
}