import { Router } from 'express';
import multer from 'multer';
import path from 'path';
import fs from 'fs';
import { fileURLToPath } from 'url';
import { requireAuth } from '../auth.js';

const __dirname = path.dirname(fileURLToPath(import.meta.url));
const UPLOAD_DIR = process.env.UPLOAD_DIR || path.join(__dirname, '..', 'uploads');

if (!fs.existsSync(UPLOAD_DIR)) {
  fs.mkdirSync(UPLOAD_DIR, { recursive: true });
}

const storage = multer.diskStorage({
  destination: (_req, _file, cb) => cb(null, UPLOAD_DIR),
  filename: (_req, file, cb) => {
    const ext = path.extname(file.originalname).toLowerCase();
    const base = path.basename(file.originalname, ext).replace(/[^a-zA-Z0-9-_]/g, '_').slice(0, 50);
    cb(null, `${base}-${Date.now()}${ext}`);
  },
});

const upload = multer({
  storage,
  limits: { fileSize: 50 * 1024 * 1024 },
  fileFilter: (_req, file, cb) => {
    const allowed = /^image\/|^video\/mp4$/;
    if (allowed.test(file.mimetype)) cb(null, true);
    else cb(new Error('Only images and MP4 videos are allowed'));
  },
});

const router = Router();

// Wrap multer for Express 5 — multer v2 doesn't handle Express 5 async errors natively
function runUpload(req, res) {
  return new Promise((resolve, reject) => {
    upload.single('file')(req, res, (err) => {
      if (err) reject(err);
      else resolve();
    });
  });
}

router.post('/', requireAuth, async (req, res) => {
  try {
    await runUpload(req, res);
  } catch (err) {
    const status = err.code === 'LIMIT_FILE_SIZE' ? 413 : 400;
    return res.status(status).json({ error: err.message, code: err.code || 'UPLOAD_ERROR' });
  }
  if (!req.file) {
    return res.status(400).json({ error: 'No file uploaded', code: 'VALIDATION' });
  }
  res.json({ url: `/uploads/${req.file.filename}`, filename: req.file.filename });
});

router.delete('/:filename', requireAuth, (req, res) => {
  const filePath = path.join(UPLOAD_DIR, path.basename(req.params.filename));
  if (fs.existsSync(filePath)) fs.unlinkSync(filePath);
  res.json({ message: 'File deleted' });
});

export default router;