const multer = require('multer');
const path = require('path');
const fs = require('fs');

// Ensure uploads directory exists
const uploadDir = path.join(__dirname, '../public/uploads/responses');
if (!fs.existsSync(uploadDir)) {
  fs.mkdirSync(uploadDir, { recursive: true });
}

// Configure storage
const storage = multer.diskStorage({
  destination: (req, file, cb) => {
    cb(null, uploadDir);
  },
  filename: (req, file, cb) => {
    // Generate unique filename: timestamp-random-originalname
    const uniqueSuffix = Date.now() + '-' + Math.round(Math.random() * 1E9);
    const ext = path.extname(file.originalname);
    const basename = path.basename(file.originalname, ext);
    cb(null, `response-${uniqueSuffix}${ext}`);
  }
});

// File filter - only images
const fileFilter = (req, file, cb) => {
  const allowedTypes = /jpeg|jpg|png|gif|webp/;
  const extname = allowedTypes.test(path.extname(file.originalname).toLowerCase());
  const mimetype = allowedTypes.test(file.mimetype);
  
  if (mimetype && extname) {
    return cb(null, true);
  } else {
    cb(new Error('Only image files (JPEG, PNG, GIF, WebP) are allowed'));
  }
};

// Configure multer
const upload = multer({
  storage: storage,
  limits: {
    fileSize: 5 * 1024 * 1024 // 5MB max file size
  },
  fileFilter: fileFilter
});

module.exports = upload;