/**
 * Response Compression Middleware
 * Compresses API responses to reduce payload size
 */
const compression = require("compression");

const compressionMiddleware = compression({
  // Only compress responses larger than 1kb
  threshold: 1024,
  // Compression level (0-9, higher = better compression but slower)
  level: 6,
  // Filter function - don't compress already compressed formats
  filter: (req, res) => {
    if (req.headers["x-no-compression"]) {
      return false;
    }
    // Check content-type
    const contentType = res.getHeader("Content-Type");
    if (!contentType) return compression.filter(req, res);

    // Don't compress images, videos, or already compressed formats
    if (
      contentType.includes("image/") ||
      contentType.includes("video/") ||
      contentType.includes("application/zip") ||
      contentType.includes("application/pdf")
    ) {
      return false;
    }

    return compression.filter(req, res);
  },
});

module.exports = compressionMiddleware;