<?php

namespace App\Http\Middleware;

use Closure;
use Illuminate\Http\Request;
use Symfony\Component\HttpFoundation\Response;

class CompressionMiddleware
{
    /**
     * Handle an incoming request.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  \Closure(\Illuminate\Http\Request): (\Symfony\Component\HttpFoundation\Response)  $next
     * @return \Symfony\Component\HttpFoundation\Response
     */
    public function handle(Request $request, Closure $next): Response
    {
        $response = $next($request);

        // Chỉ nén response cho JSON API
        if (!$this->shouldCompress($request, $response)) {
            return $response;
        }

        $content = $response->getContent();
        
        // Chỉ nén nếu content size > 1KB
        if (strlen($content) < 1024) {
            return $response;
        }

        $acceptEncoding = $request->header('Accept-Encoding', '');
        
        // Kiểm tra client hỗ trợ gzip
        if (str_contains($acceptEncoding, 'gzip') && function_exists('gzencode')) {
            $compressed = gzencode($content, 6); // Level 6 compression
            
            if ($compressed !== false) {
                $response->setContent($compressed);
                $response->headers->set('Content-Encoding', 'gzip');
                $response->headers->set('Content-Length', strlen($compressed));
                $response->headers->set('Vary', 'Accept-Encoding');
            }
        }
        // Fallback to deflate if gzip not supported
        elseif (str_contains($acceptEncoding, 'deflate') && function_exists('gzdeflate')) {
            $compressed = gzdeflate($content, 6);
            
            if ($compressed !== false) {
                $response->setContent($compressed);
                $response->headers->set('Content-Encoding', 'deflate');
                $response->headers->set('Content-Length', strlen($compressed));
                $response->headers->set('Vary', 'Accept-Encoding');
            }
        }

        return $response;
    }

    /**
     * Determine if the response should be compressed.
     */
    private function shouldCompress(Request $request, Response $response): bool
    {
        // Chỉ nén JSON responses
        $contentType = $response->headers->get('Content-Type', '');
        if (!str_contains($contentType, 'application/json')) {
            return false;
        }

        // Không nén nếu đã có Content-Encoding
        if ($response->headers->has('Content-Encoding')) {
            return false;
        }

        // Không nén file downloads
        if ($response->headers->has('Content-Disposition')) {
            return false;
        }

        // Chỉ nén response thành công
        if ($response->getStatusCode() >= 400) {
            return false;
        }

        return true;
    }
}