<?php
/**
 * Simple Rate Limiting Middleware
 */

declare(strict_types=1);

namespace App\Middleware;

final class RateLimitMiddleware
{
    /**
     * Basic file-based rate limiter to keep dependencies zero.
     * In a production multi-server setup, switch this to Redis/DB.
     */
    public static function check(int $maxRequests = 60, int $timeWindow = 60): void
    {
        $ip = $_SERVER['REMOTE_ADDR'] ?? 'unknown';
        $cacheDir = STORAGE_PATH . '/cache';
        $cacheFile = $cacheDir . '/rate_limit_' . md5($ip) . '.json';
        
        // Ensure cache directory exists
        if (!is_dir($cacheDir)) {
            mkdir($cacheDir, 0755, true);
        }
        
        $now = time();
        $requests = [];
        
        // Read existing requests if file exists and is writable
        if (file_exists($cacheFile)) {
            $content = file_get_contents($cacheFile);
            if ($content !== false) {
                $data = json_decode($content, true);
                if (is_array($data)) {
                    // Filter out requests older than the time window
                    $requests = array_filter($data, fn($timestamp) => $timestamp > ($now - $timeWindow));
                }
            }
        }
        
        // Check limit
        if (count($requests) >= $maxRequests) {
            json_error('Too Many Requests. Please try again later.', 429);
        }
        
        // Add current request
        $requests[] = $now;
        
        // Save back to file
        file_put_contents($cacheFile, json_encode(array_values($requests)));
    }
}