<?php
declare (strict_types = 1);

namespace app\api\middleware;

use Closure;
use think\Request;
use think\Response;

/**
 * 响应时间中间件
 * 计算接口耗时并将其添加到响应头中
 */
class ResponseTimeMiddleware
{
    /**
     * 处理请求
     *
     * @param Request $request
     * @param Closure $next
     * @return Response
     */
    public function handle(Request $request, Closure $next)
    {
        // 记录开始时间（微秒）
        $startTime = microtime(true);
        
        // 执行请求
        $response = $next($request);
        
        // 计算耗时（毫秒）
        $endTime = microtime(true);
        $executionTime = round(($endTime - $startTime) * 1000, 2);
        
        // 将耗时添加到响应头
        if ($response instanceof Response) {
            $response->header(['X-Response-Time' => $executionTime . 'ms']);
        }
        
        return $response;
    }
}