<?php

namespace App\Http\Middleware;

use Closure;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Redis;
use Symfony\Component\HttpFoundation\Response;

class IdempotencyMiddleware
{
    /**
     * Handle an incoming request.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  \Closure(\Illuminate\Http\Request): (\Illuminate\Http\Response)  $next
     * @return mixed
     */
    public function handle(Request $request, Closure $next)
    {
        // Only run for mutations (POST, PUT, PATCH, DELETE)
        if (!in_array($request->method(), ['POST', 'PUT', 'PATCH', 'DELETE'])) {
            return $next($request);
        }

        $idempotencyKey = $request->header('Idempotency-Key') ?? $request->header('X-Idempotency-Key');

        if (!$idempotencyKey) {
            return $next($request);
        }

        // Clean key
        $key = 'idempotency:' . hash('sha256', $idempotencyKey);
        $lockKey = $key . ':lock';
        $ttl = config('wasl.security.idempotency.ttl_seconds', 86400); // 24 hours default

        // Acquire lock using Redis SETNX (Swoole safe)
        $lockAcquired = Redis::set($lockKey, 'locked', 'EX', 10, 'NX');

        if (!$lockAcquired) {
            return response()->json([
                'error' => 'Conflict',
                'message' => 'A request with this Idempotency-Key is already in progress.',
            ], Response::HTTP_CONFLICT);
        }

        try {
            // Check if we have a cached response
            $cached = Redis::get($key);
            if ($cached) {
                $data = json_decode($cached, true);
                
                // Release lock
                Redis::del($lockKey);

                return response($data['content'], $data['status'], $data['headers']);
            }

            // Execute request
            $response = $next($request);

            // Only cache successful or non-server-error responses (2xx and 4xx, exclude 5xx)
            if ($response->getStatusCode() < 500) {
                $cacheData = json_encode([
                    'status' => $response->getStatusCode(),
                    'headers' => collect($response->headers->all())->map(fn($val) => $val[0])->toArray(),
                    'content' => $response->getContent(),
                ]);
                Redis::set($key, $cacheData, 'EX', $ttl);
            }

            return $response;

        } finally {
            // Always release lock
            Redis::del($lockKey);
        }
    }
}