<?php

declare(strict_types=1);

namespace App\Http\Middleware;

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

/**
 * RFC v0.2 R1 — 60-second Idempotency-Key replay window backed by
 * Redis cache.
 *
 * Why 60s and not the 12-hour MySQL window from ARCH §10:
 * a stale 12-hour replay of the cascade-bump endpoint can corrupt
 * timetable state in hard-to-detect ways (the persisted lanes have
 * since been edited; replaying a cached response over a fresh edit
 * would silently undo it). 60 seconds covers honest network retry
 * without giving stale requests a window in which to resurrect.
 *
 * Storage: Laravel Cache facade with the default store (Redis in
 * non-test environments). The key namespace `idempotency:60s:` is
 * deliberately distinct from any other idempotency surface in the
 * codebase — keys never collide with the FormSubmission DB-column
 * idempotency.
 *
 * Applied today only on `POST /api/v1/events/{event}/timetable/move`.
 * Other R-numbered idempotent endpoints (RFC §6 lists POST
 * /performances and POST /engagements as candidates) get the regular
 * 12-hour pattern when ARCH §10 lands; this middleware is purposely
 * narrow.
 */
final class IdempotencyKey60sRedis
{
    public function handle(Request $request, Closure $next): Response
    {
        $key = $request->header('Idempotency-Key');

        if (! is_string($key) || trim($key) === '') {
            return response()->json(
                ['error' => 'idempotency_key_required'],
                400,
            );
        }

        $cacheKey = 'idempotency:60s:'.$key;
        $cached = Cache::get($cacheKey);

        if (is_array($cached)) {
            $response = response($cached['body'], $cached['status']);
            foreach ($cached['headers'] ?? [] as $name => $value) {
                $response->headers->set($name, $value);
            }
            $response->headers->set('Idempotency-Replayed', 'true');

            return $response;
        }

        /** @var Response $response */
        $response = $next($request);

        if ($response->isSuccessful()) {
            Cache::put($cacheKey, [
                'status' => $response->getStatusCode(),
                'body' => $response->getContent(),
                'headers' => [
                    'Content-Type' => $response->headers->get('Content-Type'),
                ],
            ], 60);
        }

        return $response;
    }
}