<?php

namespace App\Http\Middleware\Api\Client\Server;

use Illuminate\Http\Request;
use App\Models\Task;
use App\Models\User;
use App\Models\Backup;
use App\Models\Server;
use App\Models\Subuser;
use App\Models\Database;
use App\Models\Schedule;
use App\Models\Allocation;
use Illuminate\Database\Eloquent\Model;
use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;

class ResourceBelongsToServer
{
    /**
     * Looks at the request parameters to determine if the given resource belongs
     * to the requested server. If not, a 404 error will be returned to the caller.
     *
     * This is critical to ensuring that all subsequent logic is using exactly the
     * server that is expected, and that we're not accessing a resource completely
     * unrelated to the server provided in the request.
     */
    public function handle(Request $request, \Closure $next): mixed
    {
        $params = $request->route()->parameters();

        $server = $params['server'] ?? null;
        if (!$server instanceof Server) {
            throw new \InvalidArgumentException('This middleware cannot be used in a context that is missing a server in the parameters.');
        }

        /** @var \App\Models\Server $server */
        $server = $request->route()->parameter('server');
        $exception = new NotFoundHttpException('The requested resource was not found for this server.');
        foreach ($params as $key => $model) {
            // Specifically skip the server, we're just trying to see if all of the
            // other resources are assigned to this server. Also skip anything that
            // is not currently a Model instance since those will just end up being
            // a 404 down the road.
            if ($key === 'server' || !$model instanceof Model) {
                continue;
            }

            switch (get_class($model)) {
                // All of these models use "server_id" as the field key for the server
                // they are assigned to, so the logic is identical for them all.
                case Allocation::class:
                case Backup::class:
                case Database::class:
                case Schedule::class:
                case Subuser::class:
                    if ($model->server_id !== $server->id) {
                        throw $exception;
                    }
                    break;
                    // Regular users are a special case here as we need to make sure they're
                    // currently assigned as a subuser on the server.
                case User::class:
                    $subuser = $server->subusers()->where('user_id', $model->id)->first();
                    if (is_null($subuser)) {
                        throw $exception;
                    }
                    // This is a special case to avoid an additional query being triggered
                    // in the underlying logic.
                    $request->attributes->set('subuser', $subuser);
                    break;
                    // Tasks are special since they're (currently) the only item in the API
                    // that requires something in addition to the server in order to be accessed.
                case Task::class:
                    /** @var Schedule $schedule */
                    $schedule = $request->route()->parameter('schedule');
                    if ($model->schedule_id !== $schedule->id || $schedule->server_id !== $server->id) {
                        throw $exception;
                    }
                    break;
                default:
                    // Don't return a 404 here since we want to make sure no one relies
                    // on this middleware in a context in which it will not work. Fail safe.
                    throw new \InvalidArgumentException('There is no handler configured for a resource of this type: ' . get_class($model));
            }
        }

        return $next($request);
    }
}
