<?php

declare(strict_types=1);

namespace Saloon\Http\Middleware;

use Saloon\Http\PendingRequest;
use Saloon\Contracts\RequestMiddleware;
use Saloon\Exceptions\InvalidHeaderException;

class ValidateProperties implements RequestMiddleware
{
    /**
     * Validate the properties on the request before it is sent
     *
     * @throws \Saloon\Exceptions\InvalidHeaderException
     */
    public function __invoke(PendingRequest $pendingRequest): void
    {
        // Validate that each header provided has a string key

        foreach ($pendingRequest->headers()->all() as $key => $unused) {
            if (! is_string($key)) {
                throw new InvalidHeaderException('One or more of the headers are invalid. Make sure to use the header name as the key. For example: [\'Content-Type\' => \'application/json\'].');
            }
        }
    }
}