<?php

declare(strict_types=1);

/*
 * This file is part of the TYPO3 CMS project.
 *
 * It is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License, either version 2
 * of the License, or any later version.
 *
 * For the full copyright and license information, please read the
 * LICENSE.txt file that was distributed with this source code.
 *
 * The TYPO3 project - inspiring people to share!
 */

namespace TYPO3\CMS\Fluid\ViewHelpers\Security;

use TYPO3\CMS\Core\Core\RequestId;
use TYPO3\CMS\Core\Security\ContentSecurityPolicy\Directive;
use TYPO3\CMS\Core\Security\ContentSecurityPolicy\SourceKeyword;
use TYPO3Fluid\Fluid\Core\ViewHelper\AbstractViewHelper;

/**
 * ViewHelper to retrieve (and consume) a `nonce` attribute from
 * the global server request object pool, or from the `PolicyProvider`
 * service as a fall-back value.
 *
 * ```
 *   <script nonce="{f:security.nonce(directive: 'script-src')}">const inline = 'script';</script>
 *   <script nonce="{f:security.nonce(directive: 'script-src', scope: 'static')}" src="app.js"></script>
 * ```
 *
 * @see https://docs.typo3.org/permalink/t3viewhelper:typo3-fluid-security-nonce
 * @see https://docs.typo3.org/permalink/t3coreapi:content-security-policy
 * @see \TYPO3\CMS\Core\Security\ContentSecurityPolicy\PolicyProvider
 */
final class NonceViewHelper extends AbstractViewHelper
{
    public function __construct(
        private readonly RequestId $requestId,
    ) {}

    public function initializeArguments(): void
    {
        parent::initializeArguments();
        $this->registerArgument('directive', 'string', 'Value of the CSP directive');
        $this->registerArgument('scope', 'string', '`inline` or `static`', false, 'inline');
    }

    public function render(): string
    {
        $applicableDirectives = SourceKeyword::nonceProxy->getApplicableDirectives();
        $directive = Directive::tryFrom($this->arguments['directive'] ?? '');
        $directive = $directive !== null && in_array($directive, $applicableDirectives, true)
            ? $directive->value
            : self::class;
        $scope = $this->arguments['scope'] ?? '';
        if ($scope === 'static') {
            return $this->requestId->nonce->consumeStatic($directive);
        }
        // `inline` is guessed here, it might be `static` as well in templates
        return $this->requestId->nonce->consumeInline($directive);
    }
}
