Digitigrade/FormattingProvider/CommonMark.php


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<?php
namespace Digitigrade\FormattingProvider;

use Digitigrade\FormattingProvider;
use Digitigrade\GlobalConfig;
use Digitigrade\Singleton;
use League\CommonMark\Environment\Environment;
use League\CommonMark\Extension\Autolink\AutolinkExtension;
use League\CommonMark\Extension\CommonMark\CommonMarkCoreExtension;
use League\CommonMark\Extension\ExternalLink\ExternalLinkExtension;
use League\CommonMark\Extension\Strikethrough\StrikethroughExtension;
use League\CommonMark\MarkdownConverter;

class CommonMark extends Singleton implements FormattingProvider {
    private MarkdownConverter $converter;

    protected function __construct() {
        $env = new Environment([
            'html_input' => 'escape',
            'renderer' => [
                'soft_break' => '<br>'
            ],
            'autolink' => [
                'allowed_protocols' => SanitisedHtml::ALLOWED_URL_SCHEMES
            ],
            'external_link' => [
                'internal_hosts' => [GlobalConfig::getInstance()->getCanonicalHost()],
                'open_in_new_window' => true,
                'nofollow' => 'all',
                'noopener' => 'all',
                'noreferrer' => 'external'
            ]
        ]);
        $env->addExtension(new CommonMarkCoreExtension);
        $env->addExtension(new AutolinkExtension);
        $env->addExtension(new ExternalLinkExtension);
        $env->addExtension(new StrikethroughExtension);
        $this->converter = new MarkdownConverter($env);
    }

    public function renderToHtml(string $input): string {
        return $this->converter->convert($input);
    }

    public function renderToPlainText(string $input): string {
        // TODO: somehow remove markup and leave the unformatted content behind
        return htmlspecialchars($input);
    }
}