<?php

namespace App\Utils;

use League\CommonMark\Environment\Environment;
use League\CommonMark\Extension\DisallowedRawHtml\DisallowedRawHtmlExtension;
use League\CommonMark\Extension\TableOfContents\TableOfContentsExtension;
use League\CommonMark\Extension\HeadingPermalink\HeadingPermalinkExtension;
use League\CommonMark\Extension\ExternalLink\ExternalLinkExtension;
use League\CommonMark\Extension\CommonMark\CommonMarkCoreExtension;
use League\CommonMark\Extension\Mention\MentionExtension;
use League\CommonMark\Extension\Table\TableExtension;
use League\CommonMark\MarkdownConverter;

class RenderHtml {
    /**
     * Converts markdown content to HTML
     *
     * @param string $content The markdown content of page
     * @return string The converted HTML content
     */
    static function markdownToHtml(string $content): string {
        $config = [
            'disallowed_raw_html' => [
                'disallowed_tags' => [
                    'title',
                    'textarea',
                    'style',
                    'xmp',
                    'iframe',
                    'noembed',
                    'noframes',
                    'script',
                    'plaintext'
                ],
            ],
            'table_of_contents' => [
                'html_class' => 'table-of-contents',
                'min_heading_level' => 3,
                'max_heading_level' => 6,
                'normalize' => 'relative',
                'placeholder' => null,
            ],
            'heading_permalink' => [
                'html_class' => '',
                'apply_id_to_heading' => false,
                'min_heading_level' => 3,
                'max_heading_level' => 6,
                'symbol' => '',
            ],
            'table' => [
                'wrap' => [
                    'enabled' => false,
                    'tag' => 'div',
                    'attributes' => [],
                ],
                'alignment_attributes' => [
                    'left'   => ['align' => 'left'],
                    'center' => ['align' => 'center'],
                    'right'  => ['align' => 'right'],
                ],
            ],
            'mentions' => [
                'tag_handle' => [
                    'prefix'    => '#',
                    'pattern'   => '[a-z\d](?:[a-z\d]|-(?=[a-z\d])){0,38}(?!\w)',
                    'generator' => '/tag/%s',
                ]
            ],
            'external_link' => [
                'internal_hosts' => 'site.knah-tsaeb.local', // TODO: Don't forget to set this!
                'open_in_new_window' => true,
                'html_class' => 'external-link',
                'nofollow' => '',
                'noopener' => 'external',
                'noreferrer' => 'external',
            ],
        ];

        $environment = new Environment($config);
        $environment->addExtension(new CommonMarkCoreExtension());
        $environment->addExtension(new MentionExtension());
        $environment->addExtension(new TableExtension());
        $environment->addExtension(new TableOfContentsExtension());
        $environment->addExtension(new ExternalLinkExtension());
        $environment->addExtension(new HeadingPermalinkExtension());
        $environment->addExtension(new DisallowedRawHtmlExtension());

        $converter = new MarkdownConverter($environment);
        return $converter->convert($content);
    }
}