Added an console command to convert the old BBCode comments to markdown

src/Helpers/BBCodeToMarkdownConverter.php

@@ -0,0 +1,63 @@
+<?php
+/**
+ *
+ * part-db version 0.1
+ * Copyright (C) 2005 Christoph Lechner
+ * http://www.cl-projects.de/
+ *
+ * part-db version 0.2+
+ * Copyright (C) 2009 K. Jacobs and others (see authors.php)
+ * http://code.google.com/p/part-db/
+ *
+ * Part-DB Version 0.4+
+ * Copyright (C) 2016 - 2019 Jan Böhmer
+ * https://github.com/jbtronics
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
+ *
+ */
+
+namespace App\Helpers;
+
+use League\HTMLToMarkdown\HtmlConverter;
+use s9e\TextFormatter\Bundles\Forum as TextFormatter;
+use SebastianBergmann\CodeCoverage\Report\Text;
+
+
+class BBCodeToMarkdownConverter
+{
+    protected $html_to_markdown;
+
+    public function __construct()
+    {
+        $this->html_to_markdown = new HtmlConverter();
+    }
+
+    /**
+     * Converts the given BBCode to markdown.
+     * BBCode tags that does not have a markdown aequivalent are outputed as HTML tags.
+     * @param $bbcode string The Markdown that should be converted.
+     * @return string The markdown version of the text.
+     */
+    public function convert(string $bbcode) : string
+    {
+        //Convert BBCode to html
+        $xml = TextFormatter::parse($bbcode);
+        $html = TextFormatter::render($xml);
+
+        //Now convert the HTML to markdown
+        return $this->html_to_markdown->convert($html);
+    }
+}