BBCodeConverter For UNIT3D

BBCodeConverter.php

<?php
/**
 * NOTICE OF LICENSE.
 *
 * UNIT3D is open-sourced software licensed under the GNU General Public License v3.0
 * The details is bundled with this project in the file LICENSE.txt.
 *
 * @project    UNIT3D
 *
 * @license    https://www.gnu.org/licenses/agpl-3.0.en.html/ GNU Affero General Public License v3.0
 * @author     HDVinnie
 */

namespace App\Helpers;

class BBCodeConverter
{
    /**
     * @brief Constructor.
     * @param string $text The text to be converted.
     */
    public function __construct($text) {
        $this->text = $text;
    }

    /**
     * @brief Removes BBCode size.
     */
    protected function removeSize() {

        $this->text = preg_replace_callback('%\[size=\d*\]([\W\D\w\s]*?)\[/size\]%iu',

            function ($matches) {
                return $matches[1];
            },

            $this->text
        );

    }

    /**
     * @brief Removes BBCode center.
     */
    protected function removeCenter() {

        $this->text = preg_replace_callback('%\[center\]([\W\D\w\s]*?)\[/center\]%iu',

            function ($matches) {
                return '<div class="text-center">'.trim($matches[1], " ").'</div>';

            },

            $this->text
        );

    }

    /**
     * @brief Replaces BBCode bold.
     */
    protected function replaceBold() {

        $this->text = preg_replace_callback('%\[b\]([\W\D\w\s]*?)\[/b\]%iu',

            function ($matches) {
                return "**".trim($matches[1], " ")."**";
            },

            $this->text
        );

    }

    /**
     * @brief Replaces BBCode italic.
     */
    protected function replaceItalic() {

        $this->text = preg_replace_callback('%\[i\]([\W\D\w\s]*?)\[/i\]%iu',

            function ($matches) {
                return "*".trim($matches[1], " ")."*";
            },

            $this->text
        );

    }

    /**
     * @brief Replaces BBCode underline. Hoedown support underline.
     */
    protected function replaceUnderline() {

        $this->text = preg_replace_callback('%\[u\]([\W\D\w\s]*?)\[/u\]%iu',

            function ($matches) {
                return "_".trim($matches[1], " ")."_";
            },

            $this->text
        );

    }

    /**
     * @brief Replaces BBCode strikethrough.
     */
    protected function replaceStrikethrough() {

        $this->text = preg_replace_callback('%\[s\]([\W\D\w\s]*?)\[/s\]%iu',

            function ($matches) {
                return "~~".trim($matches[1], " ")."~~";
            },

            $this->text
        );

    }

    /**
     * @brief Replaces BBCode lists.
     */
    protected function replaceLists() {

        $this->text = preg_replace_callback('%\[list(?P<type>=1)?\](?P<items>[\W\D\w\s]*?)\[/list\]%iu',

            function ($matches) {
                $buffer = "";

                $list = preg_replace('/\s*$|^\s*/mu', '', $matches['items']);
                if (is_null($list))
                    throw new \RuntimeException(sprintf("Text identified by '%d' has malformed BBCode lists", $this->id));

                $items = preg_split('/\[\*\]/u', $list);

                $counter = count($items);

                if (isset($matches['type']) && $matches['type'] == '=1') { // ordered list
                    // We start from 1 to discard the first string, in fact, it's empty.
                    for ($i = 1; $i < $counter; $i++)
                        if (!empty($items[$i]))
                            $buffer .= (string)($i).'. '.trim($items[$i]).PHP_EOL;
                }
                else { // unordered list
                    // We start from 1 to discard the first string, in fact, it's empty.
                    for ($i = 1; $i < $counter; $i++)
                        if (!empty($items[$i]))
                            $buffer .= '- '.trim($items[$i]).PHP_EOL;
                }

                // We need a like break above the list and another one below.
                if (!empty($buffer))
                    $buffer = PHP_EOL.$buffer.PHP_EOL;

                return $buffer;
            },

            $this->text
        );

    }

    /**
     * @brief Replaces BBCode urls.
     */
    protected function replaceUrls() {

        $this->text = preg_replace_callback('%\[url\s*=\s*("(?:[^"]*")|\A[^\']*\Z|(?:[^\'">\]\s]+))\s*(?:[^]\s]*)\]([\W\D\w\s]*?)\[/url\]%iu',

            function ($matches) {
                if (isset($matches[1]) && isset($matches[2]))
                    return "[".$matches[2]."](".$matches[1].")";
                else
                    throw new \RuntimeException(sprintf("Text identified by '%d' has malformed BBCode urls", $this->id));
            },

            $this->text
        );

    }

    /**
     * @brief Replaces BBCode images.
     */
    protected function replaceImages() {

        $this->text = preg_replace_callback('%\[img\s*\]\s*("(?:[^"]*")|\A[^\']*\Z|(?:[^\'">\]\s]+))\s*(?:[^]\s]*)\[/img\]%iu',

            function ($matches) {
                if (isset($matches[1]))
                    return PHP_EOL."![]"."(".$matches[1].")".PHP_EOL;
                else
                    throw new \RuntimeException(sprintf("Text identified by '%d' have malformed BBCode images", $this->id));
            },

            $this->text
        );

    }

    /**
     * @brief Replaces BBCode quotes.
     */
    protected function replaceQuotes() {
        // Removes the inner quotes, leaving just one level.
        $this->text = preg_replace('~\G(?<!^)(?>(\[quote\b[^]]*](?>[^[]++|\[(?!/?quote)|(?1))*\[/quote])|(?<!\[)(?>[^[]++|\[(?!/?quote))+\K)|\[quote\b[^]]*]\K~', '', $this->text);

        // Replaces all the remaining quotes with '> ' characters.
        $this->text = preg_replace_callback('%\[quote\b[^]]*\]((?>[^[]++|\[(?!/?quote))*)\[/quote\]%i',

            function($matches) {
                $quote = preg_replace('/^\s*/mu', '', trim($matches[1]));
                return "> ".$quote.PHP_EOL.PHP_EOL;
            },

            $this->text
        );
    }

    /**
     * @brief Replaces BBCode snippets.
     */
    protected function replaceSnippets() {

        $this->text = preg_replace_callback('%\[code\s*=?(?P<language>\w*)\](?P<snippet>[\W\D\w\s]*?)\[\/code\]%iu',

            function ($matches) {
                if (isset($matches['snippet'])) {
                    $language = strtolower($matches['language']);

                    if ($language == 'html4strict' or $language == 'div')
                        $language = 'html';
                    elseif ($language == 'shell' or $language == 'dos' or $language == 'batch')
                        $language = 'sh';
                    elseif ($language == 'xul' or $language == 'wpf')
                        $language = 'xml';
                    elseif ($language == 'asm')
                        $language = 'nasm';
                    elseif ($language == 'vb' or $language == 'visualbasic' or $language == 'vba')
                        $language = 'vb.net';
                    elseif ($language == 'asp')
                        $language = 'aspx-vb';
                    elseif ($language == 'xaml')
                        $language = 'xml';
                    elseif ($language == 'cplusplus')
                        $language = 'cpp';
                    elseif ($language == 'txt' or $language == 'gettext')
                        $language = 'text';
                    elseif ($language == 'basic')
                        $language = 'cbmbas';
                    elseif ($language == 'lisp')
                        $language = 'clojure';
                    elseif ($language == 'aspnet')
                        $language = 'aspx-vb';

                    return PHP_EOL."```".$language.PHP_EOL.trim($matches['snippet']).PHP_EOL."```".PHP_EOL;
                }
                else
                    throw new \RuntimeException(sprintf("Text identified by '%d' has malformed BBCode snippet.", $this->id));
            },

            $this->text
        );

    }

    /**
     * @brief Replace BBCode spoiler.
     */
    protected function replaceSpoilers() {

        $this->text = preg_replace_callback('%\[spoiler\]([\W\D\w\s]*?)\[/spoiler\]%iu',

            function ($matches) {
                return "<details><summary>Spoiler!</summary><pre><code>".trim($matches[1], " ")."</code></pre></details>";
            },

            $this->text
        );

    }

    /**
     * @brief Replace BBCode color.
     */
    protected function replaceColor() {

    }

    /**
     * @brief Converts the provided BBCode text to an equivalent Markdown text.
     */
    public function toMarkdown() {
        $this->removeCenter();
        $this->removeSize();
        $this->replaceBold();
        $this->replaceItalic();
        $this->replaceUnderline();
        $this->replaceStrikethrough();
        $this->replaceLists();
        $this->replaceUrls();
        $this->replaceImages();
        $this->replaceQuotes();
        $this->replaceSnippets();
        $this->replaceSpoilers();

        return $this->text;
    }

}