added parsedown extension for header ids (#388) (#399)

src/Utils/ParsedownExtension.php

@@ -0,0 +1,68 @@
+<?php
+
+/*
+ * This file is part of the Kimai time-tracking app.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace App\Utils;
+
+/**
+ * This Class extends the default Parsedown Class for custom methods.
+ */
+class ParsedownExtension extends \Parsedown
+{
+    private $ids = [];
+
+    protected function blockHeader($line)
+    {
+        $block = parent::blockHeader($line);
+
+        $text = $block['element']['text'];
+        $id = $this->getIDfromText($text);
+
+        // add id-attribute
+        $block['element']['attributes'] = [
+            'id' => $id
+        ];
+
+        return $block;
+    }
+
+    /**
+     * github-action for creating ids:
+     *
+     * - It downcases the header string
+     * - remove anything that is not a letter, number, space or hyphen
+     * - changes any space to a hyphen.
+     * - If that is not unique, add "-1", "-2", "-3",... to make it unique
+     *
+     * @param $text
+     * @return string
+     */
+    private function getIDfromText($text)
+    {
+        $text = strtolower($text);
+
+        $text = preg_replace('/[^A-Za-z0-9\-\ ]/', '', $text);
+        $text = strtr($text, [' ' => '-']);
+
+        if (isset($this->ids[$text])) {
+            $i = 0;
+            $numberedText = $text . '-1';
+
+            while (isset($this->ids[$numberedText])) {
+                $i++;
+                $numberedText = $text . '-' . $i;
+            }
+
+            $text = $numberedText;
+        }
+
+        $this->ids[$text] = '';
+
+        return $text;
+    }
+}