Move HTML to Markdown library to Composer

vendor/league/html-to-markdown/src/Converter/LinkConverter.php

@@ -0,0 +1,52 @@
+<?php
+
+namespace League\HTMLToMarkdown\Converter;
+
+use League\HTMLToMarkdown\ElementInterface;
+
+class LinkConverter implements ConverterInterface
+{
+    /**
+     * @param ElementInterface $element
+     *
+     * @return string
+     */
+    public function convert(ElementInterface $element)
+    {
+        $href = $element->getAttribute('href');
+        $title = $element->getAttribute('title');
+        $text = trim($element->getValue());
+
+        if ($title !== '') {
+            $markdown = '[' . $text . '](' . $href . ' "' . $title . '")';
+        } elseif ($href === $text && $this->isValidAutolink($href)) {
+            $markdown = '<' . $href . '>';
+        } else {
+            $markdown = '[' . $text . '](' . $href . ')';
+        }
+
+        if (!$href) {
+            $markdown = html_entity_decode($element->getChildrenAsString());
+        }
+
+        return $markdown;
+    }
+
+    /**
+     * @return string[]
+     */
+    public function getSupportedTags()
+    {
+        return array('a');
+    }
+
+    /**
+     * @param string $href
+     *
+     * @return bool
+     */
+    private function isValidAutolink($href)
+    {
+        return preg_match('/^[A-Za-z][A-Za-z0-9.+-]{1,31}:[^<>\x00-\x20]*/i', $href) === 1;
+    }
+}