feat: add span elements parser

src/SpanElementParser.php

@@ -0,0 +1,92 @@
+<?php
+
+namespace Ahc;
+
+class SpanElementParser
+{
+    use HtmlHelper;
+
+    const RE_URL       = '~<(https?:[\/]{2}[^\s]+?)>~';
+    const RE_EMAIL     = '~<(\S+?@\S+?)>~';
+    const RE_MD_IMG    = '~!\[(.+?)\]\s*\((.+?)\s*(".+?")?\)~';
+    const RE_MD_URL    = '~\[(.+?)\]\s*\((.+?)\s*(".+?")?\)~';
+    const RE_MD_FONT   = '!(\*{1,2}|_{1,2}|`|~~)(.+?)\\1!';
+
+    public function parse($markup)
+    {
+        return $this->spans(
+            $this->anchors(
+                $this->links($markup)
+            )
+        );
+    }
+
+    protected function links($markup)
+    {
+        $markup = $this->emails($markup);
+
+        return \preg_replace(
+            static::RE_URL,
+            '<a href="$1">$1</a>',
+            $markup
+        );
+    }
+
+    protected function emails($markup)
+    {
+        return \preg_replace(
+            static::RE_EMAIL,
+            '<a href="mailto:$1">$1</a>',
+            $markup
+        );
+    }
+
+    protected function anchors($markup)
+    {
+        $markup = $this->images($markup);
+
+        return \preg_replace_callback(static::RE_MD_URL, function ($a) {
+            $title = isset($a[3]) ? " title={$a[3]} " : '';
+
+            return "<a href=\"{$a[2]}\"{$title}>{$a[1]}</a>";
+        }, $markup);
+    }
+
+    protected function images($markup)
+    {
+        return \preg_replace_callback(static::RE_MD_IMG, function ($img) {
+            $title = isset($img[3]) ? " title={$img[3]} " : '';
+            $alt   = $img[1] ? " alt=\"{$img[1]}\" " : '';
+
+            return "<img src=\"{$img[2]}\"{$title}{$alt}/>";
+        }, $markup);
+    }
+
+    protected function spans($markup)
+    {
+        // em/code/strong/del
+        return \preg_replace_callback(static::RE_MD_FONT, function ($em) {
+            switch (\substr($em[1], 0, 2)) {
+                case  '**':
+                case '__':
+                    $tag = 'strong';
+                    break;
+
+                case '~~':
+                    $tag = 'del';
+                    break;
+
+                case $em[1] === '*':
+                case $em[1] === '_':
+                    $tag = 'em';
+                    break;
+
+                default:
+                    $tag = 'code';
+                    $em[2] = $this->escape($em[2]);
+            }
+
+            return "<$tag>{$em[2]}</$tag>";
+        }, $markup);
+    }
+}