feat: use xpier media library for uploads and markdown embeds

Store media:ID in post bodies instead of CDN URLs, and keep sablog attach tokens as a fallback.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/Blog/Support/MarkdownMediaEmbed.php

@@ -0,0 +1,131 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Blog\Support;
+
+use Xpier\FilamentMediaLibrary\Models\MediaLibrary;
+
+/**
+ * Markdown/HTML body must store library references, never CDN URLs.
+ *
+ * Markdown: ![alt](media:12)  or  [file.pdf](media:12)
+ * HTML:     [media=12]
+ */
+class MarkdownMediaEmbed
+{
+    public const PROTOCOL = 'media:';
+
+    public function snippet(MediaLibrary $media, string $format = 'markdown'): string
+    {
+        $id = (int) $media->getKey();
+        $isImage = $this->isImage($media);
+
+        if ($format === 'html') {
+            return '[media='.$id.']';
+        }
+
+        $label = $this->escapeMdLabel($this->label($media, $isImage));
+
+        return $isImage
+            ? '!['.$label.']('.self::PROTOCOL.$id.')'
+            : '['.$label.']('.self::PROTOCOL.$id.')';
+    }
+
+    public function expandMarkdown(string $markdown): string
+    {
+        return preg_replace_callback(
+            '/\]\(media:(\d+)\)/i',
+            function (array $matches): string {
+                $url = $this->publicUrl((int) $matches[1]);
+
+                return $url !== null ? ']('.$url.')' : $matches[0];
+            },
+            $markdown
+        ) ?? $markdown;
+    }
+
+    public function hydrateHtml(string $html): string
+    {
+        $html = preg_replace_callback(
+            '/\b(src|href)=([\'"])media:(\d+)\2/i',
+            function (array $matches): string {
+                $url = $this->publicUrl((int) $matches[3]);
+                if ($url === null) {
+                    return $matches[0];
+                }
+
+                return $matches[1].'='.$matches[2].$url.$matches[2];
+            },
+            $html
+        ) ?? $html;
+
+        return preg_replace_callback(
+            '/\[media=(\d+)\]/i',
+            function (array $matches): string {
+                $id = (int) $matches[1];
+                $media = $this->find($id);
+                $url = $this->publicUrl($id);
+
+                if ($url === null) {
+                    return '';
+                }
+
+                if ($media && $this->isImage($media)) {
+                    return sprintf(
+                        '<img src="%s" alt="%s" loading="lazy" />',
+                        e($url),
+                        e($this->label($media, true))
+                    );
+                }
+
+                $label = $media ? $this->label($media, false) : 'file-'.$id;
+
+                return sprintf('<a href="%s">%s</a>', e($url), e($label));
+            },
+            $html
+        ) ?? $html;
+    }
+
+    public function find(int $id): ?MediaLibrary
+    {
+        try {
+            return MediaLibrary::query()->find($id);
+        } catch (\Throwable) {
+            return null;
+        }
+    }
+
+    public function publicUrl(int $id): ?string
+    {
+        $media = $this->find($id);
+        $url = $media?->url;
+
+        return filled($url) ? (string) $url : null;
+    }
+
+    public function isImage(MediaLibrary $media): bool
+    {
+        if ($media->type === MediaLibrary::TYPE_IMAGE) {
+            return true;
+        }
+
+        return is_string($media->mime_type) && str_starts_with($media->mime_type, 'image/');
+    }
+
+    protected function label(MediaLibrary $media, bool $isImage): string
+    {
+        if (filled($media->alt_text)) {
+            return (string) $media->alt_text;
+        }
+
+        $name = (string) ($media->original_name ?: basename((string) $media->path) ?: 'media-'.$media->getKey());
+
+        return $isImage ? (pathinfo($name, PATHINFO_FILENAME) ?: $name) : $name;
+    }
+
+    protected function escapeMdLabel(string $label): string
+    {
+        return str_replace(['[', ']', '!'], ['\\[', '\\]', '\\!'], $label);
+    }
+}