laralog/app/Blog/Support/MarkdownMediaEmbed.php

<?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);
    }
}