<?php
namespace Aumframe\Kit;

if (!defined('ABSPATH')) {
    exit;
}

/**
 * References hidden inside an encoding.
 *
 * Shortcodes in the baked output are not plain text but `<!--af:shortcode:BASE64-->`
 * (see `renderShortcode` in `packages/core/src/render.js`).
 *
 * So "replace auto-increment IDs with slugs" does nothing for them: the scene's
 * `[aumframe_form id="20"]` is rewritten correctly while the copy in the baked output is still 20 — and
 * the front end renders a non-existent form as nothing, with no error and no warning, looking
 * exactly like "this page never had a form".
 *
 * This is the fourth instance of the same shape (the first three: image URLs, plain-text shortcodes,
 * routing rules). The conclusion is by now unambiguous: **any new capability that "points at other
 * content from within a layout" must answer, at the same time, what it looks like in the baked
 * output and who rewrites it when the site changes.**
 */
class Refs
{
    /**
     * Decode each shortcode marker, hand it to `$fn` to rewrite, and encode it back.
     *
     * `$fn` receives the plain-text shortcode (`[aumframe_form id="20"]`) and returns the rewritten text.
 */
    public static function map_markers(string $text, callable $fn): string
    {
        if (strpos($text, 'af:shortcode:') === false) {
            return $text;
        }

        return preg_replace_callback(
            '/<!--af:shortcode:([A-Za-z0-9+\/=]+)-->/',
            function ($m) use ($fn) {
                $code = base64_decode($m[1], true);
                if ($code === false) {
                    return $m[0];            // Not valid base64: leave it exactly as it is
                }
                $new = (string) $fn($code);
                return $new === $code ? $m[0] : '<!--af:shortcode:' . base64_encode($new) . '-->';
            },
            $text
        ) ?? $text;
    }
}