<?php

declare(strict_types=1);

namespace Sarcio\WordPress;

/**
 * PSR-4 autoloading for the plugin and the shared PHP shim, without assuming a
 * `composer install` — WordPress is installed as a zip, not as a dependency.
 *
 * The shim (`Sarcio\Shim\*`) is looked up in the places it can legally live,
 * in order: the copy `bin/build-zip.sh` bundles into `lib/sarcio-shim/`, the
 * plugin's own Composer vendor dir (the plugin as the root project), the
 * plugin's SIBLING in a vendor dir (the plugin installed as a Composer
 * dependency, where `sarcio/shim` lands next to it in `vendor/sarcio/`), and —
 * for in-repo development — a sibling `sarcio-php-shim` checkout.
 */
final class Autoloader
{
    /** Where the bundled/linked PHP shim's `src/` may be found, in priority order. */
    public static function shimRoots(string $pluginDir): array
    {
        return [
            $pluginDir . '/lib/sarcio-shim/src/',
            $pluginDir . '/vendor/sarcio/shim/src/',
            dirname($pluginDir) . '/shim/src/',
            dirname($pluginDir) . '/sarcio-php-shim/src/',
        ];
    }

    public static function register(string $pluginDir): void
    {
        if (is_file($pluginDir . '/vendor/autoload.php')) {
            require_once $pluginDir . '/vendor/autoload.php';
        }

        $shimRoot = null;
        foreach (self::shimRoots($pluginDir) as $candidate) {
            if (is_dir($candidate)) {
                $shimRoot = $candidate;
                break;
            }
        }

        spl_autoload_register(static function (string $class) use ($pluginDir, $shimRoot): void {
            $map = ['Sarcio\\WordPress\\' => $pluginDir . '/src/'];
            if ($shimRoot !== null) {
                $map['Sarcio\\Shim\\'] = $shimRoot;
            }
            foreach ($map as $prefix => $base) {
                if (strncmp($class, $prefix, strlen($prefix)) !== 0) {
                    continue;
                }
                $file = $base . str_replace('\\', '/', substr($class, strlen($prefix))) . '.php';
                if (is_file($file)) {
                    require_once $file;
                }
                return;
            }
        });
    }

    /**
     * Whether the PHP shim is present. Server-side patching is inert without it;
     * the UI side (reporter + DOM patches) has no PHP dependency at all and keeps
     * working either way.
     */
    public static function shimAvailable(): bool
    {
        return class_exists(\Sarcio\Shim\Shim::class);
    }
}