nexus

 <?php
 /**
  * Nexus Forum — Addon System
  *
  * Two hook patterns:
  *
  *  AddonManager::fire($hook, $data)
  *    FILTER pattern — each callback receives the return value of the previous.
  *    Use for transforming a single value (e.g. render_post_content: HTML string in/out).
  *
  *  AddonManager::collect($hook, $context)
  *    COLLECTOR pattern — every callback receives the same $context array.
  *    Non-empty string returns are accumulated and joined.
  *    Use for output hooks where multiple addons each contribute HTML
  *    (e.g. render_post_footer, render_topic_header, before_page_head).
  */
 if (!defined('NEXUS')) exit('Forbidden');
 
 class AddonManager {
     private static array  $hooks   = [];
     private static array  $loaded  = [];
     private static ?array $active  = null;
 
     /* ── Boot all active addons ─────────────────────────────── */
     public static function boot(): void {
         foreach (self::activeList() as $slug) {
             $main = ROOT . '/addons/' . $slug . '/main.php';
             if (file_exists($main) && !isset(self::$loaded[$slug])) {
                 try {
                     require_once $main;
                     self::$loaded[$slug] = true;
                 } catch (Throwable $e) {
                     error_log("Addon [$slug] boot error: " . $e->getMessage());
                 }
             }
         }
     }
 
     /* ── Register a hook callback ────────────────────────────── */
     public static function on(string $hook, callable $cb, int $priority = 10): void {
         self::$hooks[$hook][$priority][] = $cb;
     }
 
     /* ── FILTER: chain callbacks, each receives previous return ─ */
     public static function fire(string $hook, mixed $data = null): mixed {
         if (empty(self::$hooks[$hook])) return $data;
         $buckets = self::$hooks[$hook];
         ksort($buckets);
         foreach ($buckets as $callbacks) {
             foreach ($callbacks as $cb) {
                 try {
                     $result = $cb($data);
                     if ($result !== null) $data = $result;
                 } catch (Throwable $e) {
                     error_log("Addon hook [$hook] filter error: " . $e->getMessage());
                 }
             }
         }
         return $data;
     }
 
     /* ── COLLECTOR: all callbacks receive same $context ──────── */
     /* Each callback should return '' or an HTML string to append. */
     public static function collect(string $hook, mixed $context = null): string {
         if (empty(self::$hooks[$hook])) return '';
         $buckets = self::$hooks[$hook];
         ksort($buckets);
         $output = '';
         foreach ($buckets as $callbacks) {
             foreach ($callbacks as $cb) {
                 try {
                     $result = $cb($context);
                     if (is_string($result) && $result !== '') {
                         $output .= $result;
                     }
                 } catch (Throwable $e) {
                     error_log("Addon hook [$hook] collect error: " . $e->getMessage());
                 }
             }
         }
         return $output;
     }
 
     public static function hasHook(string $hook): bool {
         return !empty(self::$hooks[$hook]);
     }
 
     /* ── Active addon list ──────────────────────────────────── */
     public static function activeList(): array {
         if (self::$active !== null) return self::$active;
         try {
             $val = DB::val("SELECT value FROM settings WHERE `key`='active_addons'");
             self::$active = $val ? (json_decode($val, true) ?: []) : [];
         } catch (Throwable $e) {
             self::$active = [];
         }
         return self::$active;
     }
 
     /* ── Scan all installed addons ──────────────────────────── */
     public static function all(): array {
         $dir    = ROOT . '/addons';
         $active = self::activeList();
         $addons = [];
         if (!is_dir($dir)) return [];
         foreach (scandir($dir) as $slug) {
             if ($slug[0] === '.') continue;
             $manifest = $dir . '/' . $slug . '/nexus-addon.json';
             if (!file_exists($manifest)) continue;
             $info = json_decode(file_get_contents($manifest), true);
             if (!$info || empty($info['name'])) continue;
             $addons[$slug] = array_merge([
                 'slug' => $slug, 'name' => $slug, 'description' => '',
                 'version' => '1.0.0', 'author' => 'Unknown', 'url' => '',
                 'hooks' => [], 'requires' => [],
             ], $info, [
                 'slug'   => $slug,
                 'active' => in_array($slug, $active),
             ]);
         }
         return $addons;
     }
 
     /* ── Activate / deactivate ──────────────────────────────── */
     public static function activate(string $slug): bool {
         $active = self::activeList();
         if (in_array($slug, $active)) return true;
         $install = ROOT . '/addons/' . $slug . '/install.php';
         if (file_exists($install)) {
             try { require $install; } catch (Throwable $e) {
                 error_log("Addon [$slug] install error: " . $e->getMessage());
                 return false;
             }
         }
         $active[] = $slug;
         self::saveActive($active);
         self::$active = $active;
         return true;
     }
 
     public static function deactivate(string $slug): bool {
         $active = self::activeList();
         if (!in_array($slug, $active)) return true;
         $uninstall = ROOT . '/addons/' . $slug . '/uninstall.php';
         if (file_exists($uninstall)) {
             try { require $uninstall; } catch (Throwable $e) {
                 error_log("Addon [$slug] uninstall error: " . $e->getMessage());
             }
         }
         $active = array_values(array_filter($active, fn($s) => $s !== $slug));
         self::saveActive($active);
         self::$active = $active;
         return true;
     }
 
     private static function saveActive(array $active): void {
         DB::upsert('settings', 'key', 'value', 'active_addons', json_encode(array_values($active)));
     }
 }
 
 /* ── Global convenience helpers ─────────────────────────────── */
 
 /** FILTER hook — transforms a value through all callbacks */
 function addon_hook(string $hook, mixed $data = null): mixed {
     return AddonManager::fire($hook, $data);
 }
 
 /** COLLECTOR hook — every callback gets same $context, returns accumulated HTML */
 function addon_collect(string $hook, mixed $context = null): string {
     return AddonManager::collect($hook, $context);
 }
 
 /** Register a callback on a hook */
 function addon_on(string $hook, callable $cb, int $priority = 10): void {
     AddonManager::on($hook, $cb, $priority);
 }