class HookCollectorPass

class HookCollectorPass implements CompilerPassInterface {
    
    /**
     * An associative array of hook implementations.
     *
     * Keys are hook, class, method. Values are the named parameters of a Hook
     * attribute.
     */
    protected array $implementations = [];
    
    /**
     * A list of include files.
     *
     * (This is required only for BC.)
     */
    protected array $includes = [];
    
    /**
     * An array of procedural hook implementations.
     *
     * This is keyed by hook and module name, with the value always FALSE. This
     * corresponds to the $implementations parameter of
     * hook_module_implements_alter().
     *
     * (This is required only for BC.)
     */
    protected array $proceduralHooks = [];
    
    /**
     * A list of functions implementing hook_module_implements_alter().
     *
     * (This is required only for BC.)
     */
    protected array $moduleImplementsAlters = [];
    
    /**
     * The priority of the eventual event listener.
     *
     * This ensures the module order is kept.
     */
    protected int $priority = 0;
    
    /**
     * {@inheritdoc}
     */
    public function process(ContainerBuilder $container) : void {
        $collector = static::collectAllHookImplementations($container->getParameter('container.modules'));
        $map = [];
        $container->register(ProceduralCall::class, ProceduralCall::class)
            ->addArgument($collector->includes);
        foreach ($collector->implementations as $hook => $class_implementations) {
            foreach ($class_implementations as $class => $method_hooks) {
                if ($container->has($class)) {
                    $definition = $container->findDefinition($class);
                }
                else {
                    $definition = $container->register($class, $class)
                        ->setAutowired(TRUE);
                }
                foreach ($method_hooks as $method => $hook_data) {
                    $map[$hook][$class][$method] = $hook_data['module'];
                    $definition->addTag('kernel.event_listener', [
                        'event' => "drupal_hook.{$hook}",
                        'method' => $method,
                        'priority' => $hook_data['priority'],
                    ]);
                }
            }
        }
        $container->setParameter('hook_implementations_map', $map);
    }
    
    /**
     * Collects all hook implementations.
     *
     * @param array $module_filenames
     *   An associative array. Keys are the module names, values are relevant
     *   info yml file path.
     *
     * @return \Drupal\Core\Extension\HookCollectorPass
     *   A HookCollectorPass instance holding all hook implementations and
     *   include file information.
     *
     * @internal
     *   This method is only used by ModuleHandler.
     */
    public static function collectAllHookImplementations(array $module_filenames) : static {
        $modules = array_map(fn($x) => preg_quote($x, '/'), array_keys($module_filenames));
        // Longer modules first.
        usort($modules, fn($a, $b) => strlen($b) - strlen($a));
        $module_preg = '/^(?<function>(?<module>' . implode('|', $modules) . ')_(?!preprocess_)(?!update_\\d)(?<hook>[a-zA-Z0-9_\\x80-\\xff]+$))/';
        $collector = new static();
        foreach ($module_filenames as $module => $info) {
            $collector->collectModuleHookImplementations(dirname($info['pathname']), $module, $module_preg);
        }
        return $collector->convertProceduralToImplementations();
    }
    
    /**
     * Collects procedural and Attribute hook implementations.
     *
     * @param $dir
     *   The directory in which the module resides.
     * @param $module
     *   The name of the module.
     * @param $module_preg
     *   A regular expression matching every module, longer module names are
     *   matched first.
     *
     * @return void
     */
    protected function collectModuleHookImplementations($dir, $module, $module_preg) : void {
        $iterator = new \RecursiveDirectoryIterator($dir, \FilesystemIterator::SKIP_DOTS | \FilesystemIterator::UNIX_PATHS);
        $iterator = new \RecursiveCallbackFilterIterator($iterator, static::filterIterator(...));
        $iterator = new \RecursiveIteratorIterator($iterator);
        
        /** @var \RecursiveDirectoryIterator | \RecursiveIteratorIterator $iterator*/
        foreach ($iterator as $fileinfo) {
            assert($fileinfo instanceof \SplFileInfo);
            $extension = $fileinfo->getExtension();
            if ($extension === 'module' && !$iterator->getDepth()) {
                // There is an expectation for all modules to be loaded. However,
                // .module files are not supposed to be in subdirectories.
                include_once $fileinfo->getPathname();
            }
            if ($extension === 'php') {
                $namespace = preg_replace('#^src/#', "Drupal/{$module}/", $iterator->getSubPath());
                $class = $namespace . '/' . basename($fileinfo->getFilename(), '.php');
                $class = str_replace('/', '\\', $class);
                foreach (static::getHookAttributesInClass($class) as $attribute) {
                    $this->addFromAttribute($attribute, $class, $module);
                }
            }
            else {
                $finder = MockFileFinder::create($fileinfo->getPathName());
                $parser = new StaticReflectionParser('', $finder);
                foreach ($parser->getMethodAttributes() as $function => $attributes) {
                    if (!StaticReflectionParser::hasAttribute($attributes, LegacyHook::class) && preg_match($module_preg, $function, $matches)) {
                        $this->addProceduralImplementation($fileinfo, $matches['hook'], $matches['module'], $matches['function']);
                    }
                }
            }
        }
    }
    
    /**
     * Filter iterator callback. Allows include files and .php files in src/Hook.
     */
    protected static function filterIterator(\SplFileInfo $fileInfo, $key, \RecursiveDirectoryIterator $iterator) : bool {
        $sub_path_name = $iterator->getSubPathname();
        $extension = $fileInfo->getExtension();
        if (str_starts_with($sub_path_name, 'src/Hook/')) {
            return $iterator->isDir() || $extension === 'php';
        }
        if ($iterator->isDir()) {
            if ($sub_path_name === 'src' || $sub_path_name === 'src/Hook') {
                return TRUE;
            }
            // glob() doesn't support streams but scandir() does.
            return !in_array($fileInfo->getFilename(), [
                'tests',
                'js',
                'css',
            ]) && !array_filter(scandir($key), fn($filename) => str_ends_with($filename, '.info.yml'));
        }
        return in_array($extension, [
            'inc',
            'module',
            'profile',
            'install',
        ]);
    }
    
    /**
     * An array of Hook attributes on this class with $method set.
     *
     * @param string $class
     *   The class.
     *
     * @return \Drupal\Core\Hook\Attribute\Hook[]
     *   An array of Hook attributes on this class. The $method property is guaranteed to be set.
     */
    protected static function getHookAttributesInClass(string $class) : array {
        if (!class_exists($class)) {
            return [];
        }
        $reflection_class = new \ReflectionClass($class);
        $class_implementations = [];
        // Check for #[Hook] on the class itself.
        foreach ($reflection_class->getAttributes(Hook::class, \ReflectionAttribute::IS_INSTANCEOF) as $reflection_attribute) {
            $hook = $reflection_attribute->newInstance();
            assert($hook instanceof Hook);
            self::checkForProceduralOnlyHooks($hook, $class);
            if (!$hook->method) {
                if (method_exists($class, '__invoke')) {
                    $hook->setMethod('__invoke');
                }
                else {
                    throw new \LogicException("The Hook attribute for hook {$hook->hook} on class {$class} must specify a method.");
                }
            }
            $class_implementations[] = $hook;
        }
        // Check for #[Hook] on methods.
        foreach ($reflection_class->getMethods(\ReflectionMethod::IS_PUBLIC) as $method_reflection) {
            foreach ($method_reflection->getAttributes(Hook::class, \ReflectionAttribute::IS_INSTANCEOF) as $attribute_reflection) {
                $hook = $attribute_reflection->newInstance();
                assert($hook instanceof Hook);
                self::checkForProceduralOnlyHooks($hook, $class);
                $class_implementations[] = $hook->setMethod($method_reflection->getName());
            }
        }
        return $class_implementations;
    }
    
    /**
     * Adds a Hook attribute implementation.
     *
     * @param \Drupal\Core\Hook\Attribute\Hook $hook
     *   A hook attribute.
     * @param $class
     *   The class in which said attribute resides in.
     * @param $module
     *   The module in which the class resides in.
     *
     * @return void
     */
    protected function addFromAttribute(Hook $hook, $class, $module) {
        $this->implementations[$hook->hook][$class][$hook->method] = [
            'priority' => $hook->priority ?? $this->priority--,
            'module' => $hook->module ?? $module,
        ];
    }
    
    /**
     * Adds a procedural hook implementation.
     *
     * @param \SplFileInfo $fileinfo
     *   The file this procedural implementation is in. (You don't say)
     * @param string $hook
     *   The name of the hook. (Huh, right?)
     * @param string $module
     *   The name of the module. (Truly shocking!)
     * @param string $function
     *   The name of function implementing the hook. (Wow!)
     *
     * @return void
     */
    protected function addProceduralImplementation(\SplFileInfo $fileinfo, string $hook, string $module, string $function) {
        $this->proceduralHooks[$hook][$module] = FALSE;
        if ($hook === 'module_implements_alter') {
            $this->moduleImplementsAlters[] = $function;
        }
        if ($fileinfo->getExtension() !== 'module') {
            $this->includes[$function] = $fileinfo->getPathname();
        }
    }
    
    /**
     * Converts procedural hooks to attribute based hooks.
     *
     * @return $this
     */
    protected function convertProceduralToImplementations() : static {
        foreach ($this->proceduralHooks as $hook => $hook_implementations) {
            // A hook can be all numbers and because it was put into an array index
            // it might get cast into a number which might fail a
            // hook_module_implements_alter() and is guaranteed to fail the Hook
            // attribute constructor.
            $hook = (string) $hook;
            if ($hook !== 'module_implements_alter') {
                foreach ($this->moduleImplementsAlters as $alter) {
                    $alter($hook_implementations, $hook);
                }
            }
            foreach ($hook_implementations as $module => $group) {
                $this->addFromAttribute(new Hook($hook, $module . '_' . $hook), ProceduralCall::class, $module);
            }
        }
        return $this;
    }
    
    /**
     * This method is only to be used by ModuleHandler.
     *
     * @internal
     */
    public function loadAllIncludes() : void {
        foreach ($this->includes as $include) {
            include_once $include;
        }
    }
    
    /**
     * This method is only to be used by ModuleHandler.
     *
     * @internal
     */
    public function getImplementations() : array {
        return $this->implementations;
    }
    
    /**
     * Checks for hooks which can't be supported in classes.
     *
     * @param \Drupal\Core\Hook\Attribute\Hook $hook
     *   The hook to check.
     * @param string $class
     *   The class the hook is implemented on.
     *
     * @return void
     */
    public static function checkForProceduralOnlyHooks(Hook $hook, string $class) : void {
        $staticDenyHooks = [
            'install',
            'module_preinstall',
            'module_preuninstall',
            'modules_installed',
            'modules_uninstalled',
            'requirements',
            'schema',
            'uninstall',
            'update_last_removed',
        ];
        if (in_array($hook->hook, $staticDenyHooks) || preg_match('/^(post_update_|preprocess_|process_|update_\\d+$)/', $hook->hook)) {
            throw new \LogicException("The hook {$hook->hook} on class {$class} does not support attributes and must remain procedural.");
        }
    }

}