class DeprecationCollector

final class DeprecationCollector {
    public function __construct(Environment $twig) {
    }
    
    /**
     * Returns deprecations for templates contained in a directory.
     *
     * @param string $dir A directory where templates are stored
     * @param string $ext Limit the loaded templates by extension
     *
     * @return array An array of deprecations
     */
    public function collectDir(string $dir, string $ext = '.twig') : array {
        $iterator = new \RegexIterator(new \RecursiveIteratorIterator(new \RecursiveDirectoryIterator($dir), \RecursiveIteratorIterator::LEAVES_ONLY), '{' . preg_quote($ext) . '$}');
        return $this->collect(new TemplateDirIterator($iterator));
    }
    
    /**
     * Returns deprecations for passed templates.
     *
     * @param \Traversable $iterator An iterator of templates (where keys are template names and values the contents of the template)
     *
     * @return array An array of deprecations
     */
    public function collect(\Traversable $iterator) : array {
        $deprecations = [];
        set_error_handler(function ($type, $msg) use (&$deprecations) {
            if (\E_USER_DEPRECATED === $type) {
                $deprecations[] = $msg;
            }
            return false;
        });
        foreach ($iterator as $name => $contents) {
            try {
                $this->twig
                    ->parse($this->twig
                    ->tokenize(new Source($contents, $name)));
            } catch (SyntaxError $e) {
                // ignore templates containing syntax errors
            }
        }
        restore_error_handler();
        return $deprecations;
    }

}