function hooks($hook = '') {
            global $wp_filter;

            if ( isset( $wp_filter[$hook]->callbacks ) ) {
                array_walk( $wp_filter[$hook]->callbacks, function( $callbacks, $priority ) use ( &$hooks ) {
                    foreach ( $callbacks as $id => $callback )
                        $hooks[] = array_merge( [ 'id' => $id, 'priority' => $priority ], $callback );
                });
            } else {
                return [];
            }

            foreach( $hooks as &$item ) {
                // skip if callback does not exist
                if ( !is_callable( $item['function'] ) ) continue;

                // function name as string or static class method eg. 'Foo::Bar'
                if ( is_string( $item['function'] ) ) {
                    $ref = strpos( $item['function'], '::' ) ? new ReflectionClass( strstr( $item['function'], '::', true ) ) : new ReflectionFunction( $item['function'] );
                    $item['file'] = $ref->getFileName();
                    $item['line'] = get_class( $ref ) == 'ReflectionFunction'
                        ? $ref->getStartLine()
                        : $ref->getMethod( substr( $item['function'], strpos( $item['function'], '::' ) + 2 ) )->getStartLine();

                // array( object, method ), array( string object, method ), array( string object, string 'parent::method' )
                } elseif ( is_array( $item['function'] ) ) {

                    $ref = new ReflectionClass( $item['function'][0] );

                    // $item['function'][0] is a reference to existing object
                    $item['function'] = array(
                        is_object( $item['function'][0] ) ? get_class( $item['function'][0] ) : $item['function'][0],
                        $item['function'][1]
                    );
                    $item['file'] = $ref->getFileName();
                    $item['line'] = strpos( $item['function'][1], '::' )
                        ? $ref->getParentClass()->getMethod( substr( $item['function'][1], strpos( $item['function'][1], '::' ) + 2 ) )->getStartLine()
                        : $ref->getMethod( $item['function'][1] )->getStartLine();

                // closures
                } elseif ( is_callable( $item['function'] ) ) {
                    $ref = new ReflectionFunction( $item['function'] );
                    $item['function'] = get_class( $item['function'] );
                    $item['file'] = $ref->getFileName();
                    $item['line'] = $ref->getStartLine();

                }
            }

            return $hooks;
        }