import python

private import semmle.python.dataflow.new.internal.DataFlowDispatch

predicate fewer_than_two_public_methods(Class cls, int methods) {

(methods = 0 or methods = 1) and

methods = count(Function f | f = cls.getAMethod() and not f = cls.getInitMethod())

predicate does_not_define_special_method(Class cls) {

not exists(Function f | f = cls.getAMethod() and f.isSpecialMethod())

predicate no_inheritance(Class c) {

predicate is_decorated(Class c) { exists(c.getADecorator()) }

predicate is_stateful(Class c) {

predicate useless_class(Class c, int methods) {

from Class c, int methods, string msg

useless_class(c, methods) and

(

methods = 1 and

msg =

"Class " + c.getName() +

" defines only one public method, which should be replaced by a function."

or

methods = 0 and

msg =

"Class " + c.getName() +

" defines no public methods and could be replaced with a namedtuple or dictionary."

)

select c, msg