As someone who just recently decommissioned this case I can personally tell you it is not a watercooling case. Not even an AIO.
The issue with the case is that there is not enough room inside the roof for both a radiator and a set of fans. You will have to put the radiator inside and the fans outside making it look ugly.
If you decide to just go with a 120 radiator in the back, it will prevent you from using the 200mm fan in the roof. Only a 120 will be able to fit in the roof meaning dust will fall right into the case.
The HAF is a air case, not a watercooling case.