Can you help me with my kat build

I need help with my kat skill and item builds plz post ur builds and opinion on ap or ad kat

Roll AP kat shes amazing at teamfight specially at 5v5. if u have a kayle that can shield u or a zhonias so u do it after/before u start doing ur spin and pwn ability lols.. and for the build i dont know what to say.

Start with Doran's Shield and a potion
Haunting Guise + Sorcerers Shoes for both ap and damage
if ap : Zhonya , Rylai , Abyssal Scepter , Voidstaff , Mejai
if damage : Sword of the Ocult and Bloodthirsters ( get some swords first and don't upgrade till later) and Voidstaff

i see alot of ap kat's out there