If Date

Hello, Would please help me to find the proper formula for this below
if R6 is Action date
if S6 is Target date
T6 is Number of days to close the action ( =S6-R6)
U6 Date of completion or closed action

I want a formula for V6 to be as :
- Open action if date range between R6 and S6
- Over Due if date > S6
- Closed if insert date in U6 cell

Thanks