Sapui5/javascript datepicker

so
I have 3 fields: one to choose a period from the drop-down list.
two to display the dates corresponding to the chosen period.
So when I click on the period, the other two fields are filled with the corresponding dates.
there are 4 choices:
Next 3 days
Next 7 days
till today
starting today
I send you a screenshot to explain and also the project