if i have mongodb collection , the collection contains recipients medicals sessions , the collection schema have recipient information , session date , start time and end time. for example, for specific recipient he has a session on 3/5/2021 from 2pm to 4pm stored on db. how to make a gui or timepicker to get just available time or interval's on specific date that doesn't already exist on db , that i can choose in adding new session gui.