Completed → Waiting in Things

waiting-done-things.scpt

property waitingForTag : "Waiting"
property daysDue : 2

tell application "Things"
	repeat with selectedToDo in selected to dos

		set projectToDo to project of selectedToDo
		set areaToDo to area of selectedToDo
		
		set status of selectedToDo to completed
		set theTitle to "Waiting for " & name of selectedToDo
		set theDueDate to (current date) + daysDue * days

		set newToDo to make new to do ¬
			with properties {name:theTitle, due date:theDueDate}
		set tag names of newToDo to waitingForTag

		if projectToDo is not missing value then
			set project of newToDo to projectToDo
		else if areaToDo is not missing value then
			set area of newToDo to areaToDo
			move newToDo to list "Next"
		end if

	end repeat
end tell

For some documentation please see my accompanying blog post.