;;
;; quiz 4 code 
;;

;; Here are the structure definitions for the animation entities supported by draw-anim-entity

;; circle : 
;;     center is a posn
;;     radius is a number
;;     color is a symbol. 'Clear mean clear the circle!

(define-struct circle (center radius color))




;; square : 
;;     center is a posn (NOTE we use center, not topleft!)
;;     radius is a number
;;     color is a symbol. 'Clear means clear the circle

(define-struct square (center size color))

;; delay is just a time in seconds
(define-struct delay (time))



;; draw-anim-entity consumes an animation-entity (a struct that is either
;;    a circle, square or delay
;;
;; For square and circle, either draws or clears the entity (based on the color)
;; For delay, just waits for a while
; 
(define (draw-anim-entity s)
  (cond

    [(circle? s) 
	 ;; it's a circle - should we draw or clear?
	 (cond
	  [ (symbol=? (circle-color s) 'Clear)
		;; clear it
		(clear-circle (circle-center s) (circle-radius s))]

	  [ else
		;; draw it
		(draw-circle (circle-center s) (circle-radius s) (circle-color s)) ])]

    [(square? s) 
	 ;; it's a square - should we draw or clear?
	 (cond
	  [(symbol=? (square-color s) 'Clear)
	   ;; clear it - need to translate from center to topleft
	   (clear-solid-rect 
		(make-posn
		 (- (posn-x (square-center s)) (/ (square-size s) 2))
		 (- (posn-y (square-center s)) (/ (square-size s) 2)))
		(square-size s) (square-size s))]

	  [ else
		;; draw it
		(draw-solid-rect 
		 (make-posn
		  (- (posn-x (square-center s)) (/ (square-size s) 2))
		  (- (posn-y (square-center s)) (/ (square-size s) 2)))
		 (square-size s) (square-size s) (square-color s))])]

	[(delay? s)
	 ;; it's a delay - wait for a while
	 (sleep-for-a-while (delay-time s))]

	;; it's not anything we understand - report an error
    [else 
	 (error 'draw-anim-entity "I dont' know how to draw that (is it an animimation entity?)")]))
;;
;;

;; 
(start 400 400)

;;(draw-anim-entity
;; (make-square (make-posn 200 200) 141 'Blue))

;;(draw-anim-entity
;; (make-circle (make-posn 200 200) 100 'Red))