;; The structure represents a circle 
;; The structure represents a circle 
;; center is the position (posn structure) of the center
;; radius is its radius (a non-negative number), and
;; color is a symbol representing a color
(define-struct circle (center radius color))

;; draw-a-circle: circle -> true
;; the function draws a circle structure as a disk
;; and returns true
(define (draw-a-circle a-circle)
  (draw-solid-disk (circle-center a-circle)
                   (circle-radius a-circle)
                   (circle-color a-circle)) 
)

;; clear-a-circle: circle -> true
;; the function clears a disk corresponding to a circle
;; and returns true
(define (clear-a-circle a-circle)
  (clear-solid-disk (circle-center a-circle)
                   (circle-radius a-circle))
)

;; move-circle: circle number number -> circle
;; the function creates a new circle from a given one
;; with coordinates shifted by x-shift and y-shift
(define (move-circle a-circle x-shift y-shift)
  (make-circle
   (make-posn (+ (posn-x (circle-center a-circle)) x-shift) 
              (+ (posn-y (circle-center a-circle)) y-shift))
   (circle-radius a-circle)
   (circle-color a-circle)
  )
)


;; The structure represents a rectangle 
;; left-upper is the position (posn structure) of its 
;; left upper corner, height and width are its height and
;; width (non-negative numbers), and
;; color is a symbol representing a color
(define-struct rectangle (left-upper height width color))

;; draw-a-rectangle: rectangle -> true
;; the function draws a rectangle structure as a solid rectangle
;; and returns true
(define (draw-a-rectangle a-rectangle)
  (draw-solid-rect (rectangle-left-upper a-rectangle)                
                   (rectangle-height a-rectangle)
                    (rectangle-width a-rectangle)
                   (rectangle-color a-rectangle))
)

(define (draw-shapes alosh)
  (cond
    [(empty? alosh) true]
    [(circle? (first alosh)) (and (draw-a-circle (first alosh))
                                  (draw-shapes (rest alosh)))]
    [(rectangle? (first alosh)) (and (draw-a-rectangle (first alosh))
                                     (draw-shapes (rest alosh)))]
  )
)



;; nested-squares: number number color boolean posn -> list of rectangles
;; what will the fucntion draw? 
(define (nested-squares width min-width color isWhite left-upper)
  (cond 
    [(< width min-width) empty]
    [else (cons
           (make-rectangle left-upper width width 
                           (cond 
                             [isWhite 'white]
                             [else color]
                             )  
                           )
           (nested-squares (/ width 2) min-width color (not isWhite) 
                           (make-posn (+ (posn-x left-upper) (/ width 4))
                                      (+ (posn-y left-upper) (/ width 4)))))]
))

;; change the function to make the nested rectangles alternate between two different 
;; colors and each next one have 3/4 width of the previous one

(start 300 300)

(define squares (nested-squares 256 10 'blue false (make-posn 20 20)))

(draw-shapes squares)