;;; Scheme Recursive Art Contest Entry
;;;
;;; Please do not include your name or personal info in this file.
;;;
;;; Title: <Sunset Mountains>
;;;
;;; Description:
;;;   <Ping pong up and down
      by ones we get to seven
      the lucky number.>

(speed 0)

(define sc-width (screen_width))
(define sc-height (screen_height))

(define bottom-right-x (/ sc-width 2))
(define bottom-right-y (* -1 (/ sc-height 2)))

(define bottom-left-x (* -1 (/ sc-width 2)))
(define bottom-left-y (* -1 (/ sc-height 2)))


(define (has-seven k)
  (cond
    ((= (modulo k 10) 7) #t)
    ((< k 10) #f)
    (else (has-seven (quotient k 10)))
  )
)

(define lst (list 40 30 15 1 -15 -25 -30))

(define increase-lst (list 5 10 15 5 10 15 20))

(define colors (list "#FF9D48" "#FA7D47" "#EF4335" "#7F0131" "#500130" "#2C0F2B" "black"))

(define (higher-order fn lst increase-lst color)
  (if (null? lst)
    0
    (begin
          (penup)
          (begin_fill)
          (fn 1 0 (car lst) 170 bottom-left-x (car increase-lst) (car color))
          (end_fill)
          (penup)
          (higher-order fn (cdr lst) (cdr increase-lst) (cdr color)))
  )
)



(define (draw)
  (bgcolor "#FDD7C0")
  (define (pingpong direction index integer stop step increase new-color)
        (print integer)
        (color new-color)
        (setposition step (* integer 10))
        (pendown)
        (cond
              ((= index stop)
                    (begin
                      (setposition bottom-right-x bottom-right-y)
                      (setposition bottom-left-x bottom-left-y)
                      (setposition (* -1 (/(screen_width) 2)) 50)
                      1
                    ))
              ((or (= (modulo index 7) 0) (has-seven index)) (pingpong (* -1 direction) (+ 1 index) (- integer direction) stop (+ increase step) increase new-color))
              (else (pingpong direction (+ 1 index) (+ integer direction) stop (+ increase step) increase new-color))
        )
  )

  (higher-order pingpong lst increase-lst colors)

  (exitonclick)
)


; Please leave this last line alone.  You may add additional procedures above
; this line.
(draw)