;;; Scheme Recursive Art Contest Entry
;;;
;;; Please do not include your name or personal info in this file.
;;;
;;; Title: Sunset Generator with Binary Tree
;;;
;;; Description:
;;;   <for each ray in Sun
;;;    yield from shades of red and pink
;;;    generates sunset>

(define (draw)
  (ht)
  ; Sky
  (draw_sky 192 sky_colors)

  ; Sunset
  (triangle 0 75 -75 75 150 "#ffe700")
  (double_triangle 0 75 -150 -75 150 "#ffce00")
  (double_triangle 0 75 -250 -150 150 "#ff8a29")
  (double_triangle 0 75 -360 -250 150 "#f8ceb8")
  (double_triangle -360 150 -360 0 75 "#f8aeb8")

  ; Sun
  (fd 37.5)
  (dot 75 "#fdff2c")

  ; Mountains
  (double_triangle -240 0 -360 -120 -150 "#ce7d3a")
  (triangle 0 0 -180 180 -225 "#ce7d3a")

  ; Grass
  (rectangle -225 135 -360 720 "#8bb827")

  ; Palm Trees
  (palm_tree -225)
  (palm_tree 165)

  (exitonclick)
)

(define (move x y)
  (pu)
  (goto x y)
  (pd)
)

(define (draw_sky start_position colors)
  (if (null? colors)
    (rectangle 75 300 -360 720 "#8febff")
    (begin
      (rectangle start_position 42 -360 720 (car colors))
      (draw_sky (+ start_position 42) (cdr colors))
    )
  )
)

(define sky_colors '("#cff7ff" "#adf0ff" "#8febff" "#64e4ff" "#35dbff"))

(define (rectangle top_position height left_position length colour)
  (begin_fill)
  (color colour)
  (move left_position top_position)
  (setx (+ left_position length))
  (sety (- top_position height))
  (setx left_position)
  (sety top_position)
  (end_fill)
)

(define (triangle tip_x tip_y edge1_x edge2_x base_y colour)
  (begin_fill)
  (color colour)
  (move edge2_x base_y)
  (setx edge1_x)
  (goto tip_x tip_y)
  (goto edge2_x base_y)
  (end_fill)
)

(define (double_triangle tip_x tip_y edge1_x edge2_x base_y colour)
  (triangle tip_x tip_y edge1_x edge2_x base_y colour)
  (triangle (abs tip_x) tip_y (abs edge1_x) (abs edge2_x) base_y colour)
)

(define (palm_tree left_position)
  ; Tree Trunk
  (rectangle 0 292.5 left_position 60 "#644643")
  (color "#7a6564")
  (lines left_position -292.5)

  ; Tree Head
  (begin_fill)
  (color "#578335")
  (tree_head 5)
  (end_fill)
)

(define (lines left_position start)
  (if (< start 0)
    (begin
      (move (+ left_position 60) start)
      (seth 270)
      (fd 60)
      (lines left_position (+ start 11.7))
    )
  )
)

(define (tree_head n)
  (if (> n 0)
    (begin
      (fd 60)
      (rt 120)
      (fd 60)
      (lt 60)
      (tree_head (- n 1))
    )
  )
)

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