(use-modules (chickadee graphics sprite)
	     (chickadee)
	     (chickadee graphics viewport)
	     (ice-9 pretty-print)
	     (ice-9 format))

(define lane-height 65)
(define lane-length 200)
(define road (load-tileset "road.png" lane-length lane-height))
(define road-top (texture-atlas-ref road 2))
(define road-bottom (texture-atlas-ref road 0))
(define road-lane (texture-atlas-ref road 1))
(define road-start-y 80)

(define (draw-lanes x y num-lanes)
  (if (> num-lanes 0)
      (begin
	(draw-sprite road-lane (vec2 x y))
	(draw-lanes x (+ lane-height y) (- num-lanes 1)))))

(define (draw-road-section startx starty num-lanes)
  (draw-sprite road-bottom (vec2 startx starty))
  (draw-lanes startx (+ lane-height starty) (- num-lanes 2))
  (draw-sprite road-top (vec2 startx (+ starty (* lane-height (- num-lanes 1))))))

(define (draw-road startx starty num-lanes)
  (if (< startx (window-width (current-window)))
      (begin
	(draw-road-section startx starty num-lanes)
	(draw-road (+ startx lane-length) starty num-lanes))))

(define (lane-y num-lane)
  (+ road-start-y
     (* lane-height (- num-lane 1))))

(define vehicle-height 45)
(define vehicle-length 100)
(define vehicles (load-tileset "vehicles.png" vehicle-length vehicle-height))
(define selected-car (texture-atlas-ref vehicles 0))

(define car-pos-x 0.0)
(define car-steering-speed 4.0)
(define player-velocity (vec2 0 0))
(define road-min-speed 4)
(define road-max-speed 20)
(define road-speed road-min-speed)
(define road-position 0)

(define player-position
  (vec2 (/ (- (window-width (current-window)) vehicle-length) 2)
	(+ (lane-y 3)
	   (/ (- lane-height vehicle-height) 2))))

(define (draw alpha)
  (set! road-position (if (< road-position (* lane-length -1))
			  (- (+ road-position lane-length) road-speed)
			  (- road-position road-speed)))
  (draw-road road-position road-start-y 5)

  (draw-text "Turbo Racers!" (vec2 260.0 (- (window-height (current-window)) 25)))
  (draw-text (format #f "Speed: ~smph" (* road-speed 5))
	     (vec2 450.0 20.0))

  (set! player-position (vec2+ player-position player-velocity))

  (draw-sprite selected-car player-position))

(define (key-press key modifiers repeat?)
  (if (eq? key 'w)
      (set! player-velocity (vec2 0 car-steering-speed)))
  (if (eq? key 's)
      (set! player-velocity (vec2 0 (* car-steering-speed -1))))
  (if (eq? key 'a)
      (set! road-speed (max (- road-speed 1) road-min-speed)))
  (if (eq? key 'd)
      (set! road-speed (min (+ road-speed 1) road-max-speed)))
  )

(define (key-release key modifiers)
  (if (or (eq? key 'w) (eq? key 's))
      (set! player-velocity (vec2 0 0))))