(import scheme
        (chicken base)
        (prefix sdl2 "sdl2:")
        (prefix sdl2-ttf "ttf:")
        downstroke-engine
        downstroke-renderer
        downstroke-input)

(define *menu-cursor* 0)
(define *menu-items*  '("Play" "Quit"))
(define *title-font*  #f)
(define *menu-font*   #f)

(define +bg-color+   (sdl2:make-color   0   0   0 255))
(define +text-color+ (sdl2:make-color 255 255 255 255))

(define (clear-screen! renderer)
  (set! (sdl2:render-draw-color renderer) +bg-color+)
  (sdl2:render-fill-rect! renderer (sdl2:make-rect 0 0 600 400)))

;; ── States ───────────────────────────────────────────────────────────────────

(define (main-menu-update game _dt)
  (let ((input (game-input game)))
    (when (input-pressed? input 'up)
      (set! *menu-cursor* (max 0 (- *menu-cursor* 1))))
    (when (input-pressed? input 'down)
      (set! *menu-cursor* (min (- (length *menu-items*) 1) (+ *menu-cursor* 1))))
    (when (input-pressed? input 'a)
      (case *menu-cursor*
        ((0) (game-start-state! game 'playing))
        ((1) (sdl2:quit!) (exit))))))

(define (main-menu-render game)
  (let ((renderer (game-renderer game)))
    (clear-screen! renderer)
    (draw-ui-text renderer *title-font* "MENU DEMO" +text-color+ 200 80)
    (draw-menu-items renderer *menu-font* *menu-items* *menu-cursor* 150 150 50)))

(define (playing-update game _dt)
  (when (input-pressed? (game-input game) 'quit)
    (set! *menu-cursor* 0)
    (game-start-state! game 'main-menu)))

(define (playing-render game)
  (let ((renderer (game-renderer game)))
    (clear-screen! renderer)
    (draw-ui-text renderer *menu-font*
      "PLAYING! PRESS ESC TO RETURN" +text-color+ 120 150)))

;; ── Game ─────────────────────────────────────────────────────────────────────

(define *game*
  (make-game
    title: "Demo: Menu System" width: 600 height: 400

    preload: (lambda (game)
      (set! *title-font* (ttf:open-font "demo/assets/DejaVuSans.ttf" 24))
      (set! *menu-font*  (ttf:open-font "demo/assets/DejaVuSans.ttf" 16)))

    create: (lambda (game)
      (game-add-state! game 'main-menu
        (make-game-state #:update main-menu-update #:render main-menu-render))
      (game-add-state! game 'playing
        (make-game-state #:update playing-update #:render playing-render))
      (game-start-state! game 'main-menu))))

(game-run! *game*)