#|
(defpackage #:sisyphus
  (:use #:common-lisp)
  (:export #:start))

(in-package #:sisyphus)
|#

(defvar *surface* nil)
(defvar *current-frame* -1)

(defun init-sdl ()
  (sdl:init (logior sdl:+init-video+ sdl:+init-noparachute+))
  (sdl:wm-set-caption "Sisyphus" nil))

(defun create-filename (name number)
  (concatenate 'string
	       name
	       (format nil "~10,3,'0R" number)
		".ppm"))

(defun load-buffers (name frames)
  (let ((buffers (make-array (list frames))))
    
    (dotimes (i frames)
      (format t "loading ~A~%" (create-filename name i))
      (setf (aref buffers i) (img:load (create-filename name i))))
  
    ; Initialize the main surface
    (setf *surface* (sdl:set-video-mode (sdl:surface-w (aref buffers 0))
					(sdl:surface-h (aref buffers 0))
					24
					(logior sdl:+doublebuf+
						sdl:+swsurface+)))
    (when (sgum:null-pointer-p *surface*)
      (error "Unable to set video mode"))
    
    buffers))

(defun update-surface (buffers total-frames)
  (if (= *current-frame* (- total-frames 1))
      (setf *current-frame* -1))
  (sdl:blit-surface (aref buffers (incf *current-frame*)) nil *surface* nil)
  (sdl:flip *surface*)
  (sdl:delay 75))

(defun run-sdl-event-loop (buffers frames)
  (sdl:event-loop
   (:key-down (scan-code key mod unicode)
	      (if (= key (char-code #\q))
		  (return)))
   (:quit ()
	  (return))
   (:idle ()
	  (update-surface buffers frames))))

(defun start (name frames)
  (init-sdl)
  (unwind-protect
      (progn
	(let ((buffers (load-buffers name frames)))
	  (run-sdl-event-loop buffers frames)))
    (sdl:quit)))