(defpackage :klmnea
  (:use :common-lisp)
  (:export
   #:process-nmea
   #:process-nmeassage
   #:defnmeassage))

(in-package klmnea)

(defclass nmeassage () ())

(defmethod process-nmeassage ((message nmeassage))
  (values))

(defun slot-names (lst)
  (let ((vals (mapcar #'(lambda (part) (mapcar #'car part)) lst)))
    (values (apply #'append vals) vals)))

(defun unmearshall (type form)
  (case type
    (:integer `(ignore-errors (parse-integer ,form :junk-allowed t)))
    (:float `(ignore-errors (read-from-string ,form nil nil)))
    (t `(let ((f ,form)) (if (not (string= "" f)) f)))))

(defun fornmeat (slot)
  (if (null (third slot)) "~a"
      (case (second slot)
	(:integer (format nil "~~~a,,,'0@a" (third slot)))
	(:float (format nil "~~~a,4,,,'0f" (+ 5 (third slot))))
	(t "~a"))))

(defun generate-slot-setters (str index &optional slot setters (offset 0))
  (if (null slot)
      (if (null str) setters
	  (generate-slot-setters (cdr str) index (car str) setters offset))  
      (generate-slot-setters 
       (cdr str) index (car str)
       (cons `((slot-value message ',(first slot))
		    ,(unmearshall 
		      (second slot)
		      (if (and (third slot) (not (eq :float (second slot))))
			  `(subseq (nth ,index lst) 
				      ,offset ,(+ offset (third slot)))
			  `(subseq (nth ,index lst) ,offset))))
	     setters)
       (if (third slot) (+ offset (third slot)) offset))))


(defun generate-format-string (str &optional slot fmts)
  (if (null slot)
      (if (null str) (reverse fmts)
	  (generate-format-string (cdr str) (car str) fmts))  
      (generate-format-string (cdr str) (car str) (cons (fornmeat slot) fmts))))