;;; stardate.el --- Calculate and show Stardate from StarTrek
;; -*- mode: emacs-lisp -*-
;; $Id: stardate.el,v 1.5 2003-06-26 14:34:03+09 umq Exp $

;;; Copyright and licence: ----------------------------------------------------

;; Copyright (C) 2003 by Hirohisa Yamaguchi
;; 
;; This file is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.

;; This file is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;;; Code:

(eval-and-compile
  (require 'time)
  )

(defgroup stardate nil
  "Calculate and show Stardate from StarTrek"
  :group 'data
  :group 'extensions)


(defcustom display-time-stardate t
  "*Non-nil shows internet time when display-time enabled"
  :type 'boolean
  :group 'display-time
  :require 'time)

(defcustom display-time-stardate-only nil
  "*Non-nil shows internet time only"
  :type 'boolean
  :group 'display-time)

(defun stardate ()
  "calculate stardate"
  (interactive)
  (progn
    (let ((stardate-time (string-to-int (format-time-string "%s" (current-time)))))
      (let ((stardate-integer
	     (+ (/ stardate-time 17280) 9350)))
	(let
	    ((stardate-issue (floor (- (/ stardate-integer 10000) 36)))
	     (stardate-fraction (/ (* (mod stardate-time 17280) 3125) 54))
	     (stardate-string nil))
	  (setq stardate-string
		(concat (format "[%d]"
				stardate-issue)
			(format "%04d."
				(mod stardate-integer 10000))
			(substring (format "%06d"
					   stardate-fraction) 0 3)))
	  (if (interactive-p) (princ stardate-string t) stardate-string))))))

(setq display-time-string-forms
      '((if (and (not display-time-format) display-time-day-and-date)
            (format-time-string "%a %b %e " now)
          "")
        (if display-time-stardate
            (if display-time-stardate-only
		(stardate)
	      (concat
	       (format-time-string
		(or display-time-format
		    (if display-time-24hr-format "%H:%M" "%-I:%M%p"))
		now)
	       "\(" (stardate) "\)"))
          (format-time-string 
	   (or display-time-format
	       (if display-time-24hr-format "%H:%M" "%-I:%M%p"))
	   now))
        load
        (if mail " Mail" ""))
      )

(provide 'stardate)

;;; stardate.el ends here