;;;
;;; text.progress - shows progress bar
;;;  
;;;   Copyright (c) 2007  Shiro Kawai  <shiro@acm.org>
;;;   
;;;   Redistribution and use in source and binary forms, with or without
;;;   modification, are permitted provided that the following conditions
;;;   are met:
;;;   
;;;   1. Redistributions of source code must retain the above copyright
;;;      notice, this list of conditions and the following disclaimer.
;;;  
;;;   2. Redistributions in binary form must reproduce the above copyright
;;;      notice, this list of conditions and the following disclaimer in the
;;;      documentation and/or other materials provided with the distribution.
;;;  
;;;   3. Neither the name of the authors nor the names of its contributors
;;;      may be used to endorse or promote products derived from this
;;;      software without specific prior written permission.
;;;  
;;;   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
;;;   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
;;;   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
;;;   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
;;;   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
;;;   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
;;;   TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
;;;   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
;;;   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
;;;   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
;;;   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
;;;  
;;;  $Id: progress.scm,v 1.5 2007/09/27 08:23:44 shirok Exp $
;;;

(define-module text.progress
  (use srfi-19)
  (export make-text-progress-bar))
(select-module text.progress)


;; Progress bar sample:
;;
;; <-- header---> <------- bar -------> <- num -><-time->     <-- info -->
;; foo           |##############       |  123/211   01:21 ETA   sending...
;;               ^
;;             separator

;; The 'ETA' calculation is derived from the scmail's progress bar code
;; written by Satoru Takabayashi.

(define (make-text-progress-bar . args)
  (let-keywords args ((header  "progress")
                      (header-width 14)
                      (bar-char #\#)
                      (bar-width 40)
                      (num-width 9)
                      (num-format (lambda (cur max)
                                    (format "~d/~d" cur max)))
                      (time-width 7)
                      (info-width 0)
                      (info  "")
                      (separator-char #\|)
                      (max-value 100)
                      (port (current-output-port)))
    (let ((current-value 0)
          (start-time (current-time))
          (finish-time  #f))
      (define (show)
        (format port "~v,,,,va~a~v,,,,va~a~v,,,,v@a~v,,,,v@a~a~v,,,,va~a"
                header-width header-width header
                (or separator-char "")
                bar-width bar-width (make-bar)
                (or separator-char "")
                num-width num-width
                (if (> num-width 0) (num-format current-value max-value) "")
                time-width time-width
                (if (> time-width 0) (make-time) "")
                (if (and (not finish-time) (> time-width 0)) " ETA" "    ")
                info-width info-width
                (if (> info-width 0) info "")
                (if finish-time "\n" "\r"))
        (flush port))
      (define (make-bar)
        (make-string (floor->exact (* (/. current-value max-value) bar-width))
                     bar-char))
      (define (fmt-time seconds)
        (cond
         ((not seconds) "--:--")
         ((>= seconds 3600)
          (format "~d:~2,'0d:~2,'0d"
                  (quotient seconds 3600)
                  (quotient (remainder seconds 3600) 60)
                  (remainder seconds 60)))
         (else
          (format "~2,'0d:~2,'0d"
                  (quotient seconds 60)
                  (remainder seconds 60)))))
      (define (time- s t)
        (time->seconds (time-difference s t)))
      (define (make-time)
        (cond
         (finish-time
          (fmt-time (round->exact (time- finish-time start-time))))
         ((zero? current-value)
          (fmt-time #f))
         (else
          (let* ((used (time- (current-time) start-time))
                 (eta  (- (/. (* used max-value) current-value) used)))
            (fmt-time (round->exact eta))))))
                
      (lambda (msg . args)
        (case msg
          ((show) (show))
          ((set)
           (when (null? args)
             (error "text-progress-bar: message 'set requires an argument"))
           (set! current-value (car args))
           (show))
          ((inc)
           (when (null? args)
             (error "text-progress-bar: message 'inc requires an argument"))
           (set! current-value (min (+ (car args) current-value) max-value))
           (show))
          ((finish)
           (set! finish-time (current-time))
           (show))
          ((set-header)
           (when (null? args)
             (error "text-progress-bar: message 'set-header requires an argument"))
           (set! header (car args))
           (show))
          ((set-info)
           (when (null? args)
             (error "text-progress-bar: message 'set-info requires an argument"))
           (set! info (car args))
           (show))
          (else
           (error "text-progress-bar: unrecognized message:" msg))))
      )))

(provide "text/progress")
