;;; utils.scm: common utility procedures
;;; author: Anand Babu <ab@gnu.org.in> (from freehoo)
;;; ported: Anand Avati <avati@zresearch.com>

;;; This program 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 program 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 this program; if not, write to the Free Software
;;; Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA
;;; 
;;; utils.scm should be automatically loaded thru init.scm

(define (/version args)
  "display version info"
  (display (string-append "freetalk (FreeTalk) " (ft-version) "\n"
			  "Copyright (C) 2005 FreeTalk Core Team.\n"
			  "This is free software; see the source for copying conditions.  There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n")))

(add-command! /version "/version" "/version" "display freetalk version information")

(define (any->symbol item)
  "converts a number into a symbol"
  (if (number? item)
      (string->symbol (number->string item))
      (if (string? item)
	  (string->symbol item)
	  item)))
  
(define (list->asv li any) 
  "convert list to any separated vector"
  (if (=(length li) 1)
      (car li)
      (string-append (car li) any (list->asv (cdr li) any))))

(define (list->csv li) 
  "convert list to comma separated vector"
  (list->asv li ", "))

(define (list->symlist li)
  "converts a list of numbers/symbols to list of symbols"
  (if (= (length li) 1)
      (list (any->symbol (car li)))
      (append (list (any->symbol (car li))) (list->symlist (cdr li)))))

(define (list->strlist li)
  "converts a list of numbers/symbols to list of strings"
  (if (= (length li) 0)
      '()
      (if (= (length li) 1)
	  (list 
	   (symbol->string 
	    (any->symbol (car li))))
	  (append (list 
		   (symbol->string 
		    (any->symbol (car li))))
		  (list->strlist (cdr li))))))

(define (local-date-time)
  (string-append
                 (strftime "%F" (localtime (current-time)))
		 "-"
                 (strftime "%T" (localtime (current-time)))))


(define (skip-comment port)
  (let ((char (peek-char port)))
    (if (or (eof-object? char)
            (char=? #\newline char))
        char
        (begin
          (read-char port)
          (skip-comment port)))))

(define (skip-whitespace port)
  (let ((char (peek-char port)))
    (cond ((or (eof-object? char)
	       (char=? #\newline char))
	   char)
	  ((char-whitespace? char)
	   (read-char port)
	   (skip-whitespace port))
;;  	  ((char=? #\# char)
;;  	   (read-char port)
;;  	   (skip-comment port))
	  (else char))))

(define (read-token port delim)
  (letrec
      ((loop
	(lambda (chars)
	  (let ((char (peek-char port)))
	    (cond ((eof-object? char)
		   (do-eof char chars))
		  ((char=? #\newline char)
		   (do-eot chars))
		  ((char-whitespace? char)
		   (do-eot chars))
;;  		   (let ((terminator (skip-comment port)))
;;  		     (if (eof-object? char)
;;  			 (do-eof char chars)
;;  			 (do-eot chars))))
		  (else
		   (read-char port)
		   (loop (cons char chars)))))))
       (do-eof
	(lambda (eof chars)
	  (if (null? chars)
	      eof
	      (do-eot chars))))
       (do-eot
	(lambda (chars)
	  (if (null? chars)
	      #f
	      (list->string (reverse! chars))))))
    (skip-whitespace port)
    (loop '())))

(define (sentence->words sentence)
  "convert sentence to list of words"
  (with-input-from-string sentence
    (lambda ()
      (letrec
	  ((next-token
	    (lambda ()
	      (read-token (current-input-port) #\#)))
	   (append-word
	    (lambda (word-list)
	      (let
		  ((word (next-token)))
		(if (eof-object? word)
		    word-list
		    (begin
		      (append-word 
		       (append word-list (list word)))))))))
	(append-word '())))))


(define (blank-line? line)
  "return true if line is blank"
  (null? (sentence->words line)))


;;; string utils
;; for string-match procedure
(use-modules (ice-9 regex))
(use-modules (ice-9 string-fun))
(use-modules (ice-9 format))

(define (sentence->tokens sentence)
  "convert string to list of tokens"
  (with-input-from-string sentence
    (lambda ()
      (letrec
	  ((next-token (lambda ()
			 (read (current-input-port))))
	   (append-word (lambda (word-list)
			  (let
			      ((word (next-token)))
			    (if (eof-object? word)
				word-list
				(begin
				  (append-word (append word-list 
						       (list word)))))))))
	(append-word '())))))


(define (list->sentence li)
  "convert list to space separated sentence"
  (let
      ((word (if (symbol? (car li))
		 (symbol->string (car li))
		 (number->string (car li)))))
    (if (= (length li) 1)
	word
	(string-append word " " (list->sentence (cdr li))))))


(define (string-separate str ch)
  (let ((index (string-index str ch)))
    (if index
	(cons (substring str 0 index)
	      (string-separate (substring str 
				       (+ index 1) 
				       (string-length str)) 
			    ch))
	(list str))))


(define (blank-line? line)
  "return true if line is blank"
  (or (= 0 (string-length line))
      (null? (sentence->tokens line))))


(define (dollor->number dollor)
  "convert dollor symbol to number"
  (string->number 
   (cadr (string-separate (symbol->string dollor) #\$))))


(define (read-next-line fport)
  "skip blank lines and read the next line"
  (let ((line (read-line fport)))
    (if (eof-object? line)
	""
	(if (not (blank-line? line))
	    line
	    (read-next-line fport)))))


(define (string-string? str find-string)
  "returns true if find-string is a substring of str"
  (vector? (string-match find-string str)))


(define (date->list date)
  "convert flat yymmdd num to (yy mm dd) list"
  (let* 
      ((date-str (list->string 
		  (map (lambda (c) 
			 (if (eq? c #\space) #\0 c))
		       (string->list (format #f "~6d" date)))))
       (yy (substring date-str 0 2))
       (mm (substring date-str 2 4))
       (dd (substring date-str 4 6)))
    (map string->number (list yy mm dd))))

(define (for-each-line proc filename)
  "call PROC for each line in FILENAME"
  (with-input-from-file filename
    (lambda ()
      (do ((line (read-line) (read-line)))
          ((eof-object? line))
        (proc line)))))