;;; mail-utils.el --- utility functions used both by rmail and rnews

;; Copyright (C) 1985 Free Software Foundation, Inc.

;; Maintainer: FSF
;; Keywords: mail, news

;; This file is part of GNU Emacs.

;; GNU Emacs 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.

;; GNU Emacs 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, 675 Mass Ave, Cambridge, MA 02139, USA.

;;; Commentary:

;; Utility functions for maol and netnews handling.  These handle fine
;; points of header parsing.

;;; Code:

;;; We require lisp-mode to make sure that lisp-mode-syntax-table has
;;; been initialized.
(require 'lisp-mode)
		     
;;;###autoload
(defvar mail-use-rfc822 nil "\
*If non-nil, use a full, hairy RFC822 parser on mail addresses.
Otherwise, (the default) use a smaller, somewhat faster, and
often correct parser.")

(defun mail-string-delete (string start end)
  "Returns a string containing all of STRING except the part
from START (inclusive) to END (exclusive)."
  (if (null end) (substring string 0 start)
    (concat (substring string 0 start)
	    (substring string end nil))))

(defun mail-strip-quoted-names (address)
  "Delete comments and quoted strings in an address list ADDRESS.
Also delete leading/trailing whitespace and replace FOO <BAR> with just BAR.
Return a modified address list."
  (if (null address)
      nil
    (if mail-use-rfc822
	(progn (require 'rfc822)
	       (mapconcat 'identity (rfc822-addresses address) ", "))
      (let (pos)
       (string-match "\\`[ \t\n]*" address)
       ;; strip surrounding whitespace
       (setq address (substring address
				(match-end 0)
				(string-match "[ \t\n]*\\'" address
					      (match-end 0))))

       ;; Detect nested comments.
       (if (string-match "[ \t]*(\\([^)\"\\]\\|\\\\.\\|\\\\\n\\)*(" address)
	   ;; Strip nested comments.
	   (save-excursion
	     (set-buffer (get-buffer-create " *temp*"))
	     (erase-buffer)
	     (insert address)
	     (set-syntax-table lisp-mode-syntax-table)
	     (goto-char 1)
	     (while (search-forward "(" nil t)
	       (forward-char -1)
	       (skip-chars-backward " \t")
	       (delete-region (point)
			      (save-excursion
				(condition-case ()
				    (forward-sexp 1)
				  (error (goto-char (point-max))))
				  (point))))
	     (setq address (buffer-string))
	     (erase-buffer))
	 ;; Strip non-nested comments an easier way.
	 (while (setq pos (string-match 
			    ;; This doesn't hack rfc822 nested comments
			    ;;  `(xyzzy (foo) whinge)' properly.  Big deal.
			    "[ \t]*(\\([^)\"\\]\\|\\\\.\\|\\\\\n\\)*)"
			    address))
	   (setq address
		 (mail-string-delete address
				     pos (match-end 0)))))

       ;; strip `quoted' names (This is supposed to hack `"Foo Bar" <bar@host>')
       (setq pos 0)
       (while (setq pos (string-match
			  "[ \t]*\"\\([^\"\\]\\|\\\\.\\|\\\\\n\\)*\"[ \t\n]*"
			  address pos))
	 ;; If the next thing is "@", we have "foo bar"@host.  Leave it.
	 (if (and (> (length address) (match-end 0))
		  (= (aref address (match-end 0)) ?@))
	     (setq pos (match-end 0))
	   (setq address
		 (mail-string-delete address
				     pos (match-end 0)))))
       ;; Retain only part of address in <> delims, if there is such a thing.
       (while (setq pos (string-match "\\(,\\|\\`\\)[^,]*<\\([^>,]*>\\)"
				      address))
	 (let ((junk-beg (match-end 1))
	       (junk-end (match-beginning 2))
	       (close (match-end 0)))
	   (setq address (mail-string-delete address (1- close) close))
	   (setq address (mail-string-delete address junk-beg junk-end))))
       address))))
  
(or (and (boundp 'rmail-default-dont-reply-to-names)
	 (not (null rmail-default-dont-reply-to-names)))
    (setq rmail-default-dont-reply-to-names "info-"))

; rmail-dont-reply-to-names is defined in loaddefs
(defun rmail-dont-reply-to (userids)
  "Returns string of mail addresses USERIDS sans any recipients
that start with matches for `rmail-dont-reply-to-names'.
Usenet paths ending in an element that matches are removed also."
  (if (null rmail-dont-reply-to-names)
      (setq rmail-dont-reply-to-names
	    (concat (if rmail-default-dont-reply-to-names
			(concat rmail-default-dont-reply-to-names "\\|")
		        "")
		    (concat (regexp-quote (user-original-login-name))
			    "\\>"))))
  (let ((match (concat "\\(^\\|,\\)[ \t\n]*\\([^,\n]*!\\|\\)\\("
		       rmail-dont-reply-to-names
		       "\\)"))
	(case-fold-search t)
	pos epos)
    (while (setq pos (string-match match userids))
      (if (> pos 0) (setq pos (1+ pos)))
      (setq epos
	    (if (string-match "[ \t\n,]+" userids (match-end 0))
		(match-end 0)
	      (length userids)))
      (setq userids
	    (mail-string-delete
	      userids pos epos)))
    ;; get rid of any trailing commas
    (if (setq pos (string-match "[ ,\t\n]*\\'" userids))
	(setq userids (substring userids 0 pos)))
    ;; remove leading spaces. they bother me.
    (if (string-match "\\s *" userids)
	(substring userids (match-end 0))
      userids)))

(defun mail-fetch-field (field-name &optional last all)
  "Return the value of the header field FIELD-NAME.
The buffer is expected to be narrowed to just the headers of the message.
If second arg LAST is non-nil, use the last such field if there are several.
If third arg ALL is non-nil, concatenate all such fields with commas between."
  (save-excursion
    (goto-char (point-min))
    (let ((case-fold-search t)
	  (name (concat "^" (regexp-quote field-name) "[ \t]*:[ \t]*")))
      (goto-char (point-min))
      (if all
	  (let ((value ""))
	    (while (re-search-forward name nil t)
	      (let ((opoint (point)))
		(while (progn (forward-line 1)
			      (looking-at "[ \t]")))
		(setq value (concat value
				    (if (string= value "") "" ", ")
				    (buffer-substring opoint (1- (point)))))))
	    (and (not (string= value "")) value))
	(if (re-search-forward name nil t)
	    (progn
	      (if last (while (re-search-forward name nil t)))
	      (let ((opoint (point)))
		(while (progn (forward-line 1)
			      (looking-at "[ \t]")))
		(buffer-substring opoint (1- (point))))))))))

;; Parse a list of tokens separated by commas.
;; It runs from point to the end of the visible part of the buffer.
;; Whitespace before or after tokens is ignored,
;; but whitespace within tokens is kept.
(defun mail-parse-comma-list ()
  (let (accumulated
	beg)
    (skip-chars-forward " ")
    (while (not (eobp))
      (setq beg (point))
      (skip-chars-forward "^,")
      (skip-chars-backward " ")
      (setq accumulated
	    (cons (buffer-substring beg (point))
		  accumulated))
      (skip-chars-forward "^,")
      (skip-chars-forward ", "))
    accumulated))

(defun mail-comma-list-regexp (labels)
  (let (pos)
    (setq pos (or (string-match "[^ \t]" labels) 0))
    ;; Remove leading and trailing whitespace.
    (setq labels (substring labels pos (string-match "[ \t]*$" labels pos)))
    ;; Change each comma to \|, and flush surrounding whitespace.
    (while (setq pos (string-match "[ \t]*,[ \t]*" labels))
      (setq labels
	    (concat (substring labels 0 pos)
		    "\\|"
		    (substring labels (match-end 0))))))
  labels)

(provide 'mail-utils)

;;; mail-utils.el ends here