;;; mhspool.el --- MH folder access using NNTP for GNU Emacs

;; Copyright (C) 1988, 1989, 1990, 1993 Free Software Foundation, Inc.

;; Author: Masanobu UMEDA <umerin@flab.flab.fujitsu.junet>
;; 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:

;; This package enables you to read mail or articles in MH folders, or
;; articles saved by GNUS. In any case, the file names of mail or
;; articles must consist of only numeric letters.

;; Before using this package, you have to create a server specific
;; startup file according to the directory which you want to read. For
;; example, if you want to read mail under the directory named
;; `~/Mail', the file must be a file named `.newsrc-:Mail'. (There is
;; no way to specify hierarchical directory now.) In this case, the
;; name of the NNTP server passed to GNUS must be `:Mail'.

;;; Code:

(require 'nntp)

(defvar mhspool-list-folders-method
  (function mhspool-list-folders-using-sh)
  "*Function to list files in folders.
The function should accept a directory as its argument, and fill the
current buffer with file and directory names.  The output format must
be the same as that of 'ls -R1'.  Two functions
mhspool-list-folders-using-ls and mhspool-list-folders-using-sh are
provided now.  I suppose the later is faster.")

(defvar mhspool-list-directory-switches '("-R")
  "*Switches for mhspool-list-folders-using-ls to pass to `ls' for getting file lists.
One entry should appear on one line. You may need to add `-1' option.")

;;; lemacs addition: from Rick Sladkey <jrs@world.std.com>
(defvar mhspool-retrieve-headers-method
  (function mhspool-retrieve-headers-using-emacs-lisp)
  "*Function to retrieve headers from articles in an mhspool
directory.  The function accepts a list of articles to retrieve the
headers from where the articles are located in the directory
mhspool-current-directory.  Two functions
mhspool-retrieve-headers-using-emacs-lisp and
mhspool-retrieve-headers-using-gnushdrs are provided now.  For the
latter mhspool-retrieve-headers-gnushdrs-program specifies the name
of the program to execute (which see).")

;;; lemacs addition: from Rick Sladkey <jrs@world.std.com>
(defvar mhspool-retrieve-headers-gnushdrs-program "gnushdrs"
  "*The name of a program used to retrieve headers from articles when
mhspool-retrieve-headers-method is set to
mhspool-retrieve-headers-using-gnushdrs.  The program takes a directory
as it first argument and the files to retrieve articles from as the
rest of its arguments.  It must produce on its standard output an
emacs lisp expression in the same format as the value of
mhspool-retrieve-headers (which see).")



(defconst mhspool-version "MHSPOOL 1.8"
  "Version numbers of this version of MHSPOOL.")

(defvar mhspool-spool-directory "~/Mail"
  "Private mail directory.")

(defvar mhspool-current-directory nil
  "Current news group directory.")

;;;
;;; Replacement of Extended Command for retrieving many headers.
;;;

(defvar mhspool-article-header-read-size 1024
  "Number of bytes to read when processing headers from MHSPOOL.")

;;; lemacs change: from Chris Davis <ckd@kei.com>
;;; UNIMPLEMENTED!  Probably can be implemented based on 
;;; mhspool-find-article-by-message-id (you may need to fiddle
;;; together a "history file" for MH archives)
(defun mhspool-retrieve-headers-by-id (message-id)
  "UNIMPLEMENTED.  Should return same things mhspool-retrieve-headers does."
  (error "Unimplemented function, sorry."))

;;; lemacs change: from Rick Sladkey <jrs@world.std.com>
(defun mhspool-retrieve-headers (sequence)
  "Return list of article headers specified by SEQUENCE of article id.
The format of list is
 `([NUMBER SUBJECT FROM XREF LINES DATE MESSAGE-ID REFERENCES] ...)'.
If there is no References: field, In-Reply-To: field is used instead.
Reader macros for the vector are defined as `nntp-header-FIELD'.
Writer macros for the vector are defined as `nntp-set-header-FIELD'.
Newsgroup must be selected before calling this."
  (funcall mhspool-retrieve-headers-method sequence))

(defun mhspool-retrieve-headers-using-gnushdrs (sequence)
  "A method for mhspool-retrieve-headers that uses the program gnushdrs."
  (save-excursion
    (let ((msg (and (numberp nntp-large-newsgroup)
		    (> (length sequence) nntp-large-newsgroup))))
      (set-buffer nntp-server-buffer)
      (erase-buffer)
      (let ((process-connection-type nil))
	(apply 'call-process mhspool-retrieve-headers-gnushdrs-program
	       nil t nil mhspool-current-directory
	       (mapcar 'int-to-string sequence))
	(and msg (message "MHSPOOL: parsing headers..."))
	(goto-char (point-min))
	(prog1
	    (read nntp-server-buffer)
	  (erase-buffer)
	  (and msg (message "MHSPOOL: parsing headers...done.")))))))

(defun mhspool-retrieve-headers-using-emacs-lisp (sequence)
  "A method for mhspool-retrieve-headers that only uses Emacs Lisp."
  (save-excursion
    (set-buffer nntp-server-buffer)
    ;;(erase-buffer)
    (let ((file nil)
	  (number (length sequence))
	  (count 0)
	  (headers nil)			;Result list.
	  (article 0)
	  (subject nil)
	  (message-id nil)
	  (from nil)
	  (xref nil)
	  (lines 0)
	  (date nil)
	  (references nil))
      (while sequence
	;;(nntp-send-strings-to-server "HEAD" (car sequence))
	(setq article (car sequence))
	(setq file
	      (concat mhspool-current-directory (prin1-to-string article)))
	(if (and (file-exists-p file)
		 (not (file-directory-p file)))
	    (progn
	      (erase-buffer)
	      (insert-file-contents file
				    nil 0 mhspool-article-header-read-size)
	      ;; Make message body invisible.
	      (goto-char (point-min))
	      (search-forward "\n\n" nil 'move)
	      (narrow-to-region (point-min) (point))
	      ;; Fold continuation lines.
	      (goto-char (point-min))
	      (while (re-search-forward "\\(\r?\n[ \t]+\\)+" nil t)
		(replace-match " " t t))
	      ;; Make it possible to search for `\nFIELD'.
	      (goto-char (point-min))
	      (insert "\n")
	      ;; Extract From:
	      (goto-char (point-min))
	      (if (search-forward "\nFrom: " nil t)
		  (setq from (buffer-substring
			      (point)
			      (save-excursion (end-of-line) (point))))
		(setq from "(Unknown User)"))
	      ;; Extract Subject:
	      (goto-char (point-min))
	      (if (search-forward "\nSubject: " nil t)
		  (setq subject (buffer-substring
				 (point)
				 (save-excursion (end-of-line) (point))))
		(setq subject "(None)"))
	      ;; Extract Message-ID:
	      (goto-char (point-min))
	      (if (search-forward "\nMessage-ID: " nil t)
		  (setq message-id (buffer-substring
				    (point)
				    (save-excursion (end-of-line) (point))))
		(setq message-id nil))
	      ;; Extract Date:
	      (goto-char (point-min))
	      (if (search-forward "\nDate: " nil t)
		  (setq date (buffer-substring
			      (point)
			      (save-excursion (end-of-line) (point))))
		(setq date nil))
	      ;; Extract Lines:
	      (goto-char (point-min))
	      (if (search-forward "\nLines: " nil t)
		  (setq lines (string-to-int
			       (buffer-substring
				(point)
				(save-excursion (end-of-line) (point)))))
		;; Count lines since there is no lines field in most cases.
		(setq lines
		      (save-restriction
			(goto-char (point-max))
			(widen)
			(count-lines (point) (point-max)))))
	      ;; Extract Xref:
	      (goto-char (point-min))
	      (if (search-forward "\nXref: " nil t)
		  (setq xref (buffer-substring
			      (point)
			      (save-excursion (end-of-line) (point))))
		(setq xref nil))
	      ;; Extract References:
	      ;; If no References: field, use In-Reply-To: field instead.
	      ;; Suggested by tanaka@flab.fujitsu.co.jp (Hiroshi TANAKA).
	      (goto-char (point-min))
	      (if (or (search-forward "\nReferences: " nil t)
		      (search-forward "\nIn-Reply-To: " nil t))
		  (setq references (buffer-substring
				    (point)
				    (save-excursion (end-of-line) (point))))
		(setq references nil))
	      ;; Collect valid article only.
	      (and article
		   message-id
		   (setq headers
			 (cons (vector article subject from
				       xref lines date
				       message-id references) headers)))
	      ))
	(setq sequence (cdr sequence))
	(setq count (1+ count))
	(and (numberp nntp-large-newsgroup)
	     (> number nntp-large-newsgroup)
	     (zerop (% count 20))
	     (message "MHSPOOL: Receiving headers... %d%%"
		      (/ (* count 100) number)))
	)
      (and (numberp nntp-large-newsgroup)
	   (> number nntp-large-newsgroup)
	   (message "MHSPOOL: Receiving headers... done"))
      (nreverse headers)
      )))


;;;
;;; Replacement of NNTP Raw Interface.
;;;

(defun mhspool-open-server (host &optional service)
  "Open news server on HOST.
If HOST is nil, use value of environment variable `NNTPSERVER'.
If optional argument SERVICE is non-nil, open by the service name."
  (let ((host (or host (getenv "NNTPSERVER")))
	(status nil))
    ;; Get directory name from HOST name.
    (if (string-match ":\\(.+\\)$" host)
	(progn
	  (setq mhspool-spool-directory
		(file-name-as-directory
		 (expand-file-name
		  (substring host (match-beginning 1) (match-end 1))
		  (expand-file-name "~/" nil))))
	  (setq host (system-name)))
      (setq mhspool-spool-directory nil))
    (setq nntp-status-string "")
    (cond ((and (stringp host)
		(stringp mhspool-spool-directory)
		(file-directory-p mhspool-spool-directory)
		(string-equal host (system-name)))
	   (setq status (mhspool-open-server-internal host service)))
	  ((string-equal host (system-name))
	   (setq nntp-status-string
		 (format "No such directory: %s.  Goodbye."
			 mhspool-spool-directory)))
	  ((null host)
	   (setq nntp-status-string "NNTP server is not specified."))
	  (t
	   (setq nntp-status-string
		 (format "MHSPOOL: cannot talk to %s." host)))
	  )
    status
    ))

(defun mhspool-close-server ()
  "Close news server."
  (mhspool-close-server-internal))

(fset 'mhspool-request-quit (symbol-function 'mhspool-close-server))

(defun mhspool-server-opened ()
  "Return server process status, T or NIL.
If the stream is opened, return T, otherwise return NIL."
  (and nntp-server-buffer
       (get-buffer nntp-server-buffer)))

(defun mhspool-status-message ()
  "Return server status response as string."
  nntp-status-string
  )

(defun mhspool-request-article (id)
  "Select article by message ID (or number)."
  (let ((file (concat mhspool-current-directory (prin1-to-string id))))
    (if (and (stringp file)
	     (file-exists-p file)
	     (not (file-directory-p file)))
	(save-excursion
	  (mhspool-find-file file)))
    ))

(defun mhspool-request-body (id)
  "Select article body by message ID (or number)."
  (if (mhspool-request-article id)
      (save-excursion
	(set-buffer nntp-server-buffer)
	(goto-char (point-min))
	(if (search-forward "\n\n" nil t)
	    (delete-region (point-min) (point)))
	t
	)
    ))

(defun mhspool-request-head (id)
  "Select article head by message ID (or number)."
  (if (mhspool-request-article id)
      (save-excursion
	(set-buffer nntp-server-buffer)
	(goto-char (point-min))
	(if (search-forward "\n\n" nil t)
	    (delete-region (1- (point)) (point-max)))
	t
	)
    ))

(defun mhspool-request-stat (id)
  "Select article by message ID (or number)."
  (setq nntp-status-string "MHSPOOL: STAT is not implemented.")
  nil
  )

(defun mhspool-request-group (group)
  "Select news GROUP."
  (cond ((file-directory-p
	  (mhspool-article-pathname group))
	 ;; Mail/NEWS.GROUP/N
	 (setq mhspool-current-directory
	       (mhspool-article-pathname group)))
	((file-directory-p
	  (mhspool-article-pathname
	   (mhspool-replace-chars-in-string group ?. ?/)))
	 ;; Mail/NEWS/GROUP/N
	 (setq mhspool-current-directory
	       (mhspool-article-pathname
		(mhspool-replace-chars-in-string group ?. ?/))))
	))

(defun mhspool-request-list ()
  "List active newsgoups."
  (save-excursion
    (let* ((newsgroup nil)
	   (articles nil)
	   (directory (file-name-as-directory
		       (expand-file-name mhspool-spool-directory nil)))
	   (folder-regexp (concat "^" (regexp-quote directory) "\\(.+\\):$"))
	   (buffer (get-buffer-create " *MHSPOOL File List*")))
      (set-buffer nntp-server-buffer)
      (erase-buffer)
      (set-buffer buffer)
      (erase-buffer)
;;      (apply 'call-process
;;	     "ls" nil t nil
;;	     (append mhspool-list-directory-switches (list directory)))
      (funcall mhspool-list-folders-method directory)
      (goto-char (point-min))
      (while (re-search-forward folder-regexp nil t)
	(setq newsgroup
	      (mhspool-replace-chars-in-string
	       (buffer-substring (match-beginning 1) (match-end 1)) ?/ ?.))
	(setq articles nil)
	(forward-line 1)		;(beginning-of-line)
	;; Thank nobu@flab.fujitsu.junet for his bug fixes.
	(while (and (not (eobp))
		    (not (looking-at "^$")))
	  (if (looking-at "^[0-9]+$")
	      (setq articles
		    (cons (string-to-int
			   (buffer-substring
			    (match-beginning 0) (match-end 0)))
			  articles)))
	  (forward-line 1))
	(if articles
	    (princ (format "%s %d %d n\n" newsgroup
			   (apply (function max) articles)
			   (apply (function min) articles))
		   nntp-server-buffer))
	)
      (kill-buffer buffer)
      (set-buffer nntp-server-buffer)
      (buffer-size)
      )))

(defun mhspool-request-list-newsgroups ()
  "List newsgoups (defined in NNTP2)."
  (setq nntp-status-string "MHSPOOL: LIST NEWSGROUPS is not implemented.")
  nil
  )

(defun mhspool-request-list-distributions ()
  "List distributions (defined in NNTP2)."
  (setq nntp-status-string "MHSPOOL: LIST DISTRIBUTIONS is not implemented.")
  nil
  )

(defun mhspool-request-last ()
  "Set current article pointer to the previous article
in the current news group."
  (setq nntp-status-string "MHSPOOL: LAST is not implemented.")
  nil
  )

(defun mhspool-request-next ()
  "Advance current article pointer."
  (setq nntp-status-string "MHSPOOL: NEXT is not implemented.")
  nil
  )

(defun mhspool-request-post ()
  "Post a new news in current buffer."
  (setq nntp-status-string "MHSPOOL: POST: what do you mean?")
  nil
  )


;;;
;;; Replacement of Low-Level Interface to NNTP Server.
;;; 

(defun mhspool-open-server-internal (host &optional service)
  "Open connection to news server on HOST by SERVICE (default is nntp)."
  (save-excursion
    (if (not (string-equal host (system-name)))
	(error "MHSPOOL: cannot talk to %s." host))
    ;; Initialize communication buffer.
    (setq nntp-server-buffer (get-buffer-create " *nntpd*"))
    (set-buffer nntp-server-buffer)
    (buffer-disable-undo (current-buffer))
    (erase-buffer)
    (kill-all-local-variables)
    (setq case-fold-search t)		;Should ignore case.
    (if (boundp 'nntp-server-process)
	(setq nntp-server-process nil))
    (setq nntp-server-name host)
    ;; It is possible to change kanji-fileio-code in this hook.
    (run-hooks 'nntp-server-hook)
    t
    ))

(defun mhspool-close-server-internal ()
  "Close connection to news server."
  (if nntp-server-buffer
      (kill-buffer nntp-server-buffer))
  (setq nntp-server-buffer nil)
  (if (boundp 'nntp-server-process)
      (setq nntp-server-process nil)))

(defun mhspool-find-file (file)
  "Insert FILE in server buffer safely."
  (set-buffer nntp-server-buffer)
  (erase-buffer)
  (condition-case ()
      (progn
	(insert-file-contents file)
	(goto-char (point-min))
	;; If there is no body, `^L' appears at end of file. Special
	;; hack for MH folder.
	(and (search-forward "\n\n" nil t)
	     (string-equal (buffer-substring (point) (point-max)) "\^L")
	     (delete-char 1))
	t
	)
    (file-error nil)
    ))

(defun mhspool-article-pathname (group)
  "Make pathname for GROUP."
  (concat (file-name-as-directory mhspool-spool-directory) group "/"))

(defun mhspool-replace-chars-in-string (string from to)
  "Replace characters in STRING from FROM to TO."
  (let ((string (substring string 0))	;Copy string.
	(len (length string))
	(idx 0))
    ;; Replace all occurrences of FROM with TO.
    (while (< idx len)
      (if (= (aref string idx) from)
	  (aset string idx to))
      (setq idx (1+ idx)))
    string
    ))


;; Methods for listing files in folders.

(defun mhspool-list-folders-using-ls (directory)
  "List files in folders under DIRECTORY using 'ls'."
  (apply 'call-process
	 "ls" nil t nil
	 (append mhspool-list-directory-switches (list directory))))

;; Basic ideas by tanaka@flab.fujitsu.co.jp (Hiroshi TANAKA)

(defun mhspool-list-folders-using-sh (directory)
  "List files in folders under DIRECTORY using '/bin/sh'."
  (let ((buffer (current-buffer))
	(script (get-buffer-create " *MHSPOOL Shell Script Buffer*")))
    (save-excursion
      (save-restriction
	(set-buffer script)
	(erase-buffer)
	;; /bin/sh script which does 'ls -R'.
	(insert
	 "PS2=
          ffind() {
		cd $1; echo $1:
		ls -1
		echo
		for j in `echo *[a-zA-Z]*`
		do
		  if [ -d $1/$j ]; then
			ffind $1/$j
		  fi
		done
	  }
	  cd " directory "; ffind `pwd`; exit 0\n")
	(call-process-region (point-min) (point-max) "sh" nil buffer nil)
	))
    (kill-buffer script)
    ))

(provide 'mhspool)

;;; mhspool.el ends here