;;; nnwfm.el --- interfacing with a web forum
;; Copyright (C) 2000 Free Software Foundation, Inc.

;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
;; Keywords: 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, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;;; Commentary:

;; Note: You need to have `url' and `w3' installed for this
;; backend to work.

;;; Code:

(eval-when-compile (require 'cl))

(require 'nnoo)
(require 'message)
(require 'gnus-util)
(require 'gnus)
(require 'nnmail)
(require 'mm-util)
(eval-when-compile
  (ignore-errors
    (require 'nnweb)))
;; Report failure to find w3 at load time if appropriate.
(eval '(require 'nnweb))

(nnoo-declare nnwfm)

(defvoo nnwfm-directory (nnheader-concat gnus-directory "wfm/")
  "Where nnwfm will save its files.")

(defvoo nnwfm-address ""
  "The address of the Ultimate bulletin board.")

;;; Internal variables

(defvar nnwfm-groups-alist nil)
(defvoo nnwfm-groups nil)
(defvoo nnwfm-headers nil)
(defvoo nnwfm-articles nil)
(defvar nnwfm-table-regexp 
  "postings.*editpost\\|forumdisplay\\|Forum[0-9]+/HTML\\|getbio")

;;; Interface functions

(nnoo-define-basics nnwfm)

(deffoo nnwfm-retrieve-headers (articles &optional group server fetch-old)
  (nnwfm-possibly-change-server group server)
  (unless gnus-nov-is-evil
    (let* ((last (car (last articles)))
	   (did nil)
	   (start 1)
	   (entry (assoc group nnwfm-groups))
	   (sid (nth 2 entry))
	   (topics (nth 4 entry))
	   (mapping (nth 5 entry))
	   (old-total (or (nth 6 entry) 1))
	   (nnwfm-table-regexp "Thread.asp")
	   headers article subject score from date lines parent point
	   contents tinfo fetchers map elem a href garticles topic old-max
	   inc datel table string current-page total-contents pages
	   farticles forum-contents parse furl-fetched mmap farticle
	   thread-id tables hstuff bstuff time)
      (setq map mapping)
      (while (and (setq article (car articles))
		  map)
	(while (and map
		    (or (> article (caar map))
			(< (cadar map) (caar map))))
	  (pop map))
	(when (setq mmap (car map))
	  (setq farticle -1)
	  (while (and article
		      (<= article (nth 1 mmap)))
	    ;; Do we already have a fetcher for this topic?
	    (if (setq elem (assq (nth 2 mmap) fetchers))
		;; Yes, so we just add the spec to the end.
		(nconc elem (list (cons article
					(+ (nth 3 mmap) (incf farticle)))))
	      ;; No, so we add a new one.
	      (push (list (nth 2 mmap)
			  (cons article
				(+ (nth 3 mmap) (incf farticle))))
		    fetchers))
	    (pop articles)
	    (setq article (car articles)))))
      ;; Now we have the mapping from/to Gnus/nnwfm article numbers,
      ;; so we start fetching the topics that we need to satisfy the
      ;; request.
      (if (not fetchers)
	  (save-excursion
	    (set-buffer nntp-server-buffer)
	    (erase-buffer))
	(setq nnwfm-articles nil)
	(mm-with-unibyte-buffer
	  (dolist (elem fetchers)
	    (erase-buffer)
	    (setq subject (nth 2 (assq (car elem) topics))
		  thread-id (nth 0 (assq (car elem) topics)))
	    (nnweb-insert
	     (concat nnwfm-address
		     (format "Item.asp?GroupID=%d&ThreadID=%d" sid
			     thread-id)))
	    (goto-char (point-min))
	    (setq contents
		  (ignore-errors (w3-parse-buffer (current-buffer))))
	    (setq tables (caddar (caddar (cdr (caddar (caddar contents))))))
	    (setq tables (cdr (caddar (memq (assq 'div tables) tables))))
	    (setq contents nil)
	    (dolist (table tables)
	      (setq table (caddar (caddar (caddr table)))
		    hstuff (delete ":link" (nnweb-text (car table)))
		    bstuff (car (caddar (cdr table)))
		    from (car hstuff))
	      (when (nth 2 hstuff)
		(setq time (nnwfm-date-to-time (nth 2 hstuff)))
		(push (list from time bstuff) contents)))
	    (setq contents (nreverse contents))
	    (dolist (art (cdr elem))
		(push (list (car art)
			    (nth (1- (cdr art)) contents)
			    subject)
		      nnwfm-articles))))
	(setq nnwfm-articles
	      (sort nnwfm-articles 'car-less-than-car))
	;; Now we have all the articles, conveniently in an alist
	;; where the key is the Gnus article number.
	(dolist (articlef nnwfm-articles)
	  (setq article (nth 0 articlef)
		contents (nth 1 articlef)
		subject (nth 2 articlef))
	  (setq from (nth 0 contents)
		date (message-make-date (nth 1 contents)))
	  (push
	   (cons
	    article
	    (make-full-mail-header
	     article subject
	     from (or date "")
	     (concat "<" (number-to-string sid) "%"
		     (number-to-string article)
		     "@wfm>")
	     "" 0
	     (/ (length (mapconcat 'identity (nnweb-text (nth 2 contents)) ""))
		70)
	     nil nil))
	   headers))
	(setq nnwfm-headers (sort headers 'car-less-than-car))
	(save-excursion
	  (set-buffer nntp-server-buffer)
	  (mm-with-unibyte-current-buffer
	    (erase-buffer)
	    (dolist (header nnwfm-headers)
	      (nnheader-insert-nov (cdr header))))))
      'nov)))

(deffoo nnwfm-request-group (group &optional server dont-check)
  (nnwfm-possibly-change-server nil server)
  (when (not nnwfm-groups)
    (nnwfm-request-list))
  (unless dont-check
    (nnwfm-create-mapping group))
  (let ((elem (assoc group nnwfm-groups)))
    (cond
     ((not elem)
      (nnheader-report 'nnwfm "Group does not exist"))
     (t
      (nnheader-report 'nnwfm "Opened group %s" group)
      (nnheader-insert
       "211 %d %d %d %s\n" (cadr elem) 1 (cadr elem)
       (prin1-to-string group))))))

(deffoo nnwfm-request-close ()
  (setq nnwfm-groups-alist nil
	nnwfm-groups nil))

(deffoo nnwfm-request-article (article &optional group server buffer)
  (nnwfm-possibly-change-server group server)
  (let ((contents (cdr (assq article nnwfm-articles))))
    (when (setq contents (nth 2 (car contents)))
      (save-excursion
	(set-buffer (or buffer nntp-server-buffer))
	(erase-buffer)
	(nnweb-insert-html contents)
	(goto-char (point-min))
	(insert "Content-Type: text/html\nMIME-Version: 1.0\n")
	(let ((header (cdr (assq article nnwfm-headers))))
	  (mm-with-unibyte-current-buffer
	    (nnheader-insert-header header)))
	(nnheader-report 'nnwfm "Fetched article %s" article)
	(cons group article)))))

(deffoo nnwfm-request-list (&optional server)
  (nnwfm-possibly-change-server nil server)
  (mm-with-unibyte-buffer
    (nnweb-insert
     (if (string-match "/$" nnwfm-address)
	 (concat nnwfm-address "Group.asp")
       nnwfm-address))
    (let* ((nnwfm-table-regexp "Thread.asp")
	   (contents (w3-parse-buffer (current-buffer)))
	   sid elem description articles a href group forum
	   a1 a2)
      (dolist (row (cdr (nth 2 (car (nth 2 (nnwfm-find-forum-table
					    contents))))))
	(setq row (nth 2 row))
	(when (setq a (nnweb-parse-find 'a row))
	  (setq group (car (last (nnweb-text a)))
		href (cdr (assq 'href (nth 1 a))))
	  (setq description (car (last (nnweb-text (nth 1 row)))))
	  (setq articles
		(string-to-number
		 (nnweb-replace-in-string
		  (car (last (nnweb-text (nth 3 row)))) "," "")))
	  (when (and href
		     (string-match "GroupId=\\([0-9]+\\)" href))
	    (setq forum (string-to-number (match-string 1 href)))
	    (if (setq elem (assoc group nnwfm-groups))
		(setcar (cdr elem) articles)
	      (push (list group articles forum description nil nil nil nil)
		    nnwfm-groups))))))
    (nnwfm-write-groups)
    (nnwfm-generate-active)
    t))

(deffoo nnwfm-request-newgroups (date &optional server)
  (nnwfm-possibly-change-server nil server)
  (nnwfm-generate-active)
  t)

(nnoo-define-skeleton nnwfm)

;;; Internal functions

(defun nnwfm-new-threads-p (group time)
  "See whether we want to fetch the threads for GROUP written before TIME."
  (let ((old-time (nth 7 (assoc group nnwfm-groups))))
    (or (null old-time)
	(time-less-p old-time time))))

(defun nnwfm-create-mapping (group)
  (let* ((entry (assoc group nnwfm-groups))
	 (sid (nth 2 entry))
	 (topics (nth 4 entry))
	 (mapping (nth 5 entry))
	 (old-total (or (nth 6 entry) 1))
	 (current-time (current-time))
	 (nnwfm-table-regexp "Thread.asp")
	 (furls (list (concat nnwfm-address
			      (format "Thread.asp?GroupId=%d" sid))))
	 fetched-urls
	 contents forum-contents a subject href
	 garticles topic tinfo old-max inc parse elem date
	 url time)
    (mm-with-unibyte-buffer
      (while furls
	(erase-buffer)
	(push (car furls) fetched-urls)
	(nnweb-insert (pop furls))
	(goto-char (point-min))
	(while (re-search-forward "  wr(" nil t)
	  (forward-char -1)
	  (setq elem (message-tokenize-header
		      (buffer-substring
		       (1+ (point))
		       (progn
			 (forward-sexp 1)
			 (1- (point))))))
	  (push (list
		 (string-to-number (nth 1 elem))
		 (nnweb-replace-in-string (nth 2 elem) "\"" "")
		 (string-to-number (nth 5 elem)))
		forum-contents))
	(when (re-search-forward "href=\"\\(Thread.*DateLast=\\([^\"]+\\)\\)"
				 nil t)
	  (setq url (match-string 1)
		time (nnwfm-date-to-time (url-unhex-string (match-string 2))))
	  (when (and (nnwfm-new-threads-p group time)
		     (not (member
			   (setq url (concat
				      nnwfm-address
				      (nnweb-decode-entities-string url)))
			   fetched-urls)))
	    (push url furls))))
      ;; The main idea here is to map Gnus article numbers to
      ;; nnwfm article numbers.  Say there are three topics in
      ;; this forum, the first with 4 articles, the seconds with 2,
      ;; and the third with 1.  Then this will translate into 7 Gnus
      ;; article numbers, where 1-4 comes from the first topic, 5-6
      ;; from the second and 7 from the third.  Now, then next time
      ;; the group is entered, there's 2 new articles in topic one
      ;; and 1 in topic three.  Then Gnus article number 8-9 be 5-6
      ;; in topic one and 10 will be the 2 in topic three.
      (dolist (elem (nreverse forum-contents))
	(setq subject (nth 1 elem)
	      topic (nth 0 elem)
	      garticles (nth 2 elem))
	(if (setq tinfo (assq topic topics))
	    (progn
	      (setq old-max (cadr tinfo))
	      (setcar (cdr tinfo) garticles))
	  (setq old-max 0)
	  (push (list topic garticles subject) topics)
	  (setcar (nthcdr 4 entry) topics))
	(when (not (= old-max garticles))
	  (setq inc (- garticles old-max))
	  (setq mapping (nconc mapping
			       (list
				(list
				 old-total (1- (incf old-total inc))
				 topic (1+ old-max)))))
	  (incf old-max inc)
	  (setcar (nthcdr 5 entry) mapping)
	  (setcar (nthcdr 6 entry) old-total))))
    (setcar (nthcdr 7 entry) current-time)
    (setcar (nthcdr 1 entry) (1- old-total))
    (nnwfm-write-groups)
    mapping))

(defun nnwfm-possibly-change-server (&optional group server)
  (nnwfm-init server)
  (when (and server
	     (not (nnwfm-server-opened server)))
    (nnwfm-open-server server))
  (unless nnwfm-groups-alist
    (nnwfm-read-groups)
    (setq nnwfm-groups (cdr (assoc nnwfm-address
					nnwfm-groups-alist)))))

(deffoo nnwfm-open-server (server &optional defs connectionless)
  (nnheader-init-server-buffer)
  (if (nnwfm-server-opened server)
      t
    (unless (assq 'nnwfm-address defs)
      (setq defs (append defs (list (list 'nnwfm-address server)))))
    (nnoo-change-server 'nnwfm server defs)))

(defun nnwfm-read-groups ()
  (setq nnwfm-groups-alist nil)
  (let ((file (expand-file-name "groups" nnwfm-directory)))
    (when (file-exists-p file)
      (mm-with-unibyte-buffer
	(insert-file-contents file)
	(goto-char (point-min))
	(setq nnwfm-groups-alist (read (current-buffer)))))))

(defun nnwfm-write-groups ()
  (setq nnwfm-groups-alist
	(delq (assoc nnwfm-address nnwfm-groups-alist)
	      nnwfm-groups-alist))
  (push (cons nnwfm-address nnwfm-groups)
	nnwfm-groups-alist)
  (with-temp-file (expand-file-name "groups" nnwfm-directory)
    (prin1 nnwfm-groups-alist (current-buffer))))
    
(defun nnwfm-init (server)
  "Initialize buffers and such."
  (unless (file-exists-p nnwfm-directory)
    (gnus-make-directory nnwfm-directory)))

(defun nnwfm-generate-active ()
  (save-excursion
    (set-buffer nntp-server-buffer)
    (erase-buffer)
    (dolist (elem nnwfm-groups)
      (insert (prin1-to-string (car elem))
	      " " (number-to-string (cadr elem)) " 1 y\n"))))

(defun nnwfm-find-forum-table (contents)
  (catch 'found
    (nnwfm-find-forum-table-1 contents)))

(defun nnwfm-find-forum-table-1 (contents)
  (dolist (element contents)
    (unless (stringp element)
      (when (and (eq (car element) 'table)
		 (nnwfm-forum-table-p element))
	(throw 'found element))
      (when (nth 2 element)
	(nnwfm-find-forum-table-1 (nth 2 element))))))

(defun nnwfm-forum-table-p (parse)
  (when (not (apply 'gnus-or
		    (mapcar
		     (lambda (p)
		       (nnweb-parse-find 'table p))
		     (nth 2 parse))))
    (let ((href (cdr (assq 'href (nth 1 (nnweb-parse-find 'a parse 20)))))
	  case-fold-search)
      (when (and href (string-match nnwfm-table-regexp href))
	t))))

(defun nnwfm-date-to-time (date)
  (let ((time (mapcar #'string-to-number (split-string date "[\\.\\+ :]"))))
    (encode-time 0 (nth 4 time) (nth 3 time)
		 (nth 0 time) (nth 1 time)
		 (if (< (nth 2 time) 70)
		     (+ 2000 (nth 2 time))
		   (+ 1900 (nth 2 time))))))

(provide 'nnwfm)

;; Local Variables:
;; coding: iso-8859-1
;; End:

;;; nnwfm.el ends here