;;; hbdata.el --- Hyperbole button attribute accessor methods.

;; Copyright (C) 1991-1995 Free Software Foundation, Inc.
;; Developed with support from Motorola Inc.

;; Author: Bob Weiner, Brown U.
;; Maintainer: Mats Lidell <matsl@contactor.se>
;; Keywords: hypermedia

;; This file is part of GNU Hyperbole.

;; GNU Hyperbole 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 Hyperbole 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., 51 Franklin Street, Fifth Floor,
;; Boston, MA 02110-1301, USA.

;;; Commentary:
;;
;;  This module handles Hyperbole button data/attribute storage.  In
;;  general, it should not be extended by anyone other than Hyperbole
;;  maintainers.  If you alter the formats or accessors herein, you are
;;  likely to make your buttons incompatible with future releases.
;;  System developers should instead work with and extend the "hbut.el"
;;  module which provides much of the Hyperbole application programming
;;  interface and which hides the low level details handled by this
;;  module.
;;
;;
;;  Button data is typically stored within a file that holds the button
;;  data for all files within that directory.  The name of this file is
;;  given by the variable 'hattr:filename,' usually it is ".hypb".
;;
;;  Here is a sample from a Hyperbole V2 button data file.  Each button
;;  data entry is a list of fields:
;;
;;    
;;    "TO-DO"
;;    (Key            Placeholders  LinkType      <arg-list>             creator and modifier with times)
;;    ("alt.mouse.el" nil nil       link-to-file  ("./ell/alt-mouse.el") "zzz@cs.brown.edu" "19911027:09:19:26" "zzz" "19911027:09:31:36")
;;
;;  which means:  button \<(alt.mouse.el)> found in file "TO-DO" in the current
;;  directory provides a link to the local file "./ell/alt-mouse.el".  It was
;;  created and last modified by zzz@cs.brown.edu.
;;
;;  All link entries that originate from the same source file are stored
;;  contiguously, one per line, in reverse order of creation.
;;  Preceding all such entries is the source name (in the case of a file
;;  used as a source, no directory information is included, since only
;;  sources within the same directory as the button data file are used as
;;  source files within it.

;;; Code:

;;;
;;; Other required Elisp libraries
;;;

(require 'hbmap)

;;;
;;; Public functions
;;;

;;;
;;; Button data accessor functions
;;;
(defun hbdata:action (hbdata)
  "[Hyp V2] Returns action overriding button's action type or nil."
  (nth 1 hbdata))

(defun hbdata:actype (hbdata)
  "Returns the action type in HBDATA as a string."
  (let ((nm (symbol-name (nth 3 hbdata))))
    (and nm (if (or (= (length nm) 2) (string-match "::" nm))
		nm (concat "actypes::" nm)))))

(defun hbdata:args (hbdata)
  "Returns the list of any arguments given in HBDATA."
  (nth 4 hbdata))

(defun hbdata:categ (hbdata)
  "Returns the category of HBDATA's button."
  'explicit)

(defun hbdata:creator (hbdata)
  "Returns the user-id of the original creator of HBDATA's button."
  (nth 5 hbdata))

(defun hbdata:create-time (hbdata)
  "Returns the original creation time given for HBDATA's button."
  (nth 6 hbdata))

(defun hbdata:key (hbdata)
  "Returns the indexing key in HBDATA as a string."
  (car hbdata))

(defun hbdata:loc-p (hbdata)
  "[Hyp V1] Returns 'L iff HBDATA referent is within a local file system.
Returns 'R if remote and nil if irrelevant for button action type."
  (nth 1 hbdata))

(defun hbdata:modifier (hbdata)
  "Returns the user-id of the most recent modifier of HBDATA's button.
Nil is returned when button has not been modified."
  (nth 7 hbdata))

(defun hbdata:mod-time (hbdata)
  "Returns the time of the most recent change to HBDATA's button.
Nil is returned when button has not beened modified."
  (nth 8 hbdata))

(defun hbdata:referent (hbdata)
  "Returns the referent name in HBDATA."
  (nth 2 hbdata))

(defun hbdata:search (buf label partial)
  "Go to Hyperbole hbdata BUF and find LABEL whole or PARTIAL matches.
 Search is case-insensitive.  Returns list with elements:
 (<button-src> <label-key1> ... <label-keyN>)."
  (set-buffer buf)
  (let ((case-fold-search t) (src-matches) (src) (matches) (end))
    (goto-char (point-min))
    (while (re-search-forward "^\^L\n\"\\([^\"]+\\)\"" nil t)
      (setq src (buffer-substring (match-beginning 1)
				  (match-end 1))
	    matches nil)
      (save-excursion
	(setq end (if (re-search-forward "^\^L" nil t)
		      (1- (point)) (point-max))))
      (while (re-search-forward
	      (concat "^(\"\\(" (if partial "[^\"]*")
		      (regexp-quote (ebut:label-to-key label))
		      (if partial "[^\"]*") "\\)\"") nil t)
	(setq matches (cons
		       (buffer-substring (match-beginning 1)
					 (match-end 1))
		       matches)))
      (if matches
	  (setq src-matches (cons (cons src matches) src-matches)))
      (goto-char end))
    src-matches))

;;;
;;; Button data operators
;;;

(defun hbdata:build (&optional mod-lbl-key but-sym)
  "Tries to construct button data from optional MOD-LBL-KEY and BUT-SYM.
MOD-LBL-KEY nil means create a new entry, otherwise modify existing one.
BUT-SYM nil means use 'hbut:current'.  If successful, returns a cons of
 (button-data . button-instance-str), else nil."
  (let* ((but) 
	 (b (hattr:copy (or but-sym 'hbut:current) 'but))
	 (l (hattr:get b 'loc))
	 (key (or mod-lbl-key (hattr:get b 'lbl-key)))
	 (new-key (if mod-lbl-key (hattr:get b 'lbl-key) key))
	 (lbl-instance) (creator) (create-time) (modifier) (mod-time)
	 (entry) loc dir)
    (if (null l)
	nil
      (setq loc (if (bufferp l) l (file-name-nondirectory l))
	    dir (if (bufferp l) nil (file-name-directory l)))
      (if (setq entry (hbdata:to-entry key loc dir (not mod-lbl-key)))
	  (if mod-lbl-key
	      (progn
		(setq creator     (hbdata:creator entry)
		      create-time (hbdata:create-time entry)
		      modifier    (let* ((user (user-login-name))
					 (addr (concat user
						       hyperb:host-domain)))
				    (if (equal creator addr)
					user addr))
		      mod-time    (htz:date-sortable-gmt)
		      entry       (cons new-key (cdr entry)))
		(hbdata:delete-entry-at-point)
		(if (setq lbl-instance (hbdata:instance-last new-key loc dir))
		    (progn
		      (setq lbl-instance (concat ebut:instance-sep
						 (1+ lbl-instance)))
		      ;; This line is needed to ensure that the highest
		      ;; numbered instance of a label appears before
		      ;; other instances, so 'hbdata:instance-last' will work.
		      (if (hbdata:to-entry-buf loc dir) (forward-line 1))))
		)
	    (let ((inst-num (hbdata:instance-last new-key loc dir)))
	      (setq lbl-instance (if inst-num
				     (hbdata:instance-next 
				      (concat new-key ebut:instance-sep
					      (int-to-string inst-num))))))
	    ))
      (if (or entry (not mod-lbl-key))
	  (cons
	   (list (concat new-key lbl-instance)
		 (hattr:get b 'action)
		 ;; Hyperbole V1 referent compatibility, always nil in V2
		 (hattr:get b 'referent)
		 ;; Save actype without class prefix
		 (let ((actype (hattr:get b 'actype)))
		   (and actype (symbolp actype)
			(setq actype (symbol-name actype))
			(intern
			 (substring actype (if (string-match "::" actype)
					       (match-end 0) 0)))))
		 (let ((mail-dir (and (fboundp 'hmail:composing-dir)
				      (hmail:composing-dir l)))
		       (args (hattr:get b 'args)))
		   ;; Replace matches for Emacs Lisp directory variable
		   ;; values with their variable names in any pathname args.
		   (mapcar 'hpath:substitute-var
			   (if mail-dir
			       ;; Make pathname args absolute for outgoing mail and
			       ;; news messages.
			       (action:path-args-abs args mail-dir)
			     args)))
		 (or creator (concat (user-login-name) hyperb:host-domain))
		 (or create-time (htz:date-sortable-gmt))
		 modifier
		 mod-time)
	   lbl-instance)
	))))

(defun hbdata:get-entry (lbl-key key-src &optional directory)
  "Returns button data entry given by LBL-KEY, KEY-SRC and optional DIRECTORY.
Returns nil if no matching entry is found.
A button data entry is a list of attribute values.  Use methods from
class 'hbdata' to operate on the entry."
  (hbdata:apply-entry
   (function (lambda () (read (current-buffer))))
   lbl-key key-src directory))

(defun hbdata:instance-next (lbl-key)
  "Returns string for button instance number following LBL-KEY's.
nil if LBL-KEY is nil."
  (and lbl-key
       (if (string-match
	    (concat (regexp-quote ebut:instance-sep) "[0-9]+$") lbl-key)
	   (concat ebut:instance-sep
		   (int-to-string
		    (1+ (string-to-int
			 (substring lbl-key (1+ (match-beginning 0)))))))
	 ":2")))

(defun hbdata:instance-last (lbl-key key-src &optional directory)
  "Returns highest instance number for repeated button label.
1 if not repeated, nil if no instance.
Takes arguments LBL-KEY, KEY-SRC and optional DIRECTORY."
  (hbdata:apply-entry
   (function (lambda () 
	       (if (looking-at "[0-9]+")
		   (string-to-int (buffer-substring (match-beginning 0)
						    (match-end 0)))
		 1)))
   lbl-key key-src directory nil 'instance))

(defun hbdata:delete-entry (lbl-key key-src &optional directory)
  "Deletes button data entry given by LBL-KEY, KEY-SRC and optional DIRECTORY.
Returns entry deleted (a list of attribute values) or nil.
Use methods from class 'hbdata' to operate on the entry."
  (hbdata:apply-entry
   (function
    (lambda ()
      (prog1 (read (current-buffer))
	(let ((empty-file-entry "[ \t\n]*\\(\^L\\|\\'\\)")
	      (kill))
	  (beginning-of-line)
	  (hbdata:delete-entry-at-point)
	  (if (looking-at empty-file-entry)
	      (let ((end (point))
		    (empty-hbdata-file "[ \t\n]*\\'"))
		(forward-line -1)
		(if (= (following-char) ?\")
		    ;; Last button entry for filename, so del filename.
		    (progn (forward-line -1) (delete-region (point) end)))
		(save-excursion
		  (goto-char (point-min))
		  (if (looking-at empty-hbdata-file)
		      (setq kill t)))
		(if kill
		    (let ((fname buffer-file-name))
		      (erase-buffer) (save-buffer) (kill-buffer nil)
		      (hbmap:dir-remove (file-name-directory fname))
		      (call-process "rm" nil 0 nil "-f" fname)))))))))
   lbl-key key-src directory))

(defun hbdata:delete-entry-at-point ()
  (delete-region (point) (progn (forward-line 1) (point))))

(defun hbdata:to-entry (but-key key-src &optional directory instance)
  "Returns button data entry indexed by BUT-KEY, KEY-SRC, optional DIRECTORY.
Returns nil if entry is not found.  Leaves point at start of entry when
successful or where entry should be inserted if unsuccessful.
A button entry is a list.  Use methods from class 'hbdata' to operate on the
entry.  Optional INSTANCE non-nil means search for any button instance matching
but-key."
  (let ((pos-entry-cons
	 (hbdata:apply-entry
	  (function
	   (lambda ()
	     (beginning-of-line)
	     (cons (point) (read (current-buffer)))))
	  but-key key-src directory 'create instance)))
    (hbdata:to-entry-buf key-src directory)
    (forward-line 1)
    (if pos-entry-cons
	(progn
	  (goto-char (car pos-entry-cons))
	  (cdr pos-entry-cons)))))

;;;
;;; Private functions
;;;

(defun hbdata:apply-entry (function lbl-key key-src &optional directory
			   create instance)
  "Invokes FUNCTION with point at hbdata entry given by LBL-KEY, KEY-SRC, optional DIRECTORY.
With optional CREATE, if no such line exists, inserts a new file entry at the
beginning of the hbdata file (which is created if necessary).
INSTANCE non-nil means search for any button instance matching LBL-KEY and
call FUNCTION with point right after any 'ebut:instance-sep' in match.
Returns value of evaluation when a matching entry is found or nil."
  (let ((found)
	(rtn)
	(opoint)
	(end-func))
    (save-excursion
      (unwind-protect
	  (progn
	    (if (not (bufferp key-src))
		nil
	      (set-buffer key-src)
	      (cond ((hmail:editor-p)
		     (setq end-func (function (lambda ()
						(hmail:msg-narrow)))))
		    ((and (hmail:lister-p)
			  (progn (rmail:summ-msg-to) (rmail:to)))
		     (setq opoint (point)
			   key-src (current-buffer)
			   end-func (function (lambda ()
						(hmail:msg-narrow)
						(goto-char opoint)
						(lmail:to)))))
		    ((and (hnews:lister-p)
			  (progn (rnews:summ-msg-to) (rnews:to)))
		     (setq opoint (point)
			   key-src (current-buffer)
			   end-func (function (lambda ()
						(hmail:msg-narrow)
						(goto-char opoint)
						(lnews:to)))))))
	    (setq found (hbdata:to-entry-buf key-src directory create)))
	(if found
	    (let ((case-fold-search t)
		  (qkey (regexp-quote lbl-key))
		  (end (save-excursion (if (search-forward "\n\^L" nil t)
					   (point) (point-max)))))
	      (if (if instance
		      (re-search-forward
		       (concat "\n(\"" qkey "["
			       ebut:instance-sep "\"]") end t)
		    (search-forward (concat "\n(\"" lbl-key "\"") end t))
		  (progn
		    (or instance (beginning-of-line))
		    (let (buffer-read-only)
		      (setq rtn (funcall function)))))))
	(if end-func (funcall end-func))))
    rtn))

(defun hbdata:to-hbdata-buffer (dir &optional create)
  "Reads in the file containing DIR's button data, if any, and returns buffer.
If it does not exist and optional CREATE is non-nil, creates a new
one and returns buffer, otherwise returns nil."
  (let* ((file (expand-file-name hattr:filename (or dir default-directory)))
	 (existing-file (or (file-exists-p file) (get-file-buffer file)))
	 (buf (or (get-file-buffer file)
		  (and (or create existing-file)
		       (find-file-noselect file)))))
    (if buf
	(progn (set-buffer buf)
	       (or (verify-visited-file-modtime (get-file-buffer file))
		   (cond ((yes-or-no-p
			   "Hyperbole button data file has changed, read new contents? ") 
			  (revert-buffer t t)
			  )))
	       (or (= (point-max) 1) (eq (char-after 1) ?\^L)
		   (error "File %s is not a valid Hyperbole button data table." file))
	       (or (equal (buffer-name) file) (rename-buffer file))
	       (setq buffer-read-only nil)
	       (or existing-file (hbmap:dir-add (file-name-directory file)))
	       buf))))


(defun hbdata:to-entry-buf (key-src &optional directory create)
  "Moves point to end of line in but data buffer matching KEY-SRC.
Uses hbdata file in KEY-SRC's directory, or optional DIRECTORY or if nil, uses
default-directory.
With optional CREATE, if no such line exists, inserts a new file entry at the
beginning of the hbdata file (which is created if necessary).
Returns non-nil if KEY-SRC is found or created, else nil."
  (let ((rtn) (ln-dir))
    (if (bufferp key-src)
	;; Button buffer has no file attached
	(progn (setq rtn (set-buffer key-src)
		     buffer-read-only nil)
	       (if (not (hmail:hbdata-to-p))
		   (insert "\n" hmail:hbdata-sep "\n"))
	       (backward-char 1)
	       )
      (setq directory (or (file-name-directory key-src) directory))
      (let ((ln-file) (link-p key-src))
	(while (setq link-p (file-symlink-p link-p))
	  (setq ln-file link-p))
	(if ln-file
	    (setq ln-dir (file-name-directory ln-file)
		  key-src (file-name-nondirectory ln-file))
	  (setq key-src (file-name-nondirectory key-src))))
      (if (or (hbdata:to-hbdata-buffer directory create)
	      (and ln-dir (hbdata:to-hbdata-buffer ln-dir nil)
		   (setq create nil
			 directory ln-dir)))
	  (progn
	    (goto-char 1)
	    (cond ((search-forward (concat "\^L\n\"" key-src "\"")
				   nil t)
		   (setq rtn t))
		  (create
		   (setq rtn t)
		   (insert "\^L\n\"" key-src "\"\n")
		   (backward-char 1))
		  ))))
    rtn
    ))

(defun hbdata:write (&optional orig-lbl-key but-sym)
  "Tries to write Hyperbole button data from optional ORIG-LBL-KEY and BUT-SYM.
ORIG-LBL-KEY nil means create a new entry, otherwise modify existing one.
BUT-SYM nil means use 'hbut:current'.  If successful, returns 
a button instance string to append to button label or t when first instance.
On failure, returns nil."
  (let ((cns (hbdata:build orig-lbl-key but-sym))
	entry lbl-instance)
    (if (or (and buffer-file-name
		 (not (file-writable-p buffer-file-name)))
	    (null cns))
	nil
      (setq entry (car cns) lbl-instance (cdr cns))
      (prin1 entry (current-buffer))
      (terpri (current-buffer))
      (or lbl-instance t)
      )))


;;;
;;; Private variables
;;;

(provide 'hbdata)

;;; hbdata.el ends here