;;; eudcb-ph.el --- Emacs Unified Directory Client - CCSO PH/QI Backend

;; Copyright (C) 1998-2020 Free Software Foundation, Inc.

;; Author: Oscar Figueiredo <oscar@cpe.fr>
;;         Pavel Janík <Pavel@Janik.cz>
;; Maintainer: Thomas Fitzsimmons <fitzsim@fitzsim.org>
;; Keywords: comm
;; Package: eudc
;; Obsolete-since: 25.1

;; 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 3 of the License, 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.  If not, see <https://www.gnu.org/licenses/>.

;;; Commentary:

;;    This library provides specific CCSO PH/QI protocol support for the
;;    Emacs Unified Directory Client package.

;;; Code:

(require 'eudc)

;;{{{      Internal cooking

(eudc-protocol-set 'eudc-bbdb-conversion-alist 'eudc-ph-bbdb-conversion-alist 'ph)
(eudc-protocol-set 'eudc-query-function 'eudc-ph-query-internal 'ph)
(eudc-protocol-set 'eudc-list-attributes-function 'eudc-ph-get-field-list 'ph)
(eudc-protocol-set 'eudc-protocol-has-default-query-attributes t 'ph)

(defvar eudc-ph-process-buffer nil)
(defvar eudc-ph-read-point)

(defconst eudc-ph-default-server-port 105
  "Default TCP port for CCSO PH/QI directory services.")

(defun eudc-ph-query-internal (query &optional return-fields)
  "Query the PH/QI server with QUERY.
QUERY can be a string NAME or a list made of strings NAME
and/or cons cells (KEY . VALUE) where KEYs should be valid
CCSO database keys.  NAME is equivalent to (DEFAULT . NAME),
where DEFAULT is the default key of the database.
RETURN-FIELDS is a list of database fields to return,
defaulting to `eudc-default-return-attributes'."
  (let (request)
    (if (null return-fields)
	(setq return-fields eudc-default-return-attributes))
    (if (eq 'all return-fields)
	(setq return-fields '(all)))
    (setq request
	  (concat "query "
		  (if (stringp query)
		      query
		    (mapconcat (function (lambda (elt)
					   (if (stringp elt) elt)
					   (format "%s=%s" (car elt) (cdr elt))))
			       query
			       " "))
		  (if return-fields
		      (concat " return " (mapconcat 'symbol-name return-fields " ")))))
    (and (> (length request) 6)
	 (eudc-ph-do-request request)
	 (eudc-ph-parse-query-result return-fields))))

(defun eudc-ph-get-field-list (full-records)
  "Return a list of valid field names for the current server.
If FULL-RECORDS is non-nil, full records including field description
are returned"
  (interactive)
  (eudc-ph-do-request "fields")
  (if full-records
      (eudc-ph-parse-query-result)
    (mapcar #'caar (eudc-ph-parse-query-result))))

(defun eudc-ph-parse-query-result (&optional fields)
  "Return a list of alists of key/values from in `eudc-ph-process-buffer'.
Fields not in FIELDS are discarded."
  (let (record
	records
	line-regexp
	current-key
	key
	value
	ignore)
    (save-excursion
      (message "Parsing results...")
      (set-buffer eudc-ph-process-buffer)
      (goto-char (point-min))
      (while (re-search-forward "^\\(-[0-9]+\\):\\([0-9]+\\):" nil t)
	(catch 'ignore
	  (setq line-regexp (concat "^\\(-[0-9]+\\):" (match-string 2) ":[ \t]*\\([-a-zA-Z_]*\\)?:[ \t]*\\(.*\\)$"))
	  (beginning-of-line)
	  (setq record nil
		ignore nil
		current-key nil)
	  (while (re-search-forward line-regexp nil t)
	    (catch 'skip-line
	      (if (string= "-508" (match-string 1))
		  ;; A field is missing in this entry.  Skip it or skip the
		  ;; whole record (see `eudc-strict-return-matches')
		  (if (not eudc-strict-return-matches)
		      (throw 'skip-line t)
		    (while (re-search-forward line-regexp nil t))
		    (setq ignore t)
		    (throw 'ignore t)))
	      (setq key   (and (not (string= (match-string 2) ""))
			       (intern (match-string 2)))
		    value (match-string 3))
	      (if (and current-key
		       (eq key current-key))
		  (setq key nil)
		(setq current-key key))
	      (if (or (null fields)
		      (eq 'all fields)
		      (memq current-key fields))
		  (if key
		      (setq record (cons (cons key value) record)) ; New key
		    (setcdr (car record) (if (listp (cdar record))
					     (append (cdar record) (list value))
					   (list (cdar record) value))))))))
	(and (not ignore)
	     (or (null fields)
		 (eq 'all fields)
		 (setq record (nreverse record)))
	     (setq record (if (not (eq 'list eudc-duplicate-attribute-handling-method))
			      (eudc-filter-duplicate-attributes record)
			    (list record)))
	     (setq records (append record records)))))
    (message "Done")
    records))

(defun eudc-ph-do-request (request)
  "Send REQUEST to the server.
Wait for response and return the buffer containing it."
  (let (process
	buffer)
    (unwind-protect
	(progn
	  (message "Contacting server...")
	  (setq process (eudc-ph-open-session))
	  (if process
	      (with-current-buffer (setq buffer (process-buffer process))
		(eudc-ph-send-command process request)
		(message "Request sent, waiting for reply...")
		(eudc-ph-read-response process))))
      (if process
	  (eudc-ph-close-session process)))
    buffer))

(defun eudc-ph-open-session (&optional server)
  "Open a connection to the given CCSO/QI SERVER.
SERVER is either a string naming the server or a list (NAME PORT)."
  (let (process
	host
	port)
    (catch 'done
      (if (null server)
	  (setq server (or eudc-server
			   (call-interactively 'eudc-ph-set-server))))
      (string-match "\\(.*\\)\\(:\\(.*\\)\\)?" server)
      (setq host (match-string 1 server))
      (setq port (or (match-string 3 server)
		     eudc-ph-default-server-port))
      (setq eudc-ph-process-buffer (get-buffer-create (format " *PH-%s*" host)))
      (with-current-buffer eudc-ph-process-buffer
	(erase-buffer)
	(setq eudc-ph-read-point (point))
	(and (featurep 'xemacs) (featurep 'mule)
	     (set-buffer-file-coding-system 'binary t)))
      (setq process (open-network-stream "ph" eudc-ph-process-buffer host port))
      (if (null process)
	  (throw 'done nil))
      (set-process-query-on-exit-flag process t)
      process)))

(defun eudc-ph-close-session (process)
  (with-current-buffer (process-buffer process)
    (eudc-ph-send-command process "quit")
    (eudc-ph-read-response process)
    (run-at-time 2 nil 'delete-process process)))

(defun eudc-ph-send-command (process command)
  (goto-char (point-max))
  (process-send-string process command)
  (process-send-string process "\r\n")
  )

(defun eudc-ph-read-response (process &optional return-response)
  "Read a response from the PH/QI query process PROCESS.
Returns nil if response starts with an error code.  If the
response is successful the return code or the response itself is returned
depending on RETURN-RESPONSE."
  (let ((case-fold-search nil)
	return-code
	match-end)
    (goto-char eudc-ph-read-point)
    ;; CCSO protocol : response complete if status >= 200
    (while (not (re-search-forward "^\\(^[2-5].*\\):.*\n" nil t))
      (accept-process-output process)
      (goto-char eudc-ph-read-point))
    (setq match-end (point))
    (goto-char eudc-ph-read-point)
    (if (and (setq return-code (match-string 1))
	     (setq return-code (string-to-number return-code))
	     (>= (abs return-code) 300))
	(progn (setq eudc-ph-read-point match-end) nil)
      (setq eudc-ph-read-point match-end)
      (if return-response
	  (buffer-substring (point) match-end)
	return-code))))

;;}}}

;;{{{      High-level interfaces (interactive functions)

(defun eudc-ph-customize ()
  "Customize the EUDC PH support."
  (interactive)
  (customize-group 'eudc-ph))

(defun eudc-ph-set-server (server)
  "Set the PH server to SERVER."
  (interactive "sNew PH/QI Server: ")
  (message "Selected PH/QI server is now %s" server)
  (eudc-set-server server 'ph))

;;}}}

(eudc-register-protocol 'ph)

(provide 'eudcb-ph)

;;; eudcb-ph.el ends here