[elpa] externals/rt-liberation 71f0e4c 39/68: bring the code back

[Yoni Rabkin]

branch: externals/rt-liberation
commit 71f0e4c67eb174cab605139c73f9af23ae592445
Author: Yoni Rabkin <yoni@rabkins.net>
Commit: Yoni Rabkin <yoni@rabkins.net>

    bring the code back
    
    Previous attempt didn't go well.
---
 rt-liberation-viewer.el | 470 -----------------------------------------------
 rt-liberation.el        | 475 +++++++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 451 insertions(+), 494 deletions(-)

diff --git a/rt-liberation-viewer.el b/rt-liberation-viewer.el
deleted file mode 100644
index e07186d..0000000
--- a/rt-liberation-viewer.el
+++ /dev/null
@@ -1,470 +0,0 @@
-;;; rt-liberation-viewer.el --- Emacs interface to RT  -*- lexical-binding: t; 
-*-
-
-;; Copyright (C) 2020  Free Software Foundation, Inc.
-;;
-;; Authors: Yoni Rabkin <yrk@gnu.org>
-;;
-;; This file is a part of rt-liberation.
-;;
-;; This program 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.
-;;
-;; This program 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 this program; if not, write to the Free
-;; Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
-;; MA 02111-1307, USA.
-
-
-;;; Comments:
-;; By the end of 2020 is was clear that a more robust way of viewing
-;; tickets was preferable.
-
-
-;;; Code:
-(require 'rt-liberation)
-
-
-(defvar rt-liber-viewer-section-header-regexp
-  "^# [0-9]+/[0-9]+ (id/[0-9]+/total)")
-
-(defvar rt-liber-viewer-section-field-regexp
-  "^\\(.+\\): \\(.+\\)$")
-
-(defconst rt-liber-viewer-font-lock-keywords
-  (let ((header-regexp (regexp-opt '("id: " "Ticket: " "TimeTaken: "
-                                    "Type: " "Field: " "OldValue: "
-                                    "NewValue: " "Data: "
-                                    "Description: " "Created: "
-                                    "Creator: " "Attachments: ")
-                                  t)))
-    (list
-     (list (concat "^" header-regexp ".*$") 0
-          'font-lock-comment-face)))
-  "Expressions to font-lock for RT ticket viewer.")
-
-(defun rt-liber-display-ticket-history (ticket-alist &optional assoc-browser)
-  "Display history for ticket.
-
-TICKET-ALIST alist of ticket data.
-ASSOC-BROWSER if non-nil should be a ticket browser."
-  (let* ((ticket-id (rt-liber-ticket-id-only ticket-alist))
-        (contents (rt-liber-rest-run-ticket-history-base-query ticket-id))
-        (new-ticket-buffer (get-buffer-create
-                            (concat "*RT Ticket #" ticket-id "*"))))
-    (with-current-buffer new-ticket-buffer
-      (let ((inhibit-read-only t))
-       (erase-buffer)
-       (insert contents)
-       (goto-char (point-min))
-       (rt-liber-viewer-mode)
-       (set
-        (make-local-variable 'rt-liber-ticket-local)
-        ticket-alist)
-       (when assoc-browser
-         (set
-          (make-local-variable 'rt-liber-assoc-browser)
-          assoc-browser))
-       (set-buffer-modified-p nil)
-       (setq buffer-read-only t)))
-    (switch-to-buffer new-ticket-buffer)))
-
-
-;;; ------------------------------------------------------------------
-;;; viewer2 mode functions
-;;; ------------------------------------------------------------------
-(defun rt-liber-viewer-reduce (section-list f acc)
-  "A Not Invented Here tail-recursive reduce function."
-  (cond ((null (cdr section-list)) acc)
-       (t (rt-liber-viewer-reduce (cdr section-list)
-                                  f
-                                  (append acc (list
-                                               (funcall f
-                                                        (car section-list)
-                                                        (cadr 
section-list))))))))
-
-;; According to:
-;; "https://rt-wiki.bestpractical.com/wiki/REST#Ticket_History_Entry";
-;; id: <history-id>
-;; Ticket: <ticket-id>
-;; TimeTaken: <...>
-;; Type: <...>
-;; Field: <...>
-;; OldValue: <...>
-;; NewValue: <...>
-;; Data: <...>
-;; Description: <...>
-
-;; Content: <lin1-0>
-;;          <line-1>
-;;          ...
-;;          <line-n>
-
-;; Creator: <...>
-;; Created: <...>
-;; Attachments: <...>
-(defun rt-liber-viewer-parse-section (start end)
-  (goto-char start)
-  (when (not (re-search-forward
-             rt-liber-viewer-section-header-regexp
-             end t))
-    (error "invalid section"))
-  (forward-line 2)
-  (let (section-field-alist
-       (rt-field-list
-        '(id Ticket TimeTaken Type Field
-             OldValue NewValue Data Description
-             Creator Created)))
-    ;; definitely error out if any of this doesn't work
-    (setq section-field-alist
-         (mapcar
-          (lambda (field-symbol)
-            (re-search-forward (format "^%s:" (symbol-name field-symbol)) end 
nil)
-            (cons field-symbol (buffer-substring (1+ (point)) (point-at-eol))))
-          rt-field-list))
-    ;; content
-    (goto-char start)
-    (let ((content-start (re-search-forward "^Content: " end nil))
-         (content-end (progn
-                        (re-search-forward "^Creator: " end nil)
-                        (point-at-bol))))
-      (append section-field-alist
-             `(,(cons 'Content
-                      (buffer-substring content-start
-                                        content-end)))))))
-
-;; According to:
-;; "https://rt-wiki.bestpractical.com/wiki/REST#Ticket_History"; is of
-;; the form: "# <n>/<n> (id/<history-id>/total)"
-(defun rt-liber-viewer-parse-history (ticket-history)
-  "Parse the string TICKET-HISTORY."
-  (when (not (stringp ticket-history))
-    (error "invalid ticket-history"))
-  (with-temp-buffer
-    (insert ticket-history)
-    (goto-char (point-min))
-    ;; find history detail sections and procude a list of section
-    ;; (start . end) pairs
-    (let (section-point-list
-         section-list)
-      (while (re-search-forward rt-liber-viewer-section-header-regexp 
(point-max) t)
-       (setq section-point-list (append section-point-list
-                                        (list (point-at-bol)))))
-      (when (not section-point-list)
-       (error "no history detail sections found"))
-      (setq section-point-list (append section-point-list
-                                      (list (point-max)))
-           section-point-list (rt-liber-viewer-reduce section-point-list 
#'cons nil))
-      ;; collect the sections
-      (setq section-list
-           (mapcar
-            (lambda (section-points)
-              (rt-liber-viewer-parse-section
-               (car section-points)
-               (cdr section-points)))
-            section-point-list))
-      section-list)))
-
-(defun rt-liber-viewer2-format-content (content)
-  (with-temp-buffer
-    (insert content)
-
-    ;; Convert the 9 leading whitespaces from RT's comment lines.
-    (goto-char (point-min))
-    (insert "    ")
-    (while (re-search-forward "^         " (point-max) t)
-      (replace-match "    "))
-
-    (fill-region (point-min)
-                (point-max))
-
-    (buffer-substring (point-min)
-                     (point-max))))
-
-(defun rt-liber-viewer2-display-section (section)
-  (let ((ticket-id (alist-get 'Ticket section))
-       (creator   (alist-get 'Creator section))
-       (date      (alist-get 'Created section))
-       (type      (alist-get 'Type section))
-       (content   (alist-get 'Content section)))
-    (insert
-     (format "Ticket %s by %s on %s (-N- days ago) (%s)\n"
-            ticket-id
-            creator
-            date
-            type))
-    (cond ((or (string= type "Status")
-              (string= type "CustomField")
-              ;; (string= type "EmailRecord")
-              (string= type "Set"))
-          'nop-for-now)
-         (t (insert
-             (format "\n%s\n"
-                     (rt-liber-viewer2-format-content content)))))))
-
-(defun rt-liber-viewer2-display-history (contents)
-  (let ((section-list (rt-liber-viewer-parse-history contents)))
-    (mapc
-     (lambda (section)
-       (rt-liber-viewer2-display-section section))
-     section-list)))
-
-;; Before release: move this back to the top
-(defconst rt-liber-viewer2-font-lock-keywords
-  (let ((header-regexp (regexp-opt '("id: ")
-                                  t)))
-    (list
-     (list (concat "^" header-regexp ".*$") 0
-          'font-lock-comment-face)))
-  "Expressions to font-lock for RT ticket viewer.")
-
-(defun rt-liber-viewer2-display-ticket-history (ticket-alist &optional 
assoc-browser)
-  "Display history for ticket.
-
-TICKET-ALIST alist of ticket data.
-ASSOC-BROWSER if non-nil should be a ticket browser."
-  (let* ((ticket-id (rt-liber-ticket-id-only ticket-alist))
-        (contents (rt-liber-rest-run-ticket-history-base-query ticket-id))
-        (new-ticket-buffer (get-buffer-create
-                            (concat "*RT (Viewer) Ticket #" ticket-id "*"))))
-    (with-current-buffer new-ticket-buffer
-      (let ((inhibit-read-only t))
-       (erase-buffer)
-       (rt-liber-viewer2-display-history contents)
-       (goto-char (point-min))
-       (rt-liber-viewer2-mode)
-       (set
-        (make-local-variable 'rt-liber-ticket-local)
-        ticket-alist)
-       (when assoc-browser
-         (set
-          (make-local-variable 'rt-liber-assoc-browser)
-          assoc-browser))
-       (set-buffer-modified-p nil)
-       (setq buffer-read-only t)))
-    (switch-to-buffer new-ticket-buffer)))
-
-(defun rt-liber-viewer2-refresh-ticket-history (&optional _ignore-auto 
_noconfirm)
-  (interactive)
-  (if rt-liber-ticket-local
-      (rt-liber-viewer2-display-ticket-history rt-liber-ticket-local
-                                              rt-liber-assoc-browser)
-    (error "not viewing a ticket")))
-
-(defconst rt-liber-viewer2-mode-map
-  (let ((map (make-sparse-keymap)))
-    (define-key map (kbd "q") 'rt-liber-viewer-mode-quit)
-    (define-key map (kbd "n") 'rt-liber-next-section-in-viewer)
-    (define-key map (kbd "N") 'rt-liber-jump-to-latest-correspondence)
-    (define-key map (kbd "p") 'rt-liber-previous-section-in-viewer)
-    (define-key map (kbd "V") 'rt-liber-viewer-visit-in-browser)
-    (define-key map (kbd "m") 'rt-liber-viewer-answer)
-    (define-key map (kbd "M") 'rt-liber-viewer-answer-this)
-    (define-key map (kbd "t") 'rt-liber-viewer-answer-provisionally)
-    (define-key map (kbd "T") 'rt-liber-viewer-answer-provisionally-this)
-    (define-key map (kbd "F") 'rt-liber-viewer-answer-verbatim-this)
-    (define-key map (kbd "c") 'rt-liber-viewer-comment)
-    (define-key map (kbd "C") 'rt-liber-viewer-comment-this)
-    (define-key map (kbd "g") 'revert-buffer)
-    (define-key map (kbd "SPC") 'scroll-up)
-    (define-key map (kbd "DEL") 'scroll-down)
-    (define-key map (kbd "h") 'rt-liber-viewer-show-ticket-browser)
-    map)
-  "Key map for ticket viewer.")
-
-(define-derived-mode rt-liber-viewer2-mode nil
-  "RT Liberation Viewer"
-  "Major Mode for viewing RT tickets.
-\\{rt-liber-viewer-mode-map}"
-  (set
-   (make-local-variable 'font-lock-defaults)
-   '((rt-liber-viewer2-font-lock-keywords)))
-  (set (make-local-variable 'revert-buffer-function)
-       #'rt-liber-viewer2-refresh-ticket-history)
-  (set (make-local-variable 'buffer-stale-function)
-       (lambda (&optional _noconfirm) 'slow))
-  (run-hooks 'rt-liber-viewer-hook))
-
-
-;;; ------------------------------------------------------------------
-;;; viewer mode functions
-;;; ------------------------------------------------------------------
-(defun rt-liber-jump-to-latest-correspondence ()
-  "Move point to the newest correspondence section."
-  (interactive)
-  (let (latest-point)
-    (save-excursion
-      (goto-char (point-max))
-      (when (re-search-backward rt-liber-correspondence-regexp
-                               (point-min) t)
-       (setq latest-point (point))))
-    (if latest-point
-       (progn
-         (goto-char latest-point)
-         (rt-liber-next-section-in-viewer))
-      (message "no correspondence found"))))
-
-(defun rt-liber-viewer-visit-in-browser ()
-  "Visit this ticket in the RT Web interface."
-  (interactive)
-  (let ((id (rt-liber-ticket-id-only rt-liber-ticket-local)))
-    (if id
-       (browse-url
-        (concat rt-liber-base-url "Ticket/Display.html?id=" id))
-      (error "no ticket currently in view"))))
-
-(defun rt-liber-viewer-mode-quit ()
-  "Bury the ticket viewer."
-  (interactive)
-  (bury-buffer))
-
-(defun rt-liber-viewer-show-ticket-browser ()
-  "Return to the ticket browser buffer."
-  (interactive)
-  (let ((id (rt-liber-ticket-id-only rt-liber-ticket-local)))
-    (if id
-       (let ((target-buffer
-              (if rt-liber-assoc-browser
-                  (buffer-name rt-liber-assoc-browser)
-                (buffer-name rt-liber-browser-buffer-name))))
-         (if target-buffer
-             (switch-to-buffer target-buffer)
-           (error "associated ticket browser buffer no longer exists"))
-         (rt-liber-browser-move-point-to-ticket id))
-      (error "no ticket currently in view"))))
-
-(defun rt-liber-next-section-in-viewer ()
-  "Move point to next section."
-  (interactive)
-  (forward-line 1)
-  (when (not (re-search-forward rt-liber-content-regexp (point-max) t))
-    (message "no next section"))
-  (goto-char (point-at-bol)))
-
-(defun rt-liber-previous-section-in-viewer ()
-  "Move point to previous section."
-  (interactive)
-  (forward-line -1)
-  (when (not (re-search-backward rt-liber-content-regexp (point-min) t))
-    (message "no previous section"))
-  (goto-char (point-at-bol)))
-
-(defconst rt-liber-viewer-mode-map
-  (let ((map (make-sparse-keymap)))
-    (define-key map (kbd "q") 'rt-liber-viewer-mode-quit)
-    (define-key map (kbd "n") 'rt-liber-next-section-in-viewer)
-    (define-key map (kbd "N") 'rt-liber-jump-to-latest-correspondence)
-    (define-key map (kbd "p") 'rt-liber-previous-section-in-viewer)
-    (define-key map (kbd "V") 'rt-liber-viewer-visit-in-browser)
-    (define-key map (kbd "m") 'rt-liber-viewer-answer)
-    (define-key map (kbd "M") 'rt-liber-viewer-answer-this)
-    (define-key map (kbd "t") 'rt-liber-viewer-answer-provisionally)
-    (define-key map (kbd "T") 'rt-liber-viewer-answer-provisionally-this)
-    (define-key map (kbd "F") 'rt-liber-viewer-answer-verbatim-this)
-    (define-key map (kbd "c") 'rt-liber-viewer-comment)
-    (define-key map (kbd "C") 'rt-liber-viewer-comment-this)
-    (define-key map (kbd "g") 'revert-buffer)
-    (define-key map (kbd "SPC") 'scroll-up)
-    (define-key map (kbd "DEL") 'scroll-down)
-    (define-key map (kbd "h") 'rt-liber-viewer-show-ticket-browser)
-    map)
-  "Key map for ticket viewer.")
-
-(define-derived-mode rt-liber-viewer-mode nil
-  "RT Liberation Viewer"
-  "Major Mode for viewing RT tickets.
-\\{rt-liber-viewer-mode-map}"
-  (set
-   (make-local-variable 'font-lock-defaults)
-   '((rt-liber-viewer-font-lock-keywords)))
-  (set (make-local-variable 'revert-buffer-function)
-       #'rt-liber-refresh-ticket-history)
-  (set (make-local-variable 'buffer-stale-function)
-       (lambda (&optional _noconfirm) 'slow))
-  (when rt-liber-jump-to-latest
-    (rt-liber-jump-to-latest-correspondence))
-  (run-hooks 'rt-liber-viewer-hook))
-
-
-;; wrapper functions around specific functions provided by a backend
-(declare-function
- rt-liber-gnus-compose-reply-to-requestor
- "rt-liberation-gnus.el")
-(declare-function
- rt-liber-gnus-compose-reply-to-requestor-to-this
- "rt-liberation-gnus.el")
-(declare-function
- rt-liber-gnus-compose-reply-to-requestor-verbatim-this
- "rt-liberation-gnus.el")
-(declare-function
- rt-liber-gnus-compose-provisional
- "rt-liberation-gnus.el")
-(declare-function
- rt-liber-gnus-compose-provisional-to-this
- "rt-liberation-gnus.el")
-(declare-function
- rt-liber-gnus-compose-comment
- "rt-liberation-gnus.el")
-(declare-function
- rt-liber-gnus-compose-comment-this
- "rt-liberation-gnus.el")
-
-(defun rt-liber-viewer-answer ()
-  "Answer the ticket."
-  (interactive)
-  (cond ((featurep 'rt-liberation-gnus)
-        (rt-liber-gnus-compose-reply-to-requestor))
-       (t (error "no function defined"))))
-
-(defun rt-liber-viewer-answer-this ()
-  "Answer the ticket using the current context."
-  (interactive)
-  (cond ((featurep 'rt-liberation-gnus)
-        (rt-liber-gnus-compose-reply-to-requestor-to-this))
-       (t (error "no function defined"))))
-
-(defun rt-liber-viewer-answer-verbatim-this ()
-  "Answer the ticket using the current context verbatim."
-  (interactive)
-  (cond ((featurep 'rt-liberation-gnus)
-        (rt-liber-gnus-compose-reply-to-requestor-verbatim-this))
-       (t (error "no function defined"))))
-
-(defun rt-liber-viewer-answer-provisionally ()
-  "Provisionally answer the ticket."
-  (interactive)
-  (cond ((featurep 'rt-liberation-gnus)
-        (rt-liber-gnus-compose-provisional))
-       (t (error "no function defined"))))
-
-(defun rt-liber-viewer-answer-provisionally-this ()
-  "Provisionally answer the ticket using the current context."
-  (interactive)
-  (cond ((featurep 'rt-liberation-gnus)
-        (rt-liber-gnus-compose-provisional-to-this))
-       (t (error "no function defined"))))
-
-(defun rt-liber-viewer-comment ()
-  "Comment on the ticket."
-  (interactive)
-  (cond ((featurep 'rt-liberation-gnus)
-        (rt-liber-gnus-compose-comment))
-       (t (error "no function defined"))))
-
-(defun rt-liber-viewer-comment-this ()
-  "Comment on the ticket using the current context."
-  (interactive)
-  (cond ((featurep 'rt-liberation-gnus)
-        (rt-liber-gnus-compose-comment-this))
-       (t (error "no function defined"))))
-
-
-(provide 'rt-liberation-viewer)
-
-;;; rt-liberation-viewer.el ends here.
diff --git a/rt-liberation.el b/rt-liberation.el
index 9fbcdf5..143923c 100644
--- a/rt-liberation.el
+++ b/rt-liberation.el
@@ -38,14 +38,15 @@
 
 
 ;;; Code:
-
 (require 'browse-url)
 (require 'time-date)
 (require 'cl-lib)
 
 (require 'rt-liberation-rest)
 
-(declare-function rt-liber-display-ticket-history "rt-liberation-viewer.el" 
(ticket-alist &optional assoc-browser))
+(declare-function rt-liber-get-ancillary-text "rt-liberation-storage.el")
+(declare-function rt-liber-ticket-marked-p "rt-liberation-multi.el")
+(declare-function rt-liber-set-ancillary-text "rt-liberation-storage.el")
 
 
 (defgroup rt-liber nil
@@ -58,6 +59,24 @@
   :type 'string
   :group 'rt-liber)
 
+(defvar rt-liber-viewer-section-header-regexp
+  "^# [0-9]+/[0-9]+ (id/[0-9]+/total)")
+
+(defvar rt-liber-viewer-section-field-regexp
+  "^\\(.+\\): \\(.+\\)$")
+
+(defconst rt-liber-viewer-font-lock-keywords
+  (let ((header-regexp (regexp-opt '("id: " "Ticket: " "TimeTaken: "
+                                    "Type: " "Field: " "OldValue: "
+                                    "NewValue: " "Data: "
+                                    "Description: " "Created: "
+                                    "Creator: " "Attachments: ")
+                                  t)))
+    (list
+     (list (concat "^" header-regexp ".*$") 0
+          'font-lock-comment-face)))
+  "Expressions to font-lock for RT ticket viewer.")
+
 (defvar rt-liber-created-string "Created"
   "String representation of \"created\" query tag.")
 
@@ -426,7 +445,6 @@ AFTER  date after predicate."
 ;;; --------------------------------------------------------
 ;;; Ticket utilities
 ;;; --------------------------------------------------------
-
 (defun rt-liber-ticket-days-old (ticket-alist)
   "Return the age of the ticket in positive days."
   (days-between (format-time-string "%Y-%m-%dT%T%z" (current-time))
@@ -467,11 +485,6 @@ AFTER  date after predicate."
 ;;; --------------------------------------------------------
 ;;; Ticket browser
 ;;; --------------------------------------------------------
-
-(declare-function
- rt-liber-get-ancillary-text
- "rt-liberation-storage.el")
-
 ;; accept a ticket-alist object and return an alist mapping ticket
 ;; properties to format characters for use in `rt-liber-format'.
 (defun rt-liber-format-function (ticket-alist)
@@ -552,8 +565,7 @@ The ticket's priority is compared to the variable
                         '(face font-lock-comment-face)))
   (newline))
 
-(declare-function rt-liber-ticket-marked-p
-                 "rt-liberation-multi.el")
+
 
 (defun rt-liber-ticketlist-browser-redraw (ticketlist &optional query)
   "Display TICKETLIST. Optionally display QUERY as well."
@@ -645,14 +657,6 @@ If POINT is nil then called on (point)."
   (let ((ticket-alist (get-text-property (point) 'rt-ticket)))
     (rt-liber-display-ticket-history ticket-alist (current-buffer))))
 
-;; remove after release START
-(defun rt-liber-viewer2-display-ticket-at-point ()
-  "Display the contents of the ticket at point."
-  (interactive)
-  (let ((ticket-alist (get-text-property (point) 'rt-ticket)))
-    (rt-liber-viewer2-display-ticket-history ticket-alist (current-buffer))))
-;; remove after release END
-
 (defun rt-liber-browser-search (id)
   "Return point where ticket with ID is displayed or nil."
   (let ((p nil))
@@ -730,7 +734,6 @@ If POINT is nil then called on (point)."
 ;;; --------------------------------------------------------
 ;;; Ticket browser filtering
 ;;; --------------------------------------------------------
-
 ;; See the fine manual for example code.
 
 (defun rt-liber-default-filter-f (_ticket)
@@ -744,7 +747,6 @@ and as such always return t."
 ;;; --------------------------------------------------------
 ;;; Entry points
 ;;; --------------------------------------------------------
-
 (defun rt-liber-browse-query (query &optional new)
   "Run QUERY against the server and launch the browser.
 
@@ -787,7 +789,6 @@ returned as no associated text properties."
 ;;; --------------------------------------------------------
 ;;; Major mode definitions
 ;;; --------------------------------------------------------
-
 (defun rt-liber-browser-mode-quit ()
   "Bury the ticket browser."
   (interactive)
@@ -873,8 +874,6 @@ returned as no associated text properties."
   (switch-to-buffer rt-liber-browser-buffer)
   (setq buffer-read-only t))
 
-(declare-function rt-liber-set-ancillary-text "rt-liberation-storage.el")
-
 (defun rt-liber-browser-ancillary-text ()
   "Wrapper function around storage backend."
   (interactive)
@@ -888,7 +887,6 @@ returned as no associated text properties."
 ;;; --------------------------------------------------------
 ;;; Command module
 ;;; --------------------------------------------------------
-
 (defun rt-liber-command-get-dictionary-value (sym dic)
   "Utility function for retrieving alist values."
   (let ((value (cdr (assoc sym dic))))
@@ -1002,6 +1000,435 @@ returned as no associated text properties."
   (rt-liber-browser-assign rt-liber-username))
 
 
+;;; --------------------------------------------------------
+;;; Viewer
+;;; --------------------------------------------------------
+(defun rt-liber-display-ticket-history (ticket-alist &optional assoc-browser)
+  "Display history for ticket.
+TICKET-ALIST alist of ticket data.
+ASSOC-BROWSER if non-nil should be a ticket browser."
+  (let* ((ticket-id (rt-liber-ticket-id-only ticket-alist))
+        (contents (rt-liber-rest-run-ticket-history-base-query ticket-id))
+        (new-ticket-buffer (get-buffer-create
+                            (concat "*RT Ticket #" ticket-id "*"))))
+    (with-current-buffer new-ticket-buffer
+      (let ((inhibit-read-only t))
+       (erase-buffer)
+       (insert contents)
+       (goto-char (point-min))
+       (rt-liber-viewer-mode)
+       (set
+        (make-local-variable 'rt-liber-ticket-local)
+        ticket-alist)
+       (when assoc-browser
+         (set
+          (make-local-variable 'rt-liber-assoc-browser)
+          assoc-browser))
+       (set-buffer-modified-p nil)
+       (setq buffer-read-only t)))
+    (switch-to-buffer new-ticket-buffer)))
+
+
+;;; ------------------------------------------------------------------
+;;; viewer mode functions
+;;; ------------------------------------------------------------------
+(defun rt-liber-refresh-ticket-history (&optional _ignore-auto _noconfirm)
+  (interactive)
+  (if rt-liber-ticket-local
+      (rt-liber-display-ticket-history rt-liber-ticket-local
+                                       rt-liber-assoc-browser)
+    (error "not viewing a ticket")))
+
+(defun rt-liber-jump-to-latest-correspondence ()
+  "Move point to the newest correspondence section."
+  (interactive)
+  (let (latest-point)
+    (save-excursion
+      (goto-char (point-max))
+      (when (re-search-backward rt-liber-correspondence-regexp
+                               (point-min) t)
+       (setq latest-point (point))))
+    (if latest-point
+       (progn
+         (goto-char latest-point)
+         (rt-liber-next-section-in-viewer))
+      (message "no correspondence found"))))
+
+(defun rt-liber-viewer-visit-in-browser ()
+  "Visit this ticket in the RT Web interface."
+  (interactive)
+  (let ((id (rt-liber-ticket-id-only rt-liber-ticket-local)))
+    (if id
+       (browse-url
+        (concat rt-liber-base-url "Ticket/Display.html?id=" id))
+      (error "no ticket currently in view"))))
+
+(defun rt-liber-viewer-mode-quit ()
+  "Bury the ticket viewer."
+  (interactive)
+  (bury-buffer))
+
+(defun rt-liber-viewer-show-ticket-browser ()
+  "Return to the ticket browser buffer."
+  (interactive)
+  (let ((id (rt-liber-ticket-id-only rt-liber-ticket-local)))
+    (if id
+       (let ((target-buffer
+              (if rt-liber-assoc-browser
+                  (buffer-name rt-liber-assoc-browser)
+                (buffer-name rt-liber-browser-buffer-name))))
+         (if target-buffer
+             (switch-to-buffer target-buffer)
+           (error "associated ticket browser buffer no longer exists"))
+         (rt-liber-browser-move-point-to-ticket id))
+      (error "no ticket currently in view"))))
+
+(defun rt-liber-next-section-in-viewer ()
+  "Move point to next section."
+  (interactive)
+  (forward-line 1)
+  (when (not (re-search-forward rt-liber-content-regexp (point-max) t))
+    (message "no next section"))
+  (goto-char (point-at-bol)))
+
+(defun rt-liber-previous-section-in-viewer ()
+  "Move point to previous section."
+  (interactive)
+  (forward-line -1)
+  (when (not (re-search-backward rt-liber-content-regexp (point-min) t))
+    (message "no previous section"))
+  (goto-char (point-at-bol)))
+
+(defconst rt-liber-viewer-mode-map
+  (let ((map (make-sparse-keymap)))
+    (define-key map (kbd "q") 'rt-liber-viewer-mode-quit)
+    (define-key map (kbd "n") 'rt-liber-next-section-in-viewer)
+    (define-key map (kbd "N") 'rt-liber-jump-to-latest-correspondence)
+    (define-key map (kbd "p") 'rt-liber-previous-section-in-viewer)
+    (define-key map (kbd "V") 'rt-liber-viewer-visit-in-browser)
+    (define-key map (kbd "m") 'rt-liber-viewer-answer)
+    (define-key map (kbd "M") 'rt-liber-viewer-answer-this)
+    (define-key map (kbd "t") 'rt-liber-viewer-answer-provisionally)
+    (define-key map (kbd "T") 'rt-liber-viewer-answer-provisionally-this)
+    (define-key map (kbd "F") 'rt-liber-viewer-answer-verbatim-this)
+    (define-key map (kbd "c") 'rt-liber-viewer-comment)
+    (define-key map (kbd "C") 'rt-liber-viewer-comment-this)
+    (define-key map (kbd "g") 'revert-buffer)
+    (define-key map (kbd "SPC") 'scroll-up)
+    (define-key map (kbd "DEL") 'scroll-down)
+    (define-key map (kbd "h") 'rt-liber-viewer-show-ticket-browser)
+    map)
+  "Key map for ticket viewer.")
+
+(define-derived-mode rt-liber-viewer-mode nil
+  "RT Liberation Viewer"
+  "Major Mode for viewing RT tickets.
+\\{rt-liber-viewer-mode-map}"
+  (set
+   (make-local-variable 'font-lock-defaults)
+   '((rt-liber-viewer-font-lock-keywords)))
+  (set (make-local-variable 'revert-buffer-function)
+       #'rt-liber-refresh-ticket-history)
+  (set (make-local-variable 'buffer-stale-function)
+       (lambda (&optional _noconfirm) 'slow))
+  (when rt-liber-jump-to-latest
+    (rt-liber-jump-to-latest-correspondence))
+  (run-hooks 'rt-liber-viewer-hook))
+
+;; wrapper functions around specific functions provided by a backend
+(declare-function
+ rt-liber-gnus-compose-reply-to-requestor
+ "rt-liberation-gnus.el")
+(declare-function
+ rt-liber-gnus-compose-reply-to-requestor-to-this
+ "rt-liberation-gnus.el")
+(declare-function
+ rt-liber-gnus-compose-reply-to-requestor-verbatim-this
+ "rt-liberation-gnus.el")
+(declare-function
+ rt-liber-gnus-compose-provisional
+ "rt-liberation-gnus.el")
+(declare-function
+ rt-liber-gnus-compose-provisional-to-this
+ "rt-liberation-gnus.el")
+(declare-function
+ rt-liber-gnus-compose-comment
+ "rt-liberation-gnus.el")
+(declare-function
+ rt-liber-gnus-compose-comment-this
+ "rt-liberation-gnus.el")
+
+(defun rt-liber-viewer-answer ()
+  "Answer the ticket."
+  (interactive)
+  (cond ((featurep 'rt-liberation-gnus)
+        (rt-liber-gnus-compose-reply-to-requestor))
+       (t (error "no function defined"))))
+
+(defun rt-liber-viewer-answer-this ()
+  "Answer the ticket using the current context."
+  (interactive)
+  (cond ((featurep 'rt-liberation-gnus)
+        (rt-liber-gnus-compose-reply-to-requestor-to-this))
+       (t (error "no function defined"))))
+
+(defun rt-liber-viewer-answer-verbatim-this ()
+  "Answer the ticket using the current context verbatim."
+  (interactive)
+  (cond ((featurep 'rt-liberation-gnus)
+        (rt-liber-gnus-compose-reply-to-requestor-verbatim-this))
+       (t (error "no function defined"))))
+
+(defun rt-liber-viewer-answer-provisionally ()
+  "Provisionally answer the ticket."
+  (interactive)
+  (cond ((featurep 'rt-liberation-gnus)
+        (rt-liber-gnus-compose-provisional))
+       (t (error "no function defined"))))
+
+(defun rt-liber-viewer-answer-provisionally-this ()
+  "Provisionally answer the ticket using the current context."
+  (interactive)
+  (cond ((featurep 'rt-liberation-gnus)
+        (rt-liber-gnus-compose-provisional-to-this))
+       (t (error "no function defined"))))
+
+(defun rt-liber-viewer-comment ()
+  "Comment on the ticket."
+  (interactive)
+  (cond ((featurep 'rt-liberation-gnus)
+        (rt-liber-gnus-compose-comment))
+       (t (error "no function defined"))))
+
+(defun rt-liber-viewer-comment-this ()
+  "Comment on the ticket using the current context."
+  (interactive)
+  (cond ((featurep 'rt-liberation-gnus)
+        (rt-liber-gnus-compose-comment-this))
+       (t (error "no function defined"))))
+
+
+;;; ------------------------------------------------------------------
+;;; viewer2 functions
+;;; ------------------------------------------------------------------
+(defun rt-liber-viewer-reduce (section-list f acc)
+  "A Not Invented Here tail-recursive reduce function."
+  (cond ((null (cdr section-list)) acc)
+       (t (rt-liber-viewer-reduce (cdr section-list)
+                                  f
+                                  (append acc (list
+                                               (funcall f
+                                                        (car section-list)
+                                                        (cadr 
section-list))))))))
+
+;; According to:
+;; "https://rt-wiki.bestpractical.com/wiki/REST#Ticket_History_Entry";
+;; id: <history-id>
+;; Ticket: <ticket-id>
+;; TimeTaken: <...>
+;; Type: <...>
+;; Field: <...>
+;; OldValue: <...>
+;; NewValue: <...>
+;; Data: <...>
+;; Description: <...>
+
+;; Content: <lin1-0>
+;;          <line-1>
+;;          ...
+;;          <line-n>
+
+;; Creator: <...>
+;; Created: <...>
+;; Attachments: <...>
+(defun rt-liber-viewer-parse-section (start end)
+  (goto-char start)
+  (when (not (re-search-forward
+             rt-liber-viewer-section-header-regexp
+             end t))
+    (error "invalid section"))
+  (forward-line 2)
+  (let (section-field-alist
+       (rt-field-list
+        '(id Ticket TimeTaken Type Field
+             OldValue NewValue Data Description
+             Creator Created)))
+    ;; definitely error out if any of this doesn't work
+    (setq section-field-alist
+         (mapcar
+          (lambda (field-symbol)
+            (re-search-forward (format "^%s:" (symbol-name field-symbol)) end 
nil)
+            (cons field-symbol (buffer-substring (1+ (point)) (point-at-eol))))
+          rt-field-list))
+    ;; content
+    (goto-char start)
+    (let ((content-start (re-search-forward "^Content: " end nil))
+         (content-end (progn
+                        (re-search-forward "^Creator: " end nil)
+                        (point-at-bol))))
+      (append section-field-alist
+             `(,(cons 'Content
+                      (buffer-substring content-start
+                                        content-end)))))))
+
+;; According to:
+;; "https://rt-wiki.bestpractical.com/wiki/REST#Ticket_History"; is of
+;; the form: "# <n>/<n> (id/<history-id>/total)"
+(defun rt-liber-viewer-parse-history (ticket-history)
+  "Parse the string TICKET-HISTORY."
+  (when (not (stringp ticket-history))
+    (error "invalid ticket-history"))
+  (with-temp-buffer
+    (insert ticket-history)
+    (goto-char (point-min))
+    ;; find history detail sections and procude a list of section
+    ;; (start . end) pairs
+    (let (section-point-list
+         section-list)
+      (while (re-search-forward rt-liber-viewer-section-header-regexp 
(point-max) t)
+       (setq section-point-list (append section-point-list
+                                        (list (point-at-bol)))))
+      (when (not section-point-list)
+       (error "no history detail sections found"))
+      (setq section-point-list (append section-point-list
+                                      (list (point-max)))
+           section-point-list (rt-liber-viewer-reduce section-point-list 
#'cons nil))
+      ;; collect the sections
+      (setq section-list
+           (mapcar
+            (lambda (section-points)
+              (rt-liber-viewer-parse-section
+               (car section-points)
+               (cdr section-points)))
+            section-point-list))
+      section-list)))
+
+(defun rt-liber-viewer2-format-content (content)
+  (with-temp-buffer
+    (insert content)
+
+    ;; Convert the 9 leading whitespaces from RT's comment lines.
+    (goto-char (point-min))
+    (insert "    ")
+    (while (re-search-forward "^         " (point-max) t)
+      (replace-match "    "))
+
+    (fill-region (point-min)
+                (point-max))
+
+    (buffer-substring (point-min)
+                     (point-max))))
+
+(defun rt-liber-viewer2-display-section (section)
+  (let ((ticket-id (alist-get 'Ticket section))
+       (creator   (alist-get 'Creator section))
+       (date      (alist-get 'Created section))
+       (type      (alist-get 'Type section))
+       (content   (alist-get 'Content section)))
+    (insert
+     (format "Ticket %s by %s on %s (-N- days ago) (%s)\n"
+            ticket-id
+            creator
+            date
+            type))
+    (cond ((or (string= type "Status")
+              (string= type "CustomField")
+              ;; (string= type "EmailRecord")
+              (string= type "Set"))
+          'nop-for-now)
+         (t (insert
+             (format "\n%s\n"
+                     (rt-liber-viewer2-format-content content)))))))
+
+(defun rt-liber-viewer2-display-history (contents)
+  (let ((section-list (rt-liber-viewer-parse-history contents)))
+    (mapc
+     (lambda (section)
+       (rt-liber-viewer2-display-section section))
+     section-list)))
+
+;; Before release: move this back to the top
+(defconst rt-liber-viewer2-font-lock-keywords
+  (let ((header-regexp (regexp-opt '("id: ")
+                                  t)))
+    (list
+     (list (concat "^" header-regexp ".*$") 0
+          'font-lock-comment-face)))
+  "Expressions to font-lock for RT ticket viewer.")
+
+(defun rt-liber-viewer2-display-ticket-at-point ()
+  "Display the contents of the ticket at point."
+  (interactive)
+  (let ((ticket-alist (get-text-property (point) 'rt-ticket)))
+    (rt-liber-viewer2-display-ticket-history ticket-alist (current-buffer))))
+
+(defun rt-liber-viewer2-display-ticket-history (ticket-alist &optional 
assoc-browser)
+  "Display history for ticket.
+TICKET-ALIST alist of ticket data.
+ASSOC-BROWSER if non-nil should be a ticket browser."
+  (let* ((ticket-id (rt-liber-ticket-id-only ticket-alist))
+        (contents (rt-liber-rest-run-ticket-history-base-query ticket-id))
+        (new-ticket-buffer (get-buffer-create
+                            (concat "*RT (Viewer) Ticket #" ticket-id "*"))))
+    (with-current-buffer new-ticket-buffer
+      (let ((inhibit-read-only t))
+       (erase-buffer)
+       (rt-liber-viewer2-display-history contents)
+       (goto-char (point-min))
+       (rt-liber-viewer2-mode)
+       (set
+        (make-local-variable 'rt-liber-ticket-local)
+        ticket-alist)
+       (when assoc-browser
+         (set
+          (make-local-variable 'rt-liber-assoc-browser)
+          assoc-browser))
+       (set-buffer-modified-p nil)
+       (setq buffer-read-only t)))
+    (switch-to-buffer new-ticket-buffer)))
+
+(defun rt-liber-viewer2-refresh-ticket-history (&optional _ignore-auto 
_noconfirm)
+  (interactive)
+  (if rt-liber-ticket-local
+      (rt-liber-viewer2-display-ticket-history rt-liber-ticket-local
+                                              rt-liber-assoc-browser)
+    (error "not viewing a ticket")))
+
+(defconst rt-liber-viewer2-mode-map
+  (let ((map (make-sparse-keymap)))
+    (define-key map (kbd "q") 'rt-liber-viewer-mode-quit)
+    (define-key map (kbd "n") 'rt-liber-next-section-in-viewer)
+    (define-key map (kbd "N") 'rt-liber-jump-to-latest-correspondence)
+    (define-key map (kbd "p") 'rt-liber-previous-section-in-viewer)
+    (define-key map (kbd "V") 'rt-liber-viewer-visit-in-browser)
+    (define-key map (kbd "m") 'rt-liber-viewer-answer)
+    (define-key map (kbd "M") 'rt-liber-viewer-answer-this)
+    (define-key map (kbd "t") 'rt-liber-viewer-answer-provisionally)
+    (define-key map (kbd "T") 'rt-liber-viewer-answer-provisionally-this)
+    (define-key map (kbd "F") 'rt-liber-viewer-answer-verbatim-this)
+    (define-key map (kbd "c") 'rt-liber-viewer-comment)
+    (define-key map (kbd "C") 'rt-liber-viewer-comment-this)
+    (define-key map (kbd "g") 'revert-buffer)
+    (define-key map (kbd "SPC") 'scroll-up)
+    (define-key map (kbd "DEL") 'scroll-down)
+    (define-key map (kbd "h") 'rt-liber-viewer-show-ticket-browser)
+    map)
+  "Key map for ticket viewer.")
+
+(define-derived-mode rt-liber-viewer2-mode nil
+  "RT Liberation Viewer"
+  "Major Mode for viewing RT tickets.
+\\{rt-liber-viewer-mode-map}"
+  (set
+   (make-local-variable 'font-lock-defaults)
+   '((rt-liber-viewer2-font-lock-keywords)))
+  (set (make-local-variable 'revert-buffer-function)
+       #'rt-liber-viewer2-refresh-ticket-history)
+  (set (make-local-variable 'buffer-stale-function)
+       (lambda (&optional _noconfirm) 'slow))
+  (run-hooks 'rt-liber-viewer-hook))
+
+
 (provide 'rt-liberation)
 
 ;;; rt-liberation.el ends here.