feat(reveal): add org-reveal presentation workflow with ERT tests

Replaced pandoc-based reveal.js export with native ox-reveal integration.
New org-reveal-config.el module provides offline, self-contained HTML export
with keybindings under C-; p. Includes setup script for reveal.js 5.1.0
and 34 ERT tests covering header template and title-to-filename helpers.

2 files changed, 167 insertions, 47 deletions

diff --git a/modules/org-export-config.el b/modules/org-export-config.el
index 33e170f5..4451eddd 100644
--- a/modules/org-export-config.el
+++ b/modules/org-export-config.el
@@ -13,14 +13,14 @@
 ;; - Texinfo: GNU documentation and Info files
 ;;
 ;; Extended via Pandoc:
-;; - Additional formats: DOCX, EPUB, reveal.js presentations
-;; - Self-contained HTML exports with embedded resources
+;; - Additional formats: DOCX, self-contained HTML5
 ;; - Custom PDF export with Zathura integration
 ;;
 ;; Key features:
 ;; - UTF-8 encoding enforced across all backends
 ;; - Subtree export as default scope
-;; - reveal.js presentations with CDN or local embedding options
+;;
+;; Note: reveal.js presentations are handled by org-reveal-config.el (C-; p)
 ;;
 ;;; Code:
 
@@ -79,47 +79,7 @@
   (setq org-pandoc-options '((standalone . t)
 							 (mathjax . t)))
 
-  ;; Configure reveal.js specific options
-  (setq org-pandoc-options-for-revealjs
-		'((standalone . t)
-		  (variable . "revealjs-url=https://cdn.jsdelivr.net/npm/reveal.js")
-		  (variable . "theme=black")  ; or white, league, beige, sky, night, serif, simple, solarized
-		  (variable . "transition=slide") ; none, fade, slide, convex, concave, zoom
-		  (variable . "slideNumber=true")
-		  (variable . "hash=true")
-		  (self-contained . t))) ; This embeds CSS/JS when possible
-
-  ;; Custom function for self-contained reveal.js export
-  (defun my/org-pandoc-export-to-revealjs-standalone ()
-	"Export to reveal.js with embedded dependencies."
-	(interactive)
-	(let* ((org-pandoc-options-for-revealjs
-			(append org-pandoc-options-for-revealjs
-					'((self-contained . t)
-					  (embed-resources . t))))  ; pandoc 3.0+ option
-		   (html-file (org-pandoc-export-to-revealjs)))
-	  (when html-file
-		(browse-url-of-file html-file)
-		(message "Opened reveal.js presentation: %s" html-file))))
-
-  ;; Alternative: Download and embed local reveal.js
-  (defun my/org-pandoc-export-to-revealjs-local ()
-	"Export to reveal.js using local copy of reveal.js."
-	(interactive)
-	(let* ((reveal-dir (expand-file-name "reveal.js" user-emacs-directory))
-		   (org-pandoc-options-for-revealjs
-			`((standalone . t)
-			  (variable . ,(format "revealjs-url=%s" reveal-dir))
-			  (variable . "theme=black")
-			  (variable . "transition=slide")
-			  (variable . "slideNumber=true"))))
-	  (unless (file-exists-p reveal-dir)
-		(cj/log-silently "Downloading reveal.js...")
-		(shell-command
-		 (format "git clone https://github.com/hakimel/reveal.js.git %s" reveal-dir)))
-	  (org-pandoc-export-to-revealjs)))
-
-  ;; Configure specific format options (your existing config)
+  ;; Configure specific format options
   (setq org-pandoc-options-for-latex-pdf '((pdf-engine . "pdflatex")))
   (setq org-pandoc-options-for-html5 '((html-q-tags . t)
 									   (self-contained . t)))
@@ -134,12 +94,10 @@
 		(start-process "zathura-pdf" nil "zathura" pdf-file)
 		(message "Opened %s in Zathura" pdf-file))))
 
-  ;; Updated menu entries with reveal.js options
+  ;; Pandoc export menu entries
   (setq org-pandoc-menu-entry
 		'((?4 "to html5 and open" org-pandoc-export-to-html5-and-open)
 		  (?$ "as html5" org-pandoc-export-as-html5)
-		  (?r "to reveal.js (CDN) and open" org-pandoc-export-to-revealjs-and-open)
-		  (?R "to reveal.js (self-contained)" my/org-pandoc-export-to-revealjs-standalone)
 		  (?< "to markdown" org-pandoc-export-to-markdown)
 		  (?d "to docx and open" org-pandoc-export-to-docx-and-open)
 		  (?z "to pdf and open (Zathura)" my/org-pandoc-export-to-pdf-and-open))))
diff --git a/modules/org-reveal-config.el b/modules/org-reveal-config.el
new file mode 100644
index 00000000..3ab80315
--- /dev/null
+++ b/modules/org-reveal-config.el
@@ -0,0 +1,162 @@
+;;; org-reveal-config.el --- Reveal.js Presentation Configuration -*- lexical-binding: t; coding: utf-8; -*-
+;; author: Craig Jennings <c@cjennings.net>
+
+;;; Commentary:
+;; Integrates ox-reveal for creating reveal.js presentations from Org files.
+;;
+;; Fully offline workflow using a local reveal.js clone (managed by
+;; scripts/setup-reveal.sh) and self-contained HTML export.
+;;
+;; Keybindings (C-; p prefix):
+;; - C-; p e : Export to self-contained HTML and open in browser
+;; - C-; p p : Start live preview (re-exports on save)
+;; - C-; p s : Stop live preview
+;; - C-; p h : Insert #+REVEAL_ header block at top of current buffer
+;; - C-; p n : Create new presentation file (prompts for title and location)
+
+;;; Code:
+
+;; Forward declarations for byte-compiler (ox-reveal loaded via use-package)
+(defvar org-reveal-root)
+(defvar org-reveal-single-file)
+(defvar org-reveal-plugins)
+(defvar org-reveal-highlight-css)
+(defvar org-reveal-init-options)
+(declare-function org-reveal-export-to-html "ox-reveal")
+
+;; --------------------------------- Constants ---------------------------------
+
+(defconst cj/reveal-root
+  (expand-file-name "reveal.js" user-emacs-directory)
+  "Local reveal.js installation directory.")
+
+(defconst cj/reveal-default-theme "black"
+  "Default reveal.js theme for new presentations.")
+
+(defconst cj/reveal-default-transition "slide"
+  "Default reveal.js slide transition for new presentations.")
+
+;; --------------------------------- ox-reveal ---------------------------------
+
+(use-package ox-reveal
+  :after ox
+  :config
+  (setq org-reveal-root (concat "file://" cj/reveal-root))
+  (setq org-reveal-single-file t)
+  (setq org-reveal-plugins '(highlight notes search zoom))
+  (setq org-reveal-highlight-css "%r/plugin/highlight/monokai.css")
+  (setq org-reveal-init-options "slideNumber:true, hash:true"))
+
+;; ----------------------------- Private Helpers -------------------------------
+
+(defun cj/--reveal-header-template (title)
+  "Return the reveal.js header block string for TITLE."
+  (unless (stringp title)
+    (user-error "Title must be a string"))
+  (format "#+TITLE: %s
+#+AUTHOR: %s
+#+DATE: %s
+#+REVEAL_ROOT: %s
+#+REVEAL_THEME: %s
+#+REVEAL_TRANS: %s
+#+REVEAL_INIT_OPTIONS: slideNumber:true, hash:true
+#+REVEAL_PLUGINS: (highlight notes search zoom)
+#+REVEAL_HIGHLIGHT_CSS: %%r/plugin/highlight/monokai.css
+#+OPTIONS: toc:nil num:nil
+
+" title (user-full-name) (format-time-string "%Y-%m-%d")
+    (concat "file://" cj/reveal-root)
+    cj/reveal-default-theme
+    cj/reveal-default-transition))
+
+(defun cj/--reveal-title-to-filename (title)
+  "Convert TITLE to a slug-based .org filename.
+Downcases TITLE, replaces whitespace runs with hyphens, appends .org."
+  (concat (replace-regexp-in-string "[[:space:]]+" "-" (downcase title))
+          ".org"))
+
+(defun cj/--reveal-preview-export-on-save ()
+  "Export current org buffer to reveal.js HTML silently.
+Intended for use as a buffer-local `after-save-hook'."
+  (when (derived-mode-p 'org-mode)
+    (let ((inhibit-message t))
+      (org-reveal-export-to-html))))
+
+;; ----------------------------- Public Functions ------------------------------
+
+(defun cj/reveal-export ()
+  "Export current Org buffer to self-contained reveal.js HTML and open in browser."
+  (interactive)
+  (unless (derived-mode-p 'org-mode)
+    (user-error "Not in an Org buffer"))
+  (let ((html-file (org-reveal-export-to-html)))
+    (when html-file
+      (browse-url-of-file html-file)
+      (message "Opened presentation: %s" html-file))))
+
+(defun cj/reveal-preview-start ()
+  "Start live preview: re-export to HTML on every save.
+Opens the presentation in a browser on first call.  Subsequent saves
+re-export silently; refresh the browser to see changes."
+  (interactive)
+  (unless (derived-mode-p 'org-mode)
+    (user-error "Not in an Org buffer"))
+  (add-hook 'after-save-hook #'cj/--reveal-preview-export-on-save nil t)
+  (let ((html-file (org-reveal-export-to-html)))
+    (when html-file
+      (browse-url-of-file html-file)))
+  (message "Live preview started — save to re-export, refresh browser to update"))
+
+(defun cj/reveal-preview-stop ()
+  "Stop live preview by removing the after-save-hook."
+  (interactive)
+  (remove-hook 'after-save-hook #'cj/--reveal-preview-export-on-save t)
+  (message "Live preview stopped"))
+
+(defun cj/reveal-insert-header ()
+  "Insert a #+REVEAL_ header block at the top of the current Org buffer."
+  (interactive)
+  (unless (derived-mode-p 'org-mode)
+    (user-error "Not in an Org buffer"))
+  (let ((title (read-from-minibuffer "Presentation title: ")))
+    (save-excursion
+      (goto-char (point-min))
+      (insert (cj/--reveal-header-template title)))
+    (message "Inserted reveal.js headers")))
+
+(defun cj/reveal-new ()
+  "Create a new reveal.js presentation file.
+Prompts for a title and save location, then opens the file with
+reveal.js headers pre-filled."
+  (interactive)
+  (let* ((title (read-from-minibuffer "Presentation title: "))
+         (default-dir (expand-file-name "~/"))
+         (file (read-file-name "Save presentation to: " default-dir nil nil
+                               (cj/--reveal-title-to-filename title))))
+    (when (file-exists-p file)
+      (user-error "File already exists: %s" file))
+    (find-file file)
+    (insert (cj/--reveal-header-template title))
+    (insert "* Slide 1\n\n")
+    (save-buffer)
+    (message "New presentation: %s" file)))
+
+;; -------------------------------- Keybindings --------------------------------
+
+(global-set-key (kbd "C-; p e") #'cj/reveal-export)
+(global-set-key (kbd "C-; p p") #'cj/reveal-preview-start)
+(global-set-key (kbd "C-; p s") #'cj/reveal-preview-stop)
+(global-set-key (kbd "C-; p h") #'cj/reveal-insert-header)
+(global-set-key (kbd "C-; p n") #'cj/reveal-new)
+
+(with-eval-after-load 'which-key
+  (which-key-add-key-based-replacements
+    "C-; p" "presentations"
+    "C-; p e" "export & open"
+    "C-; p p" "start live preview"
+    "C-; p s" "stop live preview"
+    "C-; p h" "insert headers"
+    "C-; p n" "new presentation"))
+
+(provide 'org-reveal-config)
+;;; org-reveal-config.el ends here