;;; ox-deck.el --- deck.js Presentation Back-End for Org Export Engine

;; Copyright (C) 2013  Rick Frankel

;; Author: Rick Frankel <emacs at rickster dot com>
;; Keywords: outlines, hypermedia, slideshow

;; 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, see <http://www.gnu.org/licenses/>.

;;; Commentary:

;; This library implements a deck.js presentation back-end for the Org
;; generic exporter.

;; Installation
;; -------------
;; Get a copy of deck.js from http://imakewebthings.com/deck.js/ or
;; the gitub repository at https://github.com/imakewebthings/deck.js.
;;
;; Add the path to the extracted code to the variable
;; `org-deck-directories' There are a number of customization in the
;; org-export-deck group, most of which can be overrriden with buffer
;; local customization (starting with DECK_.)

;; See ox.el and ox-html.el for more details on how this exporter
;; works (it is derived from ox-html.)

(require 'ox-html)

(org-export-define-derived-backend deck html
  :menu-entry
  (?s "Export to deck.js HTML Presentation"
      ((?H "To temporary buffer" org-deck-export-as-html)
       (?h "To file" org-deck-export-to-html)
       (?o "To file and open"
	   (lambda (a s v b)
	     (if a (org-deck-export-to-html t s v b)
	       (org-open-file (org-deck-export-to-html nil s v b)))))))
  :options-alist
  ((:html-link-home "HTML_LINK_HOME" nil nil)
   (:html-link-up "HTML_LINK_UP" nil nil)
   (:html-mathjax "HTML_MATHJAX" nil "" space)
   (:html-postamble nil "html-postamble" nil t)
   (:html-preamble nil "html-preamble" nil t)
   (:html-style-extra "HTML_STYLE" nil org-html-style-extra newline)
   (:html-style-include-default "HTML_INCLUDE_DEFAULT" nil nil)
   (:html-style-include-scripts "HTML_INCLUDE_SCRIPTS" nil nil)
   (:deck-base-url "DECK_BASE_URL" nil org-deck-base-url)
   (:deck-theme "DECK_THEME" nil org-deck-theme)
   (:deck-transition "DECK_TRANSITION" nil org-deck-transition)
   (:deck-include-extensions "DECK_INCLUDE_EXTENSIONS" nil
		     org-deck-include-extensions split)
   (:deck-exclude-extensions "DECK_EXCLUDE_EXTENSIONS" nil
			     org-deck-exclude-extensions split)
   (:deck-directories "DECK_DIRECTORIES" nil
			   org-deck-directories split))
  :translate-alist
  ((headline . org-deck-headline)
   (inner-template . org-deck-inner-template)
   (item . org-deck-item)
   (template . org-deck-template)))

(defgroup org-export-deck nil
  "Options for exporting Org mode files to deck.js HTML Presentations."
  :tag "Org Export DECK"
  :group 'org-export-html)

(defcustom org-deck-directories nil
  "Directories to search for deck.js components (jquery,
modernizr; core, extensions and themes directories.)"
  :group 'org-export-deck
  :type '(repeat (string :tag "Directory")))

(defun org-deck--cleanup-components (components)
  (remove-duplicates
   (car (remove 'nil components))
   :test (lambda (x y)
	   (string= (file-name-nondirectory x)
		    (file-name-nondirectory y)))))

(defun org-deck--find-extensions ()
  "Returns a unique list of all extensions found in
in the extensions directories under `org-deck-directories'"
  (org-deck--cleanup-components
     (mapcar				; extensions under existing dirs
      (lambda (dir)
	(when (file-directory-p dir) (directory-files dir t "^[^.]")))
      (mapcar 	 			; possible extension directories
       (lambda (x) (expand-file-name "extensions" x))
       org-deck-directories))))

(defun org-deck--find-css (type)
  "Return a unique list of all the css stylesheets in the themes/TYPE
directories under `org-deck-directories'."
  (org-deck--cleanup-components
   (mapcar
    (lambda (dir)
      (let ((css-dir (expand-file-name
		      (concat (file-name-as-directory "themes") type) dir)))
	(when (file-directory-p css-dir)
	  (directory-files css-dir t  "\\.css$"))))
      org-deck-directories)))

(defun org-deck-list-components ()
  "List all available deck extensions, styles and
transitions (with full paths) to a temporary buffer."
  (interactive)
  (let ((outbuf (get-buffer-create "*deck.js Extensions*")))
    (with-current-buffer outbuf
      (erase-buffer)
      (insert "Extensions\n----------\n")
      (insert (mapconcat 'identity (org-deck--find-extensions) "\n"))
      (insert "\n\nStyles\n------\n")
      (insert (mapconcat 'identity (org-deck--find-css "style") "\n"))
      (insert "\n\nTransitions\n----------\n")
      (insert (mapconcat 'identity (org-deck--find-css "transition") "\n")))
    (switch-to-buffer-other-window outbuf)))

(defcustom org-deck-include-extensions nil
  "If non-nil, list of extensions to include instead of all available.
Can be overriden or set with the DECK_INCLUDE_EXTENSIONS property.
During output generation, the extensions found by
`org-deck--find-extensions' are searched for the appropriate
files (scripts and/or stylesheets) to include in the generated
html. The href/src attributes are created relative to `org-deck-base-url'."
  :group 'org-export-deck
  :type '(repeat (string :tag "Extension")))

(defcustom org-deck-exclude-extensions nil
  "If non-nil, list of extensions to exclude.
Can be overriden or set with the DECK_EXCLUDE_EXTENSIONS property."
  :group 'org-export-deck
  :type '(repeat (string :tag "Extension")))

(defcustom org-deck-theme "swiss.css"
  "deck.js theme. Can be overriden with the DECK_THEME property.
If this value contains a path component (\"/\"), it is used as a
literal path (url). Otherwise it is prepended with
`org-deck-base-url'/themes/style/."
  :group 'org-export-deck
  :type 'string)

(defcustom org-deck-transition "fade.css"
  "deck.js transition theme. Can be overriden with the
DECK_TRANSITION property.
If this value contains a path component (\"/\"), it is used as a
literal path (url). Otherwise it is prepended with
`org-deck-base-url'/themes/transition/."
  :group 'org-export-deck
  :type 'string)

(defcustom org-deck-base-url "deck.js"
  "Url prefix to deck.js base directory containing the core, extensions
and themes directories.
Can be overriden with the DECK_BASE_URL property."
  :group 'org-export-deck
  :type 'string)

(defcustom org-deck-footer-template
"<h1>%author - %title</h1>"
  "Format template to specify footer div.
Completed using `org-fill-template'.
Optional keys include %author, %email, %file, %title and %date.
This is included in a <footer> section."
  :group 'org-export-deck
  :type 'string)

(defcustom org-deck-header-template ""
  "Format template to specify page. Completed using `org-fill-template'.
Optional keys include %author, %email, %file, %title and %date.
This is included in a <header> section."
  :group 'org-export-deck
  :type 'string)

(defcustom org-deck-title-page-style
  "<style type='text/css'>
    header, footer { left: 5px; width: 100% }
    header { position: absolute; top: 10px; }
    #title-slide h1 {
        position: static; padding: 0;
        margin-top: 10%;
	-webkit-transform: none;
	-moz-transform: none;
	-ms-transform: none;
	-o-transform: none;
	transform: none;
    }
    #title-slide h2 {
        text-align: center;
        border:none;
        padding: 0;
        margin: 0;
    }
</style>"
  "CSS styles to use for title page"
  :group 'org-export-deck
  :type 'string)

(defcustom org-deck-title-page-template
  "<div class='slide' id='title-slide'>
<h1>%title</h1>
<h2>%author</h2>
<h2>%email</h2>
<h2>%date</h2>
</div>"
  "Format template to specify title page div.
Completed using `org-fill-template'.
Optional keys include %author, %email, %file, %title and %date.
Note that the wrapper div must include the class \"slide\"."
  :group 'org-export-deck
  :type 'string)

(defcustom org-deck-toc-style
  "<style type='text/css'>
    header, footer { left: 5px; width: 100% }
    header { position: absolute; top: 10px; }
    #table-of-contents h1 {
        position: static; padding: 0;
        margin-top: 10%;
	-webkit-transform: none;
	-moz-transform: none;
	-ms-transform: none;
	-o-transform: none;
	Transform: none;
    }
    #title-slide h2 {
        text-align: center;
        border:none;
        padding: 0;
        margin: 0;
    }
</style>"
  "CSS styles to use for title page"
  :group 'org-export-deck
  :type 'string)

(defun org-deck-toc (depth info)
  (concat
    "<div id=\"table-of-contents\" class=\"slide\">\n"
    (format "<h2>%s</h2>\n"
	    (org-html--translate "Table of Contents" info))
    (org-html-toc-text
     (mapcar
      (lambda (headline)
	(let* ((class (org-element-property :html-container-class headline))
	       (section-number
		(when
		    (and (not (org-export-low-level-p headline info))
			 (org-export-numbered-headline-p headline info))
		  (concat
		   (mapconcat
		    'number-to-string
		    (org-export-get-headline-number headline info) ".") ". ")))
	      (title
	       (concat
		section-number
		(replace-regexp-in-string ; remove any links in headline...
		 "</?a[^>]*>" ""
		 (org-export-data
		  (org-element-property :title headline) info)))))
	  (list
	   (if (and class (string-match-p "\\<slide\\>" class))
	       (format
		"<a href='#outline-container-%s'>%s</a>"
		(or (org-element-property :custom-id headline)
		    (mapconcat
		     'number-to-string
		     (org-export-get-headline-number headline info) "-"))
		title)
	     title)
	   (org-export-get-relative-level headline info))))
      (org-export-collect-headlines info depth)))
    "</div>\n" ))

(defun org-deck--get-packages (info)
  (let ((prefix (concat (plist-get info :deck-base-url) "/"))
	(theme (plist-get info :deck-theme))
	(transition (plist-get info :deck-transition))
	(include (plist-get info :deck-include-extensions))
	(exclude (plist-get info :deck-exclude-extensions))
	(scripts '()) (sheets '()) (snippets '()))
    (add-to-list 'scripts (concat prefix "jquery-1.7.2.min.js"))
    (add-to-list 'scripts (concat prefix "core/deck.core.js"))
    (add-to-list 'scripts (concat prefix "modernizr.custom.js"))
    (add-to-list 'sheets  (concat prefix "core/deck.core.css"))
     (mapc
      (lambda (extdir)
	(let* ((name (file-name-nondirectory extdir))
	       (dir (file-name-as-directory extdir))
	       (path (concat prefix "extensions/" name "/"))
	       (base (format "deck.%s." name)))
	  (when (and (or (eq nil include) (member name include))
		     (not (member name exclude)))
	    (when (file-exists-p (concat dir base "js"))
	      (add-to-list 'scripts (concat path base "js")))
	    (when (file-exists-p (concat dir base "css"))
	      (add-to-list 'sheets (concat path base "css")))
	    (when (file-exists-p (concat dir base "html"))
	      (add-to-list 'snippets (concat dir base "html"))))))
      (org-deck--find-extensions))
     (add-to-list 'sheets
		  (if (file-name-directory theme) theme
		    (format "%sthemes/style/%s" prefix theme)))
     (add-to-list
      'sheets
      (if (file-name-directory transition) transition
	(format "%sthemes/transition/%s" prefix transition)))
     (list :scripts (nreverse scripts) :sheets (nreverse sheets)
	   :snippets snippets)))

(defun org-html-inner-template (contents info)
  "Return body of document string after HTML conversion.
CONTENTS is the transcoded contents string.  INFO is a plist
holding export options."
  (concat
   ;; Table of contents.
   (let ((depth (plist-get info :with-toc)))
     (when depth (org-deck-toc depth info)))
   ;; Document contents.
   contents
   "\n"))

(defun org-deck-headline (headline contents info)
  (let ((org-html-toplevel-hlevel 2))
    (org-html-headline
     (if (= 1 (+ (org-element-property :level headline)
		 (plist-get info :headline-offset)))
         (org-element-put-property headline :html-container-class "slide")
       headline) contents info)))

(defun org-deck-item (item contents info)
  "Transcode an ITEM element from Org to HTML.
CONTENTS holds the contents of the item.  INFO is a plist holding
contextual information.
If the containing headline has the property :slide, then
the \"slide\" class will be added to the to the list element,
 which will make the list into a \"build\"."
  (let ((text (org-html-item item contents info)))
    (if (org-export-get-node-property :step item t)
	(replace-regexp-in-string "^<li>" "<li class='slide'>" text)
      text)))

(defun org-deck-template-alist (info)
  (list
   `("title"  . ,(car (plist-get info :title)))
   `("author" . ,(car (plist-get info :author)))
   `("email"  . ,(plist-get info :email))
   `("date"   . ,(nth 0 (plist-get info :date)))
   `("file"   . ,(plist-get info :input-file))))

(defun org-deck-template (contents info)
  "Return complete document string after HTML conversion.
CONTENTS is the transcoded contents string.  INFO is a plist
holding export options."
  (let ((pkg-info (org-deck--get-packages info)))
  (mapconcat
   'identity
   (list
    "<!DOCTYPE html>"
    (let ((lang (plist-get info :language)))
      (mapconcat
       (lambda (x)
	 (apply
	  'format
	  "<!--%s <html class='no-js %s' lang='%s'> %s<![endif]-->"
	  x))
       (list `("[if lt IE 7]>" "ie6" ,lang "")
	     `("[if IE 7]>" "ie7" ,lang "")
	     `("[if IE 8]>" "ie8" ,lang "")
	     `("[if gt IE 8]><!-->" "" ,lang "<!--")) "\n"))
    "<head>"
    (org-deck--build-meta-info info)
    (mapconcat
     (lambda (sheet)
       (format
	"<link rel='stylesheet' href='%s' type='text/css' />" sheet))
     (plist-get pkg-info :sheets) "\n")
    "<style type='text/css'>"
    "#table-of-contents a {color: inherit;}"
    "#table-of-contents ul {margin-bottom: 0;}"
    (when (plist-get info :section-numbers)
      "#table-of-contents ul li {list-style-type: none;}")
    "</style>"
    ""
    (mapconcat
     (lambda (script)
       (format
	"<script src='%s' type='text/javascript'></script>" script))
     (plist-get pkg-info :scripts) "\n")
    (org-html--build-mathjax-config info)
    "<script type='text/javascript'>"
    "  $(document).ready(function () { $.deck('.slide'); });"
    "</script>"
    (org-html--build-style info)
    org-deck-title-page-style
    "</head>"
    "<body>"
    "<header class='deck-status'>"
    (org-fill-template
     org-deck-header-template (org-deck-template-alist info))
    "</header>"
    "<div class='deck-container'>"
    ;; title page
    (org-fill-template
     org-deck-title-page-template (org-deck-template-alist info))
    ;; toc page
    (let ((depth (plist-get info :with-toc)))
      (when depth (org-deck-toc depth info)))
    contents
    (mapconcat
     (lambda (snippet)
       (with-temp-buffer (insert-file-contents snippet)
			 (buffer-string)))
     (plist-get pkg-info :snippets) "\n")
    "<footer class='deck-status'>"
    (org-fill-template
     org-deck-footer-template (org-deck-template-alist info))
    "</footer>"
    "</div>"
    "</body>"
    "</html>\n") "\n")))

(defun org-deck--build-meta-info (info)
  "Return meta tags for exported document.
INFO is a plist used as a communication channel."
  (let* ((title (org-export-data (plist-get info :title) info))
	 (author (and (plist-get info :with-author)
		      (let ((auth (plist-get info :author)))
			(and auth (org-export-data auth info)))))
	 (date (and (plist-get info :with-date)
		    (let ((date (plist-get info :date)))
		      (and date (org-export-data date info)))))
	 (description (plist-get info :description))
	 (keywords (plist-get info :keywords)))
    (mapconcat
     'identity
     (list
      (format "<title>%s</title>" title)
      (format "<meta charset='%s' />"
	      (or (and org-html-coding-system
		       (fboundp 'coding-system-get)
		       (coding-system-get
			org-html-coding-system 'mime-charset))
		  "iso-8859-1"))
      (mapconcat
       (lambda (attr)
	 (when (< 0 (length (car attr)))
	   (format "<meta name='%s' content='%s'/>\n"
		   (nth 1 attr) (car attr))))
       (list '("Org-mode" "generator")
	     `(,author "author")
	     `(,description "description")
	     `(,keywords "keywords")) "")) "\n")))
(defun org-deck-export-as-html
  (&optional async subtreep visible-only body-only ext-plist)
  "Export current buffer to an HTML buffer.

If narrowing is active in the current buffer, only export its
narrowed part.

If a region is active, export that region.

A non-nil optional argument ASYNC means the process should happen
asynchronously.  The resulting buffer should be accessible
through the `org-export-stack' interface.

When optional argument SUBTREEP is non-nil, export the sub-tree
at point, extracting information from the headline properties
first.

When optional argument VISIBLE-ONLY is non-nil, don't export
contents of hidden elements.

When optional argument BODY-ONLY is non-nil, only write code
between \"<body>\" and \"</body>\" tags.

EXT-PLIST, when provided, is a property list with external
parameters overriding Org default settings, but still inferior to
file-local settings.

Export is done in a buffer named \"*Org deck.js Export*\", which
will be displayed when `org-export-show-temporary-export-buffer'
is non-nil."
  (interactive)
  (if async
      (org-export-async-start
	  (lambda (output)
	    (with-current-buffer (get-buffer-create "*Org deck.js Export*")
	      (erase-buffer)
	      (insert output)
	      (goto-char (point-min))
	      (nxml-mode)
	      (org-export-add-to-stack (current-buffer) 'deck)))
	`(org-export-as 'deck ,subtreep ,visible-only ,body-only ',ext-plist))
    (let ((outbuf (org-export-to-buffer
		   'deck "*Org deck.js Export*"
		   subtreep visible-only body-only ext-plist)))
      ;; Set major mode.
      (with-current-buffer outbuf (nxml-mode))
      (when org-export-show-temporary-export-buffer
	(switch-to-buffer-other-window outbuf)))))

(defun org-deck-export-to-html
  (&optional async subtreep visible-only body-only ext-plist)
  "Export current buffer to a deck.js HTML file.

If narrowing is active in the current buffer, only export its
narrowed part.

If a region is active, export that region.

A non-nil optional argument ASYNC means the process should happen
asynchronously.  The resulting file should be accessible through
the `org-export-stack' interface.

When optional argument SUBTREEP is non-nil, export the sub-tree
at point, extracting information from the headline properties
first.

When optional argument VISIBLE-ONLY is non-nil, don't export
contents of hidden elements.

When optional argument BODY-ONLY is non-nil, only write code
between \"<body>\" and \"</body>\" tags.

EXT-PLIST, when provided, is a property list with external
parameters overriding Org default settings, but still inferior to
file-local settings.

Return output file's name."
  (interactive)
  (let* ((extension (concat "." org-html-extension))
	 (file (org-export-output-file-name extension subtreep))
	 (org-export-coding-system org-html-coding-system))
    (if async
	(org-export-async-start
	    (lambda (f) (org-export-add-to-stack f 'deck))
	  (let ((org-export-coding-system org-html-coding-system))
	    `(expand-file-name
	      (org-export-to-file
	       'deck ,file ,subtreep ,visible-only ,body-only ',ext-plist))))
      (let ((org-export-coding-system org-html-coding-system))
	(org-export-to-file
	 'deck file subtreep visible-only body-only ext-plist)))))

(defun org-deck-publish-to-html (plist filename pub-dir)
  "Publish an org file to deck.js HTML Presentation.
FILENAME is the filename of the Org file to be published.  PLIST
is the property list for the given project.  PUB-DIR is the
publishing directory. Returns output file name."
  (org-publish-org-to 'deck filename ".html" plist pub-dir))

(provide 'ox-deck)