;;; ox-koma-letter.el --- KOMA Scrlttr2 Back-End for Org Export Engine

;; Copyright (C) 2007-2012  Free Software Foundation, Inc.

;; Author: Nicolas Goaziou <n.goaziou AT gmail DOT com>
;;         Alan Schmitt <alan.schmitt AT polytechnique DOT org>
;; Keywords: org, wp, tex

;; 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 GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.

;;; Commentary:
;;
;; This library implements a KOMA Scrlttr2 back-end, derived from the
;; LaTeX one.
;;
;; Depending on the desired output format, three commands are provided
;; for export: `org-koma-letter-export-as-latex' (temporary buffer),
;; `org-koma-letter-export-to-latex' ("tex" file) and
;; `org-koma-letter-export-to-pdf' ("pdf" file).
;;
;; On top of buffer keywords supported by `latex' back-end (see
;; `org-latex-options-alist'), this back-end introduces the following
;; keywords: "CLOSING" (see `org-koma-letter-closing'), "FROM_ADDRESS"
;; (see `org-koma-letter-from-address'), "LCO" (see
;; `org-koma-letter-class-option-file'), "OPENING" (see
;; `org-koma-letter-opening'), "PHONE_NUMBER" (see
;; `org-koma-letter-phone-number'), "SIGNATURE" (see
;; `org-koma-letter-signature') and "TO_ADDRESS".
;;
;; You will need to add an appropriate association in
;; `org-latex-classes' in order to use the KOMA Scrlttr2 class.  For
;; example, you can use the following code:
;;
;;   (add-to-list 'org-latex-classes
;;                '("my-letter"
;;                  "\\documentclass\[%
;;   DIV=14,
;;   fontsize=12pt,
;;   parskip=half,
;;   subject=titled,
;;   backaddress=false,
;;   fromalign=left,
;;   fromemail=true,
;;   fromphone=true\]\{scrlttr2\}
;;   \[DEFAULT-PACKAGES]
;;   \[PACKAGES]
;;   \[EXTRA]"))
;;
;; Then, in your Org document, be sure to require the proper class
;; with :
;;
;;    #+LATEX_CLASS: my-letter


;;; Code:

(require 'ox-latex)

\f
;;; User-Configurable Variables

(defgroup org-export-koma-letter nil
  "Options for exporting to KOMA scrlttr2 class in LaTeX export."
  :tag "Org Koma-Letter"
  :group 'org-export)

(defcustom org-koma-letter-class-option-file "NF"
  "Letter Class Option File."
  :group 'org-export-koma-letter
  :type 'string)

(defcustom org-koma-letter-author 'user-full-name
  "The sender's name.

This variable defaults to calling the function `user-full-name'
which just returns the current `user-full-name'.  Alternatively a
string, nil or a function may be given. Functions must return a
string."
  :group 'org-export-koma-letter
  :type '(radio (function-item user-full-name)
		(string)
		(function)
		(const nil)))

(defcustom org-koma-letter-email 'org-koma-letter-email
  "The sender's email address.

This variable defaults to the value `org-koma-letter-email' which
returns `user-mail-address'.  Alternatively a string, nil or a
function may be given.  Functions must return a string."
  :group 'org-export-koma-letter
  :type '(radio (function-item org-koma-letter-email)
		(string)
		(function)
		(const nil)))

(defcustom org-koma-letter-from-address nil
  "Sender's address, as a string."
  :group 'org-export-koma-letter
  :type 'string)

(defcustom org-koma-letter-phone-number nil
  "Sender's phone number, as a string."
  :group 'org-export-koma-letter
  :type 'string)

(defcustom org-koma-letter-place nil
  "Place from which the letter is sent."
  :group 'org-export-koma-letter
  :type 'string)

(defcustom org-koma-letter-opening nil
  "Letter's opening, as a string."
  :group 'org-export-koma-letter
  :type 'string)

(defcustom org-koma-letter-closing nil
  "Koma-Letter's closing, as a string."
  :group 'org-export-koma-letter
  :type 'string)

(defcustom org-koma-letter-signature "\\usekomavar{fromname}"
  "String used as the signature."
  :group 'org-export-koma-letter
  :type 'string)

(defcustom org-koma-letter-use-subject "untitled"
  "Use the title as the letter's subject."
  :group 'org-export-koma-letter
  :type 'string)

(defcustom org-koma-letter-use-backaddress t
  "Print return address in small line above to address."
  :group 'org-export-koma-letter
  :type 'boolean)

(defcustom org-koma-letter-use-foldmarks "true"
  "Configure appearence of fold marks.

Accepts any valid value for the KOMA-Script `foldmarks' option.

Use `foldmarks:true' to activate default fold marks or
`foldmarks:nil' to deactivate fold marks."
  :group 'org-export-koma-letter
  :type 'string)

(defcustom org-koma-letter-use-phone t
  "Print sender's phone number."
  :group 'org-export-koma-letter
  :type 'boolean)

(defcustom org-koma-letter-use-email t
  "Print sender's email address."
  :group 'org-export-koma-letter
  :type 'boolean)

(defcustom org-koma-letter-use-place t
  "Print the letter's place next to the date."
  :group 'org-export-koma-letter
  :type 'boolean)

(defconst org-koma-letter-special-tags-after-closing
  '("ps" "encl" "cc")
  "Header tags to be inserted after closing")

(defconst org-koma-letter-special-tags-after-letter '("after_letter")
  "Header tags to be inserted after closing")

(defvar org-koma-letter-special-contents nil "holds special
content temporarily.")


\f
;;; Define Back-End

(org-export-define-derived-backend 'koma-letter 'latex
  :options-alist
  '((:lco "LCO" nil org-koma-letter-class-option-file)
    (:author "AUTHOR" nil (org-koma-letter--get-custom org-koma-letter-author) t)
    (:from-address "FROM_ADDRESS" nil org-koma-letter-from-address newline)
    (:phone-number "PHONE_NUMBER" nil org-koma-letter-phone-number)
    (:email "EMAIL" nil (org-koma-letter--get-custom org-koma-letter-email) t)
    (:to-address "TO_ADDRESS" nil nil newline)
    (:place "PLACE" nil org-koma-letter-place)
    (:opening "OPENING" nil org-koma-letter-opening)
    (:closing "CLOSING" nil org-koma-letter-closing)
    (:signature "SIGNATURE" nil org-koma-letter-signature newline)
    (:special-tags nil nil
		   (append org-koma-letter-special-tags-after-closing
			   org-koma-letter-special-tags-after-letter))
    (:with-after-closing nil "after-closing-order"
			 org-koma-letter-special-tags-after-closing)
    (:with-after-letter nil "after-letter-order"
			org-koma-letter-special-tags-after-letter)
    (:with-backaddress nil "backaddress" org-koma-letter-use-backaddress)
    (:with-foldmarks nil "foldmarks" org-koma-letter-use-foldmarks)
    (:with-phone nil "phone" org-koma-letter-use-phone)
    (:with-email nil "email" org-koma-letter-use-email)
    (:with-place nil "place" org-koma-letter-use-place)
    (:with-subject nil "subject" org-koma-letter-use-subject))
  :translate-alist '((export-block . org-koma-letter-export-block)
		     (export-snippet . org-koma-letter-export-snippet)
		     (headline . org-koma-letter-headline)
		     (keyword . org-koma-letter-keyword)
		     (template . org-koma-letter-template))
  :menu-entry
  '(?k "Export with KOMA Scrlttr2"
       ((?L "As LaTeX buffer" org-koma-letter-export-as-latex)
	(?l "As LaTeX file" org-koma-letter-export-to-latex)
	(?p "As PDF file" org-koma-letter-export-to-pdf)
	(?o "As PDF file and open"
	    (lambda (a s v b)
	      (if a (org-koma-letter-export-to-pdf t s v b)
		(org-open-file (org-koma-letter-export-to-pdf nil s v b))))))))

\f
;;; Helper functions

(defun org-koma-letter-email ()
  "Return the current `user-mail-address'"
  user-mail-address)

;; The following is taken from/inspired by ox-grof.el
;; Thanks, Luis!

(defun org-koma-letter--get-tagged-contents (tag)
  "Get tagged content from `org-koma-letter-special-contents'"
  (cdr (assoc tag org-koma-letter-special-contents)))

(defun org-koma-letter--get-custom (value)
  "Determines whether a value is nil, a string or a
function (a symobl).  If it is a function it it evaluates it."
  (when value
    (cond ((stringp value) value)
	  ((functionp value) (funcall value))
	  ((symbolp value) (symbol-name value)))))


(defun org-koma-letter--prepare-special-contents-as-macro (a-list &optional keep-newlines no-tag)
  "Finds all the components of `org-koma-letter-special-contents'
corresponding to members of the `a-list' and return them as a
string to be formatted.  The function is used for inserting
content of speciall headings such as PS.

If keep-newlines is t newlines will not be removed.  If no-tag is
is t the content in `org-koma-letter-special-contents' will not
be wrapped in a macro named whatever the members of a-list are called.
"
  (let (output)
    (dolist (ac a-list output)
      (let
	  ((x (org-koma-letter--get-tagged-contents ac))
	   (regexp (if keep-newlines "" "\\`\n+\\|\n*\\'")))
	(when x
	  (setq output
		(concat
		 output "\n"
		 ;; sometimes LaTeX complains about newlines
		 ;; at the end or beginning of macros.  Remove them.
		 (org-koma-letter--format-string-as-macro
		  (format "%s" (replace-regexp-in-string regexp "" x))
		  (unless no-tag  ac)))))))))

(defun org-koma-letter--format-string-as-macro (string &optional macro)
  "If a macro is given format as string as  \"\\macro{string}\" else as \"string\""
  (if macro
      (format "\\%s{%s}" macro string)
    (format "%s" string)))

;;; Transcode Functions

;;;; Export Block

(defun org-koma-letter-export-block (export-block contents info)
  "Transcode an EXPORT-BLOCK element into KOMA Scrlttr2 code.
CONTENTS is nil.  INFO is a plist used as a communication
channel."
  (when (member (org-element-property :type export-block) '("KOMA-LETTER" "LATEX"))
    (org-remove-indentation (org-element-property :value export-block))))

;;;; Export Snippet

(defun org-koma-letter-export-snippet (export-snippet contents info)
  "Transcode an EXPORT-SNIPPET object into KOMA Scrlttr2 code.
CONTENTS is nil.  INFO is a plist used as a communication
channel."
  (when (memq (org-export-snippet-backend export-snippet) '(latex koma-letter))
    (org-element-property :value export-snippet)))

;;;; Keyword

(defun org-koma-letter-keyword (keyword contents info)
  "Transcode a KEYWORD element into KOMA Scrlttr2 code.
CONTENTS is nil.  INFO is a plist used as a communication
channel."
  (let ((key (org-element-property :key keyword))
        (value (org-element-property :value keyword)))
    ;; Handle specifically BEAMER and TOC (headlines only) keywords.
    ;; Otherwise, fallback to `latex' back-end.
    (if (equal key "KOMA-LETTER") value
      (org-export-with-backend 'latex keyword contents info))))


;; Headline

(defun org-koma-letter-headline (headline contents info)
  "Transcode a HEADLINE element from Org to LaTeX.
CONTENTS holds the contents of the headline.  INFO is a plist
holding contextual information.

Note that if a headline is tagged with a tag from
`org-koma-letter-special-tags' it will not be exported, but
stored in `org-koma-letter-special-contents' and included at the
appropriate place."
  (let*
      ((tags (and (plist-get info :with-tags)
		 (org-export-get-tags headline info)))
       (tag (downcase (car tags))))
    (if (member tag (plist-get info :special-tags))
	(progn
	  (push (cons tag contents)
		org-koma-letter-special-contents)
	  nil)
      contents)))


;;;; Template

(defun org-koma-letter-template (contents info)
  "Return complete document string after KOMA Scrlttr2 conversion.
CONTENTS is the transcoded contents string.  INFO is a plist
holding export options."
  ;; FIXME: instead of setq'ing org-koma-letter-special-contents and
  ;; callying varioues stuff it might be nice to put a big let* around the templace
  ;; as in org-groff...
  (concat
   ;; Time-stamp.
   (and (plist-get info :time-stamp-file)
        (format-time-string "%% Created %Y-%m-%d %a %H:%M\n"))
   ;; Document class and packages.
   (let ((class (plist-get info :latex-class))
         (class-options (plist-get info :latex-class-options)))
     (org-element-normalize-string
      (let* ((header (nth 1 (assoc class org-latex-classes)))
             (document-class-string
              (and (stringp header)
                   (if (not class-options) header
		     (replace-regexp-in-string
		      "^[ \t]*\\\\documentclass\\(\\(\\[[^]]*\\]\\)?\\)"
		      class-options header t nil 1)))))
        (if (not document-class-string)
	    (user-error "Unknown LaTeX class `%s'")
          (org-latex-guess-babel-language
           (org-latex-guess-inputenc
            (org-splice-latex-header
             document-class-string
             org-latex-default-packages-alist ; defined in org.el
             org-latex-packages-alist nil     ; defined in org.el
	     (concat (plist-get info :latex-header)
		     (plist-get info :latex-header-extra))))
           info)))))
   (let ((lco (plist-get info :lco))
	 (author (plist-get info :author))
	 (from-address (plist-get info :from-address))
	 (phone-number (plist-get info :phone-number))
	 (email (plist-get info :email))
	 (signature (plist-get info :signature)))
     (concat
      ;; Letter Class Option File
      (when lco
	(let ((lco-files (split-string lco " "))
	      (lco-def ""))
	  (dolist (lco-file lco-files lco-def)
	    (setq lco-def (format "%s\\LoadLetterOption{%s}\n" lco-def lco-file)))
	  lco-def))
      ;; Define "From" data.
      (when author (format "\\setkomavar{fromname}{%s}\n"
			   (org-export-data author info)))
      (when from-address (format "\\setkomavar{fromaddress}{%s}\n" from-address))
      (when phone-number (format "\\setkomavar{fromphone}{%s}\n" phone-number))
      (when email (format "\\setkomavar{fromemail}{%s}\n" email))
      (when signature (format "\\setkomavar{signature}{%s}\n" signature))))
   ;; Date.
   (format "\\date{%s}\n" (org-export-data (org-export-get-date info) info))
   ;; Place
   (let ((with-place (plist-get info :with-place))
	 (place (plist-get info :place)))
     (when (or place (not with-place))
       (format "\\setkomavar{place}{%s}\n" (if with-place place ""))))
   ;; KOMA options
   (let ((with-backaddress (plist-get info :with-backaddress))
	 (with-foldmarks (plist-get info :with-foldmarks))
	 (with-phone (plist-get info :with-phone))
	 (with-email (plist-get info :with-email)))
     (concat
      (format "\\KOMAoption{backaddress}{%s}\n" (if with-backaddress "true" "false"))
      (format "\\KOMAoption{foldmarks}{%s}\n" (if with-foldmarks with-foldmarks "false"))
      (format "\\KOMAoption{fromphone}{%s}\n" (if with-phone "true" "false"))
      (format "\\KOMAoption{fromemail}{%s}\n" (if with-email "true" "false"))))
   ;; Document start
   "\\begin{document}\n\n"
   ;; Subject
   (let ((with-subject (plist-get info :with-subject)))
     (when with-subject
       (concat
	(format "\\KOMAoption{subject}{%s}\n" with-subject)
	(format "\\setkomavar{subject}{%s}\n\n"
		(org-export-data (plist-get info :title) info)))))
   ;; Letter start
   (format "\\begin{letter}{%%\n%s}\n\n"
	   (or (plist-get info :to-address) "no address given"))
   ;; Opening.
   (format "\\opening{%s}\n\n" (plist-get info :opening))
   ;; Letter body.
   contents
   ;; Closing.
   (format "\n\\closing{%s}\n" (plist-get info :closing))
   (org-koma-letter--prepare-special-contents-as-macro
    (plist-get info :with-after-closing))
   ;; Letter end.
   "\n\\end{letter}\n"
   (org-koma-letter--prepare-special-contents-as-macro
    (plist-get info :with-after-letter) t t)
   ;; Document end.
   "\n\\end{document}"
   ))

\f
;;; Commands

;;;###autoload
(defun org-koma-letter-export-as-latex
  (&optional async subtreep visible-only body-only ext-plist)
  "Export current buffer as a KOMA Scrlttr2 letter.

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 \"\\begin{letter}\" and \"\\end{letter}\".

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

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

;;;###autoload
(defun org-koma-letter-export-to-latex
  (&optional async subtreep visible-only body-only ext-plist)
  "Export current buffer as a KOMA Scrlttr2 letter (tex).

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 \"\\begin{letter}\" and \"\\end{letter}\".

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

When optional argument PUB-DIR is set, use it as the publishing
directory.

Return output file's name."
  (interactive)
  (let ((outfile (org-export-output-file-name ".tex" subtreep)))
    (if async
	(org-export-async-start
	    (lambda (f) (org-export-add-to-stack f 'koma-letter))
	  `(expand-file-name
	    (org-export-to-file
	     'koma-letter ,outfile ,subtreep ,visible-only ,body-only
	     ',ext-plist)))
      (org-export-to-file
       'koma-letter outfile subtreep visible-only body-only ext-plist))))

;;;###autoload
(defun org-koma-letter-export-to-pdf
  (&optional async subtreep visible-only body-only ext-plist)
  "Export current buffer as a KOMA Scrlttr2 letter (pdf).

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 \"\\begin{letter}\" and \"\\end{letter}\".

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

Return PDF file's name."
  (interactive)
  (if async
      (let ((outfile (org-export-output-file-name ".tex" subtreep)))
	(org-export-async-start
	    (lambda (f) (org-export-add-to-stack f 'koma-letter))
	  `(expand-file-name
	    (org-latex-compile
	     (org-export-to-file
	      'koma-letter ,outfile ,subtreep ,visible-only ,body-only
	      ',ext-plist)))))
    (org-latex-compile
     (org-koma-letter-export-to-latex
      nil subtreep visible-only body-only ext-plist))))


(provide 'ox-koma-letter)
;;; ox-koma-letter.el ends here