;;; ob-gharphviz --- org-babel functions for gharphviz evaluation of FG42
;;
;; Copyright (c) 2010-2022 Sameer Rahmani & Contributors
;;
;; Author: Sameer Rahmani <lxsameer@gnu.org>
;; URL: https://gitlab.com/FG42/FG42
;; Version: 3.0.0
;;
;; 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 file location is important and can't be under `fg42/' dir even
;; though it is part of the FG42. That's due to the `org-babel' mechanism
;; to automatically load the language backend. SO DO NOT MOVE IT.

;;; Code:
(require 'ob)
(require 'ob-ref)
(require 'ob-comint)
(require 'ob-eval)
(require 'ob-dot)


(add-to-list 'org-babel-tangle-lang-exts '("graphviz-dot" . "dot"))

(defvar org-babel-default-header-args:graphviz-dot
  '((:results . "file") (:exports . "results")))

(defun org-babel-expand-body:ghraphviz-dot (body params &optional processed-params)
  "Expand BODY according to PARAMS, return the expanded body."
  (let ((vars (org-babel--get-vars params)))
    (mapc
     (lambda (pair)
       (let ((name (symbol-name (car pair)))
	     (value (cdr pair)))
	 (setq body
	       (replace-regexp-in-string
		(concat "$" (regexp-quote name))
		(if (stringp value) value (format "%S" value))
		body
		t
		t))))
     vars)
    body))

(defun org-babel-execute:graphviz-dot (body params)
  "Execute a block of Template code with org-babel.
This function is called by `org-babel-execute-src-block'"
  (let* ((out-file (cdr (or (assq :file params)
			    (error "You need to specify a :file parameter"))))
	 (cmdline (or (cdr (assq :cmdline params))
		      (format "-T%s" (file-name-extension out-file))))
	 (cmd (or (cdr (assq :cmd params)) "dot"))
	 (coding-system-for-read 'utf-8) ;use utf-8 with sub-processes
	 (coding-system-for-write 'utf-8)
	 (in-file (org-babel-temp-file "dot-")))
    (with-temp-file in-file
      (insert (org-babel-expand-body:dot body params)))
    (org-babel-eval
     (concat cmd
	     " " (org-babel-process-file-name in-file)
	     " " cmdline
	     " -o " (org-babel-process-file-name out-file)) "")
    ;; signal that output has already been written to file
    nil))


(defun org-babel-prep-session:graphviz-dot (session params)
  "Prepare SESSION according to the header arguments specified in PARAMS."
  (error "Dot does not support sessions"))

(provide 'ob-graphviz-dot)
;;; ob-graphviz-dot.el ends here