;;; ob-plantuml.el --- Babel Functions for Plantuml  -*- lexical-binding: t; -*-

;; Copyright (C) 2010-2021 Free Software Foundation, Inc.

;; Author: Zhang Weize
;; Keywords: literate programming, reproducible research
;; Homepage: https://orgmode.org

;; This file is part of GNU Emacs.

;; GNU Emacs 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.

;; GNU Emacs 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 <https://www.gnu.org/licenses/>.

;;; Commentary:

;; Org-Babel support for evaluating plantuml script.
;;
;; Inspired by Ian Yang's org-export-blocks-format-plantuml
;; https://www.emacswiki.org/emacs/org-export-blocks-format-plantuml.el

;;; Requirements:

;; plantuml     | http://plantuml.sourceforge.net/
;; plantuml.jar | `org-plantuml-jar-path' should point to the jar file (when exec mode is `jar')

;;; Code:
(require 'ob)

(defvar org-babel-default-header-args:plantuml
  '((:results . "file") (:exports . "results"))
  "Default arguments for evaluating a plantuml source block.")

(defcustom org-plantuml-jar-path ""
  "Path to the plantuml.jar file."
  :group 'org-babel
  :version "24.1"
  :type 'string)

(defcustom org-plantuml-exec-mode 'jar
  "Method to use for PlantUML diagram generation.
`jar' means to use java together with the JAR.
The JAR can be configured via `org-plantuml-jar-path'.

`plantuml' means to use the PlantUML executable.
The executable can be configured via `org-plantuml-executable-path'.
You can also configure extra arguments via `org-plantuml-executable-args'."
  :group 'org-babel
  :package-version '(Org . "9.4")
  :type 'symbol
  :options '(jar plantuml))

(defcustom org-plantuml-executable-path "plantuml"
  "File name of the PlantUML executable."
  :group 'org-babel
  :package-version '(Org . "9.4")
  :type 'string)

(defcustom org-plantuml-executable-args (list "-headless")
  "The arguments passed to plantuml executable when executing PlantUML."
  :group 'org-babel
  :package-version '(Org . "9.4")
  :type '(repeat string))

(defcustom org-babel-plantuml-post-export-commands '(("svg" "inkscape %s -T -l %s"))
  "List of file extensions and associated commands.

The commands are run, in sequence, as a post-processing step for
each exported file with the associated extension.  Any \"%s\" in
the command is replaced with the output file's name.

For example, the default value converts text in an SVG to
paths, so that the text displays at the correct size when the
image is embedded in a PDF."
  :group 'org-babel
  :version "24.1"
  :type '(alist :key-type string :value-type (repeat string)))

(defun org-babel-variable-assignments:plantuml (params)
  "Return a list of PlantUML statements assigning the block's variables.
PARAMS is a property list of source block parameters, which may
contain multiple entries for the key `:var'.  `:var' entries in PARAMS
are expected to be scalar variables."
  (mapcar
   (lambda (pair)
       (format "!define %s %s"
	       (car pair)
	       (replace-regexp-in-string "\"" "" (cdr pair))))
   (org-babel--get-vars params)))

(defun org-babel-plantuml-make-body (body params)
  "Return PlantUML input string.

BODY is the content of the source block and PARAMS is a property list
of source block parameters.  This function relies on the
`org-babel-expand-body:generic' function to extract `:var' entries
from PARAMS and on the `org-babel-variable-assignments:plantuml'
function to convert variables to PlantUML assignments.

If BODY does not contain @startXXX ... @endXXX clauses, @startuml
... @enduml will be added."
  (let ((full-body
	 (org-babel-expand-body:generic
	  body params (org-babel-variable-assignments:plantuml params))))
    (if (string-prefix-p "@start" body t) full-body
      (format "@startuml\n%s\n@enduml" full-body))))

(defun org-babel-execute:plantuml (body params)
  "Execute a block of plantuml code with org-babel.
This function is called by `org-babel-execute-src-block'."
  (let* ((out-file (or (cdr (assq :file params))
		       (error "PlantUML requires a \":file\" header argument")))
	 (cmdline (cdr (assq :cmdline params)))
	 (in-file (org-babel-temp-file "plantuml-"))
	 (java (or (cdr (assq :java params)) ""))
	 (executable (cond ((eq org-plantuml-exec-mode 'plantuml) org-plantuml-executable-path)
			   (t "java")))
	 (executable-args (cond ((eq org-plantuml-exec-mode 'plantuml) org-plantuml-executable-args)
				((string= "" org-plantuml-jar-path)
				 (error "`org-plantuml-jar-path' is not set"))
				((not (file-exists-p org-plantuml-jar-path))
				 (error "Could not find plantuml.jar at %s" org-plantuml-jar-path))
				(t (list java
					 "-jar"
					 (shell-quote-argument (expand-file-name org-plantuml-jar-path))))))
	 (full-body (org-babel-plantuml-make-body body params))
	 (cmd (mapconcat #'identity
			 (append
			  (list executable)
			  executable-args
			  (pcase (file-name-extension out-file)
			    ("png" '("-tpng"))
			    ("svg" '("-tsvg"))
			    ("eps" '("-teps"))
			    ("pdf" '("-tpdf"))
			    ("tex" '("-tlatex"))
			    ("vdx" '("-tvdx"))
			    ("xmi" '("-txmi"))
			    ("scxml" '("-tscxml"))
			    ("html" '("-thtml"))
			    ("txt" '("-ttxt"))
			    ("utxt" '("-utxt")))
			  (list
			   "-p"
			   cmdline
			   "<"
			   (org-babel-process-file-name in-file)
			   ">"
			   (org-babel-process-file-name out-file)))
			 " ")))
    (with-temp-file in-file (insert full-body))
    (message "%s" cmd) (org-babel-eval cmd "")
    (org-babel-plantuml-post-process out-file)
    nil)) ;; signal that output has already been written to file

(defun org-babel-prep-session:plantuml (_session _params)
  "Return an error because plantuml does not support sessions."
  (error "Plantuml does not support sessions"))

(defun org-babel-plantuml-post-process (out-file)
  "Run post-processing commands on the output file.

See also `org-babel-plantuml-post-export-commands'."

  (defun org-babel-plantuml-post-process-loop (out-file command-list)
    "Run each command in the command list over the output file."
    (if command-list
        (progn
          (let ((cmd (replace-regexp-in-string "%s" out-file (car command-list)))
                (rest (cdr command-list)))
            (message "%s" cmd)
            (org-babel-eval cmd "")
            (org-babel-plantuml-post-process-loop out-file rest)))))

  (org-babel-plantuml-post-process-loop out-file
					(cdr (assoc (file-name-extension out-file)
						    org-babel-plantuml-post-export-commands))))

(provide 'ob-plantuml)

;;; ob-plantuml.el ends here