;;; ob-tmux.el --- Babel Support for Interactive Terminal -*- lexical-binding: t; -*-

;; Copyright (C) 2009-2017 Free Software Foundation, Inc.

;; Author: Benjamin Andresen, Allard Hendriksen
;; Keywords: literate programming, interactive shell
;; Homepage: http://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 interactive terminals.  Mostly shell scripts.
;; Heavily inspired by 'eev' from Eduardo Ochs
;;
;; Adding :cmd and :terminal as header arguments
;; :terminal must support the -T (title) and -e (command) parameter
;;
;; You can test the default setup. (xterm + sh) with
;; M-x org-babel-tmux-test RET

;;; Code:
(require 'ob)

(defvar org-babel-tmux-location "tmux"
  "The command location for tmux.
In case you want to use a different tmux than one selected by your $PATH")

(defvar org-babel-default-header-args:tmux
  '((:results . "silent") (:session . "default") (:cmd . "bash") (:terminal . "gnome-terminal"))
  "Default arguments to use when running tmux source blocks.")

(defun org-babel-execute:tmux (body params)
  "Send a block of code via tmux to a terminal using Babel.
\"default\" session is used when none is specified."
  (message "Sending source code block to interactive terminal session...")
  (save-window-excursion
    (let* ((session (cdr (assq :session params)))
           (socket (org-babel-tmux-session-socketname session)))
      (unless socket (org-babel-prep-session:tmux session params))
      (org-babel-tmux-session-execute-string
       session (org-babel-expand-body:generic body params)))))

(defun org-babel-prep-session:tmux (_session params)
  "Prepare SESSION according to the header arguments specified in PARAMS."
  (let* ((session (cdr (assq :session params)))
         (cmd (cdr (assq :cmd params)))
         (terminal (cdr (assq :terminal params)))
         (process-name (concat "org-babel: terminal (" session ")")))
    (apply 'start-process process-name "*Messages*"
	   terminal
	   `("--"
	     ,org-babel-tmux-location
	     "new-session" "-A" "-s"
	     ,(concat "org-babel-session-" session)))
    ;; XXX: Is there a better way than the following?
    (while (not (org-babel-tmux-session-socketname session))
      ;; wait until tmux session is available before returning
      )))

;; helper functions

(defun org-babel-tmux-session-execute-string (session body)
  "If SESSION exists, send BODY to it."
  (let ((socket (org-babel-tmux-session-socketname session)))
    (when socket
      (let ((tmpfile (org-babel-tmux-session-write-temp-file session body)))
	(shell-command
	 (concat "cat " tmpfile
		 " | xargs -I{} tmux send-keys -t org-babel-session-" session ":1  '{}' Enter"))))))

(defun org-babel-tmux-session-socketname (session)
  "Check if SESSION exists by parsing output of \"tmux ls\"."
  (let* ((tmux-ls (shell-command-to-string "tmux ls"))
	 (sockets (delq
		   nil
		   (mapcar
		    (lambda (x)
		      (when (string-match (rx "windows") x)
			x))
		    (split-string tmux-ls "\n"))))
	 (match-socket (car
			(delq
			 nil
			 (mapcar
			  (lambda (x)
			    (when (string-match
				   (concat "org-babel-session-" session) x)
			      x))
			  sockets)))))
    (when match-socket (car (split-string match-socket ":")))))

(defun org-babel-tmux-session-write-temp-file (_session body)
  "Save BODY in a temp file that is named after SESSION."
  (let ((tmpfile (org-babel-temp-file "ob-tmux-")))
    (with-temp-file tmpfile
      (insert body)

      ;; org-babel has superfluous spaces
      (goto-char (point-min))
      (delete-matching-lines "^ +$"))
    tmpfile))

;; (defun org-babel-screen-test ()
;;   "Test if the default setup works.
;; The terminal should shortly flicker."
;;   (interactive)
;;   (let* ((random-string (format "%s" (random 99999)))
;;          (tmpfile (org-babel-temp-file "ob-screen-test-"))
;;          (body (concat "echo '" random-string "' > " tmpfile "\nexit\n"))
;;          tmp-string)
;;     (org-babel-execute:screen body org-babel-default-header-args:screen)
;;     ;; XXX: need to find a better way to do the following
;;     (while (not (file-readable-p tmpfile))
;;       ;; do something, otherwise this will be optimized away
;;       (format "org-babel-screen: File not readable yet."))
;;     (setq tmp-string (with-temp-buffer
;;                        (insert-file-contents-literally tmpfile)
;;                        (buffer-substring (point-min) (point-max))))
;;     (delete-file tmpfile)
;;     (message (concat "org-babel-screen: Setup "
;;                      (if (string-match random-string tmp-string)
;;                          "WORKS."
;; 		       "DOESN'T work.")))))

(provide 'ob-tmux)



;;; ob-tmux.el ends here