;; (C) Copyright Collin J. Doering 2014
;;
;; 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/>.

;; File: scratches.el
;; Author: Collin J. Doering <collin.doering@rekahsoft.ca>
;; Date: Oct 22, 2014

(defvar scratch-buffer-alist '((python-mode . "# This buffer is for notes you don't want to save, and for Lisp evaluation.\n# If you want to create a file, visit that file with C-x C-f,\n# then enter the text in that file's own buffer.")))

(defun open-scratch-buffer (&optional buf-mode buf-name msg)
  "Opens a scratch buffer; if none exists creates one. When called with the universal argument (C-u) will ask what mode to use for the scratch buffer."
  (interactive
   (cond ((equal current-prefix-arg nil) ;; universal argument not called
	  (list initial-major-mode "*scratch*" initial-scratch-message))
	 ((equal current-prefix-arg '(4)) ;; Universal argument called (C-u)
	  (let* ((buf-mode (read-command "Mode: " initial-major-mode))
		(buf-name (if (equal buf-mode initial-major-mode)
			      "*scratch*"
			    (concat "*scratch:" (symbol-name buf-mode) "*")))
		(msg ""))
	    (list buf-mode buf-name msg)))))
  (let* ((scratch-buffer (get-buffer buf-name)))
    ;; check if the scratchpad is open. If not create it, change its mode and insert message text at the top of the buffer
    (if (null scratch-buffer)
	(with-current-buffer (get-buffer-create buf-name)
	  (funcall buf-mode)
	  (insert msg)))
    (switch-to-buffer buf-name)))

;; Bind a key to grab a scratchpad
(define-key ctl-x-4-map "s" 'open-scratch-buffer)