;;; ein-cell-edit.el --- Notebook cell editing

;; Copyright (C) 2016 John M. Miller

;; Author: John Miller <millejoh at mac.com>

;; This file is NOT part of GNU Emacs.

;; ein-cell-edit.el 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.

;; ein-cell-edit.el 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 ein-worksheet.el.  If not, see <http://www.gnu.org/licenses/>.

;;; Commentary:

;; This code inspired by borrowing from org-src.el.

;;; Code:
(require 'ein-cell)

(defvar ein:src--cell nil)
(defvar ein:src--ws nil)
(defvar ein:src--allow-write-back t)

(defvar ein:edit-cell-mode-map
  (let ((map (make-sparse-keymap)))
    (define-key map "\C-c'" 'ein:edit-cell-exit)
    (define-key map "\C-c\C-k" 'ein:edit-cell-abort)
    (define-key map "\C-c\C-c" 'ein:edit-cell-execute)
    (define-key map "\C-x\C-s" 'ein:edit-cell-save)
    map))

(define-minor-mode ein:edit-cell-mode
  "Minor mode for language major mode buffers generated by EIN.
  \\<org-mode-map>
  This minor mode is turned on when editing a source code snippet with \\[org-edit-special]

  \\{ein:edit-cell-mode-map}

  See also `org-src-mode-hook'."
  nil " EinCell" nil
  (set (make-local-variable 'header-line-format)
       (substitute-command-keys
        "Edit, then exit with \\[ein:edit-cell-exit] or abort with \
\\[ein:edit-cell-abort]"))
  ;; Possibly activate various auto-save features (for the edit buffer
  ;; or the source buffer).
  ;; (when org-edit-src-turn-on-auto-save
  ;;   (setq buffer-auto-save-file-name
  ;;   (concat (make-temp-name "org-src-")
  ;;    (format-time-string "-%Y-%d-%m")
  ;;    ".txt")))
  ;; (unless (or org-src--auto-save-timer (zerop org-edit-src-auto-save-idle-delay))
  ;;   (setq org-src--auto-save-timer
  ;;         (run-with-idle-timer
  ;;          org-edit-src-auto-save-idle-delay t
  ;;          (lambda ()
  ;;            (save-excursion
  ;;              (let (edit-flag)
  ;;                (dolist (b (buffer-list))
  ;;                  (with-current-buffer b
  ;;                    (when (org-src-edit-buffer-p)
  ;;                      (unless edit-flag (setq edit-flag t))
  ;;                      (when (buffer-modified-p) (org-edit-src-save)))))
  ;;                (unless edit-flag
  ;;                  (cancel-timer org-src--auto-save-timer)
  ;;                  (setq org-src--auto-save-timer nil))))))))
  )

(defun ein:cell-configure-edit-buffer ()
  (when (org-bound-and-true-p org-src--from-org-mode)
    (org-add-hook 'kill-buffer-hook #'org-src--remove-overlay nil 'local)
    (if (org-bound-and-true-p org-src--allow-write-back)
        (progn
          (setq buffer-offer-save t)
          (setq buffer-file-name
                (concat (buffer-file-name (marker-buffer org-src--beg-marker))
                        "[" (buffer-name) "]"))
          (setq write-contents-functions '(ein:edit-cell-save)))
      (setq buffer-read-only t))))

(defun ein:edit-cell-execute ()
  "Execute buffer contents via `ein:shared-output-eval-string'."
  (interactive)
  (ein:edit-cell-save)
  (ein:cell-execute-internal ein:src--cell
                             (slot-value ein:src--cell 'kernel)
                             (buffer-string)
                             :silent nil))

(defun ein:edit-cell-save ()
  (interactive)
  ;;(unless (ein:cell-edit-buffer-p) (user-error "Not in a sub-editing buffer"))
  (set-buffer-modified-p nil)
  (let ((edited-code (buffer-string)
                     ;;(org-src--contents-for-write-back)
                     )
        ;; (beg org-src--beg-marker)
        ;; (end org-src--end-marker)
        ;; (overlay org-src--overlay)
        )
    (setf (slot-value ein:src--cell 'input) edited-code)
    (ein:worksheet-render ein:src--ws)))

(defun ein:edit-cell-exit ()
  (interactive)
  ;;(unless (org-src-edit-buffer-p) (error "Not in a sub-editing buffer"))
  (let ((edit-buffer (current-buffer))
        (ws ein:src--ws))
    (when ein:src--allow-write-back
      (ein:edit-cell-save))
    (kill-buffer edit-buffer)
    (switch-to-buffer-other-window (ein:worksheet-buffer ws))
        ;; FIXME: put point at an appropriate location as org does?
    ))

(defun ein:edit-cell-abort ()
  (interactive)
  (let (ein:src--allow-write-back) (ein:edit-cell-exit)))

(defun ein:construct-cell-edit-buffer-name (bufname cell-type)
  (concat "*EIN Src " bufname "[ " cell-type " ]*" ))

(defun ein:edit-cell-contents ()
  (interactive)
  (let* ((cell (or (ein:worksheet-get-current-cell)
                   (error "Must be called from inside an EIN worksheet cell.")))
         (ws (ein:worksheet--get-ws-or-error))
         (contents (ein:cell-get-text cell))
         (type (slot-value cell 'cell-type))
         (name (ein:construct-cell-edit-buffer-name (buffer-name) type))
         (buffer (generate-new-buffer-name name)))
    (switch-to-buffer-other-window buffer)
    (insert contents)
    (remove-text-properties (point-min) (point-max)
                            '(display nil invisible nil intangible nil))
    (set-buffer-modified-p nil)
    (setq buffer-file-name nil)
    (condition-case e
        (ein:case-equal type
          (("markdown") (markdown-mode))
          (("code") (python-mode)))
      (error (message "Language mode `%s' fails with: %S"
                      type (nth 1 e))))
    (set (make-local-variable 'ein:src--cell) cell)
    (set (make-local-variable 'ein:src--ws) ws)
    (set (make-local-variable 'ein:src--allow-write-back) t)
    (ein:edit-cell-mode)))

(provide 'ein-cell-edit)