;;; mastodon-toot.el --- Minor mode for sending Mastodon toots

;; Copyright (C) 2017 Johnson Denen
;; Author: Johnson Denen <johnson.denen@gmail.com>
;; Version: 0.6.1
;; Homepage: https://github.com/jdenen/mastodon.el

;; This file is not part of GNU Emacs.

;; This file is part of mastodon.el.

;; mastodon.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.

;; mastodon.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 mastodon.el.  If not, see <http://www.gnu.org/licenses/>.

;;; Commentary:

;; mastodon-toot.el supports POSTing status data to Mastodon.

;;; Code:

(require 'mastodon-auth nil t)

(defgroup mastodon-toot nil
  "Capture Mastodon toots."
  :prefix "mastodon-toot-"
  :group 'mastodon)

(defvar mastodon-toot--reply-to-id nil)
(defvar mastodon-toot--content-warning nil)

(defun mastodon-toot--action-success (marker &optional rm)
  "Insert MARKER with 'success face in byline.

Remove MARKER if RM is non-nil."
  (let ((inhibit-read-only t)
        (bol (progn (move-beginning-of-line '()) (point)))
        (eol (progn (move-end-of-line '()) (point))))
    (when rm (replace-regexp (format "(%s) " marker) "" '() bol eol))
    (move-beginning-of-line '())
    (mastodon-tl--goto-next-toot)
    (unless rm
      (insert (format "(%s) "
                      (propertize marker 'face 'success))))))

(defun mastodon-toot--action (action callback)
  "Take ACTION on toot at point, then execute CALLBACK."
  (let* ((id (mastodon-tl--property 'toot-id))
         (url (mastodon-http--api (concat "statuses/"
                                         (number-to-string id)
                                         "/"
                                         action))))
    (let ((response (mastodon-http--post url nil nil)))
      (mastodon-http--triage response callback))))

(defun mastodon-toot--toggle-boost ()
  "Boost/unboost toot at `point'."
  (interactive)
  (let* ((id (mastodon-tl--property 'toot-id))
         (boosted (get-text-property (point) 'boosted-p))
         (action (if boosted "unreblog" "reblog"))
         (msg (if boosted "unboosted" "boosted"))
         (remove (when boosted t)))
    (mastodon-toot--action action
                           (lambda ()
                             (mastodon-toot--action-success "B" remove)
                             (message (format "%s #%d" msg id))))))

(defun mastodon-toot--toggle-favourite ()
  "Favourite/unfavourite toot at `point'."
  (interactive)
  (let* ((id (mastodon-tl--property 'toot-id))
         (faved (get-text-property (point) 'favourited-p))
         (action (if faved "unfavourite" "favourite"))
         (remove (when faved t)))
    (mastodon-toot--action action
                           (lambda ()
                             (mastodon-toot--action-success "F" remove)
                             (message (format "%sd #%d" action id))))))

(defun mastodon-toot--kill ()
  "Kill `mastodon-toot-mode' buffer and window.

Set `mastodon-toot--reply-to-id' to nil.
Set `mastodon-toot--content-warning' to nil."
  (kill-buffer-and-window)
  (setq mastodon-toot--reply-to-id     nil
        mastodon-toot--content-warning nil))

(defun mastodon-toot--cancel ()
  "Kill new-toot buffer/window. Does not POST content to Mastodon."
  (interactive)
  (mastodon-toot--kill))

(defun mastodon-toot--remove-docs ()
  "Get the body of a toot from the current compose buffer."
  (let ((re "^|=+=|$"))
    (save-excursion
      (goto-char 0)
      (re-search-forward re nil nil 2)
      (buffer-substring (+ 2 (point)) (+ 1 (length (buffer-string)))))))

(defun mastodon-toot--send ()
  "Kill new-toot buffer/window and POST contents to the Mastodon instance."
  (interactive)
  (let* ((toot (mastodon-toot--remove-docs))
         (endpoint (mastodon-http--api "statuses"))
         (spoiler (when mastodon-toot--content-warning
                    (read-string "Warning: ")))
         (args `(("status" . ,toot)
                 ("in_reply_to_id" . ,mastodon-toot--reply-to-id)
                 ("sensitive" . ,(when mastodon-toot--content-warning
                                   (symbol-name t)))
                 ("spoiler_text" . ,spoiler))))
    (progn
      (mastodon-toot--kill)
      (let ((response (mastodon-http--post endpoint args nil)))
        (mastodon-http--triage response
                               (lambda () (message "Toot toot!")))))))

(defun mastodon-toot--reply ()
  "Reply to toot at `point'."
  (interactive)
  (let* ((toot (mastodon-tl--property 'toot-json))
         (id (number-to-string (mastodon-tl--field 'id toot)))
         (account (mastodon-tl--field 'account toot))
         (user (cdr (assoc 'username account))))
    (mastodon-toot user id)))

(defun mastodon-toot--toggle-warning ()
  "Toggle `mastodon-toot--content-warning'."
  (interactive)
  (setq mastodon-toot--content-warning
        (not mastodon-toot--content-warning)))

;; we'll need to revisit this if the binds get
;; more diverse than two-chord bindings
(defun mastodon-toot--get-mode-kbinds ()
  "Get a list of the keybindings in the mastodon-toot-mode."
  (let* ((binds (copy-tree mastodon-toot-mode-map))
	 (prefix (car (cadr binds)))
	 (bindings (remove nil (mapcar  (lambda (i) (if (listp i) i))
					(cadr binds)))))
    (mapcar (lambda (b)
	      (progn
		(setf (car b) (vector prefix (car b)))
		b))
	    bindings)))

(defun mastodon-toot--format-kbind-command (cmd)
  "Format CMD to be more readable.
e.g. mastodon-toot--send -> Send."
  (let* ((str (symbol-name cmd))
	 (re "--\\(.*\\)$")
	 (str2 (save-match-data
		 (string-match re str)
		 (match-string 1 str))))
    (capitalize (replace-regexp-in-string "-" " " str2))))

(defun mastodon-toot--format-kbind (kbind)
  "Format a single keybinding, KBIND, for display in documentation."
  (let ((key (help-key-description (car kbind) nil))
	(command (mastodon-toot--format-kbind-command (cdr kbind))))
    (format "\t%s - %s" key command)))

(defun mastodon-toot--format-kbinds (kbinds)
  "Format a list keybindings, KBINDS, for display in documentation."
  (mapconcat 'identity (cons "" (mapcar #'mastodon-toot--format-kbind kbinds))
	       "\n"))

(defun mastodon-toot--make-mode-docs ()
  "Create formatted documentation text for the mastodon-toot-mode."
  (let ((kbinds (mastodon-toot--get-mode-kbinds)))
    (concat
     "|=================================================================|\n"
     " Compose a new toot here. The following keybindings are available:"
     (mastodon-toot--format-kbinds kbinds)
     "\n|=================================================================|\n\n")))

(defun mastodon-toot--display-docs ()
  "Display documentation about mastodon-toot mode."
  (insert
   (propertize
    (mastodon-toot--make-mode-docs)
    'face 'comment)))

(defun mastodon-toot--setup-as-reply (reply-to-user reply-to-id)
  "If REPLY-TO-USER is provided, inject their handle into the message.
If REPLY-TO-ID is provided, set the MASTODON-TOOT--REPLY-TO-ID var."
  (when reply-to-user
    (insert (format "@%s " reply-to-user))
    (setq mastodon-toot--reply-to-id reply-to-id)))

(defun mastodon-toot--compose-buffer (reply-to-user reply-to-id)
  "Create a new buffer to capture text for a new toot.
If REPLY-TO-USER is provided, inject their handle into the message.
If REPLY-TO-ID is provided, set the MASTODON-TOOT--REPLY-TO-ID var."
  (let* ((buffer-exists (get-buffer "*new toot*"))
	 (buffer (or buffer-exists (get-buffer-create "*new toot*"))))
    (switch-to-buffer-other-window buffer)
    (when (not buffer-exists)
      (mastodon-toot--display-docs)
      (mastodon-toot--setup-as-reply reply-to-user reply-to-id))
    (mastodon-toot-mode t)))

(defvar mastodon-toot-mode-map
  (let ((map (make-sparse-keymap)))
    (define-key map (kbd "C-c C-c") #'mastodon-toot--send)
    (define-key map (kbd "C-c C-k") #'mastodon-toot--cancel)
    (define-key map (kbd "C-c C-w") #'mastodon-toot--toggle-warning)
      map)
  "Keymap for `mastodon-toot'.")

(define-minor-mode mastodon-toot-mode
  "Minor mode to capture Mastodon toots."
  :group 'mastodon-toot
  :keymap mastodon-toot-mode-map
  :global nil)

(provide 'mastodon-toot)
;;; mastodon-toot.el ends here