mattermost.el/mattermost.el

;;; mattermost.el --- An Emacs Mattermost Chat Client

;; ToDo: LICENSE HERE

;; Author: Miguel de la Cruz (mgdelacroix@gmail.com)
;; Version: 0.1
;; Package-Requires: ((websocket))
;; Keywords: Mattermost, chat, client, Internet

;;; Code:

(defgroup mattermost nil
  "Mattermost chat client"
  :prefix "mattermost-"
  :group 'applications)

(defcustom mattermost-server-url ""
  "The URL of the Mattermost server"
  :group 'mattermost
  :type 'string)

;; ToDo: internal variables should be prefixed with mattermost--
;; instead?
(defvar mattermost-users-plist '()
  "A plist with the server users by id")

(defvar mattermost-token nil
  "The user token to access the server")

(defvar mattermost-user-id nil
  "The ID of the authenticated user")

(setq mattermost-server-url "https://chat.ctrlz.es")

;; ToDo: probably not the best way to get a keyword from a string
(defun mattermost-string->keyword (str)
  "Returns a keyword from a string"
  (read (concat ":" str)))

(defun mattermost-parse-json ()
  "Parses the JSON in the current buffer after a url-request"
  (let ((json-object-type 'plist)
        (json-array-type 'list)
        (json-key-type 'keyword))
    (goto-char url-http-end-of-headers)
    (json-read)))

(defun mattermost-print-post (post)
  "Prints the post in the current buffer"
  (let* ((msg (plist-get post :message))
         ;; ToDo: convert to a readable date
         ;; (update-at (plist-get post :update_at))
         (user-id (plist-get post :user_id))
         (user (mattermost--get-user user-id))
         (username (plist-get user :username)))
    (insert (format "[%s] %s\n" username msg))))

(defun mattermost--get-user (user-id)
  "Returns the user from the internal cache and fills the cache
if the user is not present"
  (let* ((user-id-keyword (mattermost-string->keyword user-id))
         (user (plist-get mattermost-users-plist user-id-keyword)))
    (if (not user)
        (let ((user (mattermost-get-user user-id)))
          (setq mattermost-users-plist (plist-put mattermost-users-plist user-id-keyword user)))
      user)))

;; ToDo: once mattermost-request parses headers, use it to fetch both
;; the user (set the id to a local var) and the headers (set the
;; token)
(defun mattermost-login (username password)
  "Log into the Mattermost Server"
  (let ((url-request-method "POST")
        (url-request-extra-headers '(("Content-Type" . "application/json")))
        (url-request-data (json-serialize `(:login_id ,username :password ,password))))
    (with-current-buffer (url-retrieve-synchronously (concat mattermost-server-url "/api/v4/users/login"))
      (beginning-of-buffer)
      (search-forward "Token: ")
      (let ((token (word-at-point))
            (response (mattermost-parse-json)))
        (setq mattermost-token token)
        (setq mattermost-user-id (plist-get response :id))
        token))))

;; ToDo: update to parse headers as well
(defun mattermost-request (method url &optional body)
  "Builds a Mattermost request and returns the JSON response"
  (let ((url-request-method method)
        (url-request-extra-headers `(("Content-Type" . "application/json")))
        (url-request-data (if body (json-serialize body))))
    (if mattermost-token
        (add-to-list 'url-request-extra-headers `("Authorization" . ,(concat "Bearer " mattermost-token))))
    (with-current-buffer (url-retrieve-synchronously (concat mattermost-server-url "/api/v4" url) t)
      (mattermost-parse-json))))

(defun mattermost-get-user (user-id)
  "Returns the user information"
  (mattermost-request "GET" (format "/users/%s" user-id)))

(defun mattermost-get-teams ()
  "Returns the user's team list"
  (mattermost-request "GET" "/teams"))

(defun mattermost-get-channels (team-id)
  "Returns the user's channel for a given team"
  (let ((url (format "/users/%s/teams/%s/channels" mattermost-user-id team-id)))
    (message "Channels url: %s" url)
    (mattermost-request "GET" url)))

(defun mattermost-get-channel-messages (channel-id &optional page per-page)
  "Returns a list of posts for a given channel"
  (let ((url (format "/channels/%s/posts" channel-id)))
    (mattermost-request "GET" url)))

(with-current-buffer (get-buffer-create "*Mattermost Teams*")
  (let ((teams (mattermost-get-teams)))
    (erase-buffer)
    (dolist (team teams)
      (let* ((team-id (plist-get team :id))
             (team-display-name (plist-get team :display_name))
             (channels (mattermost-get-channels team-id)))
        (insert (format "%s\n" team-display-name))
        (dolist (channel channels)
          (let ((channel-id (plist-get channel :id))
                (channel-display-name (plist-get channel :display_name))
                (channel-name (plist-get channel :name)))
            (insert (format "> [%s] %s\n" channel-id (if (string= channel-display-name "")
                                                         channel-name
                                                       channel-display-name)))))))))

;; ToDo: remove
(setq msgs (mattermost-get-channel-messages "68w17u1da7yg7enayudjjqqwse"))
(car (plist-get msgs :posts))

(with-current-buffer (get-buffer-create "*Town Square*")
  (erase-buffer)
  (let ((posts (plist-get msgs :posts))
        (order (plist-get msgs :order)))
    (dolist (msgid order)
      (let* ((msgid-keyword (mattermost-string->keyword msgid))
             (post (plist-get posts msgid-keyword)))
        (mattermost-print-post post)))))

(provide 'mattermost)
;;; mattermost.el ends here