;;; nordvpn.el --- NordVPN interface for Emacs -*- lexical-binding: t -*-

;;; Copyright (C) 2021 Phundrak

;; Author: Phundrak <https://phundrak.com>
;; Maintainer: Phundrak <lucien@phundrak.com>
;; Homepage: https://labs.phundrak.com/phundrak/nordvpn.el
;; Version: 0.1.0
;; Keywords: nordvpn, vpn, convenience
;; Package-Requires: ((emacs "27") (s "1.12.0") (ido "1.0.1"))

;; 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/>.

;;; Commentary:

;; Functions collection for interacting with NordVPN from Emacs.

;;; Code:

(defcustom nordvpn-default-country nil
  "Default country to which NordVPN should connect"
  :type 'string
  :group 'nordvpn)

(defcustom nordvpn-default-city nil
  "Default city to which NordVPN should connect"
  :type 'string
  :group 'nordvpn)

(defun nordvpn--cut-weird-prefix (string)
  "Cut the prefix almost always found in NordVPN's returned string
ending with some Ctrl-M char."
  (replace-regexp-in-string ".*
"
                            ""
                            string))

(defun nordvpn--get-list (string)
  "Get a list from NordVPN's output `STRING', such as cities or
countries."
  (s-split "\n"
           (nordvpn--cut-weird-prefix string)
           t))

(defun nordvpn--get-countries ()
  "Returns the list of countries offered by NordVPN."
  (nordvpn--get-list (nordvpn--cut-weird-prefix (eshell-command-result "nordvpn countries"))))

(defun nordvpn--get-country ()
  "Get a country among the ones offered by NordVPN."
  (let ((countries (nordvpn--get-countries))
        (country (ido-completing-read "Country: " countries)))
    (if (null country)
        nordvpn-default-country
      country)))

(defun nordvpn--get-cities (&optional country)
  "Get the list of cities available in `COUNTRY'. If `COUNTRY' is
nil, then it will be asked interactively to the user."
  (let ((country (if (null country)
                     (nordvpn--get-country)
                   country)))
    (nordvpn--get-list (eshell-command-result (format "nordvpn cities %s"
                                                      country)))))

(defun nordvpn--get-city (&optional country)
  "Get a specific city from the list of cities available for
`COUNTRY'. If `COUNTRY' is nil, the user will have to choose
through `nordvpn--get-country'. If the result is nil, the
function will fallback to `nordvpn-default-country'."
  (let* ((country (if (null country)
                      (nordvpn--get-country)
                    country))
         (command (format "nordvpn cities %s" country))
         (cities (nordvpn--get-list (eshell-command-result command))))
    (ido-completing-read "City: " cities)))

(defun nordvpn--get-groups ()
  "Get the list of server groups available."
  (nordvpn--get-list (eshell-command-result "nordvpn groups")))

(defun nordvpn--get-group ()
  "Select one of the available server groups."
  (ido-completing-read "Group: " (nordvpn--get-groups)))

(defun nordvpn--get-credentials ()
  "Get user credentials from `auth-source' files."
  (let* ((found (car (auth-source-search :max 1
                                         :host "nordvpn"
                                         :require '(:user :secret)
                                         :create t))))
    (if found
        (list
         (plist-get found :user)
         (let ((password (plist-get found :secret)))
           (while (functionp password)
             (setf password (funcall password)))
           password))
      nil)))

(defun nordvpn-connect-to-country (&option country)
  "Connect with NordVPN to a specific country. If `COUNTRY' is nil,
then \"nordvpn c\" is called, otherwise \"nordvpc c `COUNTRY'\"
is called."
  (message "NordVPN: %s"
           (nordvpn--cut-weird-prefix
            (eshell-command-result
             (if country
                 (format "nordvpn c %s" country)
               "nordvpn c")))))

(defun nordvpn-connect-to-city (city &optinal country)
  "Connect with NordVPN to a specific `CITY'. An additional
`COUNTRY' may be specified. If no country is provided to the
function, \"nordvpn c `CITY'\" will be called, otherwise
\"nordvpn c `COUNTRY' `CITY'\" will be called."
  (message "NordVPN: %s"
           (nordvpn--cut-weird-prefix
            (eshell-command-result
             (if country
                 (format "nordvpn c %s %s" country city)
               (format "nordvpn c %s" city))))))

(defun nordvpn-connect-to-group (group)
  "Connect with NordVPN to the specified `GROUP'."
  (message "NordVPN: %s"
           (nordvpn--cut-weird-prefix
            (eshell-command-result
             (format "nordvpn c %s")))))

(defun nordvpn-connect (&optional arg)
  "Connect to NordVPN.

If `ARG' is non nil or if `nordvpn-default-country' is nil, will
ask the user which country to connect to."
  (interactive "P")
  (nordvpn-connect-to-country (if arg
                                  (nordvpn--get-country)
                                nordvpn-default-country)))

;; nordvpn-connect-to-city &option country city
;; C-u nordvpn-connect-to-city &option city country

(defun nordvpn-disconnect ()
  "Disconnect NordVPN from the current server."
  (interactive)
  (message "NordVPN: %s"
           (nordvpn--cut-weird-prefix (eshell-command-result "nordvpn d"))))

(defun nordvpn-logout ()
  "Logout from NordVPN."
  (interactive)
  (message "NordVPN: %s"
           (nordvpn--cut-weird-prefix (shell-command-to-string "nordvpn logout"))))

(defun nordvpn-login ()
  "Log into your NordVPN account. Credentials are read from
`auth-source' files."
  (interactive)
  (let* ((credentials (nordvpn--get-credentials))
         (username    (car credentials))
         (password    (cadr credentials))
         (command     (format "nordvpn login -u %s -p \"%s\"" username
                              password)))
    (message "NordVPN: %s"
             (nordvpn--cut-weird-prefix (shell-command-to-string command)))))

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