;;; evil-relative-linum.el --- Show relative line numbers during operator state

;; Author: INA Lintaro <tarao.gnn at gmail.com>
;; URL: http://github.com/tarao/evil-plugins
;; Version: 0.1
;; Keywords: evil, plugin

;; This file is NOT part of GNU Emacs.

;;; License:
;;
;; 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/>.

;;; Code:

(require 'linum+) ;; See http://github.com/tarao/elisp/raw/master/linum+.el
(require 'evil)

(defgroup evil-relative-linum nil
  "Relative line numbers when operators are activated."
  :prefix "evil-relative-linum-"
  :group 'evil)

(defcustom evil-relative-linum-delay 0.3
  "Delay in showing line numbers after the operator is activated."
  :group 'evil-relative-linum
  :type 'float)

(defvar evil-relative-linum-timer nil)
(defvar evil-relative-linum-activated nil)

(define-minor-mode evil-relative-linum-mode
  "Show relative line numbers when operators are activated."
  :group 'evil-relative-linum
  (let ((exit-cmd `(lambda ()
                     (interactive)
                     (save-excursion (set-buffer ,(current-buffer))
                                     (evil-relative-linum-off)))))
    (if evil-relative-linum-mode
        (progn
          (add-hook 'pre-command-hook exit-cmd)
          (add-hook 'post-command-hook exit-cmd)
          (setq evil-relative-linum-timer
                (run-with-idle-timer evil-relative-linum-delay nil
                                     'evil-relative-linum-activate)))
      (cancel-timer evil-relative-linum-timer)
      (when evil-relative-linum-activated
        (relative-linum-mode 0)
        (setq evil-relative-linum-activated nil))
      (remove-hook 'pre-command-hook exit-cmd)
      (remove-hook 'post-command-hook exit-cmd))))

(defun evil-relative-linum-off ()
  (interactive)
  (evil-relative-linum-mode 0))

(defun evil-relative-linum-on ()
  (interactive)
  (evil-relative-linum-mode 1))

(defun evil-relative-linum-activate ()
  (setq evil-relative-linum-activated t)
  (relative-linum-mode 1))

(add-hook 'evil-operator-state-entry-hook 'evil-relative-linum-on)

(provide 'evil-relative-linum)
;;; evil-relative-linum.el ends here