;;; js2-highlight-vars.el --- highlight occurrences of the variable under cursor

;; Copyright (C) 2009  Free Software Foundation, Inc.
;; Author:  Mihai Bazon <mihai.bazon@gmail.com>
;; Version: 0.1.0
;; Package-Version: 20170418.1829
;; Package-Commit: e3bb177e50f76b272e8073a94d4f46be6512a163
;; URL: http://mihai.bazon.net/projects/editing-javascript-with-emacs-js2-mode/js2-highlight-vars-mode
;; Package-Requires: ((emacs "24.4") (js2-mode "20150908"))

;;; Commentary:
;;
;; This is a minor mode on top of js2-mode which highlights all
;; occurrences of the variable under the cursor within its defining
;; scope.

;;; Installation:
;;
;; Install this package from MELPA using `M-x install-package` and put
;; the following in your ~/.emacs.d/init.el:
;; (eval-after-load "js2-highlight-vars-autoloads"
;;   '(add-hook 'js2-mode-hook (lambda () (js2-highlight-vars-mode))))
;;
;; If you aren't already using MELPA, see:
;; http://melpa.milkbox.net/#/getting-started

;; GNU Emacs 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.

;; GNU Emacs 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 GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.

;;; Code:

(require 'js2-mode)

(js2-deflocal js2-highlight-vars-mode nil)

(defface js2-highlight-vars-face
  `((((class color) (background light))
     (:background "light green"))
    (((class color) (background dark))
     (:background "royal blue")))
  "Face for highlighting variables"
  :group 'js2-mode)

(defface js2-highlight-vars-second-face
  `((((class color) (background light))
     (:background "light pink"))
    (((class color) (background dark))
     (:background "blue violet")))
  "Face for highlighting variables"
  :group 'js2-mode)

(defvar js2-highlight-vars-local-keymap
  (let ((map (make-sparse-keymap)))
    (define-key map (kbd "M-n")       'js2-highlight-vars-next)
    (define-key map (kbd "C-<down>")  'js2-highlight-vars-next)
    (define-key map (kbd "M-p")       'js2-highlight-vars-prev)
    (define-key map (kbd "C-<up>")    'js2-highlight-vars-prev)
    (define-key map (kbd "M-r")       'js2-highlight-vars-rename)
    map))

(js2-deflocal js2--highlight-vars-tokens nil)
(js2-deflocal js2--highlight-vars-current-token nil)
(js2-deflocal js2--highlight-vars-current-token-name nil)
(js2-deflocal js2--highlight-vars-post-command-timer nil)

(defun js2--do-highlight-vars ()
  "Highlight variable under cursor within the defining scope"
  (interactive)
  (setq js2--highlight-vars-post-command-timer nil)
  (unless js2--highlight-vars-tokens
    (let ((node (js2-node-at-point))
          (tokens nil)
          name
          scope)
      (unless (js2-name-node-p node)
        (setq node (js2-node-at-point (- (point) 1))))
      (when (and node (js2-name-node-p node))
        (setq scope (js2-node-get-enclosing-scope node)
              name (js2-name-node-name node)
              js2--highlight-vars-current-token (js2-node-abs-pos node)
              js2--highlight-vars-current-token-name name)
        (setq scope (js2-get-defining-scope scope name))
        (with-silent-modifications
          (js2-visit-ast
           scope
           (lambda (node end-p)
             (when (and (not end-p)
                        (js2-name-node-p node)
                        (string= name (js2-name-node-name node)))
               (let* ((beg (js2-node-abs-pos node))
                      (end (+ beg (js2-node-len node)))
                      (new-scope (js2-node-get-enclosing-scope node))
                      (new-scope (js2-get-defining-scope new-scope name))
                      (ovl (make-overlay beg end)))
                 (add-to-list 'tokens beg t)
                 (overlay-put ovl 'keymap js2-highlight-vars-local-keymap)
                 (overlay-put ovl 'face
                              (if (eq new-scope scope)
                                  'js2-highlight-vars-face
                                'js2-highlight-vars-second-face))
                 (overlay-put ovl 'evaporate t)
                 (overlay-put ovl 'js2-highlight-vars t)))
             t)))
        (setq js2--highlight-vars-tokens tokens)))))

(defun js2-highlight-vars-next ()
  (interactive)
  (let ((inhibit-point-motion-hooks t)
        (diff (- (point) js2--highlight-vars-current-token))
        (next (catch 'done
                (dolist (pos js2--highlight-vars-tokens)
                  (when (> pos (point))
                    (throw 'done pos))))))
    (when next
      (setq js2--highlight-vars-current-token next)
      (goto-char next)
      (forward-char diff))))

(defun js2-highlight-vars-prev ()
  (interactive)
  (let ((inhibit-point-motion-hooks t)
        (diff (- (point) js2--highlight-vars-current-token))
        (prev (catch 'done
                (dolist (pos (reverse js2--highlight-vars-tokens))
                  (when (and (< pos (point))
                             (not (= pos js2--highlight-vars-current-token)))
                    (throw 'done pos))))))
    (when prev
      (setq js2--highlight-vars-current-token prev)
      (goto-char prev)
      (forward-char diff))))

(defun js2-highlight-vars-rename (new-name)
  (interactive "*sRename variable to: ")
  (let ((len (length js2--highlight-vars-current-token-name))
        (inhibit-point-motion-hooks t)
        (ovl (make-overlay 1 1))
        (all nil)
        doit)
    (unwind-protect
        (progn
          (overlay-put ovl 'face 'highlight)
          (dolist (pos (mapcar (lambda(pos)
                                 (let ((m (make-marker)))
                                   (set-marker m pos))) js2--highlight-vars-tokens))
            (goto-char pos)
            (move-overlay ovl pos (+ pos len))
            (setq doit (if all
                           ?y
                         (read-char "Replace this occurrence? (y/n/!)")))
            (when (= doit ?!)
              (setq all t
                    doit ?y))
            (when (= doit ?y)
              (insert new-name)
              (delete-char len))))
      (delete-overlay ovl))))

(defun js2--unhighlight-vars (&rest ignore)
  (setq js2--highlight-vars-tokens nil
        js2--highlight-vars-current-token nil)
  (remove-overlays (point-min) (point-max)
                   'js2-highlight-vars t))

(defun js2-highlight-vars-post-command-hook ()
  (ignore-errors
    (let* ((overlays (overlays-at (point)))
           (ovl (and overlays
                     (catch 'found
                       (dolist (ovl overlays)
                         (when (overlay-get ovl 'js2-highlight-vars)
                           (throw 'found ovl)))
                       nil))))
      (if (and ovl
               (string= js2--highlight-vars-current-token-name
                        (buffer-substring (overlay-start ovl)
                                          (overlay-end ovl))))
          (setq js2--highlight-vars-current-token (overlay-start ovl))
        (js2--unhighlight-vars)
        (when js2--highlight-vars-post-command-timer
          (cancel-timer js2--highlight-vars-post-command-timer))
        (setq js2--highlight-vars-post-command-timer
              (run-with-timer 0.5 nil 'js2--do-highlight-vars))))))

;;;###autoload
(define-minor-mode js2-highlight-vars-mode
  "Minor mode that highlights occurrences of the variable under
cursor in js2-mode buffers"
  nil " vars" nil
  (if js2-highlight-vars-mode
      (progn
        (add-hook 'post-command-hook 'js2-highlight-vars-post-command-hook nil t))
    (remove-hook 'post-command-hook 'js2-highlight-vars-post-command-hook t)
    (js2--unhighlight-vars)
    (kill-local-variable js2--highlight-vars-tokens)
    (kill-local-variable js2--highlight-vars-current-token)))

(provide 'js2-highlight-vars)

;;; js2-highlight-vars.el ends here