;;; gdscript-utils.el --- Utility functions for gdscript-mode -*- lexical-binding: t; -*-

;; Copyright (C) 2020 GDQuest, Free Software Foundation, Inc.

;; Author: Nathan Lovato <nathan@gdquest.com>, Fabián E. Gallina <fgallina@gnu.org>
;; URL: https://github.com/GDQuest/emacs-gdscript-mode/
;; Version: 0.1.0
;; Package-Requires: ((emacs "26.0"))
;; Maintainer: nathan@gdquest.com
;; Created: Jan 2020
;; Keywords: languages

;; 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 <https://www.gnu.org/licenses/>.


;;; Commentary:

;; Misc utility functions for GDScript mode.

;;; Code:

(defun gdscript--util-goto-line (line-number)
  "Move point to LINE-NUMBER."
  (goto-char (point-min))
  (forward-line (1- line-number)))

(defun gdscript--util-forward-comment (&optional direction)
  "Gdscript mode specific version of `forward-comment'.
Optional argument DIRECTION defines the direction to move to."
  (let ((comment-start (gdscript-syntax-context 'comment))
        (factor (if (< (or direction 0) 0)
                    -99999
                  99999)))
    (when comment-start
      (goto-char comment-start))
    (forward-comment factor)))

(defun gdscript--util-list-directories (directory &optional predicate max-depth)
  "List DIRECTORY subdirs, filtered by PREDICATE and limited by MAX-DEPTH.
Argument PREDICATE defaults to `identity' and must be a function
that takes one argument (a full path) and returns non-nil for
allowed files.  When optional argument MAX-DEPTH is non-nil, stop
searching when depth is reached, else don't limit."
  (let* ((dir (expand-file-name directory))
         (dir-length (length dir))
         (predicate (or predicate #'identity))
         (to-scan (list dir))
         (tally nil))
    (while to-scan
      (let ((current-dir (car to-scan)))
        (when (funcall predicate current-dir)
          (setq tally (cons current-dir tally)))
        (setq to-scan (append (cdr to-scan)
                              (gdscript--util-list-files
                               current-dir #'file-directory-p)
                              nil))
        (when (and max-depth
                   (<= max-depth
                       (length (split-string
                                (substring current-dir dir-length)
                                "/\\|\\\\" t))))
          (setq to-scan nil))))
    (nreverse tally)))

(defun gdscript--util-list-files (dir &optional predicate)
  "List files in DIR, filtering with PREDICATE.
Argument PREDICATE defaults to `identity' and must be a function
that takes one argument (a full path) and returns non-nil for
allowed files."
  (let ((dir-name (file-name-as-directory dir)))
    (apply #'nconc
           (mapcar (lambda (file-name)
                     (let ((full-file-name (expand-file-name file-name dir-name)))
                       (when (and
                              (not (member file-name '("." "..")))
                              (funcall (or predicate #'identity) full-file-name))
                         (list full-file-name))))
                   (directory-files dir-name)))))

(provide 'gdscript-utils)

;;; gdscript-utils.el ends here