;;; bandali-utils.el --- useful utilities -*- lexical-binding: t; -*-

;; Copyright (c) 2018-2025 Amin Bandali <bandali@gnu.org>

;; Author: Amin Bandali <bandali@gnu.org>
;; Keywords: convenience

;; 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:

;; Some useful utilities.

;;; Code:

(defun b/insert-asterism ()
  "Insert a centred asterism."
  (interactive)
  (let ((asterism "* * *"))
    (insert
     (concat
      "\n"
      (make-string
       (floor (/ (- fill-column (length asterism)) 2))
       ?\s)
      asterism
      "\n"))))

(defun b/join-line-top ()
  "Like `join-line', but join next line to the current line."
  (interactive)
  (join-line 1))

(defun b/*scratch* ()
  "Switch to `*scratch*' buffer, creating it if it does not exist."
  (interactive)
  (let ((fun (if (functionp #'get-scratch-buffer-create)
                 #'get-scratch-buffer-create ; (version<= "29" emacs-version)
               #'startup--get-buffer-create-scratch))) ; (version< emacs-version "29")
    (switch-to-buffer (funcall fun))))

(defun b/duplicate-line-or-region (&optional n)
  "Duplicate the current line, or region (if active).
Make N (default: 1) copies of the current line or region."
  (interactive "*p")
  (let ((u-r-p (use-region-p))          ; if region is active
        (n1 (or n 1)))
    (save-excursion
      (let ((text
             (if u-r-p
                 (buffer-substring (region-beginning) (region-end))
               (prog1 (thing-at-point 'line)
                 (end-of-line)
                 (if (eobp)
                     (newline)
                   (forward-line 1))))))
        (dotimes (_ (abs n1))
          (insert text))))))

(defun b/invert-default-face (arg)
  "Invert the `default' and `mode-line' faces for the current frame.
Swap the background and foreground for the two `default' and
`mode-line' faces, effectively acting like a simple light/dark
theme toggle.  If prefix argument ARG is given, invert the faces
for all frames."
  (interactive "P")
  (let ((frame (unless arg
                 (selected-frame))))
    (invert-face 'default frame)
    (invert-face 'mode-line frame)
    (when (fboundp #'exwm-systemtray--refresh-background-color)
      (exwm-systemtray--refresh-background-color 'remap))))

(defun b/unfill-paragraph-or-region (&optional beg end)
  "Unfill paragraph, or region (if active)."
  (interactive "r")
  (let ((fill-column most-positive-fixnum))
    (if (use-region-p)
        (fill-region beg end)
      (fill-paragraph))))

(defun b/setq-local-indent-tabs-mode-nil ()
  "Locally disable indent-tabs-mode.
Useful mainly as a hook for other modes."
  (setq-local indent-tabs-mode nil))


;;; Key bindings
(b/keymap-global-set "C-c s c" #'b/*scratch*)
(b/keymap-global-set "C-c d" #'b/duplicate-line-or-region)
(b/keymap-global-set "C-c j" #'b/join-line-top)
(b/keymap-global-set "C-S-j" #'b/join-line-top)
(b/keymap-global-set "C-c v" #'b/invert-default-face)
(b/keymap-global-set "C-c q" #'b/unfill-paragraph-or-region)
(b/keymap-set text-mode-map "M-RET" #'b/insert-asterism)

(provide 'bandali-utils)
;;; bandali-utils.el ends here