;;; init.el --- A (reasonably) minimal init file for Emacs. -*- lexical-binding: t; -*-

;;; Commentary:

;;; Code:


;; ----------------------------------------------------------------------------
;; Manage packages via `use-package`.
;; https://github.com/jwiegley/use-package

(require 'package)
(setq package-enable-at-startup nil)

(setq package-archives
      '(("gnu"    . "https://elpa.gnu.org/packages/")
        ("melpa"  . "https://melpa.org/packages/")
        ("stable" . "https://stable.melpa.org/packages/")))

(unless (package-installed-p 'use-package)
  (package-refresh-contents)
  (package-install 'use-package))


;; ----------------------------------------------------------------------------
;; Define some simple helper functions for loading user-defined configuration
;; files. Load all configuration files for third-party packages and language
;; support.

(defconst user-init-dir "~/.emacs.d/")

(defun load-user-file (file)
  "Load FILE in the current user's configuration directory.
   File names which are prefixed with an underscore and/or which do not have
   the extension '.el' will be ignored."
  (interactive "f")
  (setq file-name (file-name-nondirectory file))
  (when (and (string-suffix-p ".el" file-name)
             (not (string-prefix-p "_" file-name)))
    (load-file (expand-file-name file user-init-dir))))

(defun load-user-dir (dir)
  "Recursively load all files in directory DIR.
   DIR should be relative to the user's configuration directory."
  (interactive "f")
  (setq config-dir (file-name-concat user-init-dir dir))
  (dolist (file (directory-files-recursively config-dir ""))
    (load-user-file file)))


(load-user-dir "pkg")
(load-user-dir "lang")


;; ----------------------------------------------------------------------------
;; Configure how and where backup files are created.

(setq backup-directory-alist '(("." . "~/.emacs.d/backup"))
      backup-by-copying    t  ; Don't delink hardlinks
      version-control      t  ; Use version numbers on backups
      delete-old-versions  t  ; Automatically delete excess backups
      kept-new-versions   20  ; How many of the newest versions to keep
      kept-old-versions    5  ; How many of the oldest versions to keep
      )


;; ----------------------------------------------------------------------------
;; Interface settings:
;; - Open new windows to the right, not on the bottom
;; - Don't use double-spaces after periods
;; - Use unicode ellipses
;; - Don't require full yes/no answers, allow y/n instead
;; - Hide the menu bar
;; - Make it easier to move between windows. Windows can be navigated using
;;   <shift> in combination with the arrow keys

(setq split-height-threshold    nil
      split-width-threshold       0
      sentence-end-double-space nil
      truncate-string-ellipsis  "…")

(fset 'yes-or-no-p 'y-or-n-p)
(menu-bar-mode -1)

(setq windmove-wrap-around t)
(windmove-default-keybindings)


;; ----------------------------------------------------------------------------
;; Mode line configuration:
;; - Hide the frame identifier
;; - Display the column and line numbers of the cursor
;; - Display the file size

(setq mode-line-frame-identification " ")

(column-number-mode)
(size-indication-mode)


;; ----------------------------------------------------------------------------
;; Editor configuration:
;; - Scroll line-by-line, rather than jumping around haphazardly
;; - Automatically reload files if modified outside of the editor
;; - Overwrite selected text when typing
;; - Display line numbers
;; - Prettify symbols (eg. lambda -> λ)
;; - Enable mouse support
;; - Display a ruler in the 80th column
;; - Make sure that UTF-8 is *ALWAYS* the default encoding

(setq scroll-conservatively           10000
      scroll-margin                       0
      scroll-preserve-screen-position     1)

(global-auto-revert-mode)
(delete-selection-mode)
(global-display-line-numbers-mode)
(global-prettify-symbols-mode)
(xterm-mouse-mode +1)

(setq-default display-fill-column-indicator-column 80)
(add-hook 'prog-mode-hook #'display-fill-column-indicator-mode)
(add-hook 'text-mode-hook #'display-fill-column-indicator-mode)

(set-charset-priority 'unicode)
(prefer-coding-system 'utf-8-unix)


;; ----------------------------------------------------------------------------
;; Whitespace settings:
;; - Tabs are 4 space characters (as the gods intended)
;; - Ensure a newline character is present at the end files when saving
;; - Clean up extraneous whitespace when saving

(setq-default indent-tabs-mode      nil
              tab-width               4
              require-final-newline   t)

(add-hook 'before-save-hook 'whitespace-cleanup)


;; ----------------------------------------------------------------------------
;; Dired-mode configuration:
;; - Show human-readable file sizes in dired mode
;; - On macOS, `ls` does not support the `--dired` option

(setq dired-listing-switches "-alh")

(when (string= system-type "darwin")
  (setq dired-use-ls-dired nil))


;; ----------------------------------------------------------------------------
;; Diminish some built-in modes that we don't really care about.

(add-hook 'eldoc-mode-hook    (lambda () (diminish 'eldoc-mode)))
(add-hook 'hs-minor-mode-hook (lambda () (diminish 'hs-minor-mode)))


;; ----------------------------------------------------------------------------
;; Custom key-bindings.

;; Globally un-set "C-z", which suspends Emacs by default.
(global-unset-key (kbd "C-z"))

;; Enable code folding in programming modes, and set some more reasonable
;; shortcuts.
(add-hook 'prog-mode-hook #'hs-minor-mode)
(global-set-key (kbd "C-c C-h") (kbd "C-c @ C-h")) ; Hide a block
(global-set-key (kbd "C-c C-s") (kbd "C-c @ C-s")) ; Show a block


;; ----------------------------------------------------------------------------
;; WARNING: Don't touch anything after this comment!

(custom-set-variables
 ;; custom-set-variables was added by Custom.
 ;; If you edit it by hand, you could mess it up, so be careful.
 ;; Your init file should contain only one such instance.
 ;; If there is more than one, they won't work right.
 '(git-gutter:added-sign " +")
 '(git-gutter:deleted-sign " -")
 '(git-gutter:modified-sign " *")
 '(package-selected-packages nil))
(custom-set-faces
 ;; custom-set-faces was added by Custom.
 ;; If you edit it by hand, you could mess it up, so be careful.
 ;; Your init file should contain only one such instance.
 ;; If there is more than one, they won't work right.
 )

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