;; -*- lexical-binding: t -*-

;;; UI customization ;;;
(column-number-mode)
(electric-pair-mode)
(global-so-long-mode)
(menu-bar-mode -1)
(scroll-bar-mode -1)
(show-paren-mode)
(tool-bar-mode -1)

(setq frame-title-format "%b — Emacs")
(setq uniquify-buffer-name-style 'forward)
(setq-default truncate-lines t)

(load-theme 'monokai t)

;; <102 or >109 will make Ioveska look squished rather than tall,
;; narrow, and beautiful.
(set-face-attribute 'default nil :height 104)

;; Disabling bidirectional text will make Emacs less slow with very
;; long lines.
(setq bidi-paragraph-direction 'left-to-right)
(setq bidi-inhibit-bpa t)

;;; Utility functions ;;;

;; Set an environment variable value for a single buffer.
(defun setenv-local (variable &optional value substitute-env-vars)
  ;; If process-environment is the global one, make a copy of it.
  (when (eq process-environment (default-value 'process-environment))
    (make-local-variable 'process-environment)
    (setq process-environment (mapcar 'concat process-environment)))
  (setenv variable value substitute-env-vars))

(defun enable-ansi-color ()
  (setenv-local "TERM" "dumb-emacs-ansi"))

;;; Major modes ;;;
(add-to-list 'auto-mode-alist '("\\.adoc\\'" . adoc-mode))
(add-to-list 'auto-mode-alist '("\\.quirks\\'" . conf-unix-mode))
(add-to-list 'auto-mode-alist '("\\.tmac\\'" . nroff-mode))
(add-to-list 'auto-mode-alist '("/Cargo\\.lock\\'" . toml-mode))

;;; Backups ;;;
(let ((backup-dir
       (concat (file-name-as-directory user-emacs-directory) "backups")))
  (make-directory backup-dir t)
  (setq backup-directory-alist `(("." . ,backup-dir)))
  (setq message-auto-save-directory backup-dir))

;;; CC Mode ;;;
(with-eval-after-load 'cc-styles
  ;; Default to kernel style.
  (add-to-list 'c-default-style '(other . "linux")))

;;; Comint ;;;
;; This relies on an Emacs patch to apply to async-shell-command.
(setq comint-terminfo-terminal "dumb-emacs-ansi")

;;; Diff Mode ;;;
;; Unbind M-DEL from scroll-down-command, so it does the same thing as
;; in the rest of Emacs (backward-kill-word).
(with-eval-after-load 'diff-mode
  (define-key diff-mode-map (kbd "M-DEL") nil))

;;; Dired ;;;
(with-eval-after-load 'dired
  ;; Use human-readable sizes.
  (setq dired-listing-switches
	(combine-and-quote-strings `(,dired-listing-switches "-h")))

  ;; Don't open new windows when clicking directory entries.
  (define-key dired-mode-map [mouse-2] 'dired-find-file))

;;; Direnv ;;;
(direnv-mode)
(global-set-key (kbd "C-c d") #'direnv-update-environment)

;;; Ediff ;;;
;; Don't make a new frame for Ediff controls.
(setq ediff-window-setup-function 'ediff-setup-windows-plain)

;;; EditorConfig ;;;
(editorconfig-mode)

;;; Eglot ;;;
(with-eval-after-load 'eglot
  ;; Override default LSPs for languages.
  (add-to-list 'eglot-server-programs '(rust-mode "rust-analyzer"))
  (add-to-list 'eglot-server-programs '((c++-mode c-mode) "clangd"))

  ;; Underline all occurrences of the symbol at point in the current
  ;; buffer (default is to bold instead).
  (set-face-attribute 'eglot-highlight-symbol-face nil :inherit 'underline)

  ;; Add keybindings for eglot actions.
  (define-key eglot-mode-map (kbd "C-c e a") #'eglot-code-actions)
  (define-key eglot-mode-map (kbd "C-c e r") #'eglot-rename))

;; Tell rust-analyzer not to allow colons inside Rust import.
(setq-default eglot-workspace-configuration
	      '((:rust-analyzer . (:assist (:importMergeBehaviour "last")))))

;;; Environment ;;;

;; Provide a way to turn paging back on for modes like terminal emulators.
(let ((pager (getenv "PAGER")))
  (defun enable-pager ()
    (setenv-local "PAGER" pager)))

;; Set PAGER to the empty string, which Git and journalctl will
;; interpret as an explicit opt-out of paging.
(setenv "PAGER" "")

;;; Eshell ;;;
(add-hook 'eshell-mode-hook #'enable-ansi-color)

;;; Ibuffer ;;;
;; Open ibuffer in other window, to match behaviour of the default
;; list-buffers.
(global-set-key (kbd "C-x C-b") (lambda () (interactive) (ibuffer t)))

;;; ispell ;;;
;; System locale is Esperanto, but I write in English much more, and
;; spelling in Esperanto is easy anyway. ;)
(setq ispell-dictionary "english")

;;; Magit ;;;
(setq magit-delete-by-moving-to-trash delete-by-moving-to-trash)
(setq magit-repository-directories
      `((,(expand-file-name "~/src") . 1)))
(global-set-key (kbd "C-x g") #'magit-status)
(global-set-key (kbd "C-x M-g") #'magit-dispatch)

(with-eval-after-load "magit"
  ;; Add a --no-gpg-sign option to Magit.  This is only useful with
  ;; commit.gpgsign=true.  It would be nice if commit.gpgsign=true just
  ;; meant that Magit showed the --gpg-sign option as enabled by
  ;; default, and disabling it would make Magit pass --no-gpg-sign to
  ;; git, but that's not currently the case, so we need a seperate
  ;; option for --no-gpg-sign.  See
  ;; <https://github.com/magit/magit/issues/3832>.
  (dolist (command '(magit-commit magit-merge magit-cherry-pick
		     magit-revert magit-am magit-rebase))
    (transient-append-suffix command ["-S"]
      '("=S" "Don't sign using gpg" "--no-gpg-sign"))))

;;; Man ;;;
;; Open man pages in the current window.  I don't really care what
;; happens when I do M-x man, but I don't want my whole frame to be
;; taken over with man buffers if I'm following a bunch of
;; cross-references.
(setq Man-notify-method 'pushy)

;;; MML ;;;
(setq mml-secure-openpgp-signers '("757356D779BBB888773E415E736CCDF9EF51BD97"))

;;; Nix support ;;;
(defun browse-url-nixpkgs (attr)
  "Open a browser to the homepage for the Nixpkgs attribute ATTR."
  (interactive "sAttribute: ")
  (let* ((full-attr-quoted (shell-quote-argument (concat attr ".meta.homepage")))
	 (command (concat "nix eval --raw -f '<nixpkgs>' " full-attr-quoted))
	 (homepage (shell-command-to-string command)))
    (browse-url homepage)))

;;; Rainbow Delimiters ;;;
(add-hook 'prog-mode-hook #'rainbow-delimiters-mode)

;;; Revert buffers ;;;
(global-set-key (kbd "C-c r") #'revert-buffer)

;;; Rust ;;;
;; Indent with spaces in Rust code.
(add-hook 'rust-mode-hook (lambda () (setq indent-tabs-mode nil)))

(with-eval-after-load 'rust-mode
  ;; Cargo keybindings
  (define-key rust-mode-map (kbd "C-c c b") 'rust-compile)
  (define-key rust-mode-map (kbd "C-c c c") 'rust-check)
  (define-key rust-mode-map (kbd "C-c c r") 'rust-run)
  (define-key rust-mode-map (kbd "C-c c t") 'rust-test))

;;; save-some-buffers ;;;
;; Allow reverting buffers directly from the "Save file ...?" message.
(add-to-list 'save-some-buffers-action-alist
  `(?r ,(lambda (buf) (with-current-buffer buf (revert-buffer t t)))
       ,(purecopy "revert this buffer")))

;;; sendmail ;;;
;; Use the system "sendmail" program to send mail.
(setq send-mail-function 'sendmail-send-it)

;;; Term ;;;
(add-hook 'term-mode-hook #'enable-pager)

;;; Transient ;;;
;; Make all Magit options available, even those that are disabled by
;; default because they're too obscure.
(setq transient-default-level 7)

;;; with-editor ;;;
(add-hook 'eshell-mode-hook 'with-editor-export-editor)
(add-hook 'shell-mode-hook 'with-editor-export-editor)
(add-hook 'term-exec-hook 'with-editor-export-editor)