;;; Eshell

;;; Eshell gets initialized differently.  When eshell.el first gets loaded, only
;;; the core is defined and `eshell-load-hook' is called. For every Eshell
;;; session, `eshell-mode' is run: it resets `eshell-mode-map', it loads
;;; modules, runs their hooks and concludes with `eshell-first-time-mode-hook'
;;; (for the first session only) and `eshell-mode-hook'.

;; Emacs pinentry for GPG.
(require 'main)

;;; REVIEW: If history contains read-only text (e.g. accidental insertion of the prompt),
;;; `eshell-write-history' won't work.
;;; See #29153.

;;; REVIEW: Sometimes transmission-daemon does not start from Eshell.
;;; See #30465.

;;; REVIEW: Redirecting big output to file (e.g. /dev/null) is extremely slow.
;; > cat /usr/share/dict/british-english | wc -l
;;; The above line yields rancom results.  Plus it's much slower than
;; > wc -l /usr/share/dict/british-english
;;; while it should only cost an additional process to launch.
;;; See #29154.

;;; REVIEW: Cannot "C-c C-c" during a `sudo pacman -Syu`.  A bug was filed about that already.

;;; TODO: The buffer stutters when writing "in-place", e.g. pacman, git.
;;; It seems that it does not do it as much in `emacs -Q`.

;;; REVIEW: `eshell/sudo' should not read -u in command arguments.
;;; This fails: sudo pacman -Syu --noconfirm.
;;; http://www.gnu.org/software/emacs/manual/html_node/eshell/Built_002dins.html
;;; https://emacs.stackexchange.com/questions/5608/how-to-let-eshell-remember-sudo-password-for-two-minutes
;;; See http://debbugs.gnu.org/cgi/bugreport.cgi?bug=27411
;;; and #28323.

;;; REVIEW: Eshell/Shell completion fails when PATH has a non-readable element.
;;; See https://github.com/emacs-helm/helm/issues/1785
;;; and https://debbugs.gnu.org/cgi/bugreport.cgi?bug=27300.

;;; REVIEW: 40M+ output: Stack overflow in regexp matcher
;;; See bug#28329.
;;; I guess the chunking is significant too.  Could you try saving
;;; the output chunks, with this:
;;
;; (defvar eshell-chunk-number 0)
;; (defconst eshell-output-chunk-dir "eshell-output")
;; (make-directory eshell-output-chunk-dir t)
;;
;; (defun catch-eshell-output-chunk ()
;;   (write-region eshell-last-output-block-begin
;;                 eshell-last-output-end
;;                 (format "%s/chunk.%d"
;;                         eshell-output-chunk-dir
;;                         eshell-chunk-number)
;;                 nil :quiet)
;;   (setq eshell-chunk-number (1+ eshell-chunk-number)))
;;
;; (add-hook 'eshell-output-filter-functions
;;           'catch-eshell-output-chunk)
;;;
;;; And then afterwards 'cat eshell-output/chunk.*' should hopefully
;;; reproduce it?


;;; REVIEW: Eshell mixes stderr and stdout it seems.
;;; Example:
;;; $ mu find --nocolor --sortfield=d --maxnum=500 flag:unread AND NOT flag:trashed >/dev/null
;;; mu: no matches for search expression (4)
;;; See #21605 "24.3; Eshell not using stderr".

;;; REVIEW: eshell/date does not support many options from GNU date.
;;; > date +%Z
;;; See #29157.
(require 'patch-eshell)

;;; TODO: Change face of eshell/* commands in commandline to avoid confusion
;;; with system programs.

;;; TODO: Merge/re-use documentation of eshell/* commands with their docstring.

;;; TODO: Hour is printed twice. We don't need to set this?
;; (setq eshell-ls-date-format (replace-regexp-in-string "^\\+*" "" (getenv "TIME_STYLE")))

;;; TODO: ls: Sort using locale.

;;; REVIEW: `kill -#' does not work.
;;; See #29156.

;;; Use TRAMP to use Eshell as root.
(require 'em-tramp)
(setq password-cache t)
(setq password-cache-expiry 3600)

(with-eval-after-load 'esh-module
  ;; REVIEW: It used to work, but now the early `provide' seems to backfire.
  (unless (boundp 'eshell-modules-list)
    (load "esh-module"))
  ;; Don't print the banner.
  (delq 'eshell-banner eshell-modules-list)
  (push 'eshell-tramp eshell-modules-list))

(setq
 eshell-ls-use-colors t
 ;; ffap-shell-prompt-regexp changes the behaviour of `helm-find-files' when
 ;; point is on prompt. I find this disturbing.
 ffap-shell-prompt-regexp nil
 eshell-history-size 1024
 eshell-hist-ignoredups t
 eshell-destroy-buffer-when-process-dies t)

(with-eval-after-load 'em-term
  (dolist (p '("alsamixer" "gtypist" "htop" "mpsyt" "mpv" "watch"))
    (add-to-list 'eshell-visual-commands p))
  (setq eshell-visual-subcommands
        ;; Some Git commands use a pager by default.
        ;; Either invoke the subcommands in a term ("visual") or configure Git
        ;; to disable the pager globally.
        ;; '(("git" "log" "diff" "show")
        '(("sudo" "vi" "visudo"))))

;;; Alias management possibilities:
;;; - Version eshell-alias and store it in user-emacs-directory. Simplest and
;;; fastest, but aliases cannot be included conditionnaly, e.g. depending on the
;;; existence of a program.
;;; - Store eshell-alias in cache and populate it dynamically on startup.
;; (setq eshell-aliases-file (concat user-emacs-directory "eshell-alias"))
;;;
;;; `eshell/alias' is too slow as it reads and write the file on each definition.
;;; Let's write manually instead.
(with-eval-after-load 'em-alias
  ;;; If we read the alias list here, it means we make commandline-defined aliases persistent.
  ;; (eshell-read-aliases-list)
  (dolist
      (alias
       '(("l" "ls -1 $*")
         ("la" "ls -lAh $*")
         ("ll" "ls -lh $*")
         ;; TODO: Aliasing eshell/{cp,mv,ln} does not work.
         ;; REVIEW: Eshell/TRAMP's sudo does not work with aliases.
         ;; See #28320, #27168.
         ;; ("ls" "ls -F $*") ; not supported
         ;; ("emacs" "find-file $1")
         ;; ("cp" "eshell/cp -iv $*")
         ;; ("mv" "eshell/mv -iv $*")
         ("cpv" "cp -iv $*")
         ("mvv" "mv -iv $*")
         ("rmv" "rm -v $*")
         ("md" "eshell/mkdir -p $*")
         ("mkcd" "eshell/mkdir -p $* ; cd $1"))) ; TODO: '&&' does not work because mkdir exits with nil?
    (add-to-list 'eshell-command-aliases-list alias))
  (eshell-write-aliases-list))

;;; Hooks
;;; `nobreak-char-display' makes some output look weird, e.g. with 'tree'.
(add-hook 'eshell-mode-hook 'ambrevar/turn-off-nobreak-char-display)

;;; History
;;; REVIEW: history: do not save failed Eshell commands (See `eshell-last-command-status')
;;; Eshell commands always return 0.
(setq eshell-input-filter
      (lambda (str)
        (not (or
              ;; Here we can filter out failing commands.  This is usually a bad
              ;; idea since a lot of useful commands have non-zero exit codes
              ;; (including Emacs/Eshell functions).
              ;; (/= eshell-last-command-status 0)
              (string= "" str)
              (string= "cd" str)
              (string-prefix-p "cd " str)
              ;; Filter out space-beginning commands from history.
              (string-prefix-p " " str)))))

;;; Shared history.
(defvar ambrevar/eshell-history-global-ring nil
  "The history ring shared across Eshell sessions.")

(defun ambrevar/eshell-hist-use-global-history ()
  "Make Eshell history shared across different sessions."
  (unless ambrevar/eshell-history-global-ring
    (when eshell-history-file-name
      (eshell-read-history nil t))
    (setq ambrevar/eshell-history-global-ring (or eshell-history-ring (make-ring eshell-history-size))))
  (setq eshell-history-ring ambrevar/eshell-history-global-ring))
(add-hook 'eshell-mode-hook 'ambrevar/eshell-hist-use-global-history)

(defun ambrevar/eshell-history-remove-duplicates ()
  (require 'functions) ; For `ambrevar/ring-delete-first-item-duplicates'.
  (ambrevar/ring-delete-first-item-duplicates eshell-history-ring))
(add-hook 'eshell-pre-command-hook 'ambrevar/eshell-history-remove-duplicates)

;; Always save history
(add-hook 'eshell-pre-command-hook 'eshell-save-some-history)

;;; Version and encrypt history.
;; TODO: The following makes EPA always prompt for recipients for some reason.  Bug?
;; (make-directory "~/projects/personal/history/" :parents)
;; (setq eshell-history-file-name (expand-file-name "eshell.gpg" "~/projects/personal/history"))
;; (defun ambrevar/fix-local-epa-file-encrypt-to ()
;;   (unless (local-variable-p 'epa-file-encrypt-to (current-buffer))
;;     (make-local-variable 'epa-file-encrypt-to))
;;   (setq epa-file-encrypt-to "mail@ambrevar.xyz"))
;; (add-hook 'eshell-mode-hook 'ambrevar/fix-local-epa-file-encrypt-to)

(when (require 'helm nil :noerror)
  (defun ambrevar/helm/eshell-set-keys ()
    (define-key eshell-mode-map [remap eshell-pcomplete] 'helm-esh-pcomplete)
    (define-key eshell-mode-map (kbd "M-p") 'helm-eshell-history)
    (define-key eshell-mode-map (kbd "M-s") nil) ; Useless when we have 'helm-eshell-history.
    (define-key eshell-mode-map (kbd "M-s f") 'helm-eshell-prompts-all))
  (add-hook 'eshell-mode-hook 'ambrevar/helm/eshell-set-keys))

;;; Auto-suggestion
(when (require 'esh-autosuggest nil t)
  (setq esh-autosuggest-delay 0.75)
  (add-hook 'eshell-mode-hook 'esh-autosuggest-mode)
  (define-key esh-autosuggest-active-map (kbd "<tab>") 'company-complete-selection)
  (when (require 'helm-config nil t)
    ;; TODO: Why is this in esh-autosuggest?  Move to toplevel.
    (define-key company-active-map (kbd "M-p") 'helm-eshell-history)))

;;; Detach
(when (require 'package-eshell-detach nil t)
  (defun ambrevar/eshell-detach-set-keys ()
    (define-key eshell-mode-map (kbd "C-c C-z") 'eshell-detach-stop)
    (define-key eshell-mode-map (kbd "S-<return>") 'eshell-detach-send-input)
    (define-key eshell-mode-map (kbd "C-<return>") 'eshell-detach-attach))
  (add-hook 'eshell-mode-hook 'ambrevar/eshell-detach-set-keys))

;; Man
(when (string= (file-symlink-p (executable-find "man")) "mandoc")
  ;; Some systems like Void Linux use mandoc instead of man and do not know the
  ;; --nj, --nh flags.
  (defun ambrevar/pcmpl-args-mandoc-man-function (name)
    (let ((process-environment process-environment))
      ;; Setting MANWIDTH to a high number makes most paragraphs fit on a single
      ;; line, reducing the number of false positives that result from lines
      ;; starting with `-' that aren't really options.
      (push "MANWIDTH=10000" process-environment)
      (pcmpl-args-process-file "man" "--" name)))
  (setq pcmpl-args-man-function 'ambrevar/pcmpl-args-mandoc-man-function))

;; Completion
(when (require 'bash-completion nil t)
  (when (and (or (executable-find "fish")
                 ;; "fish" needs not be in PATH with guix.
                 (executable-find "guix"))
             (require 'fish-completion nil t))
    (setq fish-completion-fallback-on-bash-p t)
    (global-fish-completion-mode)))

;; Misc.
(defun ambrevar/eshell-append-region-to-command-line (begin end)
  (interactive "r")
  (require 'subr-x)                     ; For `string-trim'.
  (save-mark-and-excursion
    (let ((string (buffer-substring-no-properties begin end)))
      (setq string (string-trim string))
      (setq string (concat string " "))
      (goto-char (point-max))
      (ignore-errors (cycle-spacing 0))
      (insert string))))

;; TODO: Fix eshell-did-you-mean.
;; (when (require 'eshell-did-you-mean nil 'noerror)
;;   (eshell-did-you-mean-setup))

(when (require 'eshell-prompt-extras nil 'noerror)
  ;; Leave `eshell-highlight-prompt' to t as it sets the read-only property.
  (setq epe-path-style 'full)
  (setq eshell-prompt-function #'epe-theme-multiline-with-status))

(when (require 'helm-fish-completion nil 'noerror)
  (define-key shell-mode-map (kbd "<tab>") 'helm-fish-completion)
  (setq helm-esh-pcomplete-build-source-fn #'helm-fish-completion-make-eshell-source))

(require 'patch-eshell-inside-emacs)    ; Still required as of Emacs 27.1.

(defun ambrevar/eshell-narrow-to-prompt ()
  "Narrow buffer to prompt at point."
  (interactive)

  (narrow-to-region
   (save-excursion
     (forward-line)
     (call-interactively #'eshell-previous-prompt)
     (beginning-of-line)
     (point))
   (save-excursion
     (forward-line)
     (call-interactively #'eshell-next-prompt)
     (re-search-backward eshell-prompt-regexp nil t)
     (when (and (require 'eshell-prompt-extras nil 'noerror)
              (eq eshell-prompt-function #'epe-theme-multiline-with-status))
       (previous-line))
     (point))))

(defun ambrevar/eshell-set-keys ()
  (define-key eshell-mode-map (kbd "C-x n d") 'ambrevar/eshell-narrow-to-prompt))
(add-hook 'eshell-mode-hook 'ambrevar/eshell-set-keys)

(provide 'init-eshell)