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dotfiles/Emacs/.config/emacs/elisp/eshell-prompt.el

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EmacsLisp

;;; eshell-prompt.el --- Generating a good prompt for Eshell -*- lexical-binding: t; -*-
;; Copyright (C) 2024 Aryadev Chavali
;; Author: Aryadev Chavali <aryadev@aryadevchavali.com>
;; Keywords:
;; This program is free software; you can redistribute it and/or
;; modify it under the terms of the GNU General Public License Version
;; 2 as published by the Free Software Foundation.
;; 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:
;; We provide a function ep which generates a prompt on
;; demand.
;;; Code:
(defvar ep/user-prompt " λ>"
"Prompt for user to input.")
(defvar ep/pwd-max-len 30)
(defvar ep/git-branch-max-len 5)
(defvar ep/dir-colour "deepskyblue")
(defvar ep/success-colour "green2")
(defvar ep/failure-colour "red")
(defvar ep/branch-name-colour "LightSalmon")
(defvar ep/pipe-colour "green4")
(defvar ep/ahead-colour "dodger blue")
(defvar ep/remote-colour "DarkGoldenrod")
(defun ep/make-prompt ()
(let ((git (ep/--git-status)))
(thread-last
`(("┌──" :foreground ,ep/pipe-colour)
"["
(,(ep/--user-and-remote) :foreground ,ep/remote-colour)
(,(ep/--pwd)
:foreground ,ep/dir-colour)
,(if (string= git "")
""
(concat "]─[" git))
"]"
"\n"
("└─>" :foreground ,ep/pipe-colour)
(,(if (= eshell-last-command-status 0)
ep/user-prompt
(format " [%d]%s" eshell-last-command-status ep/user-prompt))
:foreground ,(ep/--colour-on-last-command))
(" " default))
(mapconcat
#'(lambda (item)
(thread-last
(propertize (car item)
'font-lock-face (cdr item)
'front-sticky '(font-lock-face read-only)
'rear-nonsticky '(font-lock-face read-only))
(if (not (listp item))
item)))))))
(defun ep/--colour-on-last-command ()
"Returns an Emacs colour based on ESHELL-LAST-COMMAND-STATUS."
(if (zerop eshell-last-command-status)
ep/success-colour
ep/failure-colour))
(defun ep/--with-fg-colour (s colour)
"Helper which propertises a string `s' with foreground colour `colour'"
(propertize s 'font-lock-face `(:foreground ,colour)))
(defun ep/--user-and-remote ()
"If in a remote directory, return a string representing that host,
otherwise empty string."
(if (file-remote-p default-directory)
(let ((user (file-remote-p default-directory 'user))
(host (file-remote-p default-directory 'host)))
(thread-first
(if user
(format "%s@%s" user host)
host)
(concat ":")))
""))
(defun ep/--git-status ()
"Returns a completely formatted string of form
BRANCH-NAME(REMOTE-STATUS)(CHANGES)."
(let ((git-branch (ep/--git-branch-name)))
(if (null git-branch)
""
(format
"%s(%s)(%s)"
(ep/--with-fg-colour git-branch ep/branch-name-colour)
(ep/--git-remote-status)
(ep/--git-change-status)))))
(defun ep/--git-remote-status ()
"Returns a propertized string for the status of a repository
in comparison to its remote. 3 differing strings are returned
dependent on:
- Is it equivalent to the remote?
- Is it ahead of the remote?
- Is it behind the remote?
The latter 2 also have a number for exactly how many commits
behind or ahead the local repository is."
(let* ((git-cmd "git status | grep 'Your branch is'")
(branch-status (split-string (shell-command-to-string git-cmd)))
(status (nth 3 branch-status))
(diff (cl-position "by" branch-status :test #'string=)))
(if (null diff)
(ep/--with-fg-colour "=" ep/success-colour)
(concat
(cond
((string= status "ahead")
(ep/--with-fg-colour "" ep/ahead-colour))
((string= status "behind")
(ep/--with-fg-colour "" ep/failure-colour)))
(thread-first diff
1+
(nth branch-status))))))
(defun ep/--git-change-status ()
"Returns a propertized string for the condition of the worktree in
a repository.
If there are no changes i.e. the worktree is clean then a green tick is
returned.
If there are changes then we characterise it by the following parameters:
- staged changes in green
- unstaged but tracked changes in blue
- untracked files in red
"
(let* ((git-cmd "git status -s")
(command-output (thread-first
(shell-command-to-string git-cmd)
(split-string "\n")
butlast))
(status-codes (mapcar #'(lambda (s) (cons (substring s 0 1) (substring s 1 2)))
command-output))
(count-f (lambda (coll) (thread-first
(lambda (x) (not (or (string= x "?") (string= x " "))))
(cl-count-if
coll))))
(total (length status-codes))
(staged (funcall count-f (mapcar #'car status-codes)))
(modified (funcall count-f (mapcar #'cdr status-codes)))
(not-tracked (cl-count-if (lambda (x) (string= (cdr x) "?")) status-codes)))
(if (= total 0)
(ep/--with-fg-colour "" ep/success-colour)
(thread-last
(list
(ep/--with-fg-colour (number-to-string staged) ep/success-colour)
(ep/--with-fg-colour (number-to-string modified) ep/ahead-colour)
(ep/--with-fg-colour (number-to-string not-tracked) ep/failure-colour))
(cl-remove-if #'(lambda (s) (string= s "0")))
(mapconcat #'(lambda (s) (concat s "/")))))))
(defun ep/--git-branch-name ()
"Get the branch name of the current working directory.
If a deteached head, return the SHA."
(let* ((branch-name (thread-last
(split-string (shell-command-to-string "git branch") "\n")
(cl-remove-if #'(lambda (s) (thread-last (length s) (= 0))))
(cl-find-if #'(lambda (s) (thread-last (substring s 0 1) (string= "*"))))))
(branch-name (thread-last
(substring branch-name 2)
(if (null branch-name) nil))))
(if branch-name
(ep/--abbreviate-str
(cond
((string= "(" (substring branch-name 0 1))
(replace-regexp-in-string
"\n$" ""
(shell-command-to-string "git rev-parse --short HEAD")))
(t branch-name))
"-"
ep/git-branch-max-len))))
(defun ep/--pwd ()
(let ((pwd (thread-last (eshell/pwd)
tramp-file-local-name
abbreviate-file-name)))
(ep/--abbreviate-str pwd "/" ep/pwd-max-len)))
(defun ep/--abbreviate-str (to-abbrev sep max-len)
(if (<= (length to-abbrev) max-len)
to-abbrev
(let ((str "")
(len (length to-abbrev))
(components (split-string to-abbrev sep)))
(while (and (> len max-len)
(cdr components))
(let* ((comp (car components))
(ab-comp (cond
((= 0 (length comp)) "")
((= 1 (length comp)) comp)
((char-equal (elt comp 0) ?.)
(substring comp 0 3))
(t
(substring comp 0 2)))))
(setq str (concat str ab-comp sep)
len (- len (length ab-comp))
components (cdr components))))
(thread-last
components
(cl-reduce #'(lambda (a b) (concat a sep b)))
(if (null components) "")
(concat str)))))
(provide 'eshell-prompt)
;;; eshell-prompt.el ends here
;; Local Variables:
;; read-symbol-shorthands: (("ep" . "eshell-prompt"))
;; End: