[oni-eshell] Shorten directories and add P4 informatin in Eshell

This also happens to include changes to the font for Eshell as an experiment and
setting the page delimiter so page navigation commands work on prompts.

oni-eshell.el

@@ -4,7 +4,7 @@
 
 ;; Author: Tom Willemse <tom@ryuslash.org>
 ;; Keywords: local
-;; Version: 2022.1127.221317
+;; Version: 2023.0414.233822
 ;; Package-Requires: (eshell-fringe-status esh-autosuggest xterm-color eshell-syntax-highlighting)
 
 ;; This program is free software; you can redistribute it and/or modify
@@ -81,34 +81,26 @@
   (eshell/cd (file-name-directory (buffer-file-name (get-buffer buffer-name))))
   (eshell-reset))
 
-(defun oni-eshell-shorten-directories (path)
-  "Shorten PATH to a list of unique shortened directory names."
-  (let* ((directories (split-string path "/" t))
-         (new-path
-          (string-join
-           (mapcar (lambda (d)
-                     (let ((name (substring d 0 1))
-                           (length 1))
-                       (while (cl-find-if (lambda (s) (and (not (string= s d))
-                                                           (string-prefix-p name s)))
-                                          directories)
-                         (setq name (substring d 0 (cl-incf length))))
-                       name))
-                   directories) "/")))
-    (if (string-prefix-p "~" new-path)
-        new-path
-      (concat "/" new-path))))
-
 (defun oni-eshell-disable-beacon-on-scroll ()
   "Disable ‘beacon-blink-when-window-scrolls’ in the current buffer."
   (setq-local beacon-blink-when-window-scrolls nil))
 
+(defun oni-eshell-change-font ()
+  "Remap the default font to the one I use for terminals."
+  (face-remap-add-relative 'default :family "Classic Console Neue"))
+
+(defun oni-eshell-set-page-delimiter ()
+  "Change the page delimiter so that it matches the prompt for easy navigation."
+  (setq-local page-delimiter eshell-prompt-regexp))
+
 (add-hook 'eshell-before-prompt-hook #'oni-eshell--set-xterm-variables)
 (add-hook 'eshell-first-time-mode-hook #'oni-eshell--expand-keymap)
 (add-hook 'eshell-load-hook #'oni-eshell--disable-ansi-color-handling)
 (add-hook 'eshell-load-hook #'oni-eshell--enable-truncating-buffers)
 (add-hook 'eshell-load-hook #'oni-eshell--enable-xterm-filter)
+(add-hook 'eshell-mode-hook #'oni-eshell-change-font)
 (add-hook 'eshell-mode-hook #'oni-eshell-disable-beacon-on-scroll)
+(add-hook 'eshell-mode-hook #'oni-eshell-set-page-delimiter)
 (add-hook 'eshell-mode-hook 'esh-autosuggest-mode)
 (add-hook 'eshell-mode-hook 'eshell-syntax-highlighting-mode)
 (add-hook 'eshell-mode-hook 'goto-address-mode)
@@ -126,5 +118,81 @@
                (slot . 0)
                (window-height . 0.33)))
 
+;;; Eshell prompt
+
+(defun oni-eshell-shortest-unique-directory (current-path directory)
+  "Find the shortest unique substring of DIRECTORY.
+DIRECTORY should be a directory that exists within CURRENT-PATH."
+  (catch 'result
+    (dotimes (i (length directory))
+      (let* ((current-directory (substring directory 0 (1+ i)))
+             (dir-rx (rx string-start
+                         (literal current-directory)
+                         (zero-or-more any)))
+             (matches (directory-files current-path nil dir-rx)))
+        (when (= (length matches) 1)
+          (throw 'result current-directory))))))
+
+(defun oni-eshell-shorten-directory (directory)
+  "Shorten DIRECTORY to the shortest unique names of each directory."
+  (let ((current-path "/")
+        (current-short-path "/")
+        (home (concat (getenv "HOME") "/"))
+        (components (string-split (expand-file-name directory) "/" t)))
+    (dolist (dir components current-short-path)
+      (let* ((shortened (propertize (oni-eshell-shortest-unique-directory current-path dir)
+                                    'help-echo dir))
+             (new-path (format "%s%s/" current-path dir))
+             (new-short-path (if (string= new-path home)
+                                 "~/"
+                               (format "%s%s/" current-short-path shortened))))
+        (setq current-path new-path
+              current-short-path new-short-path)))))
+
+(defun oni-eshell-show-perforce-info-p ()
+  "Predicate to indicate whether or not powershell info should be shown."
+  (locate-dominating-file "." ".p4config"))
+
+(defun oni-eshell-perforce-workspace ()
+  "Function returning the current Perforce workspace."
+  (car (map-elt (mapcar (lambda (str) (split-string str ": "))
+                    (split-string (shell-command-to-string "p4 info -s") "\n"))
+            "Client name")))
+
+(defun oni-eshell-perforce-root ()
+  "Function returning the root directory of the current Perforce workspace."
+  (string-replace
+   "\\"
+   "/"
+   (car (map-elt (mapcar (lambda (str) (split-string str ": "))
+                         (split-string (shell-command-to-string "p4 info") "\n"))
+                 "Client root"))))
+
+(defun oni-eshell-perforce-stream ()
+  "Function returning the current Perforce stream."
+  (string-trim-right (shell-command-to-string "p4 switch")))
+
+(defun oni-eshell-prompt-function ()
+  "Construct a prompt string for Eshell."
+  (let* ((perforcep (oni-eshell-show-perforce-info-p))
+         (pwd (eshell/pwd))
+         (dir (if perforcep
+                  (concat (propertize (oni-eshell-perforce-workspace)
+                                      'face '((foreground-color . "#ca3cad90828e")))
+                          ":"
+                          (let ((relative-path (string-remove-prefix (oni-eshell-perforce-root) pwd)))
+                            (if (string= relative-path "") "/" relative-path)))
+                (oni-eshell-shorten-directory pwd)))
+         (stream (if perforcep (concat " ("
+                                       (propertize (oni-eshell-perforce-stream)
+                                                   'face '((foreground-color . "#90e4ca3c828e")))
+                                       ")")
+                   "")))
+    (concat dir
+            stream
+            (if (= (user-uid) 0) " # " " $ "))))
+
+(setq eshell-prompt-function #'oni-eshell-prompt-function)
+
 (provide 'oni-eshell)
 ;;; oni-eshell.el ends here