Add configurable extension status faces (#210)

* Add extension status faces

* Make extension status faces discoverable

Extension status face customization is keyed by the statusKey that an extension sends, not necessarily by the extension package name.  Say that in the user option and README so users do not have to guess.\n\nPut the status key on header-line status text as local help, and give that text a mouse highlight so the hover target is visible.  Tighten the Customize type to accept face symbols or face attribute plists.\n\nTest the full header-line path with a pi-sub-shaped key.

---------

Co-authored-by: Daniel Nouri <daniel.nouri@gmail.com>

Author: bobrowadam

README.org

@@ -259,7 +259,8 @@ Several features match the TUI experience:
 pi-coding-agent has basic support for pi extensions.  Extension commands
 show up in slash completion and the transient menu, extension tools run
 normally, and extensions can use notifications, confirm/select/input
-prompts, prefill the input buffer, and show status text.
+prompts, prefill the input buffer, and show status text.  Hover status text
+to see the exact =statusKey= used for =pi-coding-agent-extension-status-faces=.
 
 Rich TUI-specific extension UI is not supported in Emacs yet: custom
 widgets, custom editor components, custom headers/footers, and other

pi-coding-agent-ui.el

@@ -172,6 +172,23 @@ When nil (the default), only the visible text is copied."
   :type 'boolean
   :group 'pi-coding-agent)
 
+(defcustom pi-coding-agent-extension-status-faces nil
+  "Alist mapping extension status keys to faces in the header line.
+Keys are exact `statusKey' strings sent by extension `setStatus' requests,
+not necessarily extension package names.  Hovering header status text shows
+the key to use here.  Values are face symbols or face attribute plists
+accepted by `propertize'.
+
+For example:
+  \='((\"sub-status:usage\" . (:foreground \"#c6a0f6\"))
+    (\"solveit-mode\" . warning))"
+  :type '(alist :key-type string
+                :value-type (choice (face :tag "Face")
+                                     (plist :tag "Face attributes"
+                                            :key-type symbol
+                                            :value-type sexp)))
+  :group 'pi-coding-agent)
+
 (defcustom pi-coding-agent-quit-without-confirmation nil
   "Whether `pi-coding-agent-quit' skips confirmation for a live process.
 When non-nil, quitting a session never asks whether a running pi process
@@ -1775,7 +1792,17 @@ Returns extension statuses joined with \" · \", or empty string."
   (if (null ext-status)
       ""
     (mapconcat (lambda (pair)
-                 (pi-coding-agent--header-escape-text (cdr pair)))
+                 (let* ((key (car pair))
+                        (text (pi-coding-agent--header-escape-text (cdr pair)))
+                        (face (cdr (assoc key pi-coding-agent-extension-status-faces)))
+                        (properties (and (stringp key)
+                                         (list 'help-echo key
+                                               'mouse-face 'highlight))))
+                   (when face
+                     (setq properties (append properties (list 'face face))))
+                   (if properties
+                       (apply #'propertize text properties)
+                     text)))
                ext-status
                " · ")))
 

test/pi-coding-agent-ui-test.el

@@ -692,6 +692,35 @@ Buffer is read-only with `inhibit-read-only' used for insertion.
   "Hot-tail turn count defaults to 3 headed turns."
   (should (= 3 pi-coding-agent-hot-tail-turn-count)))
 
+(ert-deftest pi-coding-agent-test-extension-status-properties-apply-in-header-line ()
+  "Extension status properties are applied by status key in the header line."
+  (let ((pi-coding-agent-extension-status-faces
+         '(("sub-status:usage" . (:foreground "#c6a0f6")))))
+    (with-temp-buffer
+      (pi-coding-agent-chat-mode)
+      (setq pi-coding-agent--state '(:model "claude-sonnet-4")
+            pi-coding-agent--extension-status
+            '(("solveit-mode" . "⚡ concise")
+              ("sub-status:usage" . "4h51m 1% · 9h9m 41%")))
+      (let ((header (pi-coding-agent--header-line-string)))
+        (should (string-match-p "⚡ concise · 4h51m 1%% · 9h9m 41%%"
+                                (substring-no-properties header)))
+        (should-not (get-text-property (string-match-p "⚡" header) 'face header))
+        (should (equal (get-text-property (string-match-p "⚡" header)
+                                          'help-echo header)
+                       "solveit-mode"))
+        (should (eq (get-text-property (string-match-p "⚡" header)
+                                       'mouse-face header)
+                    'highlight))
+        (should (equal (get-text-property (string-match-p "4h" header) 'face header)
+                       '(:foreground "#c6a0f6")))
+        (should (equal (get-text-property (string-match-p "4h" header)
+                                          'help-echo header)
+                       "sub-status:usage"))
+        (should (eq (get-text-property (string-match-p "4h" header)
+                                       'mouse-face header)
+                    'highlight))))))
+
 (ert-deftest pi-coding-agent-test-kill-ring-save-strips-by-default ()
   "kill-ring-save strips hidden markup by default."
   (pi-coding-agent-test--with-chat-markup "Hello **bold** world"