fix: emoji dimming can disagree with tooltip staleness

The emoji face (dimmed/normal) was frozen at the last update-display
call, but the tooltip computes staleness dynamically. Between
refreshes, data could cross the stale threshold — tooltip says "Stale"
while the emoji is still normal.

Track the rendered staleness state. When the tooltip detects a
transition, trigger a re-render so the emoji dimming matches.

2 files changed, 36 insertions, 0 deletions

diff --git a/tests/test-wttrin--mode-line-update-display.el b/tests/test-wttrin--mode-line-update-display.el
index 81fbded..0635b5f 100644
--- a/tests/test-wttrin--mode-line-update-display.el
+++ b/tests/test-wttrin--mode-line-update-display.el
@@ -210,6 +210,32 @@
         (should-not wttrin-mode-line-string))
     (test-wttrin--mode-line-update-display-teardown)))
 
+(ert-deftest test-wttrin--mode-line-update-display-stale-emoji-dims-on-hover-transition ()
+  "When data crosses the stale threshold between refreshes, hovering should
+trigger an emoji re-render so dimming matches the tooltip's staleness state."
+  (test-wttrin--mode-line-update-display-setup)
+  (unwind-protect
+      (let ((wttrin-mode-line-refresh-interval 900)
+            (wttrin-mode-line-emoji-font nil))
+        ;; Initial render: data is fresh (age=200, threshold=1800)
+        (cl-letf (((symbol-function 'float-time) (lambda () 1200.0)))
+          (setq wttrin--mode-line-cache (cons 1000.0 "Paris: X +61°F Clear"))
+          (wttrin--mode-line-update-display)
+          ;; Emoji should NOT be dimmed
+          (let ((face (get-text-property 1 'face wttrin-mode-line-string)))
+            (should-not (and face (equal (plist-get face :foreground) "gray60")))))
+
+        ;; Time passes: data is now stale (age=2001, threshold=1800)
+        ;; Invoke the tooltip (simulating a hover) — this should trigger a re-render
+        (cl-letf (((symbol-function 'float-time) (lambda () 3001.0)))
+          (let ((help-echo-fn (get-text-property 0 'help-echo wttrin-mode-line-string)))
+            (funcall help-echo-fn nil nil nil))
+          ;; After hover detected staleness transition, emoji should now be dimmed
+          (let ((face (get-text-property 1 'face wttrin-mode-line-string)))
+            (should face)
+            (should (equal (plist-get face :foreground) "gray60")))))
+    (test-wttrin--mode-line-update-display-teardown)))
+
 ;;; --------------------------------------------------------------------------
 ;;; wttrin--mode-line-fetch-weather
 ;;; --------------------------------------------------------------------------
diff --git a/wttrin.el b/wttrin.el
index c2cb74d..e584d3c 100644
--- a/wttrin.el
+++ b/wttrin.el
@@ -200,6 +200,9 @@ Set this to t BEFORE loading wttrin, typically in your init file:
 When non-nil, car is the `float-time' when data was fetched,
 and cdr is the weather string from the API.")
 
+(defvar wttrin--mode-line-rendered-stale nil
+  "Whether the mode-line emoji is currently rendered as stale (dimmed).")
+
 (defvar wttrin--mode-line-map
   (let ((map (make-sparse-keymap)))
     (define-key map [mode-line mouse-1] 'wttrin-mode-line-click)
@@ -594,6 +597,8 @@ On failure with no cache, shows error placeholder."
 (defun wttrin--mode-line-tooltip (&optional _window _object _pos)
   "Compute tooltip text from `wttrin--mode-line-cache'.
 Calculates age at call time so the tooltip is always current.
+If staleness has changed since the last render, triggers a re-render
+so the emoji dimming matches.
 Optional arguments are ignored (required by `help-echo' function protocol)."
   (when wttrin--mode-line-cache
     (let* ((timestamp (car wttrin--mode-line-cache))
@@ -601,6 +606,9 @@ Optional arguments are ignored (required by `help-echo' function protocol)."
            (age (- (float-time) timestamp))
            (stale-p (> age (* 2 wttrin-mode-line-refresh-interval)))
            (age-str (wttrin--format-age age)))
+      ;; Re-render emoji if staleness state has changed
+      (unless (eq stale-p wttrin--mode-line-rendered-stale)
+        (wttrin--mode-line-update-display))
       (if stale-p
           (format "%s\nStale: updated %s — fetch failed, will retry"
                   weather-string age-str)
@@ -623,6 +631,7 @@ shows staleness info in tooltip."
                      "?")))
         (wttrin--debug-log "mode-line-display: Extracted emoji = %S, stale = %s"
                            emoji stale-p)
+        (setq wttrin--mode-line-rendered-stale stale-p)
         (setq wttrin-mode-line-string
               (propertize (concat " " (wttrin--make-emoji-icon emoji (when stale-p "gray60")))
                           'help-echo #'wttrin--mode-line-tooltip
@@ -708,6 +717,7 @@ opens the weather buffer."
     (setq wttrin--buffer-refresh-timer nil))
   (setq wttrin-mode-line-string nil)
   (setq wttrin--mode-line-cache nil)
+  (setq wttrin--mode-line-rendered-stale nil)
   (force-mode-line-update t))
 
 ;;;###autoload