feat: mode-line: show hourglass placeholder before first weather fetch

Display ⏳ with "Fetching weather..." tooltip immediately when
mode-line mode starts, so the user sees wttrin is active before
the first API response arrives.

2 files changed, 86 insertions, 0 deletions

diff --git a/tests/test-wttrin--mode-line-update-display.el b/tests/test-wttrin--mode-line-update-display.el
index 0bcb154..07ab73f 100644
--- a/tests/test-wttrin--mode-line-update-display.el
+++ b/tests/test-wttrin--mode-line-update-display.el
@@ -221,5 +221,74 @@
           (should (equal wttrin--mode-line-tooltip-data "Paris: ☀️ +61°F Clear"))))
     (test-wttrin--mode-line-update-display-teardown)))
 
+;;; --------------------------------------------------------------------------
+;;; wttrin--mode-line-set-placeholder
+;;; --------------------------------------------------------------------------
+
+;;; Normal Cases
+
+(ert-deftest test-wttrin--mode-line-set-placeholder-normal-sets-mode-line-string ()
+  "Placeholder sets wttrin-mode-line-string to non-nil."
+  (test-wttrin--mode-line-update-display-setup)
+  (unwind-protect
+      (let ((wttrin-favorite-location "Paris"))
+        (wttrin--mode-line-set-placeholder)
+        (should wttrin-mode-line-string))
+    (test-wttrin--mode-line-update-display-teardown)))
+
+(ert-deftest test-wttrin--mode-line-set-placeholder-normal-contains-hourglass ()
+  "Placeholder displays hourglass emoji."
+  (test-wttrin--mode-line-update-display-setup)
+  (unwind-protect
+      (let ((wttrin-favorite-location "Paris")
+            (wttrin-mode-line-emoji-font nil))
+        (wttrin--mode-line-set-placeholder)
+        (should (string-match-p "⏳" (substring-no-properties wttrin-mode-line-string))))
+    (test-wttrin--mode-line-update-display-teardown)))
+
+(ert-deftest test-wttrin--mode-line-set-placeholder-normal-has-fetching-tooltip ()
+  "Placeholder tooltip mentions fetching weather."
+  (test-wttrin--mode-line-update-display-setup)
+  (unwind-protect
+      (let ((wttrin-favorite-location "Paris"))
+        (wttrin--mode-line-set-placeholder)
+        (let ((tooltip (get-text-property 0 'help-echo wttrin-mode-line-string)))
+          (should (string-match-p "Fetching" tooltip))
+          (should (string-match-p "Paris" tooltip))))
+    (test-wttrin--mode-line-update-display-teardown)))
+
+(ert-deftest test-wttrin--mode-line-set-placeholder-normal-has-local-map ()
+  "Placeholder has mouse interaction keymap."
+  (test-wttrin--mode-line-update-display-setup)
+  (unwind-protect
+      (let ((wttrin-favorite-location "Paris"))
+        (wttrin--mode-line-set-placeholder)
+        (should (eq (get-text-property 0 'local-map wttrin-mode-line-string)
+                    wttrin--mode-line-map)))
+    (test-wttrin--mode-line-update-display-teardown)))
+
+(ert-deftest test-wttrin--mode-line-set-placeholder-normal-replaced-by-real-data ()
+  "Placeholder is replaced when real weather data arrives."
+  (test-wttrin--mode-line-update-display-setup)
+  (unwind-protect
+      (let ((wttrin-favorite-location "Paris")
+            (wttrin-mode-line-emoji-font nil))
+        (wttrin--mode-line-set-placeholder)
+        (should (string-match-p "⏳" (substring-no-properties wttrin-mode-line-string)))
+        (wttrin--mode-line-update-display "Paris: ☀️ +61°F Clear")
+        (should-not (string-match-p "⏳" (substring-no-properties wttrin-mode-line-string))))
+    (test-wttrin--mode-line-update-display-teardown)))
+
+;;; Boundary Cases
+
+(ert-deftest test-wttrin--mode-line-set-placeholder-boundary-does-not-set-tooltip-data ()
+  "Placeholder does not contaminate tooltip data variable."
+  (test-wttrin--mode-line-update-display-setup)
+  (unwind-protect
+      (let ((wttrin-favorite-location "Paris"))
+        (wttrin--mode-line-set-placeholder)
+        (should-not wttrin--mode-line-tooltip-data))
+    (test-wttrin--mode-line-update-display-teardown)))
+
 (provide 'test-wttrin--mode-line-update-display)
 ;;; test-wttrin--mode-line-update-display.el ends here
diff --git a/wttrin.el b/wttrin.el
index d6e9e90..5af7f44 100644
--- a/wttrin.el
+++ b/wttrin.el
@@ -573,6 +573,21 @@ Force-refresh cache and update tooltip without opening buffer."
     (let ((wttrin--force-refresh t))
       (wttrin--mode-line-fetch-weather))))
 
+(defun wttrin--mode-line-set-placeholder ()
+  "Set a placeholder icon in the mode-line while waiting for weather data."
+  (let ((icon (if wttrin-mode-line-emoji-font
+                  (propertize "⏳"
+                              'face (list :family wttrin-mode-line-emoji-font
+                                          :height 1.0))
+                "⏳")))
+    (setq wttrin-mode-line-string
+          (propertize (concat " " icon)
+                      'help-echo (format "Fetching weather for %s..."
+                                         wttrin-favorite-location)
+                      'mouse-face 'mode-line-highlight
+                      'local-map wttrin--mode-line-map)))
+  (force-mode-line-update t))
+
 (defun wttrin--mode-line-start ()
   "Start mode-line weather display and refresh timer."
   (when (featurep 'wttrin-debug)
@@ -580,6 +595,8 @@ Force-refresh cache and update tooltip without opening buffer."
                        wttrin-favorite-location
                        wttrin-mode-line-refresh-interval))
   (when wttrin-favorite-location
+    ;; Show placeholder immediately so user knows wttrin is active
+    (wttrin--mode-line-set-placeholder)
     ;; Delay initial fetch to allow network to initialize during startup
     (run-at-time wttrin-mode-line-startup-delay nil #'wttrin--mode-line-fetch-weather)
     ;; Set up refresh timer (starts after the interval from now)