feat: add current-location detection to the weather picker

Geolocation used to live in a separate command, so getting weather for where you are meant knowing a second command existed. I added a "Current location (detect)" entry pinned to the top of the M-x wttrin picker. Selecting it detects your location and shows its weather. If the guess is wrong (VPN, hotspot) the detected city is visible in the header, so you reopen the picker and type one. Press d to keep the detected city as the default.

The entry is pinned first through a completion table whose display-sort-function holds against completion frameworks that re-sort, and it never enters location history or the cache as a place.

A new wttrin-geolocation-enabled (default t) turns every geolocation surface off for users who want that: the picker entry, the auto-detect favorite, and the command. It stays on by default.

The older wttrin-set-location-from-geolocation command is now obsolete in favor of the picker. Its customize-save-variable persistence advice is replaced by savehist, which already carries the favorite across sessions.

1 files changed, 118 insertions, 32 deletions

diff --git a/wttrin.el b/wttrin.el
index 89db893..d628932 100644
--- a/wttrin.el
+++ b/wttrin.el
@@ -168,6 +168,16 @@ When cache reaches `wttrin-cache-max-entries', remove the oldest 20%
 to avoid frequent cleanup cycles.  This value (0.20) means remove 1/5
 of entries, providing a reasonable buffer before the next cleanup.")
 
+(defcustom wttrin-geolocation-enabled t
+  "Whether geolocation features are available.
+When non-nil (the default), the \"Current location (detect)\" entry is
+offered in the picker, the `wttrin-favorite-location' = t auto-detect
+runs, and the geolocation command works.  Set to nil to opt out: no
+geolocation surface is offered and no detection request is made.
+Geolocation is on by default; you opt out, you never have to opt in."
+  :group 'wttrin
+  :type 'boolean)
+
 (defcustom wttrin-favorite-location nil
   "Favorite location to display weather for.
 
@@ -221,7 +231,8 @@ On success the resolved string is stored in
 `wttrin--resolved-favorite-location'.  Failures (network error, parse
 error) leave the cache empty and clear the pending flag, so the next
 call retries."
-  (unless wttrin--favorite-location-pending
+  (when (and wttrin-geolocation-enabled
+             (not wttrin--favorite-location-pending))
     (setq wttrin--favorite-location-pending t)
     (require 'wttrin-geolocation)
     (wttrin-geolocation-detect
@@ -549,13 +560,20 @@ would otherwise drop the entries before they could be saved."
   (wttrin--savehist-register)
   (add-hook 'savehist-save-hook #'wttrin--savehist-register))
 
+(defconst wttrin--geolocation-sentinel "Current location (detect)"
+  "Picker candidate that triggers geolocation detection.
+Selecting it routes through `wttrin--query-selection' to a
+detect-then-query flow instead of being treated as a literal place
+name.  It is never persisted to history or the cache as a location.")
+
 (defun wttrin--add-to-location-history (location)
   "Record LOCATION as a recent successful search.
-No-op when LOCATION is nil, empty, or already a default location.  An existing
-entry is promoted to most-recent, and the list is trimmed to
-`wttrin-location-history-max'."
+No-op when LOCATION is nil, empty, the geolocation sentinel, or already a
+default location.  An existing entry is promoted to most-recent, and the list
+is trimmed to `wttrin-location-history-max'."
   (when (and location
              (not (string= location ""))
+             (not (string= location wttrin--geolocation-sentinel))
              (not (member location wttrin-default-locations)))
     (setq wttrin--location-history (delete location wttrin--location-history))
     (push location wttrin--location-history)
@@ -571,11 +589,61 @@ History already excludes defaults (see `wttrin--add-to-location-history'), and
 `wttrin--set-favorite-location' drops the favorite from history.  The favorite
 \(`wttrin-favorite-location', when a string) is prepended unless it is already a
 default, so it always appears exactly once."
-  (let ((candidates (append wttrin-default-locations wttrin--location-history)))
-    (if (and (stringp wttrin-favorite-location)
-             (not (member wttrin-favorite-location candidates)))
-        (cons wttrin-favorite-location candidates)
-      candidates)))
+  (let* ((candidates (append wttrin-default-locations wttrin--location-history))
+         (with-favorite (if (and (stringp wttrin-favorite-location)
+                                 (not (member wttrin-favorite-location candidates)))
+                            (cons wttrin-favorite-location candidates)
+                          candidates)))
+    (if wttrin-geolocation-enabled
+        (cons wttrin--geolocation-sentinel with-favorite)
+      with-favorite)))
+
+(defun wttrin--sort-completions (candidates)
+  "Return CANDIDATES with the geolocation sentinel pinned first.
+The remaining candidates keep the order `wttrin--completion-candidates'
+produced (favorite, defaults, then history).  Used as the completion
+metadata `display-sort-function' so sorting UIs (vertico, icomplete, the
+default *Completions* buffer) keep the sentinel at the top instead of
+re-sorting it into alphabetical position."
+  (if (member wttrin--geolocation-sentinel candidates)
+      (cons wttrin--geolocation-sentinel
+            (remove wttrin--geolocation-sentinel candidates))
+    candidates))
+
+(defun wttrin--completion-table (candidates)
+  "Return a completion table over CANDIDATES that pins the sentinel first.
+The table answers the `metadata' action with a `display-sort-function'
+of `wttrin--sort-completions', and otherwise completes over CANDIDATES.
+Wrapping the list this way is what keeps the sentinel first across
+completion frameworks that impose their own sort order."
+  (lambda (string predicate action)
+    (if (eq action 'metadata)
+        `(metadata (display-sort-function . ,#'wttrin--sort-completions))
+      (complete-with-action action candidates string predicate))))
+
+(defun wttrin--detect-then-query ()
+  "Detect the current location asynchronously, then query weather for it.
+No-op with a message when `wttrin-geolocation-enabled' is nil.  On detection
+failure, show an actionable message and leave the favorite untouched; the user
+can fall back to typing a city in the picker."
+  (if (not wttrin-geolocation-enabled)
+      (message "Geolocation is disabled (set wttrin-geolocation-enabled to enable it)")
+    (require 'wttrin-geolocation)
+    (message "Detecting location...")
+    (wttrin-geolocation-detect
+     (lambda (location)
+       (if location
+           (wttrin-query location)
+         (message "Could not detect location (network or provider error)"))))))
+
+(defun wttrin--query-selection (selection)
+  "Route a picker SELECTION to the right query path.
+The geolocation sentinel routes to `wttrin--detect-then-query'; any other
+SELECTION is queried literally via `wttrin-query'.  This is the single guard
+that keeps the sentinel from reaching `wttrin-query' as a place name."
+  (if (string= selection wttrin--geolocation-sentinel)
+      (wttrin--detect-then-query)
+    (wttrin-query selection)))
 
 (defun wttrin-remove-location-history (location)
   "Remove LOCATION from the search history.
@@ -597,13 +665,15 @@ Prompts with completion over the current history entries."
   "Kill current weather buffer and query NEW-LOCATION."
   (when (get-buffer "*wttr.in*")
     (kill-buffer "*wttr.in*"))
-  (wttrin-query new-location))
+  (wttrin--query-selection new-location))
 
 (defun wttrin-requery ()
   "Kill buffer and requery wttrin."
   (interactive)
   (let ((new-location (completing-read
-                       "Location Name: " (wttrin--completion-candidates) nil nil
+                       "Location Name: "
+                       (wttrin--completion-table (wttrin--completion-candidates))
+                       nil nil
                        (when (= (length wttrin-default-locations) 1)
                          (car wttrin-default-locations)))))
     (wttrin--requery-location new-location)))
@@ -812,30 +882,44 @@ This creates headroom to avoid frequent cleanups."
   "Detect your location via IP geolocation and set it as the favorite.
 Uses the provider named by `wttrin-geolocation-provider' to fetch
 \"City, Region\", asks for confirmation, and on yes assigns the
-result to `wttrin-favorite-location' for this session.
+result to `wttrin-favorite-location'.
 
-To persist the setting across Emacs sessions, either run
-\\[customize-save-variable] on `wttrin-favorite-location', or add
-\(setq wttrin-favorite-location ...\) to your init file.
+With `savehist-mode' on, the favorite persists across sessions
+automatically (wttrin registers it with savehist); no
+`customize-save-variable' step is needed.
 
 IP-based geolocation can be wrong behind a VPN or a mobile hotspot.
 The confirmation prompt shows the detected location so you can
-reject inaccurate results."
+reject inaccurate results.
+
+This command is obsolete.  Prefer the \"Current location (detect)\"
+entry in \\[wttrin], then press `d' in the weather buffer to keep
+the detected city as your default."
   (interactive)
-  (require 'wttrin-geolocation)
-  (message "Detecting location...")
-  (wttrin-geolocation-detect
-   (lambda (location)
-     (cond
-      ((null location)
-       (message "Could not detect location (network or provider error)"))
-      ((yes-or-no-p (format "Detected location: %s. Set as favorite? "
-                            location))
-       (setq wttrin-favorite-location location)
-       (message "Set wttrin-favorite-location to: %s. Run M-x customize-save-variable to persist."
-                location))
-      (t
-       (message "Location detection cancelled"))))))
+  (if (not wttrin-geolocation-enabled)
+      (message "Geolocation is disabled (set wttrin-geolocation-enabled to enable it)")
+    (require 'wttrin-geolocation)
+    (message "Detecting location...")
+    (wttrin-geolocation-detect
+     (lambda (location)
+       (cond
+        ((null location)
+         (message "Could not detect location (network or provider error)"))
+        ((yes-or-no-p (format "Detected location: %s. Set as favorite? "
+                              location))
+         (setq wttrin-favorite-location location)
+         (message "Set wttrin-favorite-location to: %s%s"
+                  location
+                  (if (bound-and-true-p savehist-mode)
+                      " (persisted via savehist)."
+                    ". Enable savehist-mode to persist it across sessions.")))
+        (t
+         (message "Location detection cancelled")))))))
+
+(make-obsolete
+ 'wttrin-set-location-from-geolocation
+ "use the \"Current location (detect)\" entry in `wttrin', then press `d' to keep it as the default."
+ "0.4.0")
 
 (defvar-local wttrin--current-location nil
   "Current location displayed in this weather buffer.")
@@ -1158,10 +1242,12 @@ When enabled, shows weather for `wttrin-favorite-location'."
 Weather data is fetched asynchronously to avoid blocking Emacs."
   (interactive
    (list
-    (completing-read "Location Name: " (wttrin--completion-candidates) nil nil
+    (completing-read "Location Name: "
+                     (wttrin--completion-table (wttrin--completion-candidates))
+                     nil nil
                      (when (= (length wttrin-default-locations) 1)
                        (car wttrin-default-locations)))))
-  (wttrin-query location))
+  (wttrin--query-selection location))
 
 (when wttrin-mode-line-auto-enable
   (wttrin-mode-line-mode 1))