feat: add external-command geolocation, opt-out, and example adapters

These build on the current-location picker with the rest of the geolocation work.

wttrin-geolocation-command runs a command that prints {lat,lng} (and optionally an address) and queries wttr.in by those coordinates. IP geolocation only finds the network's exit point, which is wrong on a VPN or hotspot. A command that scans nearby WiFi resolves to street level. It runs asynchronously, falls back to the IP provider when unset or failing, and assumes nothing about the OS, so it's inert until set. When the command returns an address, wttrin shows it on a "Location:" line, so the resolved place is readable even though the fetch is by raw coordinates.

wttrin-use-current-location is a labeled command that sets the favorite to auto-detect, so the bare t value never has to be typed into init by hand.

wttrin-geolocation-enabled (default t) turns every geolocation surface off for anyone who wants that: the picker entry, the auto-detect favorite, and the command.

examples/geolocation/ ships two reference adapters for the command: google-geolocate.py (Google API, key via the environment or ~/.authinfo.gpg) and apple-wps.py (Apple's keyless WiFi positioning, which uses an undocumented endpoint, so read its caveat). Both are Python 3 standard library and scan via nmcli, with notes on adapting the scan to other systems.

1 files changed, 47 insertions, 8 deletions

diff --git a/wttrin.el b/wttrin.el
index d628932..da2881b 100644
--- a/wttrin.el
+++ b/wttrin.el
@@ -236,7 +236,7 @@ call retries."
     (setq wttrin--favorite-location-pending t)
     (require 'wttrin-geolocation)
     (wttrin-geolocation-detect
-     (lambda (location)
+     (lambda (location &optional _address)
        (setq wttrin--favorite-location-pending nil)
        (when location
          (setq wttrin--resolved-favorite-location location)
@@ -631,9 +631,9 @@ can fall back to typing a city in the picker."
     (require 'wttrin-geolocation)
     (message "Detecting location...")
     (wttrin-geolocation-detect
-     (lambda (location)
+     (lambda (location &optional address)
        (if location
-           (wttrin-query location)
+           (wttrin-query location address)
          (message "Could not detect location (network or provider error)"))))))
 
 (defun wttrin--query-selection (selection)
@@ -765,10 +765,20 @@ Looks up the cache timestamp for LOCATION and formats a line like
         (propertize (format "Last updated: %s (%s)" (string-trim time-str) age-str)
                     'face 'wttrin-staleness-header)))))
 
-(defun wttrin--display-weather (location-name raw-string &optional error-msg)
+(defun wttrin--format-location-line (address)
+  "Return a propertized \"Location: ADDRESS\" line, or nil when ADDRESS is empty.
+Shown in the weather buffer when a geolocation command supplied a human-readable
+place name alongside its coordinates, so the resolved location is recognizable
+even though the weather was fetched by raw coordinates."
+  (when (and (stringp address) (> (length address) 0))
+    (propertize (concat "Location: " address) 'face 'wttrin-staleness-header)))
+
+(defun wttrin--display-weather (location-name raw-string &optional error-msg address)
   "Display weather data RAW-STRING for LOCATION-NAME in weather buffer.
 When ERROR-MSG is provided and data is invalid, show that instead of
-the generic error message."
+the generic error message.  When ADDRESS is non-empty, show it on a
+\"Location:\" line below the weather (used by the geolocation command path,
+which fetches by coordinates but can name the place)."
   (when wttrin-debug
     (wttrin--save-debug-data location-name raw-string))
 
@@ -795,6 +805,9 @@ the generic error message."
         (goto-char (point-min))
         (when (re-search-forward "^Weather report: .*$" nil t)
           (replace-match (concat "Weather report: " location-name)))
+        (let ((location-line (wttrin--format-location-line address)))
+          (when location-line
+            (insert "\n" location-line)))
         (let ((staleness (wttrin--format-staleness-header location-name)))
           (when staleness
             (insert "\n" staleness)))
@@ -804,8 +817,11 @@ the generic error message."
       (setq-local wttrin--current-location location-name)
       (wttrin--debug-mode-line-info))))
 
-(defun wttrin-query (location-name)
-  "Asynchronously query weather of LOCATION-NAME, display result when ready."
+(defun wttrin-query (location-name &optional address)
+  "Asynchronously query weather of LOCATION-NAME, display result when ready.
+LOCATION-NAME is what weather is fetched by (and the cache key).  Optional
+ADDRESS is a human-readable place name shown on a \"Location:\" line, used when
+LOCATION-NAME is raw coordinates from a geolocation command."
   (let ((buffer (get-buffer-create (format "*wttr.in*"))))
     (switch-to-buffer buffer)
     (setq buffer-read-only nil)
@@ -817,7 +833,7 @@ the generic error message."
      (lambda (raw-string &optional error-msg)
        (when (buffer-live-p buffer)
          (with-current-buffer buffer
-           (wttrin--display-weather location-name raw-string error-msg)))))))
+           (wttrin--display-weather location-name raw-string error-msg address)))))))
 
 (defun wttrin--make-cache-key (location)
   "Create cache key from LOCATION and current settings."
@@ -921,6 +937,29 @@ the detected city as your default."
  "use the \"Current location (detect)\" entry in `wttrin', then press `d' to keep it as the default."
  "0.4.0")
 
+;;;###autoload
+(defun wttrin-use-current-location ()
+  "Make your current location the persistent favorite (always auto-detect).
+Sets `wttrin-favorite-location' to t after confirmation, so the mode-line
+and buffer track wherever you are via geolocation rather than a fixed city.
+This is the labeled way to choose auto-detect without typing the bare symbol
+t into your init.
+
+With `savehist-mode' on, the choice persists across sessions automatically.
+Does nothing when `wttrin-geolocation-enabled' is nil."
+  (interactive)
+  (cond
+   ((not wttrin-geolocation-enabled)
+    (message "Geolocation is disabled (set wttrin-geolocation-enabled to enable it)"))
+   ((yes-or-no-p "Always use your current location (auto-detect via geolocation)? ")
+    (setq wttrin-favorite-location t)
+    (message "Favorite location set to auto-detect%s"
+             (if (bound-and-true-p savehist-mode)
+                 " (persisted via savehist)."
+               ". Enable savehist-mode to persist it across sessions.")))
+   (t
+    (message "Cancelled"))))
+
 (defvar-local wttrin--current-location nil
   "Current location displayed in this weather buffer.")