Fix proximity distance calculation

The distance is now calculated to the edge of the zone instead of the centre

Author: Spcemarine

homeassistant/components/proximity/coordinator.py

@@ -164,16 +164,21 @@ def _calc_distance_to_zone(
             )
             return None
 
-        distance_to_zone = distance(
+        distance_to_centre = distance(
             zone.attributes[ATTR_LATITUDE],
             zone.attributes[ATTR_LONGITUDE],
             latitude,
             longitude,
         )
 
         # it is ensured, that distance can't be None, since zones must have lat/lon coordinates
-        assert distance_to_zone is not None
-        return round(distance_to_zone)
+        assert distance_to_centre is not None
+
+        zone_radius: float = zone.attributes["radius"]
+        distance_to_edge: int = round(distance_to_centre - zone_radius)
+        # return 0 if distance to edge is negative as that means the device is located inside the zone
+        # but the device's current zone is a different one than the zone in this distance calculation
+        return max(distance_to_edge, 0)
 
     def _calc_direction_of_travel(
         self,