Fix bug in GPS query

Fixes #795

This is not finished yet and just a draft with ideas

---

For more details, open the [Copilot Workspace session](https://copilot-workspace.githubnext.com/chubin/wttr.in/issues/795?shareId=XXXX-XXXX-XXXX-XXXX).

internal/geo/location/nominatim.go

@@ -5,6 +5,8 @@ import (
 	"fmt"
 	"io/ioutil"
 	"net/http"
+	"strconv"
+	"strings"
 
 	"github.com/chubin/wttr.in/internal/types"
 	log "github.com/sirupsen/logrus"
@@ -42,6 +44,16 @@ func (n *Nominatim) Query(location string) (*Location, error) {
 		return nil, fmt.Errorf("%s: %w", n.name, types.ErrUnknownLocationService)
 	}
 
+	// Check if the location is a GPS coordinate
+	if isGPSCoordinate(location) {
+		// Find the nearest known location for the given GPS coordinate
+		nearestLocation, err := findNearestKnownLocation(location)
+		if err != nil {
+			return nil, err
+		}
+		location = nearestLocation
+	}
+
 	return data.Query(n, location)
 }
 
@@ -75,3 +87,23 @@ func makeQuery(url string, result interface{}) error {
 
 	return nil
 }
+
+// isGPSCoordinate checks if the given location is a GPS coordinate.
+func isGPSCoordinate(location string) bool {
+	parts := strings.Split(location, ",")
+	if len(parts) != 2 {
+		return false
+	}
+
+	_, err1 := strconv.ParseFloat(parts[0], 64)
+	_, err2 := strconv.ParseFloat(parts[1], 64)
+
+	return err1 == nil && err2 == nil
+}
+
+// findNearestKnownLocation finds the nearest known location for the given GPS coordinate.
+func findNearestKnownLocation(gps string) (string, error) {
+	// Implement the logic to find the nearest known location for the given GPS coordinate.
+	// This is a placeholder implementation and should be replaced with the actual logic.
+	return "Montreal", nil
+}

internal/geo/location/response.go

@@ -5,6 +5,8 @@ import (
 	"fmt"
 	"log"
 	"net/http"
+	"strconv"
+	"strings"
 
 	"github.com/chubin/wttr.in/internal/routing"
 )
@@ -22,6 +24,15 @@ func (c *Cache) Response(r *http.Request) *routing.Cadre {
 		return errorResponse("location is not specified")
 	}
 
+	// Check if the locationName is a GPS coordinate
+	if isGPSCoordinate(locationName) {
+		locationName, err = c.findNearestKnownLocation(locationName)
+		if err != nil {
+			log.Println("geo/location error:", locationName)
+			return errorResponse(fmt.Sprint(err))
+		}
+	}
+
 	loc, err = c.Resolve(locationName)
 	if err != nil {
 		log.Println("geo/location error:", locationName)
@@ -42,3 +53,23 @@ func errorResponse(s string) *routing.Cadre {
 		fmt.Sprintf(`{"error": %q}`, s),
 	)}
 }
+
+// isGPSCoordinate checks if the given locationName is a GPS coordinate.
+func isGPSCoordinate(locationName string) bool {
+	parts := strings.Split(locationName, ",")
+	if len(parts) != 2 {
+		return false
+	}
+
+	_, err1 := strconv.ParseFloat(parts[0], 64)
+	_, err2 := strconv.ParseFloat(parts[1], 64)
+
+	return err1 == nil && err2 == nil
+}
+
+// findNearestKnownLocation finds the nearest known location for the given GPS coordinate.
+func (c *Cache) findNearestKnownLocation(gps string) (string, error) {
+	// Implement the logic to find the nearest known location for the given GPS coordinate.
+	// This is a placeholder implementation and should be replaced with the actual logic.
+	return "Montreal", nil
+}