[trails] Use half way waypoints

vrobbler/apps/scrobbles/importers/trail_gpx.py

@@ -27,6 +27,27 @@ def haversine(lat1, lon1, lat2, lon2):
     return R * 2 * asin(sqrt(a))
 
 
+def find_route_waypoint(points):
+    if not points:
+        return None
+    total = 0.0
+    for i in range(1, len(points)):
+        lat1, lon1 = points[i - 1][0], points[i - 1][1]
+        lat2, lon2 = points[i][0], points[i][1]
+        if lat1 is not None and lon1 is not None and lat2 is not None and lon2 is not None:
+            total += haversine(lat1, lon1, lat2, lon2)
+    halfway = total / 2.0
+    cumulative = 0.0
+    for i in range(1, len(points)):
+        lat1, lon1 = points[i - 1][0], points[i - 1][1]
+        lat2, lon2 = points[i][0], points[i][1]
+        if lat1 is not None and lon1 is not None and lat2 is not None and lon2 is not None:
+            cumulative += haversine(lat1, lon1, lat2, lon2)
+            if cumulative >= halfway:
+                return (lat2, lon2)
+    return (points[-1][0], points[-1][1])
+
+
 def compute_trail_stats(points):
     distance_m = 0.0
     elevation_gain = 0.0
@@ -221,15 +242,27 @@ def import_trail_gpx(file_path, user_id, original_filename=None):
         logger.warning(f"No timestamps in {file_path}")
         return []
 
+    route_pt = find_route_waypoint(points)
+
     geo, _ = GeoLocation.objects.get_or_create(
         lat=round(first_lat, 6),
         lon=round(first_lon, 6),
         defaults={"altitude": None},
     )
 
-    trail = Trail.find_by_trailhead(first_lat, first_lon, tolerance_m=100)
+    trail = Trail.find_by_trailhead(
+        first_lat, first_lon,
+        route_lat=route_pt[0] if route_pt else None,
+        route_lon=route_pt[1] if route_pt else None,
+        tolerance_m=100,
+    )
     if not trail:
-        trail = Trail.objects.create(title=track_name, trailhead_location=geo)
+        trail = Trail.objects.create(
+            title=track_name,
+            trailhead_location=geo,
+            route_lat=route_pt[0] if route_pt else None,
+            route_lon=route_pt[1] if route_pt else None,
+        )
 
     timestamp = first_time
     stop_timestamp = last_time