From 85f216b86954bfcca3681b94635b2a9b431e0397 Mon Sep 17 00:00:00 2001
From: Tim Staat <tim@noe-danke.de>
Date: Thu, 11 Sep 2025 00:51:54 +0200
Subject: [PATCH] Fix timezone / utc issue, ignore gps invalid date

As the gps time reading is quite unreliable, instead use
current server system time when the gps time is farer away
than 24h (timezone adjusted).
---
 server/python_server.py | 55 ++++++++++++++++++++++++++++++++---------
 1 file changed, 43 insertions(+), 12 deletions(-)

diff --git a/server/python_server.py b/server/python_server.py
index 5b26eb3..9570131 100644
--- a/server/python_server.py
+++ b/server/python_server.py
@@ -27,7 +27,7 @@ with sqlite3.connect('location.db', check_same_thread=False) as conn:
 ureg = pint.UnitRegistry()
 geodesic = Geod(ellps='WGS84')
 
-current_datetime = datetime.utcnow()
+current_datetime = datetime.now(dttz.utc)
 date_yesterday = current_datetime - timedelta(days=1)
 date_tomorrow = current_datetime +  timedelta(days=1)
 
@@ -53,12 +53,12 @@ def getGpsDistance():
     try:
         gpsDateTime = datetime.strptime(request.args.get('gpsDateTime')[:11], '%d%m%y%H%M%S')
         if gpsDateTime > date_tomorrow or current_datetime < date_yesterday:
-            valid_date = False
-        print(gpsDateTime)
+            gpsDateTime = datetime.now(dttz.utc)
+            print(gpsDateTime)
     except ValueError:
         print("No gpsDateTime")
-        gpsDateTime = datetime.now()
-        valid_date = False
+        gpsDateTime = datetime.now(dttz.utc)
+        
 
         
 
@@ -78,16 +78,16 @@ def getGpsDistance():
             else:
                 req_lat = 0.0
                 req_long = 0.0
-                req_dateTime = datetime.now()
-                rTime = datetime.now()
+                req_dateTime = datetime.now(dttz.utc)
+                rTime = datetime.now(dttz.utc)
 
         except sqlite3.Error as error:
             print("Failed to read data from table, using default values", error)
             req_lat = 0.0
             req_long = 0.0
-            req_dateTime = datetime.now()
+            req_dateTime = datetime.now(dttz.utc)
         
-        if (lat != 0.0 and long != 0.0 and valid_date):
+        if (((lat > 0.005 or lat < -0.005) and (long > 0.005 or long < - 0.005)) and valid_date):
             cur.execute(f'INSERT INTO location_data(sender_id, lat, long, gpsDateTime) VALUES({own_id}, {lat}, {long}, "{gpsDateTime.isoformat()}");')
             conn.commit()
 
@@ -109,9 +109,40 @@ def getGpsDistance():
 
                 print(rTime)
         else:
-            prettyDistance = "Invalid GPS Signal"
-            fwd_azimuth = 0.0
-            rTime = datetime.utcnow()
+            
+            try:
+
+                res = cur.execute(f'SELECT lat, long, gpsDateTime, insertDateTime FROM location_data WHERE sender_id = {own_id} ORDER BY ROWID DESC LIMIT 1;')
+                row = res.fetchone()
+
+                if  row:
+                    lat, long, lastOwnDateTime, lastOwnInsertDateTime = row
+                    print(f'lat: {lat}, long: {long}, req_lat: {req_lat}, req_long: {req_long}, req_dateTime: {req_dateTime}')
+
+                    fwd_azimuth, back_azimuth, distance = geodesic.inv(long, lat, req_long, req_lat)
+
+                    distance = distance * ureg.meter
+                    prettyDistance = f"{distance:.1f~#P}" + '    (N)' if not bear_correction else ''
+                    print(f'fwd: {fwd_azimuth}, bwd: {back_azimuth}, dist: {prettyDistance}')
+                    tf = timezonefinder.TimezoneFinder()
+                    timezone_str = tf.certain_timezone_at(lat=lat, lng=long)
+                    if timezone_str is None:
+                        print("Could not determine the time zone")
+                    else:
+                         print(rTime)
+
+
+
+                else:
+
+                    print(timezone_str)
+                    print(pytz.timezone(timezone_str))
+                    rTime = rTime.replace(tzinfo=dttz.utc).astimezone(pytz.timezone(timezone_str))
+            except sqlite3.Error as error:
+                print("Failed to read data for last own entry from table -- ignore", error)
+                prettyDistance = "Invalid GPS Signal"
+                fwd_azimuth = 0.0
+                rTime = datetime.now(dttz.utc)
 
     return jsonify({'distance': prettyDistance, 'azimuth': fwd_azimuth, 'lastUpdateTZ': rTime.strftime("%m/%d %H:%M:%S"), 'bear_correction': bear_correction})