fix(timezone): fix timer clock-skew

apps/time_entries/api/serializers.py

@@ -1,4 +1,5 @@
 from rest_framework import serializers
+from django.utils import timezone
 
 from core.serializers.base import BaseModelSerializer
 from apps.time_entries.models import TimeEntry
@@ -31,6 +32,27 @@ class TimeEntrySerializer(BaseModelSerializer):
     tag_details = serializers.SerializerMethodField()
     start_time = serializers.DateTimeField(format="%Y-%m-%d %H:%M:%S")
     end_time = serializers.DateTimeField(format="%Y-%m-%d %H:%M:%S", allow_null=True)
+    start_time_ms = serializers.SerializerMethodField()
+    end_time_ms = serializers.SerializerMethodField()
+    server_now_ms = serializers.SerializerMethodField()
+
+    @staticmethod
+    def _epoch_ms(value):
+        if value is None:
+            return None
+        if timezone.is_naive(value):
+            value = timezone.make_aware(value, timezone.get_current_timezone())
+        return int(value.timestamp() * 1000)
+
+    def get_start_time_ms(self, obj):
+        return self._epoch_ms(obj.start_time)
+
+    def get_end_time_ms(self, obj):
+        return self._epoch_ms(obj.end_time)
+
+    def get_server_now_ms(self, obj):
+        server_now = self.context.get("server_now") or timezone.now()
+        return self._epoch_ms(server_now)
 
     def get_tags(self, obj):
         return [str(tag.id) for tag in Tag.all_objects.filter(time_entries=obj).order_by("-updated_at", "-created_at")]
@@ -76,7 +98,10 @@ class TimeEntrySerializer(BaseModelSerializer):
             "project_details",
             "description",
             "start_time",
+            "start_time_ms",
             "end_time",
+            "end_time_ms",
+            "server_now_ms",
             "duration",
             "tags",
             "tag_details",