fix(valid-due-date): update serializer to compare only dates in the user's timezone (#241)

* fix(valid-due-date): update serializer to compare only dates in IST
timezone

* fix(due-date-issue): added timezone field to validate current date using
the user's time in serializer

* fix(due-date): add error message for timezone
- update serializer to validate timezone too
- update tests

* fix(due-date): updated update_task_serializer to throw error immediately
if invalid timezone

Author: Hariom01010

todo/constants/messages.py

@@ -61,6 +61,8 @@ class ValidationErrors:
     BLANK_TITLE = "Title must not be blank."
     INVALID_OBJECT_ID = "{0} is not a valid ObjectId."
     PAST_DUE_DATE = "Due date must be in the future."
+    REQUIRED_TIMEZONE = "Timezone is required if dueAt is provided."
+    INVALID_TIMEZONE = "Invalid timezone."
     PAST_DEFERRED_TILL_DATE = "deferredTill cannot be in the past."
     CANNOT_DEFER_TOO_CLOSE_TO_DUE_DATE = "Cannot defer task too close to the due date."
     CANNOT_DEFER_A_DONE_TASK = "Cannot defer a task that is already marked as done."

todo/serializers/create_task_serializer.py

@@ -1,8 +1,9 @@
 from rest_framework import serializers
 from bson import ObjectId
-from datetime import datetime, timezone
+from datetime import datetime
 from todo.constants.task import TaskPriority, TaskStatus
 from todo.constants.messages import ValidationErrors
+from zoneinfo import ZoneInfo, ZoneInfoNotFoundError
 
 
 class CreateTaskSerializer(serializers.Serializer):
@@ -35,6 +36,9 @@ class CreateTaskSerializer(serializers.Serializer):
         default=list,
         help_text="List of label IDs",
     )
+    timezone = serializers.CharField(
+        required=True, allow_null=False, help_text="IANA timezone string like 'Asia/Kolkata'"
+    )
     dueAt = serializers.DateTimeField(
         required=False, allow_null=True, help_text="Due date and time in ISO format (UTC)"
     )
@@ -50,13 +54,6 @@ def validate_labels(self, value):
                 raise serializers.ValidationError(ValidationErrors.INVALID_OBJECT_ID.format(label_id))
         return value
 
-    def validate_dueAt(self, value):
-        if value is not None:
-            now = datetime.now(timezone.utc)
-            if value <= now:
-                raise serializers.ValidationError(ValidationErrors.PAST_DUE_DATE)
-        return value
-
     def validate(self, data):
         # Compose the 'assignee' dict if assignee_id and user_type are present
         assignee_id = data.pop("assignee_id", None)
@@ -69,4 +66,22 @@ def validate(self, data):
             if user_type not in ["user", "team"]:
                 raise serializers.ValidationError({"user_type": "user_type must be either 'user' or 'team'"})
             data["assignee"] = {"assignee_id": assignee_id, "user_type": user_type}
+
+        due_at = data.get("dueAt")
+        timezone_str = data.get("timezone")
+
+        if due_at:
+            if not timezone_str:
+                raise serializers.ValidationError({"timezone": ValidationErrors.REQUIRED_TIMEZONE})
+            try:
+                tz = ZoneInfo(timezone_str)
+            except ZoneInfoNotFoundError:
+                raise serializers.ValidationError({"timezone": ValidationErrors.INVALID_TIMEZONE})
+
+            now_date = datetime.now(tz).date()
+            value_date = due_at.astimezone(tz).date()
+
+            if value_date < now_date:
+                raise serializers.ValidationError({"dueAt": ValidationErrors.PAST_DUE_DATE})
+
         return data

todo/serializers/update_task_serializer.py

@@ -4,6 +4,7 @@
 
 from todo.constants.task import TaskPriority, TaskStatus
 from todo.constants.messages import ValidationErrors
+from zoneinfo import ZoneInfo, ZoneInfoNotFoundError
 
 
 class UpdateTaskSerializer(serializers.Serializer):
@@ -25,6 +26,9 @@ class UpdateTaskSerializer(serializers.Serializer):
         required=False,
         allow_null=True,
     )
+    timezone = serializers.CharField(
+        required=False, allow_null=True, help_text="IANA timezone string like 'Asia/Kolkata'"
+    )
     dueAt = serializers.DateTimeField(required=False, allow_null=True)
     startedAt = serializers.DateTimeField(required=False, allow_null=True)
     isAcknowledged = serializers.BooleanField(required=False)
@@ -49,17 +53,6 @@ def validate_labels(self, value):
 
         return value
 
-    def validate_dueAt(self, value):
-        if value is None:
-            return value
-        errors = []
-        now = datetime.now(timezone.utc)
-        if value <= now:
-            errors.append(ValidationErrors.PAST_DUE_DATE)
-        if errors:
-            raise serializers.ValidationError(errors)
-        return value
-
     def validate_startedAt(self, value):
         if value and value > datetime.now(timezone.utc):
             raise serializers.ValidationError(ValidationErrors.FUTURE_STARTED_AT)
@@ -85,3 +78,25 @@ def validate_assignee(self, value):
             raise serializers.ValidationError(ValidationErrors.INVALID_OBJECT_ID.format(assignee_id))
 
         return value
+
+    def validate(self, data):
+        due_at = data.get("dueAt")
+        timezone_str = data.get("timezone")
+        errors = {}
+        if due_at is not None:
+            if not timezone_str:
+                errors["timezone"] = [ValidationErrors.REQUIRED_TIMEZONE]
+            else:
+                try:
+                    tz = ZoneInfo(timezone_str)
+
+                    now_date = datetime.now(tz).date()
+                    value_date = due_at.astimezone(tz).date()
+
+                    if value_date < now_date:
+                        errors["dueAt"] = [ValidationErrors.PAST_DUE_DATE]
+                except ZoneInfoNotFoundError:
+                    errors["timezone"] = [ValidationErrors.INVALID_TIMEZONE]
+            if errors:
+                raise serializers.ValidationError(errors)
+        return data

todo/tests/unit/serializers/test_create_task_serializer.py

@@ -17,6 +17,7 @@ def setUp(self):
             "user_type": "user",
             "labels": [],
             "dueAt": (datetime.now(timezone.utc) + timedelta(days=2)).isoformat().replace("+00:00", "Z"),
+            "timezone": "Asia/Calcutta",
         }
 
     def test_serializer_validates_correct_data(self):

todo/tests/unit/serializers/test_update_task_serializer.py

@@ -24,6 +24,7 @@ def test_valid_full_payload(self):
             "dueAt": self.future_date.isoformat(),
             "startedAt": (datetime.now(timezone.utc) - timedelta(hours=1)).isoformat(),
             "isAcknowledged": True,
+            "timezone": "Asia/Calcutta",
         }
         serializer = UpdateTaskSerializer(data=data)
         self.assertTrue(serializer.is_valid(), serializer.errors)
@@ -54,6 +55,7 @@ def test_all_fields_can_be_null_or_empty_if_allowed(self):
             "labels": None,
             "dueAt": None,
             "startedAt": None,
+            "timezone": None,
         }
         serializer = UpdateTaskSerializer(data=data, partial=True)
         self.assertTrue(serializer.is_valid(), serializer.errors)
@@ -101,14 +103,14 @@ def test_labels_can_be_empty_list(self):
         self.assertEqual(serializer.validated_data["labels"], [])
 
     def test_due_at_validation_past_date(self):
-        data = {"dueAt": self.past_date.isoformat()}
+        data = {"dueAt": self.past_date.isoformat(), "timezone": "Asia/Calcutta"}
         serializer = UpdateTaskSerializer(data=data, partial=True)
         self.assertFalse(serializer.is_valid())
         self.assertIn("dueAt", serializer.errors)
         self.assertEqual(str(serializer.errors["dueAt"][0]), ValidationErrors.PAST_DUE_DATE)
 
     def test_due_at_validation_future_date(self):
-        data = {"dueAt": self.future_date.isoformat()}
+        data = {"dueAt": self.future_date.isoformat(), "timezone": "Asia/Calcutta"}
         serializer = UpdateTaskSerializer(data=data, partial=True)
         self.assertTrue(serializer.is_valid(), serializer.errors)
         self.assertEqual(serializer.validated_data["dueAt"], datetime.fromisoformat(data["dueAt"]))

todo/tests/unit/views/test_task.py

@@ -402,6 +402,7 @@ def setUp(self):
             "assignee": {"assignee_id": self.user_id, "user_type": "user"},
             "labels": [],
             "dueAt": (datetime.now(timezone.utc) + timedelta(days=2)).isoformat().replace("+00:00", "Z"),
+            "timezone": "Asia/Calcutta",
         }
 
     @patch("todo.services.task_service.TaskService.create_task")
@@ -491,6 +492,7 @@ def test_create_task_returns_400_when_label_ids_are_not_objectids(self):
     def test_create_task_returns_400_when_dueAt_is_past(self):
         invalid_payload = self.valid_payload.copy()
         invalid_payload["dueAt"] = (datetime.now(timezone.utc) - timedelta(days=1)).isoformat().replace("+00:00", "Z")
+        invalid_payload["timezone"] = "Asia/Kolkata"
 
         response = self.client.post(self.url, data=invalid_payload, format="json")