From 78e26258833f6dec94f2dc57746c14fb19d05119 Mon Sep 17 00:00:00 2001
From: ramvignesh-b <ramvignesh-b@github.com>
Date: Sat, 18 Apr 2026 04:39:18 +0530
Subject: [PATCH] refactor: handle exception on vault unlock date check for
 validation

---
 ...tter_notified_at_alter_letter_unlock_at.py | 22 +++++++++++++++++++
 backend/letters/serializers.py                | 15 ++++++++-----
 2 files changed, 32 insertions(+), 5 deletions(-)
 create mode 100644 backend/letters/migrations/0009_alter_letter_notified_at_alter_letter_unlock_at.py

diff --git a/backend/letters/migrations/0009_alter_letter_notified_at_alter_letter_unlock_at.py b/backend/letters/migrations/0009_alter_letter_notified_at_alter_letter_unlock_at.py
new file mode 100644
index 0000000..b3e2ee3
--- /dev/null
+++ b/backend/letters/migrations/0009_alter_letter_notified_at_alter_letter_unlock_at.py
@@ -0,0 +1,22 @@
+# Generated by Django 6.0.4 on 2026-04-17 18:08
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("letters", "0008_letter_notified_at"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="letter",
+            name="notified_at",
+            field=models.DateTimeField(blank=True, db_index=True, null=True),
+        ),
+        migrations.AlterField(
+            model_name="letter",
+            name="unlock_at",
+            field=models.DateTimeField(blank=True, db_index=True, null=True),
+        ),
+    ]
diff --git a/backend/letters/serializers.py b/backend/letters/serializers.py
index 455c805..aad04c1 100644
--- a/backend/letters/serializers.py
+++ b/backend/letters/serializers.py
@@ -39,11 +39,14 @@ class LetterSerializer(serializers.ModelSerializer):
     def to_representation(self, instance):
         fields = super().to_representation(instance)
         if fields["type"] == Letter.Type.VAULT and fields["status"] == Letter.Status.SEALED:
-            unlock_datetime = datetime.fromisoformat(fields["unlock_at"]).replace(tzinfo=UTC)
-            if unlock_datetime - datetime.now(tz=UTC) > timedelta(seconds=0):
-                fields["encrypted_content"] = None
-                fields["images"] = None
-                fields["encrypted_dek"] = None
+            try:
+                unlock_datetime = datetime.fromisoformat(fields["unlock_at"]).replace(tzinfo=UTC)
+                if unlock_datetime - datetime.now(tz=UTC) > timedelta(seconds=0):
+                    fields["encrypted_content"] = None
+                    fields["images"] = None
+                    fields["encrypted_dek"] = None
+            except (ValueError, TypeError):
+                pass
         return fields
 
     def validate(self, data):
@@ -54,4 +57,6 @@ class LetterSerializer(serializers.ModelSerializer):
             raise serializers.ValidationError(
                 "encrypted_dek is required when encrypted_content and encrypted_metadata are present"
             )
+        if data.get("type") == Letter.Type.VAULT and not data.get("unlock_at"):
+            raise serializers.ValidationError("unlock_at is required for vault letters")
         return data