apps/chat/exceptions.py

@@ -0,0 +1,2 @@
+class ConversationClosedError(Exception):
+    """Raised when attempting to send a message to a closed conversation."""

apps/chat/migrations/0003_conversation_closed_by_uuid_conversation_status_and_more.py

@@ -0,0 +1,27 @@
+# Generated by Django 5.2.13 on 2026-07-19 09:05
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('chat', '0002_remove_conversationparticipant_unique_participant_per_conversation_and_more'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='conversation',
+            name='closed_by_uuid',
+            field=models.UUIDField(blank=True, null=True),
+        ),
+        migrations.AddField(
+            model_name='conversation',
+            name='status',
+            field=models.CharField(choices=[('open', 'Open'), ('closed', 'Closed')], default='open', max_length=20),
+        ),
+        migrations.AddIndex(
+            model_name='conversation',
+            index=models.Index(fields=['status'], name='chat_conver_status_9f0685_idx'),
+        ),
+    ]

apps/chat/models/__init__.py

@@ -1,4 +1,4 @@
-from apps.chat.models.conversation import Conversation, ConversationType
+from apps.chat.models.conversation import Conversation, ConversationStatus, ConversationType
 from apps.chat.models.mapping import MattermostAccountMapping
 from apps.chat.models.participant import ConversationParticipant
 from apps.chat.models.read_state import ConversationReadState
@@ -6,6 +6,7 @@ from apps.chat.models.read_state import ConversationReadState
 __all__ = [
     "Conversation",
     "ConversationType",
+    "ConversationStatus",
     "ConversationParticipant",
     "MattermostAccountMapping",
     "ConversationReadState",

apps/chat/models/conversation.py

@@ -8,6 +8,11 @@ class ConversationType(models.TextChoices):
     GROUP = "group", "Group"
 
 
+class ConversationStatus(models.TextChoices):
+    OPEN = "open", "Open"
+    CLOSED = "closed", "Closed"
+
+
 class Conversation(models.Model):
     uuid = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
     # Internal only — never exposed through any public API or serializer
@@ -17,6 +22,13 @@ class Conversation(models.Model):
         choices=ConversationType.choices,
         default=ConversationType.DIRECT,
     )
+    status = models.CharField(
+        max_length=20,
+        choices=ConversationStatus.choices,
+        default=ConversationStatus.OPEN,
+    )
+    # Set only while status is CLOSED; identifies who is allowed to reopen it.
+    closed_by_uuid = models.UUIDField(null=True, blank=True)
     created_at = models.DateTimeField(auto_now_add=True)
     updated_at = models.DateTimeField(auto_now=True)
 
@@ -24,6 +36,7 @@ class Conversation(models.Model):
         indexes = [
             models.Index(fields=["type"]),
             models.Index(fields=["created_at"]),
+            models.Index(fields=["status"]),
         ]
 
     def __str__(self):

apps/chat/serializers/conversations.py

@@ -9,12 +9,16 @@ class CreateConversationSerializer(serializers.Serializer):
     user_2_uuid = serializers.UUIDField()
 
 
+class ConversationUserActionSerializer(serializers.Serializer):
+    user_uuid = serializers.UUIDField()
+
+
 class ConversationSerializer(serializers.ModelSerializer):
     participants = serializers.SerializerMethodField()
 
     class Meta:
         model = Conversation
-        fields = ["uuid", "type", "created_at", "participants"]
+        fields = ["uuid", "type", "status", "closed_by_uuid", "created_at", "participants"]
 
     @extend_schema_field(serializers.ListField(child=serializers.UUIDField()))
     def get_participants(self, obj):
@@ -28,6 +32,8 @@ class ConversationSerializer(serializers.ModelSerializer):
 class ConversationListSerializer(serializers.Serializer):
     uuid = serializers.UUIDField()
     type = serializers.CharField()
+    status = serializers.CharField()
+    closed_by_uuid = serializers.UUIDField(allow_null=True)
     created_at = serializers.DateTimeField()
     participants = serializers.ListField(child=serializers.UUIDField())
     has_unread = serializers.BooleanField()

apps/chat/services/conversation.py

@@ -6,6 +6,7 @@ from apps.chat.integrations.mattermost.client import MattermostClient
 from apps.chat.models import (
     Conversation,
     ConversationParticipant,
+    ConversationStatus,
     MattermostAccountMapping,
 )
 from apps.chat.services.account import AccountService
@@ -63,3 +64,28 @@ class ConversationService:
                 "-created_at"
             )[offset : offset + page_size]
         )
+
+    def close(self, conversation_uuid: UUID, user_uuid: UUID) -> Conversation:
+        conversation = Conversation.objects.get(uuid=conversation_uuid)
+        if conversation.status == ConversationStatus.CLOSED:
+            return conversation
+
+        conversation.status = ConversationStatus.CLOSED
+        conversation.closed_by_uuid = user_uuid
+        conversation.save(update_fields=["status", "closed_by_uuid", "updated_at"])
+        return conversation
+
+    def reopen(self, conversation_uuid: UUID, user_uuid: UUID) -> Conversation:
+        conversation = Conversation.objects.get(uuid=conversation_uuid)
+        if conversation.status == ConversationStatus.OPEN:
+            return conversation
+
+        if conversation.closed_by_uuid != user_uuid:
+            raise PermissionError(
+                "Only the user who closed this conversation can reopen it"
+            )
+
+        conversation.status = ConversationStatus.OPEN
+        conversation.closed_by_uuid = None
+        conversation.save(update_fields=["status", "closed_by_uuid", "updated_at"])
+        return conversation

apps/chat/services/message.py

@@ -5,8 +5,9 @@ from apps.chat.events.event import MessageSentEvent
 from apps.chat.events.publishers.longpoll import LongPollPublisher
 from apps.chat.events.publishers.push import PushPublisher
 from apps.chat.events.publishers.websocket import WebSocketPublisher
+from apps.chat.exceptions import ConversationClosedError
 from apps.chat.integrations.mattermost.client import MattermostClient
-from apps.chat.models import Conversation, MattermostAccountMapping
+from apps.chat.models import Conversation, ConversationStatus, MattermostAccountMapping
 from apps.chat.services.account import AccountService
 from apps.chat.services.storage import StorageService
 
@@ -42,6 +43,10 @@ class MessageService:
         text: str | None = None,
         file=None,
     ) -> dict:
+        conversation = Conversation.objects.get(uuid=conversation_uuid)
+        if conversation.status == ConversationStatus.CLOSED:
+            raise ConversationClosedError(f"Conversation {conversation_uuid} is closed")
+
         if not self._account.validate_user(sender_uuid):
             raise ValueError(f"Sender {sender_uuid} is not valid")
 
@@ -55,7 +60,6 @@ class MessageService:
         else:
             mm_message = file_url or text or ""
 
-        conversation = Conversation.objects.get(uuid=conversation_uuid)
         post_id = self._mm.post_message(conversation.mattermost_channel_id, mm_message)
 
         event = MessageSentEvent(

apps/chat/tests/test_conversation_close.py

@@ -0,0 +1,112 @@
+import uuid
+from unittest.mock import Mock
+
+import pytest
+
+from apps.chat.exceptions import ConversationClosedError
+from apps.chat.models import Conversation, ConversationStatus
+from apps.chat.services.conversation import ConversationService
+from apps.chat.services.message import MessageService
+
+
+def _make_conv(status=ConversationStatus.OPEN, closed_by_uuid=None, channel_id="ch-close"):
+    return Conversation.objects.create(
+        mattermost_channel_id=channel_id,
+        status=status,
+        closed_by_uuid=closed_by_uuid,
+    )
+
+
+def _svc():
+    return ConversationService(mattermost_client=Mock())
+
+
+@pytest.mark.django_db
+def test_close_sets_status_and_closed_by():
+    conv = _make_conv()
+    closer = uuid.uuid4()
+
+    result = _svc().close(conv.uuid, closer)
+
+    assert result.status == ConversationStatus.CLOSED
+    assert result.closed_by_uuid == closer
+
+    conv.refresh_from_db()
+    assert conv.status == ConversationStatus.CLOSED
+    assert conv.closed_by_uuid == closer
+
+
+@pytest.mark.django_db
+def test_close_is_idempotent():
+    closer = uuid.uuid4()
+    other = uuid.uuid4()
+    conv = _make_conv(status=ConversationStatus.CLOSED, closed_by_uuid=closer)
+
+    result = _svc().close(conv.uuid, other)
+
+    assert result.status == ConversationStatus.CLOSED
+    assert result.closed_by_uuid == closer  # unchanged — original closer preserved
+
+
+@pytest.mark.django_db
+def test_reopen_by_closer_succeeds():
+    closer = uuid.uuid4()
+    conv = _make_conv(status=ConversationStatus.CLOSED, closed_by_uuid=closer)
+
+    result = _svc().reopen(conv.uuid, closer)
+
+    assert result.status == ConversationStatus.OPEN
+    assert result.closed_by_uuid is None
+
+
+@pytest.mark.django_db
+def test_reopen_by_other_user_raises_permission_error():
+    closer = uuid.uuid4()
+    other = uuid.uuid4()
+    conv = _make_conv(status=ConversationStatus.CLOSED, closed_by_uuid=closer)
+
+    with pytest.raises(PermissionError):
+        _svc().reopen(conv.uuid, other)
+
+    conv.refresh_from_db()
+    assert conv.status == ConversationStatus.CLOSED
+
+
+@pytest.mark.django_db
+def test_reopen_is_idempotent_when_already_open():
+    conv = _make_conv(status=ConversationStatus.OPEN)
+    someone = uuid.uuid4()
+
+    result = _svc().reopen(conv.uuid, someone)
+
+    assert result.status == ConversationStatus.OPEN
+
+
+@pytest.mark.django_db
+def test_send_message_to_closed_conversation_raises():
+    closer = uuid.uuid4()
+    conv = _make_conv(status=ConversationStatus.CLOSED, closed_by_uuid=closer)
+    sender_uuid = uuid.uuid4()
+
+    svc = MessageService(mattermost_client=Mock(), storage_service=Mock(), publishers=[])
+
+    with pytest.raises(ConversationClosedError):
+        svc.send(conv.uuid, sender_uuid, "text", text="hello")
+
+
+@pytest.mark.django_db
+def test_send_message_after_reopen_succeeds():
+    closer = uuid.uuid4()
+    conv = _make_conv(status=ConversationStatus.CLOSED, closed_by_uuid=closer)
+    sender_uuid = uuid.uuid4()
+
+    _svc().reopen(conv.uuid, closer)
+
+    mm_client = Mock()
+    mm_client.post_message.return_value = "post-1"
+    svc = MessageService(mattermost_client=mm_client, storage_service=Mock(), publishers=[])
+
+    result = svc.send(conv.uuid, sender_uuid, "text", text="hello again")
+
+    assert result["post_id"] == "post-1"
+    mm_client.post_message.assert_called_once_with("ch-close", "hello again")

apps/chat/urls.py

@@ -1,7 +1,9 @@
 from django.urls import path
 
 from apps.chat.views.conversations import (
+    ConversationCloseView,
     ConversationCreateView,
+    ConversationReopenView,
     UserConversationListView,
 )
 from apps.chat.views.messages import MessageView
@@ -13,4 +15,6 @@ urlpatterns = [
     path("api/chats/<uuid:chat_uuid>/messages/", MessageView.as_view(), name="chat-messages"),
     path("api/chats/<uuid:chat_uuid>/read/", ReadStateView.as_view(), name="chat-read"),
     path("api/chats/<uuid:chat_uuid>/events/", ChatEventsView.as_view(), name="chat-events"),
+    path("api/chats/<uuid:chat_uuid>/close/", ConversationCloseView.as_view(), name="chat-close"),
+    path("api/chats/<uuid:chat_uuid>/reopen/", ConversationReopenView.as_view(), name="chat-reopen"),
 ]

apps/chat/views/conversations.py

@@ -9,6 +9,7 @@ from apps.chat.models import ConversationParticipant
 from apps.chat.serializers.conversations import (
     ConversationListSerializer,
     ConversationSerializer,
+    ConversationUserActionSerializer,
     CreateConversationSerializer,
 )
 from apps.chat.services.conversation import ConversationService
@@ -84,6 +85,8 @@ class UserConversationListView(APIView):
                 {
                     "uuid": conv.uuid,
                     "type": conv.type,
+                    "status": conv.status,
+                    "closed_by_uuid": conv.closed_by_uuid,
                     "created_at": conv.created_at,
                     "participants": participants,
                     "has_unread": has_unread,
@@ -92,3 +95,44 @@ class UserConversationListView(APIView):
             )
 
         return Response(ConversationListSerializer(result, many=True).data)
+
+
+class ConversationCloseView(APIView):
+    authentication_classes = []
+    permission_classes = []
+
+    @extend_schema(
+        request=ConversationUserActionSerializer,
+        responses={200: ConversationSerializer},
+    )
+    def post(self, request, chat_uuid):
+        serializer = ConversationUserActionSerializer(data=request.data)
+        serializer.is_valid(raise_exception=True)
+
+        conversation = ConversationService().close(
+            UUID(str(chat_uuid)), serializer.validated_data["user_uuid"]
+        )
+
+        return Response(ConversationSerializer(conversation).data)
+
+
+class ConversationReopenView(APIView):
+    authentication_classes = []
+    permission_classes = []
+
+    @extend_schema(
+        request=ConversationUserActionSerializer,
+        responses={200: ConversationSerializer, 403: None},
+    )
+    def post(self, request, chat_uuid):
+        serializer = ConversationUserActionSerializer(data=request.data)
+        serializer.is_valid(raise_exception=True)
+
+        try:
+            conversation = ConversationService().reopen(
+                UUID(str(chat_uuid)), serializer.validated_data["user_uuid"]
+            )
+        except PermissionError as exc:
+            return Response({"detail": str(exc)}, status=status.HTTP_403_FORBIDDEN)
+
+        return Response(ConversationSerializer(conversation).data)

apps/chat/views/messages.py

@@ -5,6 +5,7 @@ from rest_framework import status
 from rest_framework.response import Response
 from rest_framework.views import APIView
 
+from apps.chat.exceptions import ConversationClosedError
 from apps.chat.serializers.messages import MessageSerializer, SendMessageSerializer
 from apps.chat.services.message import MessageService
 
@@ -15,13 +16,14 @@ class MessageView(APIView):
 
     @extend_schema(
         request=SendMessageSerializer,
-        responses={201: MessageSerializer},
+        responses={201: MessageSerializer, 403: None},
     )
     def post(self, request, chat_uuid):
         serializer = SendMessageSerializer(data=request.data)
         serializer.is_valid(raise_exception=True)
         data = serializer.validated_data
 
+        try:
             result = MessageService().send(
                 conversation_uuid=UUID(str(chat_uuid)),
                 sender_uuid=data["sender_uuid"],
@@ -29,6 +31,8 @@ class MessageView(APIView):
                 text=data.get("text"),
                 file=data.get("file"),
             )
+        except ConversationClosedError as exc:
+            return Response({"detail": str(exc)}, status=status.HTTP_403_FORBIDDEN)
 
         return Response(MessageSerializer(result).data, status=status.HTTP_201_CREATED)