Send out notifications on invitations

src/api/invitations.py

@@ -1,5 +1,5 @@
 from datetime import UTC, datetime
-from typing import Literal, cast, final
+from typing import Literal, cast, final, overload
 
 from beanie import Link, PydanticObjectId
 from fastapi import APIRouter, HTTPException, Response, status
@@ -7,6 +7,7 @@ from pydantic import BaseModel
 
 from src.db.models.event import Event
 from src.db.models.invitation import Invitation
+from src.db.models.notification import Notification
 from src.db.models.user import User
 from src.utils.db import IdNotFoundError, MissingIdError, UnfetchedLinkError, expr
 from src.utils.logging import get_logger
@@ -77,10 +78,26 @@ class InvitationCreateData(_BaseInvitationData):
     This structure is intended to be used for POST requests.
     """
 
-    async def create_invitation(self, user: User) -> Invitation:
+    @overload
+    async def create_invitation(
+        self,
+        user: User,
+        create_notification: Literal[True] = True,
+    ) -> tuple[Invitation, Notification]: ...
+
+    @overload
+    async def create_invitation(self, user: User, create_notification: Literal[False]) -> Invitation: ...
+
+    async def create_invitation(
+        self,
+        user: User,
+        create_notification: bool = True,
+    ) -> Invitation | tuple[Invitation, Notification]:
         """Create a new invitation in the database.
 
         If one the event or invitee doesn't exist, the IdNotFoundError will be raised.
+        If create_notification is True, a notification will be created for the invitee. In most cases,
+        this is the desired behavior.
         """
         event = await Event.get(self.event_id)
         if event is None:
@@ -96,7 +113,20 @@ class InvitationCreateData(_BaseInvitationData):
             invitor=user,
             status="pending",
         )
-        return await invitation.create()
+        invitation = await invitation.create()
+
+        if create_notification:
+            notification = Notification(
+                user=invitee,
+                event_type="invitation",
+                message="new-invitation",
+                data=invitation.id,
+                read=False,
+            )
+            notification = await notification.create()
+            return invitation, notification
+
+        return invitation
 
 
 @base_router.get("/users/{user_id}/invitations")
@@ -155,7 +185,7 @@ async def get_invitation(invitation_id: PydanticObjectId, user: CurrentUserDep)
 @invitations_router.post("")
 async def create_invitation(data: InvitationCreateData, user: CurrentUserDep) -> InvitationData:
     """Create a new invitation."""
-    invitation = await data.create_invitation(user)
+    invitation, _notification = await data.create_invitation(user)
     return InvitationData.from_invitation(invitation)
 
 
@@ -197,6 +227,16 @@ async def accept_invitation(invitation_id: PydanticObjectId, user: CurrentUserDe
     invitation.responded_at = datetime.now(tz=UTC)
     _ = await invitation.save()
 
+    # Send back a notification to the invitor about the acceptance
+    notification = Notification(
+        user=invitation.invitor,
+        event_type="invitation",
+        message="invitation-accepted",
+        data=invitation.id,
+        read=False,
+    )
+    notification = await notification.create()
+
     return Response(status.HTTP_204_NO_CONTENT)
 
 
@@ -220,6 +260,16 @@ async def decline_invitation(invitation_id: PydanticObjectId, user: CurrentUserD
     invitation.responded_at = datetime.now(tz=UTC)
     _ = await invitation.save()
 
+    # Send back a notification to the invitor about the decline
+    notification = Notification(
+        user=invitation.invitor,
+        event_type="invitation",
+        message="invitation-declined",
+        data=invitation.id,
+        read=False,
+    )
+    notification = await notification.create()
+
     return Response(status_code=status.HTTP_204_NO_CONTENT)