From 480fa70b1f44a5d0a6ed1a363ec4305aaa7492fe Mon Sep 17 00:00:00 2001
From: Andrew Godwin <andrew@aeracode.org>
Date: Wed, 21 Dec 2022 16:11:58 +0000
Subject: [PATCH] Handle rejected follows

---
 users/models/follow.py        | 18 ++++++++++++++++++
 users/models/inbox_message.py |  8 ++++++++
 users/services/identity.py    |  6 +-----
 3 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/users/models/follow.py b/users/models/follow.py
index 697c464..1a93421 100644
--- a/users/models/follow.py
+++ b/users/models/follow.py
@@ -16,11 +16,13 @@ class FollowStates(StateGraph):
     undone = State(try_interval=60 * 60)
     undone_remotely = State()
     failed = State()
+    rejected = State()
 
     unrequested.transitions_to(local_requested)
     unrequested.transitions_to(remote_requested)
     unrequested.times_out_to(failed, seconds=86400 * 7)
     local_requested.transitions_to(accepted)
+    local_requested.transitions_to(rejected)
     remote_requested.transitions_to(accepted)
     accepted.transitions_to(undone)
     undone.transitions_to(undone_remotely)
@@ -279,3 +281,19 @@ class Follow(StatorModel):
             raise ValueError("No Follow locally for incoming Undo", data)
         # Delete the follow
         follow.delete()
+
+    @classmethod
+    def handle_reject_ap(cls, data):
+        """
+        Handles an incoming Follow Reject for one of our follows
+        """
+        # Ensure the Accept actor is the Follow's object
+        if data["actor"] != data["object"]["object"]:
+            raise ValueError("Accept actor does not match its Follow object", data)
+        # Resolve source and target and see if a Follow exists (it really should)
+        try:
+            follow = cls.by_ap(data["object"])
+        except KeyError:
+            raise ValueError("No Follow locally for incoming Reject", data)
+        # Mark the follow rejected
+        follow.transition_perform(FollowStates.rejected)
diff --git a/users/models/inbox_message.py b/users/models/inbox_message.py
index d6f3839..533f152 100644
--- a/users/models/inbox_message.py
+++ b/users/models/inbox_message.py
@@ -69,6 +69,14 @@ class InboxMessageStates(StateGraph):
                         raise ValueError(
                             f"Cannot handle activity of type accept.{unknown}"
                         )
+            case "reject":
+                match instance.message_object_type:
+                    case "follow":
+                        await sync_to_async(Follow.handle_reject_ap)(instance.message)
+                    case unknown:
+                        raise ValueError(
+                            f"Cannot handle activity of type reject.{unknown}"
+                        )
             case "undo":
                 match instance.message_object_type:
                     case "follow":
diff --git a/users/services/identity.py b/users/services/identity.py
index e6b44f4..743258a 100644
--- a/users/services/identity.py
+++ b/users/services/identity.py
@@ -19,11 +19,7 @@ class IdentityService:
         existing_follow = Follow.maybe_get(from_identity, self.identity)
         if not existing_follow:
             Follow.create_local(from_identity, self.identity)
-        elif existing_follow.state in [
-            FollowStates.undone,
-            FollowStates.undone_remotely,
-            FollowStates.failed,
-        ]:
+        elif existing_follow.state not in FollowStates.group_active():
             existing_follow.transition_perform(FollowStates.unrequested)
         return cast(Follow, existing_follow)