From 6d65e8ecb09a61b33a5ac665202cb85de3b3875c Mon Sep 17 00:00:00 2001
From: Kahanis <6c41n7bt3x16@opayq.com>
Date: Tue, 21 Feb 2023 16:02:39 +0100
Subject: [PATCH] Adds a worker to pull new replies to discovered messages.

---
 config/config.exs                            |  3 +-
 lib/pleroma/web/activity_pub/side_effects.ex |  2 +
 lib/pleroma/workers/reply_refresh_worker.ex  | 76 ++++++++++++++++++++
 3 files changed, 80 insertions(+), 1 deletion(-)
 create mode 100644 lib/pleroma/workers/reply_refresh_worker.ex

diff --git a/config/config.exs b/config/config.exs
index 5eaa8ce76..596bc59a7 100644
--- a/config/config.exs
+++ b/config/config.exs
@@ -568,7 +568,8 @@
     mute_expire: 5,
     search_indexing: 10,
     nodeinfo_fetcher: 1,
-    database_prune: 1
+    database_prune: 1,
+    reply_refresher: 50,
   ],
   plugins: [
     Oban.Plugins.Pruner,
diff --git a/lib/pleroma/web/activity_pub/side_effects.ex b/lib/pleroma/web/activity_pub/side_effects.ex
index 34617a218..37c43b605 100644
--- a/lib/pleroma/web/activity_pub/side_effects.ex
+++ b/lib/pleroma/web/activity_pub/side_effects.ex
@@ -22,6 +22,7 @@ defmodule Pleroma.Web.ActivityPub.SideEffects do
   alias Pleroma.Web.Push
   alias Pleroma.Web.Streamer
   alias Pleroma.Workers.PollWorker
+  alias Pleroma.Workers.ReplyRefresherWorker
 
   require Pleroma.Constants
   require Logger
@@ -230,6 +231,7 @@ def handle(%{data: %{"type" => "Create"}} = activity, meta) do
       end)
 
       Pleroma.Search.add_to_index(Map.put(activity, :object, object))
+      ReplyRefresherWorker.schedule(object.data["id"])
 
       meta =
         meta
diff --git a/lib/pleroma/workers/reply_refresh_worker.ex b/lib/pleroma/workers/reply_refresh_worker.ex
new file mode 100644
index 000000000..5bf4bc942
--- /dev/null
+++ b/lib/pleroma/workers/reply_refresh_worker.ex
@@ -0,0 +1,76 @@
+defmodule Pleroma.Workers.ReplyRefresherWorker do
+  @moduledoc """
+  The worker to pull new replies to discovered posts.
+  """
+
+  use Pleroma.Workers.WorkerHelper, queue: "reply_refresher"
+
+  alias Pleroma.Object
+  alias Pleroma.Object.Fetcher
+  alias Pleroma.Workers.ReplyRefresherWorker
+
+  @backoff_time {60, 600, 3600, 6 * 3600, 24 * 3600, 3 * 24 * 3600}
+
+  @impl Oban.Worker
+  def perform(%Job{args: %{"object_id" => object_id, "run_count" => run_count}}) do
+    case process_object(object_id) do
+      {:ok, true} -> reschedule(object_id, 0)
+      {:ok, false} -> reschedule(object_id, run_count + 1)
+      e -> e
+    end
+  end
+
+  def schedule(id) do
+    %{object_id: id, run_count: 0}
+    |> ReplyRefresherWorker.new(schedule_in: elem(@backoff_time, 0))
+    |> Oban.insert()
+  end
+
+  defp reschedule(id, run_count) when run_count < tuple_size(@backoff_time) do
+    %{object_id: id, run_count: run_count}
+    |> ReplyRefresherWorker.new(schedule_in: elem(@backoff_time, run_count))
+    |> Oban.insert()
+    {:ok, nil}
+  end
+
+  defp reschedule(_, _) do
+    {:ok, nil}
+  end
+
+  defp reply_to_id(id) when is_binary(id) do
+    id
+  end
+  defp reply_to_id(%{"id" => id}) do
+    id
+  end
+  defp process_reply(reply) do
+    id = reply_to_id(reply)
+    with {_, nil} <- {:find, Object.get_by_ap_id(id)},
+         {_, {:ok, _}} <- {:fetch, Fetcher.fetch_object_from_id(id)} do
+      {:ok, true}
+    else
+      {:find, _obj} -> {:ok, false}
+      {:fetch, err} -> {:ok, err}
+    end
+  end
+  defp process_object(id) do
+    obj = Object.get_by_ap_id(id)
+    with {:ok, new_obj} <- Fetcher.refetch_object(obj),
+         {:ok, replies} <- fetch_reply_list(new_obj.data["replies"]) do
+         Enum.reduce_while(Enum.map(replies, &process_reply/1), {:ok, false}, fn x, acc ->
+	   case x do
+	     {:ok, false} -> {:cont, acc}
+	     {:ok, true} -> {:cont, {:ok, true}}
+	     e -> {:halt, e}
+	   end
+	 end)
+    end
+  end
+  defp fetch_reply_list(replies) when is_list(replies) do
+    {:ok, replies}
+  end
+  defp fetch_reply_list(%{"type" => type} = replies)
+      when type in ["Collection", "OrderedCollection", "CollectionPage", "OrderedCollectionPage"] do
+    Akkoma.Collections.Fetcher.fetch_collection(replies)
+  end
+end