Implement announcement read relationships

lib/pleroma/announcement_read_relationship.ex

@@ -0,0 +1,55 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2022 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.AnnouncementReadRelationship do
+  use Ecto.Schema
+
+  import Ecto.Changeset
+
+  alias FlakeId.Ecto.CompatType
+  alias Pleroma.Announcement
+  alias Pleroma.Repo
+  alias Pleroma.User
+
+  @type t :: %__MODULE__{}
+
+  schema "announcement_read_relationships" do
+    belongs_to(:user, User, type: CompatType)
+    belongs_to(:announcement, Announcement, type: CompatType)
+
+    timestamps(updated_at: false)
+  end
+
+  def mark_read(user, announcement) do
+    %__MODULE__{}
+    |> cast(%{user_id: user.id, announcement_id: announcement.id}, [:user_id, :announcement_id])
+    |> validate_required([:user_id, :announcement_id])
+    |> foreign_key_constraint(:user_id)
+    |> foreign_key_constraint(:announcement_id)
+    |> unique_constraint([:user_id, :announcement_id])
+    |> Repo.insert()
+  end
+
+  def mark_unread(user, announcement) do
+    with relationship <- get(user, announcement),
+         {:exists, true} <- {:exists, not is_nil(relationship)},
+         {:ok, _} <- Repo.delete(relationship) do
+      :ok
+    else
+      {:exists, false} ->
+        :ok
+
+      _ ->
+        :error
+    end
+  end
+
+  def get(user, announcement) do
+    Repo.get_by(__MODULE__, user_id: user.id, announcement_id: announcement.id)
+  end
+
+  def exists?(user, announcement) do
+    not is_nil(get(user, announcement))
+  end
+end