Add part of room creation endpoint

lib/matrix_server/room_server.ex

@@ -1,15 +1,16 @@
 defmodule MatrixServer.RoomServer do
   use GenServer
 
-  alias MatrixServer.{Repo, Room}
+  alias MatrixServer.{Repo, Room, Event}
   alias MatrixServerWeb.API.CreateRoom
+  alias Ecto.Multi
 
   def start_link(_opts) do
     GenServer.start_link(__MODULE__, :ok, name: __MODULE__)
   end
 
-  def create_room(params) do
-    GenServer.call(__MODULE__, {:create_room, params})
+  def create_room(%CreateRoom{} = input, account) do
+    GenServer.call(__MODULE__, {:create_room, input, account})
   end
 
   @impl true
@@ -18,10 +19,18 @@ defmodule MatrixServer.RoomServer do
   end
 
   @impl true
-  def handle_call({:create_room, %CreateRoom{} = api}, _from, state) do
-    Room.create(api)
-    |> Repo.transaction()
+  def handle_call({:create_room, input, account}, _from, state) do
+    # TODO: preset events, initial_state events, invite, invite_3pid
+    result =
+      Multi.new()
+      |> Multi.insert(:room, Room.create_changeset(input))
+      |> Multi.run(:create_room_event, Event.room_creation_create_room(input, account))
+      |> Multi.run(:join_creator_event, Event.room_creation_join_creator())
+      |> Multi.run(:power_levels_event, Event.room_creation_power_levels(input))
+      |> Multi.run(:name_event, Event.room_creation_name(input))
+      |> Multi.run(:topic_event, Event.room_creation_topic(input))
+      |> Repo.transaction()
 
-    {:reply, :ok, state}
+    {:reply, result, state}
   end
 end