Allow modules to define collections of responders

lib/hedwig/robot.ex

@@ -79,7 +79,8 @@ defmodule Hedwig.Robot do
         opts = robot.config(opts)
         aka = Keyword.get(opts, :aka)
         name = Keyword.get(opts, :name)
-        {responders, opts} = Keyword.pop(opts, :responders, [])
+        {responder_list, opts} = Keyword.pop(opts, :responders, [])
+        responders = collect_responders(responder_list)
 
         unless responders == [] do
           GenServer.cast(self(), {:install_responders, responders})
@@ -199,6 +200,18 @@ defmodule Hedwig.Robot do
         {:ok, state}
       end
 
+      def collect_responders([]), do: []
+      def collect_responders([{module, list_fun, opts} | responders])
+          when is_atom(list_fun) do
+        collection = apply(module, list_fun, [opts])
+          |> collect_responders()
+
+        collection ++ collect_responders(responders)
+      end
+      def collect_responders([{module, opts} = responder | responders]) do
+        [responder] ++ collect_responders(responders)
+      end
+
       defp log_incorrect_return(atom) do
         Logger.warn """
         #{inspect atom} return value from `handle_in/2` only works with `%Hedwig.Message{}` structs.

test/hedwig/robot_test.exs

@@ -12,6 +12,25 @@ defmodule Hedwig.RobotTest do
     assert [{TestResponder, []}] = Hedwig.Robot.responders(robot)
   end
 
+  def collection_fill_opts(opts), do: [{A, opts}, {B, opts}]
+
+  @tag start_robot: true, responders: [{Hedwig.RobotTest, :collection_fill_opts, [foo: "bar"]}]
+  test "collect_responders/1 expands responder list with common options", %{robot: robot} do
+    assert [{A, [foo: "bar"]}, {B, [foo: "bar"]}] = Hedwig.Robot.responders(robot)
+  end
+
+  def collection_empty_opts(_opts), do: [{A, []}, {B, []}]
+
+  @tag start_robot: true, responders: [{Hedwig.RobotTest, :collection_empty_opts, [foo: "bar"]}]
+  test "collect_responders/1 expands responder list", %{robot: robot} do
+    assert [{A, []}, {B, []}] = Hedwig.Robot.responders(robot)
+  end
+
+  @tag start_robot: true, responders: [{TestResponder, []}, {Hedwig.RobotTest, :collection_empty_opts, []}]
+  test "collect_responders/1 includes normal responder definition at start", %{robot: robot} do
+    assert [{TestResponder, []}, {A, []}, {B, []}] = Hedwig.Robot.responders(robot)
+  end
+
   @tag start_robot: true
   test "handle_connect/1", %{robot: robot} do
     assert ^robot = :global.whereis_name("hedwig")