Added feature flags

lib/smart_home_firmware/application.ex

@@ -19,7 +19,8 @@ defmodule SmartHomeFirmware.Application do
         # Don't add stuff here that needs a Network connection!
         # Add it in `NetworkSupervisor`
         {SmartHomeFirmware.State, name: SmartHomeFirmware},
-        SmartHomeFirmware.Lock,
+        SmartHomeFirmware.FeatureSupervisor,
+        SmartHomeFirmware.FeatureManager,
         SmartHomeFirmware.HubClient
       ] ++ children(target())
 

lib/smart_home_firmware/client/hub_client.ex

@@ -160,10 +160,16 @@ defmodule SmartHomeFirmware.HubClient do
   end
 
   defp handle_handshake_resp(body) do
+    # TODO: Adapt backend to modularize this more -
+    # I don't like having to split this out here.
     SmartHomeFirmware.State.put(:lock, %{
       mode: body["mode"],
       uuid: body["uuid"],
-      name: body["name"]
+    })
+
+    SmartHomeFirmware.State.put(:self, %{
+      name: body["name"],
+      feature_flags: body["feature_flags"]
     })
   end
 

lib/smart_home_firmware/feature_manager.ex

@@ -0,0 +1,47 @@
+defmodule SmartHomeFirmware.FeatureManager do
+  @moduledoc """
+  Manages what features are currently enabled and which ones aren't.
+  """
+  require Logger
+
+  # Feature flags allow certain processes to be turned on and off.
+  # Here we define the flags and associated modules
+  @feature_flags [
+    lock: SmartHomeFirmware.Lock,
+    display: SmartHomeFirmware.NotImplemented
+  ]
+
+  use GenServer
+
+  alias SmartHomeFirmware.FeatureSupervisor
+
+  def start_link(opts) do
+    GenServer.start_link(__MODULE__, opts, name: __MODULE__)
+  end
+
+  def init(_opts) do
+    SmartHomeFirmware.State.subscribe(:self)
+    {:ok, %{}}
+  end
+
+  def handle_info({:store_update, :self, %{feature_flags: flags}}, state) do
+    # flags are stored as strings, we need to convert them to atoms
+    flags
+    |> Enum.map(&String.to_existing_atom(&1))
+    |> enable_features()
+
+    {:noreply, state}
+  end
+
+  @doc """
+  enable_features takes a list of features and enables them on the firmware.
+
+  E.g. [:lock, :display]
+  """
+  def enable_features(features) do
+    Logger.info(inspect features)
+    features
+    |> Enum.map(&Keyword.get(@feature_flags, &1))
+    |> Enum.each(&DynamicSupervisor.start_child(FeatureSupervisor, &1))
+  end
+end

lib/smart_home_firmware/feature_supervisor.ex

@@ -0,0 +1,18 @@
+defmodule SmartHomeFirmware.FeatureSupervisor do
+  use DynamicSupervisor
+
+
+  @moduledoc """
+  This supervisor allows us to dynamically toggle on and off features of
+  the firmware.
+  """
+
+  def start_link(opts) do
+    DynamicSupervisor.start_link(__MODULE__, opts, name: __MODULE__)
+  end
+
+  def init(_opts) do
+    DynamicSupervisor.init(strategy: :one_for_one)
+  end
+
+end