feat: create Room context

- add a Registry, Supervisor, DynamicSupervisor to manage game state in Engine.

lib/viral_spiral/application.ex

@@ -12,6 +12,7 @@ defmodule ViralSpiral.Application do
       ViralSpiral.Repo,
       {DNSCluster, query: Application.get_env(:viral_spiral, :dns_cluster_query) || :ignore},
       {Phoenix.PubSub, name: ViralSpiral.PubSub},
+      ViralSpiral.Room,
       # Start the Finch HTTP client for sending emails
       {Finch, name: ViralSpiral.Finch},
       # Start a worker by calling: ViralSpiral.Worker.start_link(arg)

lib/viral_spiral/room.ex

@@ -0,0 +1,64 @@
+defmodule ViralSpiral.Room do
+  @moduledoc """
+  Context for activities within a Viral Spiral Room.
+
+  This architecture is heavily borrowed from [here](https://dashbit.co/blog/homemade-analytics-with-ecto-and-elixir).
+  Rooms in viral spiral need to manage mutable state of the game, hence they are wrapped in a `GenServer`. These genservers are then supervised by a Dynamic Supervisor, which is managed by this Supervisor. This supervisor is started by the application and is part of its supervision tree.
+
+  ## Usage :
+  Room.new("vanilla-bean-23")
+  engine = ViralSpiral.Room.room_gen!("ok-pista-4")
+  send(engine, msg)
+  """
+
+  use Supervisor
+  alias ViralSpiral.Room.NotFound
+
+  @room_gen ViralSpiral.Room.GameEngine
+  @registry ViralSpiral.Room.Registry
+  @supervisor ViralSpiral.Room.GameEngineSupervisor
+
+  def start_link(_opts) do
+    Supervisor.start_link(__MODULE__, :ok, name: __MODULE__)
+  end
+
+  @impl true
+  def init(:ok) do
+    children = [
+      {Registry, keys: :unique, name: @registry},
+      {DynamicSupervisor, name: @supervisor, strategy: :one_for_one}
+    ]
+
+    Supervisor.init(children, strategy: :one_for_all)
+  end
+
+  def new(path) when is_binary(path) do
+    pid =
+      case Registry.lookup(@registry, path) do
+        [{pid, _}] ->
+          pid
+
+        [] ->
+          pid =
+            case DynamicSupervisor.start_child(@supervisor, {@room_gen, path}) do
+              {:ok, pid} -> pid
+              {:error, {:already_started, pid}} -> pid
+            end
+
+          pid
+      end
+
+    send(pid, :new_room)
+  end
+
+  def room_gen!(path) do
+    case Registry.lookup(@registry, path) do
+      [{pid, _}] -> pid
+      _ -> raise NotFound
+    end
+  end
+end
+
+defmodule ViralSpiral.Room.NotFound do
+  defexception message: "Unable to find room"
+end

lib/viral_spiral/room/game_engine.ex

@@ -0,0 +1,54 @@
+defmodule ViralSpiral.Room.GameEngine do
+  alias ViralSpiral.Room.State.Root
+  alias ViralSpiral.Room.State.Room
+  use GenServer
+
+  @registry ViralSpiral.Room.Registry
+
+  def start_link(path) do
+    GenServer.start_link(__MODULE__, path, name: {:via, Registry, {@registry, path}})
+  end
+
+  @impl true
+  def init(_init_arg) do
+    # room = Room.new() |> Room.start(4)
+    # # root = Root.new(room, init_arg.players)
+    # root = Root.new(room, ["adhiraj", "krys", "aman", "farah"])
+
+    {:ok, [1]}
+  end
+
+  @impl true
+  def handle_cast({:join, player_name}, state) do
+  end
+
+  @impl true
+  def handle_cast({:pass, from, to}, state) do
+  end
+
+  @impl true
+  def handle_cast({:keep, from}, state) do
+  end
+
+  @impl true
+  def handle_cast({:discard, from}, state) do
+  end
+
+  @impl true
+  def handle_cast({:check_source, from}, state) do
+  end
+
+  @impl true
+  def handle_cast({:cancel, from, target}, state) do
+  end
+
+  @impl true
+  def handle_cast({:viral_spiral, from, targets}, state) do
+  end
+
+  @impl true
+  def handle_info(msg, state) do
+    IO.inspect("msg in genserver #{msg}")
+    {:noreply, state}
+  end
+end

lib/viral_spiral/room/store.ex

@@ -0,0 +1,5 @@
+defmodule ViralSpiral.Game.Store do
+  @doc """
+  Persist game state to disk.
+  """
+end