Implement presence and fix email test

assets/js/app.js

@@ -17,6 +17,6 @@ const liveSocket = new LiveSocket(
 
 liveSocket.connect();
 
-liveSocket.enableDebug();
+// liveSocket.enableDebug();
 
 window.liveSocket = liveSocket;

lib/chess/board.ex

@@ -65,7 +65,7 @@ defmodule Chess.Board do
     })
   end
 
-  def castling_move(board, %{"from" => [4, rank], "to" => [6, _rank]}) do
+  def castling_move(board, %{from: {4, rank}, to: {6, _rank}}) do
     move_piece(board, %{
       from: {7, rank},
       to: {5, rank}

lib/chess/emails.ex

@@ -19,8 +19,8 @@ defmodule Chess.Emails do
   end
 
   def opponent_moved_email(socket, game) do
-    user = Repo.get(User, socket.assigns.user_id)
-    opponent = opponent(game, socket.assigns.user_id)
+    user = Repo.get(User, socket.assigns.user.id)
+    opponent = opponent(game, socket.assigns.user.id)
 
     new_email()
     |> to(opponent)

lib/chess_web/channels/presence.ex

@@ -1,73 +1,4 @@
 defmodule ChessWeb.Presence do
-  @moduledoc """
-  Provides presence tracking to channels and processes.
-
-  See the [`Phoenix.Presence`](http://hexdocs.pm/phoenix/Phoenix.Presence.html)
-  docs for more details.
-
-  ## Usage
-
-  Presences can be tracked in your channel after joining:
-
-      defmodule Chess.MyChannel do
-        use ChessWeb, :channel
-        alias Chess.Presence
-
-        def join("some:topic", _params, socket) do
-          send(self, :after_join)
-          {:ok, assign(socket, :user_id, ...)}
-        end
-
-        def handle_info(:after_join, socket) do
-          push socket, "presence_state", Presence.list(socket)
-          {:ok, _} = Presence.track(socket, socket.assigns.user_id, %{
-            online_at: inspect(System.system_time(:second))
-          })
-          {:noreply, socket}
-        end
-      end
-
-  In the example above, `Presence.track` is used to register this
-  channel's process as a presence for the socket's user ID, with
-  a map of metadata. Next, the current presence list for
-  the socket's topic is pushed to the client as a `"presence_state"` event.
-
-  Finally, a diff of presence join and leave events will be sent to the
-  client as they happen in real-time with the "presence_diff" event.
-  See `Phoenix.Presence.list/2` for details on the presence datastructure.
-
-  ## Fetching Presence Information
-
-  The `fetch/2` callback is triggered when using `list/1`
-  and serves as a mechanism to fetch presence information a single time,
-  before broadcasting the information to all channel subscribers.
-  This prevents N query problems and gives you a single place to group
-  isolated data fetching to extend presence metadata.
-
-  The function receives a topic and map of presences and must return a
-  map of data matching the Presence datastructure:
-
-      %{"123" => %{metas: [%{status: "away", phx_ref: ...}],
-        "456" => %{metas: [%{status: "online", phx_ref: ...}]}
-
-  The `:metas` key must be kept, but you can extend the map of information
-  to include any additional information. For example:
-
-      def fetch(_topic, entries) do
-        users = entries |> Map.keys() |> Accounts.get_users_map(entries)
-        # => %{"123" => %{name: "User 123"}, "456" => %{name: nil}}
-
-        for {key, %{metas: metas}} <- entries, into: %{} do
-          {key, %{metas: metas, user: users[key]}}
-        end
-      end
-
-  The function above fetches all users from the database who
-  have registered presences for the given topic. The fetched
-  information is then extended with a `:user` key of the user's
-  information, while maintaining the required `:metas` field from the
-  original presence data.
-  """
   use Phoenix.Presence,
     otp_app: :chess,
     pubsub_server: Chess.PubSub

lib/chess_web/templates/game/game_info.html.leex

@@ -1,7 +1,11 @@
 <div class="game-info">
   <p>
     Playing <%= opponent(@game, @user.id).name %>
-    <img class="game-info__opponent-status" src="/images/eye-closed.svg" alt="offline">
+    <%= if Map.has_key?(@presence, opponent(@game, @user.id).id) do %>
+      <img class="game-info__opponent-status" src="/images/eye-open.svg" alt="online">
+    <% else %>
+      <img class="game-info__opponent-status" src="/images/eye-closed.svg" alt="offline">
+    <% end %>
   </p>
 </div>
 

lib/chess_web/views/game_view.ex

@@ -2,6 +2,7 @@ defmodule ChessWeb.GameView do
   use ChessWeb, :view
 
   alias Chess.GameState
+  alias Chess.Repo
 
   import Phoenix.Component
   import Chess.Auth, only: [current_user: 1]
@@ -88,6 +89,14 @@ defmodule ChessWeb.GameView do
     end
   end
 
+  def opponent_id(game, user_id) do
+    if game.user_id == user_id do
+      game.opponent_id
+    else
+      game.user_id
+    end
+  end
+
   def opponent(game, user_id) do
     if game.user_id == user_id do
       game.opponent

lib/chess_web/views/live/board_live.ex

@@ -1,6 +1,8 @@
 defmodule ChessWeb.BoardLive do
   use Phoenix.LiveView, container: {:div, class: "board__container"}
 
+  alias Chess.Emails
+  alias Chess.Mailer
   alias Chess.Store.User
   alias Chess.Store.Game
   alias Chess.Store.Move
@@ -8,6 +10,7 @@ defmodule ChessWeb.BoardLive do
   alias Chess.Moves
 
   alias ChessWeb.GameView
+  alias ChessWeb.Presence
 
   import Ecto.Query
 
@@ -25,6 +28,7 @@ defmodule ChessWeb.BoardLive do
     game =
       Game.for_user(user)
       |> Repo.get!(game_id)
+      |> Repo.preload([:user, :opponent])
 
     {:ok, assign(socket, default_assigns(game, user))}
   end
@@ -51,10 +55,14 @@ defmodule ChessWeb.BoardLive do
     {:noreply, assign(socket, state)}
   end
 
+  def handle_info(%{event: "presence_diff", payload: _params}, socket) do
+    {:noreply, socket}
+  end
+
   defp handle_click(socket, file, rank) do
-    game = socket.assigns[:game]
+    game = socket.assigns.game
     board = game.board
-    user = socket.assigns[:user]
+    user = socket.assigns.user
 
     colour = GameView.player_colour(user, game)
 
@@ -65,7 +73,7 @@ defmodule ChessWeb.BoardLive do
             handle_selection(board, colour, file, rank)
 
           _ ->
-            handle_move(socket.assigns, file, rank)
+            handle_move(socket, file, rank)
         end
       end
 
@@ -85,17 +93,16 @@ defmodule ChessWeb.BoardLive do
     end
   end
 
-  defp handle_move(
-         %{game: game, available: available, selected: selected},
-         file,
-         rank
-       ) do
+  defp handle_move(socket, file, rank) do
+    %{game: game, available: available, selected: selected} = socket.assigns
+
     if {file, rank} in available do
       game
       |> Moves.make_move(%{from: selected, to: {file, rank}})
       |> case do
         {:ok, %{game: game}} ->
           game
+          |> Repo.reload()
           |> Repo.preload([:user, :opponent])
           |> Repo.preload(
             moves:
@@ -106,6 +113,8 @@ defmodule ChessWeb.BoardLive do
           )
           |> broadcast_move(game.board)
 
+          email_move(socket, game)
+
           [
             {:selected, nil},
             {:available, []},
@@ -118,6 +127,24 @@ defmodule ChessWeb.BoardLive do
     end
   end
 
+  defp email_move(socket, game) do
+    opponent_id =
+      GameView.opponent_id(game, socket.assigns.user.id)
+      |> Integer.to_string()
+
+    "game:#{game.id}"
+    |> Presence.list()
+    |> case do
+      %{^opponent_id => _} ->
+        nil
+
+      _ ->
+        socket
+        |> Emails.opponent_moved_email(game)
+        |> Mailer.deliver_later()
+    end
+  end
+
   defp broadcast_move(game, board) do
     ChessWeb.Endpoint.broadcast_from(
       self(),

lib/chess_web/views/live/game_info_live.ex

@@ -5,6 +5,7 @@ defmodule ChessWeb.GameInfoLive do
   alias Chess.Store.Game
   alias Chess.Store.Move
   alias Chess.Repo
+  alias ChessWeb.Presence
 
   import Ecto.Query
 
@@ -15,7 +16,9 @@ defmodule ChessWeb.GameInfoLive do
   end
 
   def mount(_params, %{"game_id" => game_id, "user_id" => user_id}, socket) do
-    ChessWeb.Endpoint.subscribe("game:#{game_id}")
+    topic = "game:#{game_id}"
+
+    ChessWeb.Endpoint.subscribe(topic)
 
     user = Repo.get!(User, user_id)
 
@@ -32,10 +35,38 @@ defmodule ChessWeb.GameInfoLive do
       )
       |> Repo.get!(game_id)
 
-    {:ok, assign(socket, game: game, user: user)}
+    Presence.track(self(), topic, :user, %{id: user_id})
+
+    {:ok, assign(socket, game: game, user: user, presence: presence_list(topic))}
   end
 
   def handle_info(%{event: "move", payload: state}, socket) do
     {:noreply, assign(socket, state)}
   end
+
+  def handle_info(
+        %{event: "presence_diff", payload: %{joins: joins, leaves: leaves}},
+        socket
+      ) do
+    {:noreply, socket |> handle_joins(joins) |> handle_leaves(leaves)}
+  end
+
+  defp presence_list(topic) do
+    Presence.list(topic)
+    |> Map.get("user")
+    |> Map.get(:metas)
+    |> Map.new(fn meta -> {meta.id, meta} end)
+  end
+
+  defp handle_joins(socket, joins) do
+    Enum.reduce(joins, socket, fn {"user", %{metas: [meta | _]}}, socket ->
+      assign(socket, :presence, Map.put(socket.assigns.presence, meta.id, meta))
+    end)
+  end
+
+  defp handle_leaves(socket, leaves) do
+    Enum.reduce(leaves, socket, fn {"user", %{metas: [meta | _]}}, socket ->
+      assign(socket, :presence, Map.delete(socket.assigns.presence, meta.id))
+    end)
+  end
 end

test/chess/board_test.exs

@@ -72,7 +72,7 @@ defmodule Chess.BoardTest do
       "3,0" => %{"type" => "queen", "colour" => "white"}
     }
 
-    %{board: new_board} = Board.move_piece(board, %{"from" => [3, 0], "to" => [5, 2]})
+    %{board: new_board} = Board.move_piece(board, %{from: {3, 0}, to: {5, 2}})
 
     assert new_board == %{
              "5,2" => %{"type" => "queen", "colour" => "white"}
@@ -85,7 +85,7 @@ defmodule Chess.BoardTest do
       "7,0" => %{"type" => "rook", "colour" => "white"}
     }
 
-    %{board: new_board} = Board.move_piece(board, %{"from" => [4, 0], "to" => [6, 0]})
+    %{board: new_board} = Board.move_piece(board, %{from: {4, 0}, to: {6, 0}})
 
     assert new_board == %{
              "6,0" => %{"type" => "king", "colour" => "white"},
@@ -99,7 +99,7 @@ defmodule Chess.BoardTest do
       "0,0" => %{"type" => "rook", "colour" => "white"}
     }
 
-    %{board: new_board} = Board.move_piece(board, %{"from" => [4, 0], "to" => [2, 0]})
+    %{board: new_board} = Board.move_piece(board, %{from: {4, 0}, to: {2, 0}})
 
     assert new_board == %{
              "2,0" => %{"type" => "king", "colour" => "white"},