feat(chat): add auth logic for room memberships

lib/slax/chat.ex

@@ -29,6 +29,12 @@ defmodule Slax.Chat do
     Repo.insert!(%RoomMembership{room: room, user: user})
   end
 
+  def joined?(%Room{} = room, %User{} = user) do
+    Repo.exists?(
+      from rm in RoomMembership, where: rm.room_id == ^room.id and rm.user_id == ^user.id
+    )
+  end
+
   def change_room(room, attrs \\ %{}) do
     Room.changeset(room, attrs)
   end
@@ -47,6 +53,13 @@ defmodule Slax.Chat do
     Repo.all(query)
   end
 
+  def list_joined_rooms(%User{} = user) do
+    user
+    |> Repo.preload(:rooms)
+    |> Map.fetch!(:rooms)
+    |> Enum.sort_by(& &1.name)
+  end
+
   def list_messages_in_room(%Room{id: room_id}) do
     query =
       from(m in Message,

lib/slax_web/live/chat_room_live.ex

@@ -65,6 +65,7 @@ defmodule SlaxWeb.ChatRoomLive do
           <h1 class="text-sm font-bold leading-none">
             #<%= @room.name %>
             <.link
+              :if={@joined?}
               class="font-normal text-xs text-blue-600 hover:text-blue-700"
               navigate={~p"/rooms/#{@room}/edit"}
             >
@@ -135,7 +136,7 @@ defmodule SlaxWeb.ChatRoomLive do
           timezone={@timezone}
         />
       </div>
-      <div class="h-12 bg-white px-4 pb-4">
+      <div :if={@joined?} class="h-12 bg-white px-4 pb-4">
         <.form
           id="new-message-form"
           for={@new_message_form}
@@ -158,13 +159,41 @@ defmodule SlaxWeb.ChatRoomLive do
           </button>
         </.form>
       </div>
+      <div
+        :if={!@joined?}
+        class="flex justify-around mx-5 mb-5 p-6 bg-slate-100 border-slate-300 border rounded-lg"
+      >
+        <div class="max-w-3-xl text-center">
+          <div class="mb-4">
+            <h1 class="text-xl font-semibold"><%= @room.name %></h1>
+            <p :if={@room.topic} class="text-sm mt-1 text-gray-600"><%= @room.topic %></p>
+          </div>
+          <div class="flex items-center justify-around">
+            <buttom
+              phx-click="join-room"
+              class="px-4 py-2 bg-green-600 text-white rounded hover:bg-green-600 focus:outline-none focus:ring-2 focus:ring-green-500"
+            >
+              Join Room
+            </buttom>
+          </div>
+          <div class="mt-4">
+            <.link
+              navigate={~p"/rooms"}
+              href="#"
+              class="text-sm text-slate-500 underline hover:text-slate-600"
+            >
+              Back to All Rooms
+            </.link>
+          </div>
+        </div>
+      </div>
     </div>
     """
   end
 
   @impl Phoenix.LiveView
   def mount(_params, _session, socket) do
-    rooms = Chat.list_rooms()
+    rooms = Chat.list_joined_rooms(socket.assigns.current_user)
     users = Accounts.list_users()
 
     timezone = get_connect_params(socket)["timezone"]
@@ -206,7 +235,12 @@ defmodule SlaxWeb.ChatRoomLive do
 
     {:noreply,
      socket
-     |> assign(hide_topic?: false, page_title: "# #{room.name}", room: room)
+     |> assign(
+       hide_topic?: false,
+       joined?: Chat.joined?(room, socket.assigns.current_user),
+       page_title: "# #{room.name}",
+       room: room
+     )
      |> stream(:messages, messages, reset: true)
      |> assign_message_form(Chat.change_message(%Message{}))
      |> push_event("scroll_messages_to_bottom", %{})}
@@ -228,12 +262,16 @@ defmodule SlaxWeb.ChatRoomLive do
     %{current_user: user, room: room} = socket.assigns
 
     socket =
-      case Chat.create_message(room, user, message_params) do
-        {:ok, _message} ->
-          assign_message_form(socket, Chat.change_message(%Message{}))
+      if Chat.joined?(room, user) do
+        case Chat.create_message(room, user, message_params) do
+          {:ok, _message} ->
+            assign_message_form(socket, Chat.change_message(%Message{}))
 
-        {:error, changeset} ->
-          assign_message_form(socket, changeset)
+          {:error, changeset} ->
+            assign_message_form(socket, changeset)
+        end
+      else
+        socket
       end
 
     {:noreply, socket}
@@ -246,6 +284,16 @@ defmodule SlaxWeb.ChatRoomLive do
     {:noreply, socket}
   end
 
+  @impl Phoenix.LiveView
+  def handle_event("join-room", _, socket) do
+    current_user = socket.assigns.current_user
+    room = socket.assigns.room
+    Chat.join_room!(room, current_user)
+    Chat.subscribe_to_room(room)
+    socket = assign(socket, joined?: true, rooms: Chat.list_joined_rooms(current_user))
+    {:noreply, socket}
+  end
+
   @impl Phoenix.LiveView
   def handle_info({:new_message, message}, socket) do
     socket =

lib/slax_web/live/chat_room_live/edit.ex

@@ -33,12 +33,19 @@ defmodule SlaxWeb.ChatRoomLive.Edit do
   @impl Phoenix.LiveView
   def mount(%{"id" => id}, _session, socket) do
     room = Chat.get_room!(id)
-    changeset = Chat.change_room(room)
 
     socket =
-      socket
-      |> assign(page_title: "Edit chat room", room: room)
-      |> assign_form(changeset)
+      if Chat.joined?(room, socket.assigns.current_user) do
+        changeset = Chat.change_room(room)
+
+        socket
+        |> assign(page_title: "Edit chat room", room: room)
+        |> assign_form(changeset)
+      else
+        socket
+        |> put_flash(:error, "Permission denied")
+        |> push_navigate(to: ~p"/")
+      end
 
     {:ok, socket}
   end