feat(chat): toggle room membership on index page

lib/slax/chat.ex

@@ -35,6 +35,18 @@ defmodule Slax.Chat do
     )
   end
 
+  def toggle_room_membership(%Room{} = room, %User{} = user) do
+    case Repo.get_by(RoomMembership, room_id: room.id, user_id: user.id) do
+      %RoomMembership{} = membership ->
+        Repo.delete(membership)
+        {room, false}
+
+      nil ->
+        join_room!(room, user)
+        {room, true}
+    end
+  end
+
   def change_room(room, attrs \\ %{}) do
     Room.changeset(room, attrs)
   end

lib/slax_web/live/chat_room_live/index.ex

@@ -37,6 +37,17 @@ defmodule SlaxWeb.ChatRoomLive.Index do
                 <% end %>
               </div>
             </div>
+            <button
+              class="opacity-0 group-hover:opacity-100 bg-white hover:bg-gray-100 border border-gray-400 text-gray-700 px-3 py-1.5 w-24 rounded-sm font-bold"
+              phx-click="toggle-room-membership"
+              phx-value-id={room.id}
+            >
+              <%= if joined? do %>
+                Leave
+              <% else %>
+                Join
+              <% end %>
+            </button>
           </div>
         </div>
       </div>
@@ -56,4 +67,14 @@ defmodule SlaxWeb.ChatRoomLive.Index do
 
     {:ok, socket}
   end
+
+  @impl Phoenix.LiveView
+  def handle_event("toggle-room-membership", %{"id" => id}, socket) do
+    {room, joined?} =
+      id
+      |> Chat.get_room!()
+      |> Chat.toggle_room_membership(socket.assigns.current_user)
+
+    {:noreply, stream_insert(socket, :rooms, {room, joined?})}
+  end
 end