feat(chat): show joined rooms on index page

lib/slax/chat.ex

@@ -60,6 +60,18 @@ defmodule Slax.Chat do
     |> Enum.sort_by(& &1.name)
   end
 
+  def list_rooms_with_joined(%User{} = user) do
+    query =
+      from(r in Room,
+        left_join: m in RoomMembership,
+        on: r.id == m.room_id and m.user_id == ^user.id,
+        select: {r, not is_nil(m.id)},
+        order_by: [asc: :name]
+      )
+
+    Repo.all(query)
+  end
+
   def list_messages_in_room(%Room{id: room_id}) do
     query =
       from(m in Message,

lib/slax_web/live/chat_room_live/index.ex

@@ -13,7 +13,7 @@ defmodule SlaxWeb.ChatRoomLive.Index do
       <div class="bg-slate-50 border rounded">
         <div id="rooms" class="divide-y" phx-update="stream">
           <div
-            :for={{id, room} <- @streams.rooms}
+            :for={{id, {room, joined?}} <- @streams.rooms}
             class="cursor-pointer p-4 flex justify-between items-center group first:rounded-t last:rounded-b"
             id={id}
             phx-click={JS.navigate(~p"/rooms/#{room}")}
@@ -26,6 +26,12 @@ defmodule SlaxWeb.ChatRoomLive.Index do
                 </span>
               </div>
               <div class="text-gray-500 text-sm">
+                <%= if joined? do %>
+                  <span class="text-green-600 font-bold">✓ Joined</span>
+                <% end %>
+                <%= if joined? && room.topic do %>
+                  <span class="mx-1">·</span>
+                <% end %>
                 <%= if room.topic do %>
                   <%= room.topic %>
                 <% end %>
@@ -40,8 +46,14 @@ defmodule SlaxWeb.ChatRoomLive.Index do
 
   @impl Phoenix.LiveView
   def mount(_params, _session, socket) do
-    rooms = Chat.list_rooms()
-    socket = socket |> assign(page_title: "All rooms") |> stream(:rooms, rooms)
+    rooms = Chat.list_rooms_with_joined(socket.assigns.current_user)
+
+    socket =
+      socket
+      |> assign(page_title: "All rooms")
+      |> stream_configure(:rooms, dom_id: fn {room, _joined?} -> "rooms-#{room.id}" end)
+      |> stream(:rooms, rooms)
+
     {:ok, socket}
   end
 end