Update Book and SelectedPublisher component to require Publisher.

lib/decentralised_book_index_web/components/my_components/selected_publisher.ex

@@ -2,6 +2,8 @@ defmodule DecentralisedBookIndexWeb.Components.MyComponents.SelectedPublisher do
   use Phoenix.Component
   use DecentralisedBookIndexWeb, :verified_routes
 
+  alias DecentralisedBookIndexWeb.CoreComponents
+
   attr :publisher_form, :map, default: nil
 
   def selected_publisher(assigns) do
@@ -14,16 +16,29 @@ defmodule DecentralisedBookIndexWeb.Components.MyComponents.SelectedPublisher do
         DecentralisedBookIndex.Metadata.get_publisher_by_id!(publisher_id)
       end
 
-    assigns = assign(assigns, :publisher, publisher)
+    errors =
+      if Phoenix.Component.used_input?(assigns.publisher_form), do: assigns.publisher_form.errors, else: []
+
+    assigns =
+      assigns
+      |> assign(:publisher, publisher)
+      |> assign(:errors, Enum.map(errors, &CoreComponents.translate_error(&1)))
 
     ~H"""
-    <button type="button" phx-click="open-select-publisher" phx-target={@notify_component} class="text-white bg-blue-700 hover:bg-blue-800 focus:outline-none focus:ring-4 focus:ring-blue-300 font-medium rounded-full text-sm px-5 py-2.5 text-center dark:bg-blue-600 dark:hover:bg-blue-700 dark:focus:ring-blue-800">
+    <button
+      type="button"
+      phx-click="open-select-publisher"
+      phx-target={@notify_component}
+      class="text-white bg-blue-700 hover:bg-blue-800 focus:outline-none focus:ring-4 focus:ring-blue-300 font-medium rounded-full text-sm px-5 py-2.5 text-center dark:bg-blue-600 dark:hover:bg-blue-700 dark:focus:ring-blue-800"
+    >
       <%= if @publisher != nil do %>
         {@publisher.name}
       <% else %>
         Select a publisher
       <% end %>
     </button>
+
+    <CoreComponents.error :for={msg <- @errors}>{msg}</CoreComponents.error>
     """
   end
 end