ML-174: add empty action to record set dropdown menu

Add RecordSets.empty_record_set/1 that bulk-deletes all items in a set via
a single DELETE query and returns the reloaded empty set. Add Empty button
with confirmation prompt to both index and show view dropdowns.

lib/music_library/record_sets.ex

@@ -88,6 +88,14 @@ defmodule MusicLibrary.RecordSets do
     end
   end
 
+  @spec empty_record_set(RecordSet.t()) :: {:ok, RecordSet.t()}
+  def empty_record_set(%RecordSet{} = record_set) do
+    from(i in RecordSetItem, where: i.record_set_id == ^record_set.id)
+    |> Repo.delete_all()
+
+    {:ok, get_record_set!(record_set.id)}
+  end
+
   @spec delete_record_set(RecordSet.t()) :: {:ok, RecordSet.t()} | {:error, Changeset.t()}
   def delete_record_set(%RecordSet{} = record_set) do
     Repo.delete(record_set)

lib/music_library_web/live/record_set_live/index.ex

@@ -221,6 +221,11 @@ defmodule MusicLibraryWeb.RecordSetLive.Index do
     {:noreply, push_patch(socket, to: ~p"/record-sets?#{qs}")}
   end
 
+  def handle_event("empty_set", %{"id" => id}, socket) do
+    {:ok, updated_set} = RecordSets.empty_record_set(%RecordSet{id: id})
+    {:noreply, update_record_set_in_list(socket, updated_set)}
+  end
+
   def handle_event("delete_set", %{"id" => id}, socket) do
     record_set = RecordSets.get_record_set!(id)
     {:ok, _} = RecordSets.delete_record_set(record_set)
@@ -319,6 +324,13 @@ defmodule MusicLibraryWeb.RecordSetLive.Index do
               {gettext("Edit")}
             </.dropdown_link>
             <.dropdown_separator />
+            <.dropdown_button
+              phx-click="empty_set"
+              phx-value-id={@record_set.id}
+              data-confirm={gettext("Remove all records from this set?")}
+            >
+              {gettext("Empty")}
+            </.dropdown_button>
             <.dropdown_button
               phx-click="delete_set"
               phx-value-id={@record_set.id}

lib/music_library_web/live/record_set_live/show.ex

@@ -48,6 +48,12 @@ defmodule MusicLibraryWeb.RecordSetLive.Show do
                 {gettext("Edit")}
               </.dropdown_link>
               <.dropdown_separator />
+              <.dropdown_button
+                phx-click="empty_set"
+                data-confirm={gettext("Remove all records from this set?")}
+              >
+                {gettext("Empty")}
+              </.dropdown_button>
               <.dropdown_button
                 phx-click="delete_set"
                 data-confirm={gettext("Are you sure?")}
@@ -236,6 +242,15 @@ defmodule MusicLibraryWeb.RecordSetLive.Show do
   end
 
   @impl true
+  def handle_event("empty_set", _params, socket) do
+    {:ok, updated_set} = RecordSets.empty_record_set(socket.assigns.record_set)
+
+    {:noreply,
+     socket
+     |> assign(:record_set, updated_set)
+     |> put_toast(:info, gettext("Set emptied"))}
+  end
+
   def handle_event("delete_set", _params, socket) do
     case RecordSets.delete_record_set(socket.assigns.record_set) do
       {:ok, _} ->