refactor: fix credo warnings and format code

- Replace Enum.map/2 |> Enum.join/2 with Enum.map_join/3 for efficiency
- Refactor get_existing_form_values to reduce cyclomatic complexity
- Replace length/1 with Enum.empty?/1 for better performance
- Update gettext translations

lib/mv_web/helpers/membership_fee_helpers.ex

@@ -28,6 +28,7 @@ defmodule MvWeb.Helpers.MembershipFeeHelpers do
     # Use German format: comma as decimal separator, always 2 decimal places
     # Normalize to 2 decimal places
     normalized = Decimal.round(amount, 2)
+
     normalized_str =
       normalized
       |> Decimal.to_string(:normal)

lib/mv_web/live/member_live/show.ex

@@ -248,6 +248,7 @@ defmodule MvWeb.MemberLive.Show do
     # Calculate last and current cycle status from loaded cycles
     last_cycle_status = get_last_cycle_status(member)
     current_cycle_status = get_current_cycle_status(member)
+
     member =
       member
       |> Map.put(:last_cycle_status, last_cycle_status)

lib/mv_web/live/member_live/show/membership_fees_component.ex

@@ -39,7 +39,9 @@ defmodule MvWeb.MemberLive.Show.MembershipFeesComponent do
               </span>
             </div>
           <% else %>
-            <span class="text-base-content/60 italic">{gettext("No membership fee type assigned")}</span>
+            <span class="text-base-content/60 italic">
+              {gettext("No membership fee type assigned")}
+            </span>
           <% end %>
         </div>
 
@@ -369,9 +371,7 @@ defmodule MvWeb.MemberLive.Show.MembershipFeesComponent do
 
       {:error, %Ash.Error.Invalid{} = error} ->
         error_msg =
-          error.errors
-          |> Enum.map(fn e -> e.message end)
-          |> Enum.join(", ")
+          Enum.map_join(error.errors, ", ", fn e -> e.message end)
 
         {:noreply,
          socket
@@ -424,7 +424,6 @@ defmodule MvWeb.MemberLive.Show.MembershipFeesComponent do
     end
   end
 
-
   def handle_event("edit_cycle_amount", %{"cycle_id" => cycle_id}, socket) do
     cycle = find_cycle(socket.assigns.cycles, cycle_id)
 

lib/mv_web/live/membership_fee_settings_live.ex

@@ -44,7 +44,8 @@ defmodule MvWeb.MembershipFeeSettingsLive do
         Map.put(params, "include_joining_cycle", false)
       end
 
-    {:noreply, assign(socket, form: AshPhoenix.Form.validate(socket.assigns.form, normalized_params))}
+    {:noreply,
+     assign(socket, form: AshPhoenix.Form.validate(socket.assigns.form, normalized_params))}
   end
 
   def handle_event("save", %{"settings" => params}, socket) do

lib/mv_web/live/membership_fee_type_live/form.ex

@@ -324,55 +324,32 @@ defmodule MvWeb.MembershipFeeTypeLive.Form do
   defp get_existing_form_values(form) do
     # Extract values directly from form fields to get current state
     # This ensures we get the actual current values, not just initial params
-    existing_values = %{}
-
-    existing_values =
-      if form[:name] && form[:name].value do
-        Map.put(existing_values, "name", to_string(form[:name].value))
-      else
-        existing_values
-      end
-
-    existing_values =
-      if form[:amount] && form[:amount].value do
-        # Convert Decimal to string for form
-        amount_str =
-          case form[:amount].value do
-            %Decimal{} = amount -> Decimal.to_string(amount, :normal)
-            value when is_binary(value) -> value
-            value -> to_string(value)
-          end
-
-        Map.put(existing_values, "amount", amount_str)
-      else
-        existing_values
-      end
-
-    existing_values =
-      if form[:interval] && form[:interval].value do
-        # Convert atom to string for form
-        interval_str =
-          case form[:interval].value do
-            value when is_atom(value) -> Atom.to_string(value)
-            value when is_binary(value) -> value
-            value -> to_string(value)
-          end
-
-        Map.put(existing_values, "interval", interval_str)
-      else
-        existing_values
-      end
-
-    existing_values =
-      if form[:description] && form[:description].value do
-        Map.put(existing_values, "description", to_string(form[:description].value))
-      else
-        existing_values
-      end
-
-    existing_values
+    %{}
+    |> extract_form_value(form, :name, &to_string/1)
+    |> extract_form_value(form, :amount, &format_amount_value/1)
+    |> extract_form_value(form, :interval, &format_interval_value/1)
+    |> extract_form_value(form, :description, &to_string/1)
   end
 
+  # Helper to extract a single form field value
+  defp extract_form_value(acc, form, field, formatter) do
+    if form[field] && form[field].value do
+      Map.put(acc, to_string(field), formatter.(form[field].value))
+    else
+      acc
+    end
+  end
+
+  # Formats amount value (Decimal or string) to string
+  defp format_amount_value(%Decimal{} = amount), do: Decimal.to_string(amount, :normal)
+  defp format_amount_value(value) when is_binary(value), do: value
+  defp format_amount_value(value), do: to_string(value)
+
+  # Formats interval value (atom or string) to string
+  defp format_interval_value(value) when is_atom(value), do: Atom.to_string(value)
+  defp format_interval_value(value) when is_binary(value), do: value
+  defp format_interval_value(value), do: to_string(value)
+
   @spec return_path(String.t(), MembershipFeeType.t() | nil) :: String.t()
   defp return_path("index", _membership_fee_type), do: ~p"/membership_fee_types"