refactor: fix credo issues

lib/mv_web/live/member_live/index.ex

@@ -1194,32 +1194,13 @@ defmodule MvWeb.MemberLive.Index do
       params
       |> Enum.filter(fn {key, _value} -> String.starts_with?(key, @boolean_filter_prefix) end)
       |> Enum.reduce(%{}, fn {key, value_str}, acc ->
-        # Extract custom field ID from parameter name (explicitly remove prefix)
-        # This is more secure than String.replace_prefix which only removes first occurrence
-        custom_field_id_str = String.slice(key, prefix_length, String.length(key) - prefix_length)
-
-        # Validate custom field ID length (UUIDs are max @max_uuid_length characters)
-        # This provides an additional security layer beyond UUID format validation
-        if String.length(custom_field_id_str) <= @max_uuid_length do
-          # Validate custom field ID exists and is boolean type
-          case Ecto.UUID.cast(custom_field_id_str) do
-            {:ok, _custom_field_id} ->
-              if Map.has_key?(boolean_custom_fields, custom_field_id_str) do
-                # Validate filter value
-                case determine_boolean_filter(value_str) do
-                  nil -> acc
-                  filter_value -> Map.put(acc, custom_field_id_str, filter_value)
-                end
-              else
-                acc
-              end
-
-            :error ->
-              acc
-          end
-        else
+        process_boolean_filter_param(
+          key,
+          value_str,
+          prefix_length,
+          boolean_custom_fields,
           acc
-        end
+        )
       end)
 
     # Security: Limit number of filters to prevent DoS attacks
@@ -1240,6 +1221,73 @@ defmodule MvWeb.MemberLive.Index do
     assign(socket, :boolean_custom_field_filters, filters)
   end
 
+  # Processes a single boolean filter parameter from URL params.
+  #
+  # Validates the parameter and adds it to the accumulator if valid.
+  # Returns the accumulator unchanged if validation fails.
+  defp process_boolean_filter_param(
+         key,
+         value_str,
+         prefix_length,
+         boolean_custom_fields,
+         acc
+       ) do
+    # Extract custom field ID from parameter name (explicitly remove prefix)
+    # This is more secure than String.replace_prefix which only removes first occurrence
+    custom_field_id_str = String.slice(key, prefix_length, String.length(key) - prefix_length)
+
+    # Validate custom field ID length (UUIDs are max @max_uuid_length characters)
+    # This provides an additional security layer beyond UUID format validation
+    if String.length(custom_field_id_str) > @max_uuid_length do
+      acc
+    else
+      validate_and_add_boolean_filter(
+        custom_field_id_str,
+        value_str,
+        boolean_custom_fields,
+        acc
+      )
+    end
+  end
+
+  # Validates UUID format and custom field existence, then adds filter if valid.
+  defp validate_and_add_boolean_filter(
+         custom_field_id_str,
+         value_str,
+         boolean_custom_fields,
+         acc
+       ) do
+    case Ecto.UUID.cast(custom_field_id_str) do
+      {:ok, _custom_field_id} ->
+        add_boolean_filter_if_valid(
+          custom_field_id_str,
+          value_str,
+          boolean_custom_fields,
+          acc
+        )
+
+      :error ->
+        acc
+    end
+  end
+
+  # Adds boolean filter to accumulator if custom field exists and value is valid.
+  defp add_boolean_filter_if_valid(
+         custom_field_id_str,
+         value_str,
+         boolean_custom_fields,
+         acc
+       ) do
+    if Map.has_key?(boolean_custom_fields, custom_field_id_str) do
+      case determine_boolean_filter(value_str) do
+        nil -> acc
+        filter_value -> Map.put(acc, custom_field_id_str, filter_value)
+      end
+    else
+      acc
+    end
+  end
+
   # Determines valid boolean filter value from URL parameter.
   #
   # SECURITY: This function whitelists allowed filter values. Only "true" and "false"