fix: add validation for required custom fields

lib/membership/member.ex

@@ -329,6 +329,63 @@ defmodule Mv.Membership.Member do
         {:error, field: :email, message: "is not a valid email"}
       end
     end
+
+    # Validate required custom fields
+    validate fn changeset, _ ->
+      custom_field_values_arg = Ash.Changeset.get_argument(changeset, :custom_field_values)
+
+      # If argument is not provided (nil), check existing values from member data (update scenario)
+      # If argument is provided (empty list or list with values), use those values
+      provided_values =
+        if is_nil(custom_field_values_arg) do
+          # Update scenario: check existing custom field values from member
+          case Ash.load(changeset.data, :custom_field_values) do
+            {:ok, %{custom_field_values: existing_values}} ->
+              Enum.reduce(existing_values, %{}, fn cfv, acc ->
+                value = if is_map(cfv.value), do: Map.get(cfv.value, :value), else: nil
+                Map.put(acc, cfv.custom_field_id, value)
+              end)
+
+            _ ->
+              %{}
+          end
+        else
+          # Create or update scenario: use provided argument values
+          Enum.reduce(custom_field_values_arg, %{}, fn cfv, acc ->
+            custom_field_id = Map.get(cfv, "custom_field_id")
+            value_map = Map.get(cfv, "value", %{})
+            actual_value = Map.get(value_map, "value")
+            Map.put(acc, custom_field_id, actual_value)
+          end)
+        end
+
+      # Load all required custom fields
+      case Mv.Membership.list_custom_fields() do
+        {:ok, all_custom_fields} ->
+          required_custom_fields = Enum.filter(all_custom_fields, & &1.required)
+
+          # Check each required custom field
+          missing_fields =
+            Enum.filter(required_custom_fields, fn cf ->
+              value = Map.get(provided_values, cf.id)
+              not value_present?(value, cf.value_type)
+            end)
+
+          if Enum.empty?(missing_fields) do
+            :ok
+          else
+            missing_names = Enum.map_join(missing_fields, ", ", & &1.name)
+
+            {:error,
+             field: :custom_field_values,
+             message: "Required custom fields missing: #{missing_names}"}
+          end
+
+        {:error, _} ->
+          # If we can't load custom fields, skip validation (shouldn't happen in normal operation)
+          :ok
+      end
+    end
   end
 
   attributes do
@@ -665,4 +722,18 @@ defmodule Mv.Membership.Member do
       query
     end
   end
+
+  # Helper function to check if a value is present for a given custom field type
+  # Boolean: false is valid, only nil is invalid
+  # String: nil or empty strings are invalid
+  # Integer: nil is invalid, 0 is valid
+  # Date: nil is invalid
+  # Email: nil is invalid
+  defp value_present?(nil, _type), do: false
+  defp value_present?(value, :boolean), do: not is_nil(value)
+  defp value_present?(value, :string), do: is_binary(value) and String.trim(value) != ""
+  defp value_present?(value, :integer), do: not is_nil(value)
+  defp value_present?(value, :date), do: not is_nil(value)
+  defp value_present?(value, :email), do: not is_nil(value)
+  defp value_present?(_value, _type), do: false
 end