refactor: fix review blockers

lib/mv_web/live/join_live.ex

@@ -6,6 +6,7 @@ defmodule MvWeb.JoinLive do
   use MvWeb, :live_view
 
   alias Ash.Resource.Info
+  alias Mv.Membership.CustomFieldLookup
   alias Mv.Membership
   alias MvWeb.JoinRateLimit
   alias MvWeb.Translations.MemberFields
@@ -87,6 +88,7 @@ defmodule MvWeb.JoinLive do
                         <span class="label-text">{field.label}{if field.required, do: " *"}</span>
                       </label>
                       <%= if field.input_type == "checkbox" do %>
+                        <input type="hidden" name={field.id} value="off" />
                         <input
                           type="checkbox"
                           name={field.id}
@@ -249,32 +251,10 @@ defmodule MvWeb.JoinLive do
     end
   end
 
-  defp custom_field_map(allowlist, member_field_strings) do
-    custom_field_ids =
-      allowlist
-      |> Enum.map(& &1.id)
-      |> Enum.reject(&(&1 in member_field_strings))
-
-    case custom_field_ids do
-      [] ->
-        %{}
-
-      ids ->
-        Mv.Membership.CustomField
-        |> Ash.Query.select([:id, :name, :value_type])
-        |> Ash.read(domain: Mv.Membership, authorize?: false)
-        |> case do
-          {:ok, fields} ->
-            allowed_ids = MapSet.new(ids)
-
-            fields
-            |> Enum.filter(&MapSet.member?(allowed_ids, &1.id))
-            |> Map.new(&{&1.id, &1})
-
-          {:error, _} ->
-            %{}
-        end
-    end
+  defp custom_field_map(allowlist, _member_field_strings) do
+    allowlist
+    |> Enum.map(& &1.id)
+    |> CustomFieldLookup.fetch_map_by_ids(authorize?: false, select: [:id, :name, :value_type])
   end
 
   defp initial_form_params(join_fields) do
@@ -342,9 +322,12 @@ defmodule MvWeb.JoinLive do
       }
 
       form_data =
-        params
-        |> Enum.filter(fn {key, _} -> key in allowlist_ids and key not in typed end)
-        |> Map.new(fn {k, v} -> {k, String.trim(to_string(v))} end)
+        join_fields
+        |> Enum.filter(&(&1.id not in typed))
+        |> Map.new(fn field ->
+          {field.id, normalize_join_field_value(params[field.id], field.input_type)}
+        end)
+        |> Map.take(MapSet.to_list(allowlist_ids))
 
       attrs = %{attrs | form_data: form_data}
       {:ok, attrs}
@@ -356,6 +339,10 @@ defmodule MvWeb.JoinLive do
     if is_binary(v), do: String.trim(v), else: nil
   end
 
+  defp normalize_join_field_value(raw, _input_type) when is_binary(raw), do: String.trim(raw)
+  defp normalize_join_field_value(_raw, "checkbox"), do: "off"
+  defp normalize_join_field_value(_raw, _input_type), do: ""
+
   # Prefer X-Forwarded-For / X-Real-IP when behind a reverse proxy; fall back to peer_data.
   # Uses :inet.ntoa/1 for correct IPv4 and IPv6 string representation.
   defp client_ip_from_socket(socket) do