defmodule Formex.Ecto.Validator do
  alias Formex.FormCollection
  alias Formex.FormNested
  alias Formex.Form

  @moduledoc false

  def assign_changeset_errors(form, changeset) do
    form_items =
      Enum.map(form.items, fn item ->
        if Form.is_controllable(item) and Map.has_key?(changeset.changes, item.struct_name) do
          case item do
            collection = %FormCollection{} ->
              forms =
                collection.forms
                |> Enum.with_index()
                |> Enum.map(fn {nested, index} ->
                  nested_changeset =
                    changeset.changes
                    |> Map.get(item.struct_name)
                    |> Enum.at(index)

                  form = assign_changeset_errors(nested.form, nested_changeset)

                  %{nested | form: form}
                end)

              %{collection | forms: forms}

            nested = %FormNested{} ->
              nested_changeset =
                changeset.changes
                |> Map.get(item.struct_name)

              %{nested | form: assign_changeset_errors(nested.form, nested_changeset)}

            _ ->
              item
          end
        else
          item
        end
      end)

    errors =
      changeset.errors
      |> Enum.reduce([], fn {key, val}, acc ->
        name = Form.get_name_by_struct_name(form, key)

        Keyword.update(acc, name, [val], &[val | &1])
      end)

    form
    |> Map.put(:items, form_items)
    |> Map.put(:errors, errors)
    |> Formex.Validator.translate_errors()
  end
end