Maybe/app/controllers/concerns/accountable_resource.rb

module AccountableResource
  extend ActiveSupport::Concern

  included do
    include ScrollFocusable, Periodable

    before_action :set_account, only: [ :show, :edit, :update, :destroy ]
    before_action :set_link_token, only: :new
  end

  class_methods do
    def permitted_accountable_attributes(*attrs)
      @permitted_accountable_attributes = attrs if attrs.any?
      @permitted_accountable_attributes ||= [ :id ]
    end
  end

  def new
    @account = Current.family.accounts.build(
      currency: Current.family.currency,
      accountable: accountable_type.new
    )
  end

  def show
    @chart_view = params[:chart_view] || "balance"
    @q = params.fetch(:q, {}).permit(:search)
    entries = @account.entries.search(@q).reverse_chronological

    set_focused_record(entries, params[:focused_record_id])

    @pagy, @entries = pagy(entries, limit: params[:per_page] || "10", params: ->(params) { params.except(:focused_record_id) })
  end

  def edit
  end

  def create
    @account = Current.family.accounts.create_and_sync(account_params.except(:return_to))
    redirect_to account_params[:return_to].presence || @account, notice: t("accounts.create.success", type: accountable_type.name.underscore.humanize)
  end

  def update
    @account.update_with_sync!(account_params.except(:return_to))
    redirect_back_or_to @account, notice: t("accounts.update.success", type: accountable_type.name.underscore.humanize)
  end

  def destroy
    @account.destroy_later
    redirect_to accounts_path, notice: t("accounts.destroy.success", type: accountable_type.name.underscore.humanize)
  end

  private
    def set_link_token
      @us_link_token = Current.family.get_link_token(
        webhooks_url: plaid_us_webhooks_url,
        redirect_url: accounts_url,
        accountable_type: accountable_type.name,
        region: :us
      )

      if Current.family.eu?
        @eu_link_token = Current.family.get_link_token(
          webhooks_url: plaid_eu_webhooks_url,
          redirect_url: accounts_url,
          accountable_type: accountable_type.name,
          region: :eu
        )
      end
    end

    def plaid_us_webhooks_url
      return webhooks_plaid_url if Rails.env.production?

      ENV.fetch("DEV_WEBHOOKS_URL", root_url.chomp("/")) + "/webhooks/plaid"
    end

    def plaid_eu_webhooks_url
      return webhooks_plaid_eu_url if Rails.env.production?

      ENV.fetch("DEV_WEBHOOKS_URL", root_url.chomp("/")) + "/webhooks/plaid_eu"
    end

    def accountable_type
      controller_name.classify.constantize
    end

    def set_account
      @account = Current.family.accounts.find(params[:id])
    end

    def account_params
      params.require(:account).permit(
        :name, :is_active, :balance, :subtype, :currency, :accountable_type, :return_to,
        accountable_attributes: self.class.permitted_accountable_attributes
      )
    end
end