module Stripe::APIOperations::NestedResource

def nested_resource_class_methods(resource, path: nil, operations: nil,
                                  resource_plural: nil)
  resource_plural ||= "#{resource}s"
  path ||= resource_plural
  raise ArgumentError, "operations array required" if operations.nil?
  resource_url_method = :"#{resource}s_url"
  define_singleton_method(resource_url_method) do |id, nested_id = nil|
    url = "#{resource_url}/#{CGI.escape(id)}/#{CGI.escape(path)}"
    url += "/#{CGI.escape(nested_id)}" unless nested_id.nil?
    url
  end
  operations.each do |operation|
    case operation
    when :create
      define_singleton_method(:"create_#{resource}") \
          do |id, params = {}, opts = {}|
        url = send(resource_url_method, id)
        resp, opts = request(:post, url, params, opts)
        Util.convert_to_stripe_object(resp.data, opts)
      end
    when :retrieve
      define_singleton_method(:"retrieve_#{resource}") \
          do |id, nested_id, opts = {}|
        url = send(resource_url_method, id, nested_id)
        resp, opts = request(:get, url, {}, opts)
        Util.convert_to_stripe_object(resp.data, opts)
      end
    when :update
      define_singleton_method(:"update_#{resource}") \
          do |id, nested_id, params = {}, opts = {}|
        url = send(resource_url_method, id, nested_id)
        resp, opts = request(:post, url, params, opts)
        Util.convert_to_stripe_object(resp.data, opts)
      end
    when :delete
      define_singleton_method(:"delete_#{resource}") \
          do |id, nested_id, params = {}, opts = {}|
        url = send(resource_url_method, id, nested_id)
        resp, opts = request(:delete, url, params, opts)
        Util.convert_to_stripe_object(resp.data, opts)
      end
    when :list
      define_singleton_method(:"list_#{resource_plural}") \
          do |id, params = {}, opts = {}|
        url = send(resource_url_method, id)
        resp, opts = request(:get, url, params, opts)
        Util.convert_to_stripe_object(resp.data, opts)
      end
    else
      raise ArgumentError, "Unknown operation: #{operation.inspect}"
    end
  end
end