class OmniAuth::Builder

def before_callback_phase(&block)
  OmniAuth.config.before_callback_phase = block
end

def before_options_phase(&block)
  OmniAuth.config.before_options_phase = block
end

def before_request_phase(&block)
  OmniAuth.config.before_request_phase = block
end

def call(env)
  to_app.call(env)
end

def configure(&block)
  OmniAuth.configure(&block)
end

def on_failure(&block)
  OmniAuth.config.on_failure = block
end

def options(options = false)
  return @options ||= {} if options == false
  @options = options
end

def provider(klass, *args, **opts, &block)
  if klass.is_a?(Class)
    middleware = klass
  else
    begin
      middleware = OmniAuth::Strategies.const_get(OmniAuth::Utils.camelize(klass.to_s).to_s, false)
    rescue NameError
      raise(LoadError.new("Could not find matching strategy for #{klass.inspect}. You may need to install an additional gem (such as omniauth-#{klass})."))
    end
  end
  use middleware, *args, **options.merge(opts), &block
end