if ENV['SKYLIGHT_AUTHENTICATION']

  require 'skylight/sinatra'
  require 'tool/thread_local'
  Skylight.start!

  module Travis
    module Api
      module ConditionalSkylight
        FEATURES        = Tool::ThreadLocal.new
        CHECK_FREQUENCY = 120
        NOT_JSON        = %r(\.(xml|png|txt|atom|svg)$)

        module Middleware
          ::Skylight::Middleware.send(:prepend, self)
          def call(env)
            if ConditionalSkylight.track?(env)
              super(env)
            else
              t { "skipping middleware (condition not met)".freeze }
              @app.call(env)
            end
          end
        end

        extend self

        def track?(env)
          return false unless feature_active? :skylight
          return false if     feature_active? :skylight_json_only and env['PATH_INFO'.freeze] =~ NOT_JSON
          true
        end

        def feature_active?(feature)
          last_clear = Time.now.to_i - FEATURES[:last_clear].to_i

          if last_clear > CHECK_FREQUENCY
            FEATURES.clear
            FEATURES[:last_clear] = Time.now.to_i
          end

          FEATURES.fetch(feature) { FEATURES[feature] = Travis::Features.feature_active?(feature) }
        end
      end
    end
  end

else
  Travis.logger.info('SKYLIGHT_AUTHENTICATION not set, skipping Skylight.')
end