module Devise
  class TaggedLogging
    def initialize(app)
      @app = app
    end

    def call(env)
      if logger.respond_to?(:tagged)
        logger.tagged(compute_devise_tags(env)) { @app.call(env) }
      else
        @app.call(env)
      end
    end

    private

    def compute_devise_tags(env)
      serializer = Warden::SessionSerializer.new(env)

      Devise.mappings.keys.map do |scope|
        key = serializer.key_for(scope)

        if session_data = serializer.session[key]
          ["current #{scope}", session_data[1]].join(": ")
        end
      end.compact
    end

    def logger
      Rails.logger
    end
  end
end