# encoding: utf-8

require 'one_apm/support/method_tracer'
require 'one_apm/transaction'
require 'one_apm/transaction/transaction_state'
require 'one_apm/inst/support/queue_time'
require 'one_apm/inst/transaction_base'
require 'one_apm/rack/middleware_tracing'

module OneApm::Rack
  class MiddlewareWrapper
    include MiddlewareTracing

    class MiddlewareClassWrapper

      def initialize(middleware_class)
        @middleware_class = middleware_class
      end

      def new(*args, &blk)
        middleware_instance = @middleware_class.new(*args, &blk)
        MiddlewareWrapper.wrap(middleware_instance)
      end

    end

    class << self

      def is_sinatra_app?(target)
        defined?(::Sinatra::Base) && target.kind_of?(::Sinatra::Base)
      end

      def wrap_class(target_class)
        MiddlewareClassWrapper.new(target_class)
      end

      def needs_wrapping?(target)
        !target.respond_to?(:_oa_has_middleware_tracing) &&
        !is_sinatra_app?(target)
      end

      def wrap(target, is_app = false)
        if needs_wrapping?(target)
          self.new(target, is_app)
        else
          target
        end
      end

    end

    attr_reader :target, :category, :transaction_options

    def initialize(target, is_app = false)
      @target               = target
      @is_app               = is_app
      @category             = determine_category
      @target_class_name    = determine_class_name
      @transaction_name     = "#{determine_prefix}#{@target_class_name}/call"
      @transaction_options  = {
        :transaction_name => @transaction_name
      }
    end

    def determine_category
      @is_app ? :rack : :middleware
    end

    def determine_prefix
      OneApm::TransactionNamer.prefix_for_category(nil, @category)
    end

    # In 'normal' usage, the target will be an application instance that
    # responds to #call. With Rails, however, the target may be a subclass
    # of Rails::Application that defines a method_missing that proxies #call
    # to a singleton instance of the the subclass. We need to ensure that we
    # capture the correct name in both cases.
    def determine_class_name
      if @target.is_a?(Class)
        @target.name
      else
        @target.class.name
      end
    end
  end
end