require 'rack/utils'
require 'rack/request'
require 'rack/session/abstract/id'
require 'action_dispatch/middleware/cookies'
require 'action_dispatch/request/session'

module ActionDispatch
  module Session
    class SessionRestoreError < StandardError #:nodoc:

      def initialize(const_error = nil)
        if const_error
          ActiveSupport::Deprecation.warn("Passing #original_exception is deprecated and has no effect. " \
                                          "Exceptions will automatically capture the original exception.", caller)
        end

        super("Session contains objects whose class definition isn't available.\n" +
          "Remember to require the classes for all objects kept in the session.\n" +
          "(Original exception: #{$!.message} [#{$!.class}])\n")
        set_backtrace $!.backtrace
      end

      def original_exception
        ActiveSupport::Deprecation.warn("#original_exception is deprecated. Use #cause instead.", caller)
        cause
      end
    end

    module Compatibility
      def initialize(app, options = {})
        options[:key] ||= '_session_id'
        super
      end

      def generate_sid
        sid = SecureRandom.hex(16)
        sid.encode!(Encoding::UTF_8)
        sid
      end

    protected

      def initialize_sid
        @default_options.delete(:sidbits)
        @default_options.delete(:secure_random)
      end

      private
      def make_request(env)
        ActionDispatch::Request.new env
      end
    end

    module StaleSessionCheck
      def load_session(env)
        stale_session_check! { super }
      end

      def extract_session_id(env)
        stale_session_check! { super }
      end

      def stale_session_check!
        yield
      rescue ArgumentError => argument_error
        if argument_error.message =~ %r{undefined class/module ([\w:]*\w)}
          begin
            # Note that the regexp does not allow $1 to end with a ':'
            $1.constantize
          rescue LoadError, NameError
            raise ActionDispatch::Session::SessionRestoreError
          end
          retry
        else
          raise
        end
      end
    end

    module SessionObject # :nodoc:
      def prepare_session(req)
        Request::Session.create(self, req, @default_options)
      end

      def loaded_session?(session)
        !session.is_a?(Request::Session) || session.loaded?
      end
    end

    class AbstractStore < Rack::Session::Abstract::Persisted
      include Compatibility
      include StaleSessionCheck
      include SessionObject

      private

      def set_cookie(request, session_id, cookie)
        request.cookie_jar[key] = cookie
      end
    end
  end
end