module SessionLogger

  module SessionLogging
    extend ActiveSupport::Concern

    module ClassMethods #:nodoc:

      # Options are the same as the ones for around filter. See docs for around filter
      def enable_session_logging(options={})

        raise "Session Logging can't occur without specifying logged_models in initializers" if SessionLogger.logged_models.blank?

        SessionLogger::SessionObserver.observe(SessionLogger.logged_models)

        if !ActiveRecord::Base.observers.include? SessionLogger::SessionObserver
          ActiveRecord::Base.observers << SessionLogger::SessionObserver if defined?(ActiveRecord) and defined?(ActiveRecord::Base)
        end

        sweeper_instance = SessionLogger::SessionObserver.instance

        around_filter(sweeper_instance, options)
      end
    end
  end


  class SessionObserver < ActiveRecord::Observer
    attr_accessor :controller

    #Required to prevent the observer from un-cleverly looking for Session...
    def self.observed_class
      nil
    end

    # ------------------------------------------- Legacy around filter calls
    def before(controller)
      self.controller = controller
      true # before method from SessionObserver should always return true
    end

    def after(controller)
      self.controller = controller
      # Clean up, so that the controller can be collected after this request
      self.controller = nil
    end

    # ------------------------------------------- ActiveRecord callbacks
    def before_create(record)
      return if controller.blank? || controller.session.blank?

      candidate_columns = record.attributes.select { |attr| attr.starts_with? SessionLogger.model_prefix }
      candidate_columns.keys.each do |column|
        column = column.to_s
        #Only setting if present prevents empty strings from overriding defaults in the schema
        set_if_present(record, column, controller.session[column])
      end
      #pp controller.session["sl_campaign"]
      #pp record
    end

    private
    def set_if_present(obj, key, val)
      pp obj
      pp key
      pp val
      obj.send("#{key}=", val) if val.present?
    end
  end

end