module Impressionist
  module Impressionable

    def self.included(base)
      base.extend ClassMethods
      base.send(:include, InstanceMethods)
    end

    module ClassMethods
      attr_accessor :cache_options
      @cache_options = nil

      def is_impressionable(options={})
        has_many :impressions, :as=>:impressionable
        @cache_options = options[:counter_cache]
      end

      def counter_cache_options
        if @cache_options
          options = { :column_name => :impressions_count, :unique => false }
          options.merge!(@cache_options) if @cache_options.is_a?(Hash)
          options
        end
      end

      def counter_caching?
        counter_cache_options.present?
      end
    end

    module InstanceMethods
      def impressionable?
        true
      end

      def impressionist_count(options={})
        options.reverse_merge!(:filter=>:request_hash, :start_date=>nil, :end_date=>Time.now)
        imps = options[:start_date].blank? ? impressions : impressions.where("created_at>=? and created_at<=?",options[:start_date],options[:end_date])
        if options[:filter]!=:all
          imps = imps.select(options[:filter]).group(options[:filter])
        end
        imps.all.size
      end

      def update_counter_cache
        cache_options = self.class.counter_cache_options
        column_name = cache_options[:column_name].to_sym
        count = cache_options[:unique] ? impressionist_count(:filter => :ip_address) : impressionist_count
        update_attribute(column_name, count)
      end

      # OLD METHODS - DEPRECATE IN V0.5
      def impression_count(start_date=nil,end_date=Time.now)
        impressionist_count({:start_date=>start_date, :end_date=>end_date, :filter=>:all})
      end

      def unique_impression_count(start_date=nil,end_date=Time.now)
        impressionist_count({:start_date=>start_date, :end_date=>end_date, :filter=> :request_hash})
      end

      def unique_impression_count_ip(start_date=nil,end_date=Time.now)
        impressionist_count({:start_date=>start_date, :end_date=>end_date, :filter=> :ip_address})
      end

      def unique_impression_count_session(start_date=nil,end_date=Time.now)
        impressionist_count({:start_date=>start_date, :end_date=>end_date, :filter=> :session_hash})
      end
    end

  end
end