def c_stats(campaign_class=["dynamic",'static','event'])
    # puts "Listing campaigns of type: #{campaign_class}"

    campaigns_info = campaigns.in(type: campaign_class).only(:_id, :name, :type, :status )
    ids = campaigns_info.map { |c| c._id}

    # puts "Ids: #{ids}"

    pipeline = [
      # {"$match" => {project_id: self._id} },
      {"$match" => {'campaign_id' => {'$in' => ids}} },
      {"$project" => {
       campaign_id: '$campaign_id',
       non_opened: {"$ifNull" => [ '$action', 1 ]},
       opened: {"$cond" => [{"$eq" => ['$action', 0]}, 1, 0]},
       engaged: {"$cond" => [{"$eq" => ['$action', 1]}, 1, 0]}
      }},
      { "$group" => {
       _id: '$campaign_id',
       non_opened: {"$sum" => '$non_opened'},
       opened: {"$sum" => '$opened'},
       engaged: {"$sum" => '$engaged'}
      }}
    ]


    hashed_campaigns = Hash[campaigns_info.map { |u| [u._id, u] }]

    aggregation = Notification.collection.aggregate(pipeline)
    hashed_aggregation = Hash[aggregation.map { |u| [u['_id'], u] }]

    final_data = []
    new_data = hashed_campaigns.as_json.each do |k,v|

           v["engaged"] = hashed_aggregation.as_json.key?(k) ? hashed_aggregation.as_json[k]["engaged"] : 0
        v["non_opened"] = hashed_aggregation.as_json.key?(k) ? hashed_aggregation.as_json[k]["non_opened"] : 0
            v["opened"] = hashed_aggregation.as_json.key?(k) ? hashed_aggregation.as_json[k]["opened"] : 0

    end

    return new_data.map { |key,value| value }
  end