gistfile1.rb

    def filter_by_country
      funds = Fund.any_in(institution_id: current_account.institutions.map(&:id))
                .only(:asset_ids)
      asset_ids = funds.map(&:asset_ids).flatten.uniq

      map = <<-MAP
        function() {
          country = db.countries.find(this.country_id)
          emit(country.name, 1)
        }
      MAP

      reduce = <<-REDUCE
        function(k, values) {
          var sum = 0; 
          for(var i in values) 
            sum += values[i]; 
          return sum;
        }
      REDUCE

      @assets = Asset.collection.map_reduce(map, reduce, { query: { _id: { in: asset_ids } } } )
      
      # assets = Asset.any_in(_id: asset_ids).order_by([[:country_id, :asc]])
      # @assets_by_country = assets.group_by(&:country_name) do |country, assets|
      #   [country, assets.count]
      # end
    end