how to do if doc_count ==0 then 1 else 0 in elastic search

checked Bucket Script Aggregation A parent pipeline aggregation which executes a script which can perform per bucket computations on specified metrics in the parent multi-bucket aggregation. The specified metric must be numeric and the script must return a numeric value.

when using bucket script I am having the below query,but unable to print 1000 for product_id= 6435532 when _count ==0 or [] instead it doesn't print anything. please help. it is working fine when _count > 0.

POST index_name/_search?size=0
{
  "aggs": {
"group by products": {
  "terms": {
    "field": "product_id.keyword",

  },
  "aggs": {
    "filter for PVW": {
      "filter": {
        "term": {
          "event_type.keyword": "PVW"
        }
      }
    },
    "group_by_CIP": {
      "terms": {
        "field": "event_type.keyword",
        "include": "CIP"

      },
      "aggregations": {
        "print product id": {
          "aggs": {
            "CIP doc count": {
              "bucket_script": {
                "buckets_path": {
                  "var1": "_count"

                },
                "script": "if (params.var1 == 'N/A') {1000 } else { params.var1 }" -- unable to print 1000 for _count value Null or 0 value
              }
            }
          },
          "terms": {
            "field": "web_prod_id.keyword"
          }
        }
      }
    }
  }
}

} }

output looks like

 "aggregations": {
"group by products": {
  "doc_count_error_upper_bound": 111,
  "sum_other_doc_count": 115547,
  "buckets": [
    {
      "key": "6435532",
      "doc_count": 282,
      "group_by_CIP": {
        "doc_count_error_upper_bound": 0,
        "sum_other_doc_count": 0,
        "buckets": []
      },
      "filter for PVW": {
        "doc_count": 282
      }
    },
    {
      "key": "5697273",
      "doc_count": 247,
      "group_by_CIP": {
        "doc_count_error_upper_bound": 0,
        "sum_other_doc_count": 0,
        "buckets": [
          {
            "key": "CIP",
            "doc_count": 13,
            "print product id": {
              "doc_count_error_upper_bound": 0,
              "sum_other_doc_count": 0,
              "buckets": [
                {
                  "key": "5697273",
                  "doc_count": 13,
                  "CIP doc count": {
                    "value": 13
                  }
                }
              ]
            }
          }
        ]
      },
      "filter for PVW": {
        "doc_count": 234
      }
    }
   ]
 }

} }

any one facing this same issue?