How to update nested field using query in elasticsearch 2.4?

I have made an Elasticsearch query:

GET shop/products/_search
{
   "_source": [
      "similar_group.product_info.product_id",
      "shop_id",
      "similar_group.product_info.tags",
      "similar_group.product_info.inventory",
      "similar_group.product_info.name"
   ],
   "query": {
      "bool": {
         "must": [
            {
               "nested": {
                  "path": "similar_group.product_info",
                  "query": {
                     "bool": {
                        "must": {
                           "term": {
                              "similar_group.product_info.product_id": 82
                           }
                        }
                     }
                  }
               }
            },
            {
               "term": {
                  "shop_id": 11
               }
            }
         ]
      }
   }
}

Running this query, I'm getting this as a response:

{
   "took": 3,
   "timed_out": false,
   "_shards": {
      "total": 7,
      "successful": 7,
      "failed": 0
   },
   "hits": {
      "total": 1,
      "max_score": 9.741081,
      "hits": [
         {
            "_index": "shop",
            "_type": "products",
            "_id": "m11g82",
            "_score": 9.741081,
            "_source": {
               "shop_id": 11,
               "similar_group": {
                  "product_info": [
                     {
                        "product_id": 82,
                        "name": "SpiderMan Toy",
                        "tags": [],
                        "inventory": 12
                     },
                     {
                        "product_id": 44,
                        "name": "Beyblade",
                        "tags": ["mattel"],
                        "inventory": 2
                     }
                  ]
               }
            }
         }
      ]
   }
}

I need to update product_id - 82 with inventory as 0 and want to add tags for it.

How should I proceed to update these two fields which I've mentioned above?

Tried to look over solution over internet, found that we can use inline-scripts. Most of the examples are in "painless" language. Elasticsearch 2.4 uses "groovy" language. It would be great if anyone can help me with this.

Thanks a lot! in advance :slight_smile:

It would be great if anyone can help me with this issue, I'm still not able to get the desired results.