Query to Determine All Unique IDs that are distance X away from a particular ID?

[brolo (ibro)]

I have data in this format generated from a random walk (to simulate people walking around). It is set up in this manner { location : { lat: someLat, lon: someLong }, id: uniqueId, date:date }. I am trying to write a query given a users unique ID, find how many other unique IDs came within X distance of the given ID between a certain time range. Any hints on how to accomplish this?

My idea is to have a top level filter aggregration, with a nested geo-query of some sort. I think the geo-distance query is the way to go, but I am not sure how to include it into the below query to get all of unique IDs that come within X distance of the ID I am filtering on. The query below is where I am starting from, I am filtering all documents from now - 1 day to now, where the documents user Id is the provided value. How would I check all other documents for their distances against documents that match this query?

{
    "aggs" : {
        "range": {
            "date_range": {
                "field": "date",
                "format": "MM-yyyy",
                "ranges": [
                    { "to": "now" }, 
                    { "from": "now-1d" } 
                ]
            }
        },
        "locations" : {
            "filter" : { 
              "term": { "id.keyword": "7a50ab18-886b-42a2-80ad-3d45112e3cfd" }
            }
        }
    }
}