Query Mongo 2 json

[
    // select max(datetime), sum(precipitation)
    // from rain where source._id = 5bb4f8cd37a346769874ecdf and precipitation >= 4
    // group by year, month, day
    // order by datetime desc
    /*
    {
        "_id": ..,
        "source": {
            "name": ...
            "_id": ...
        }
    }
    */
    {
        "$match": {
            "$and": [
                {
                    "source._id": "5bb4f8cd37a346769874ecdf"
                },
                {
                    "precipitation": {
                        "$gt": "4"
                    }
                }
            ]
        }
    },
    {
        "$group": {
            "_id": {
                "year": {
                    "$year": "$datetime"
                },
                "month": {
                    "$month": "$datetime"
                },
                "day": {
                    "$dayOfMonth": "$datetime"
                },
                "source\u1390_id": "$source._id",
                "source\u1390name": "$source.name"
            },
            "datetime": {
                "$max": "$datetime"
            },
            "precipitation": {
                "$sum": "$precipitation"
            }
        }
    },
    {
        "$project": {
            "_id": "1",
            "source.name": "$_id.source\u1390name",
            "source._id": "$_id.source\u1390_id",
            "datetime": "1",
            "location": "1",
            "precipitation": "1"
        }
    },
    {
        "$sort": {
            "datetime": "-1"
        }
    },
    {
        "$limit": "1"
    }
]