Given I have a collection User and a collection Calendar and a Calendar belongs_to User and I want to sort calendars by the user name. When I use the aggregation framework:

collection = Calendar.collection.aggregate([
  {'$match' => { _id:

{ '$in' => @selectedCalendars.pluck(:id) }

}},
  {'$lookup' => { from: 'users', localField: 'owner_id', foreignField: '_id', as: 'owners' }},
  {'$unwind' => '$owners' },
  {'$sort' =>

{ 'owners.last_name' => -1, 'owners.first_name' => -1 }

},
  {'$group' => { _id: nil, ids:

{ '$addToSet' => '$_id' }

} },
  {'$project' =>

{ _id: 0 }

}
])

I get back a Mongo::Collection::View::Aggregation instance. But what I need back is a Mongoid::Criteria, because I need to be able to chain additiona query methods like where, or, and even paginate. This data needs to be paginated with the pagination library I am using which is expecting a criteria.

You might say well you have no other option but to get the ids from $project and wrap that in an '$in' query, as such:

> collection.entries
=> [{"ids"=>[BSON::ObjectId('5d8546593ed149344bfa5667'), BSON::ObjectId('5d8546363ed14934356506ee'), BSON::ObjectId('5d8546593ed149344bfa5665')]}]
> Calendar.in(_id: collection[0]['ids'])

While this will give me a Mongoid::Criteria, it no longer preserves the sort order I had created in the aggregation (the call to in() ignores the order of the ids). So now I don't know how this issue could be resolved. I need to be able to preserve that expensive sort order. What is one to do without this feature?