mongo-driver: Unknown operator: $meta

I want to write this query db.station.find({$and:[ {available:true}, { $text: {$search: "Romania SunFolk Radio"}}]}, {score: {$meta: "textScore"}}).sort({score:{$meta:"textScore"}})

I wrote

filter := bson.D{
	{"$and", bson.A{
		bson.M{"available": true},
		bson.M{"$text": bson.M{
			"$search": query,
		}},
	}},
	{"score", bson.M{"$meta": "textScore"}},
}

opts := options.Find()
opts.SetSort(bson.M{"score": bson.M{"$meta": "textScore"}})
opts.SetLimit(1)

cursor, err := s.collection.Find(ctx, filter, opts)
if err != nil {
	log.Println(err)
}

But this code return error (BadValue) unknown operator: $meta.
How to write this query correctly?

The $meta operator is a projection operator not a filter operator (see docs). You're passing it in to the filter. This actually is the answer to your question as already pointed out in the comments. If all you need is to sort based on the textScore, you can do it like this.

filter := bson.D{
	{"$and", bson.A{
		bson.M{"available": true},
		bson.M{"$text": bson.M{
			"$search": query,
		}},
	}},
}

opts := options.Find()
opts.SetSort(bson.M{"score": bson.M{"$meta": "textScore"}})
opts.SetLimit(1)

cursor, err := s.collection.Find(ctx, filter, opts)
if err != nil {
	log.Println(err)
}