How to create a random instance of a case class?

Suppose I've got a few case classes, e.g.:

case class C(c1: Int, c2: Double, c3: Option[String])
case class B(b: Int, cs: Seq[C])
case class A(a: String, bs: Seq[B]) 

Now I would like to generate a few instances of A with random values.

I am looking for a generic way to do that. I can probably do it with runtime reflection but I prefer a compile-time solution.

def randomInstance[A](a: A): A = ???

How can I do it ? Can it be done with shapeless ?