#include <boost/mpi.hpp>
namespace mpi = boost::mpi;
#include <boost/variant.hpp>
#include <boost/serialization/access.hpp>
#include <boost/serialization/variant.hpp>

#include <iostream>
#include <sstream>

struct Base {
  std::string msg_;

  Base(std::string msg) : msg_(msg) { };
  Base() : msg_() { }; // default ctor needed for serialization
  virtual ~Base() { }; 

  virtual void greet(std::ostream& out) const { out << "A base greeting: " <<this-> msg_ << std::endl; };

  template<typename Archive>
  void serialize(Archive& ar, const unsigned int version)
  {
    ar & msg_;
  };
};

struct Derived1 : public Base {
  Derived1(std::string msg) : Base(msg) { };
  Derived1() : Base() { };

  virtual void greet(std::ostream& out) const { out << "A first derived greeting: " << this->Base::msg_ << std::endl; };
};

struct Derived2 : public Base {
  Derived2(std::string msg) : Base(msg) { };
  Derived2() : Base() { };

  virtual void greet(std::ostream& out) const { out << "Another derived greeting: " << this->Base::msg_ << std::endl; };
};

typedef boost::variant<Base, Derived1, Derived2> my_variant_t;

struct do_greet: public boost::static_visitor<> {
 template <typename T>
 void operator()(const T& t) const
 {
   t.greet(std::cout);
 };
};

int main(int argc, char** argv)
{
  mpi::environment env(argc, argv);
  mpi::communicator world;

  const int me = world.rank();
  const int np = world.size();

  std::cout << "rank " << me << " of " << np << " starting..." << std::endl;

  for (int i = 0; i < 10; ++i) {
    const int root = i % np;

    my_variant_t v;
    if (me == root) {
      std::ostringstream ostr;
      ostr << "message no." << i << " from rank " << me;
      switch (i % 3) {
      case 0: { Base c(ostr.str()); v = c; break; };
      case 1: { Derived1 c(ostr.str()); v = c; break; };
      case 2: { Derived2 c(ostr.str()); v = c; break; };
      };
    };
    mpi::broadcast(world, v, root);

    std::cout << "rank " << me << ": ";
    boost::apply_visitor(do_greet(), v);
    std::cout << std::endl;
  };

  return 0;
};