#ifndef STAN_MATH_PRIM_MAT_PROB_MULTINOMIAL_RNG_HPP
#define STAN_MATH_PRIM_MAT_PROB_MULTINOMIAL_RNG_HPP

#include <stan/math/prim/mat/err/check_simplex.hpp>
#include <stan/math/prim/scal/err/check_size_match.hpp>
#include <stan/math/prim/scal/err/check_nonnegative.hpp>
#include <stan/math/prim/scal/err/check_positive.hpp>
#include <stan/math/prim/scal/fun/multiply_log.hpp>
#include <stan/math/prim/scal/fun/constants.hpp>
#include <stan/math/prim/scal/prob/binomial_rng.hpp>
#include <stan/math/prim/scal/meta/include_summand.hpp>
#include <boost/math/special_functions/gamma.hpp>
#include <boost/random/uniform_01.hpp>
#include <boost/random/variate_generator.hpp>
#include <vector>

namespace stan {

  namespace math {

    template <class RNG>
    inline std::vector<int>
    multinomial_rng(const Eigen::Matrix<double, Eigen::Dynamic, 1>& theta,
                    const int N,
                    RNG& rng) {
      static const char* function("stan::math::multinomial_rng");
      using stan::math::check_simplex;
      using stan::math::check_positive;

      check_simplex(function, "Probabilites parameter", theta);
      check_positive(function, "number of trials variables", N);

      std::vector<int> result(theta.size(), 0);
      double mass_left = 1.0;
      int n_left = N;
      for (int k = 0; n_left > 0 && k < theta.size(); ++k) {
        double p = theta[k] / mass_left;
        if (p > 1.0) p = 1.0;
        result[k] = binomial_rng(n_left, p, rng);
        n_left -= result[k];
        mass_left -= theta[k];
      }
      return result;
    }


  }
}
#endif
