#ifndef STAN_MATH_PRIM_SCAL_PROB_UNIFORM_CDF_HPP
#define STAN_MATH_PRIM_SCAL_PROB_UNIFORM_CDF_HPP

#include <stan/math/prim/scal/meta/is_constant_struct.hpp>
#include <stan/math/prim/scal/meta/partials_return_type.hpp>
#include <stan/math/prim/scal/meta/operands_and_partials.hpp>
#include <stan/math/prim/scal/err/check_consistent_sizes.hpp>
#include <stan/math/prim/scal/err/check_finite.hpp>
#include <stan/math/prim/scal/err/check_greater.hpp>
#include <stan/math/prim/scal/err/check_not_nan.hpp>
#include <stan/math/prim/scal/fun/constants.hpp>
#include <stan/math/prim/scal/fun/value_of.hpp>
#include <stan/math/prim/scal/meta/VectorBuilder.hpp>
#include <stan/math/prim/scal/meta/include_summand.hpp>
#include <stan/math/prim/scal/meta/scalar_seq_view.hpp>
#include <boost/random/uniform_real_distribution.hpp>
#include <boost/random/variate_generator.hpp>

namespace stan {
  namespace math {

    template <typename T_y, typename T_low, typename T_high>
    typename return_type<T_y, T_low, T_high>::type
    uniform_cdf(const T_y& y, const T_low& alpha, const T_high& beta) {
      static const char* function("uniform_cdf");
      typedef typename stan::partials_return_type<T_y, T_low, T_high>::type
        T_partials_return;

      if (!(stan::length(y) && stan::length(alpha) && stan::length(beta)))
        return 1.0;

      T_partials_return cdf(1.0);
      check_not_nan(function, "Random variable", y);
      check_finite(function, "Lower bound parameter", alpha);
      check_finite(function, "Upper bound parameter", beta);
      check_greater(function, "Upper bound parameter", beta, alpha);
      check_consistent_sizes(function,
                             "Random variable", y,
                             "Lower bound parameter", alpha,
                             "Upper bound parameter", beta);

      scalar_seq_view<T_y> y_vec(y);
      scalar_seq_view<T_low> alpha_vec(alpha);
      scalar_seq_view<T_high> beta_vec(beta);
      size_t N = max_size(y, alpha, beta);

      for (size_t n = 0; n < N; n++) {
        const T_partials_return y_dbl = value_of(y_vec[n]);
        if (y_dbl < value_of(alpha_vec[n])
            || y_dbl > value_of(beta_vec[n]))
          return 0.0;
      }

      operands_and_partials<T_y, T_low, T_high>
        ops_partials(y, alpha, beta);
      for (size_t n = 0; n < N; n++) {
        const T_partials_return y_dbl = value_of(y_vec[n]);
        const T_partials_return alpha_dbl = value_of(alpha_vec[n]);
        const T_partials_return beta_dbl = value_of(beta_vec[n]);
        const T_partials_return b_min_a = beta_dbl - alpha_dbl;
        const T_partials_return cdf_ = (y_dbl - alpha_dbl) / b_min_a;

        cdf *= cdf_;

        if (!is_constant_struct<T_y>::value)
          ops_partials.edge1_.partials_[n] += 1.0 / b_min_a / cdf_;
        if (!is_constant_struct<T_low>::value)
          ops_partials.edge2_.partials_[n] += (y_dbl - beta_dbl) / b_min_a
            / b_min_a / cdf_;
        if (!is_constant_struct<T_high>::value)
          ops_partials.edge3_.partials_[n] -= 1.0 / b_min_a;
      }

      if (!is_constant_struct<T_y>::value) {
        for (size_t n = 0; n < stan::length(y); ++n)
          ops_partials.edge1_.partials_[n] *= cdf;
      }
      if (!is_constant_struct<T_low>::value) {
        for (size_t n = 0; n < stan::length(alpha); ++n)
          ops_partials.edge2_.partials_[n] *= cdf;
      }
      if (!is_constant_struct<T_high>::value) {
        for (size_t n = 0; n < stan::length(beta); ++n)
          ops_partials.edge3_.partials_[n] *= cdf;
      }

      return ops_partials.build(cdf);
    }

  }
}
#endif
