// Arguments: Doubles, Doubles, Doubles, Doubles
#include <stan/math/prim/prob/skew_normal_ccdf_log.hpp>
#include <stan/math/prim/fun/log.hpp>
#include <stan/math/prim/fun/erfc.hpp>
#include <stan/math/prim/fun/sqrt.hpp>
#include <stan/math/prim/fun/owens_t.hpp>

using stan::math::var;
using std::numeric_limits;
using std::vector;

class AgradCcdfLogSkewNormal : public AgradCcdfLogTest {
 public:
  void valid_values(vector<vector<double> >& parameters,
                    vector<double>& ccdf_log) {
    vector<double> param(4);

    param[0] = 0;  // y
    param[1] = 0;  // mu
    param[2] = 1;  // sigma
    param[3] = 1;  // alpha
    parameters.push_back(param);
    ccdf_log.push_back(
        std::log(1.0 - 0.2500000000000001110223));  // expected ccdf_log

    param[0] = 1;  // y
    param[1] = 0;  // mu
    param[2] = 1;  // sigma
    param[3] = 1;  // alpha
    parameters.push_back(param);
    ccdf_log.push_back(
        std::log(1.0 - 0.7078609817371410706244));  // expected ccdf_log

    param[0] = -1;  // y
    param[1] = 0;   // mu
    param[2] = 1;   // sigma
    param[3] = 3;   // alpha
    parameters.push_back(param);
    ccdf_log.push_back(std::log(
        1.0
        - 0.00005624443371187709415635692284235862134252368571012732206706451807484923689534924660749487716440408152));  // expected ccdf_log

    param[0] = -0.3;  // y
    param[1] = 0.1;   // mu
    param[2] = 1.2;   // sigma
    param[3] = 1.9;   // alpha
    parameters.push_back(param);
    ccdf_log.push_back(
        std::log(1.0 - 0.05529792943083011724781));  // expected ccdf_log
  }

  void invalid_values(vector<size_t>& index, vector<double>& value) {
    // y

    // mu
    index.push_back(1U);
    value.push_back(-numeric_limits<double>::infinity());

    index.push_back(1U);
    value.push_back(numeric_limits<double>::infinity());

    // sigma
    index.push_back(2U);
    value.push_back(-numeric_limits<double>::infinity());

    index.push_back(2U);
    value.push_back(-1.0);

    index.push_back(2U);
    value.push_back(0.0);

    // alpha
    index.push_back(3U);
    value.push_back(-numeric_limits<double>::infinity());

    index.push_back(3U);
    value.push_back(numeric_limits<double>::infinity());
  }

  bool has_lower_bound() { return false; }

  bool has_upper_bound() { return false; }

  template <typename T_y, typename T_loc, typename T_scale, typename T_shape,
            typename T4, typename T5>
  stan::return_type_t<T_y, T_loc, T_scale, T_shape> ccdf_log(
      const T_y& y, const T_loc& mu, const T_scale& sigma, const T_shape& alpha,
      const T4&, const T5&) {
    return stan::math::skew_normal_ccdf_log(y, mu, sigma, alpha);
  }

  template <typename T_y, typename T_loc, typename T_scale, typename T_shape,
            typename T4, typename T5>
  stan::return_type_t<T_y, T_loc, T_scale, T_shape> ccdf_log_function(
      const T_y& y, const T_loc& mu, const T_scale& sigma, const T_shape& alpha,
      const T4&, const T5&) {
    using stan::math::owens_t;
    return log(1.0
               - (0.5 * erfc(-(y - mu) / (sqrt(2.0) * sigma))
                  - 2.0 * owens_t((y - mu) / sigma, alpha)));
  }
};
