/**
  \file

  \brief Graybody implementation.

  \who \kpr
*/
#include "mutils/nmath.h"

#include "Detector.h"
#include "Graybody.h"

namespace mu = mutils;

namespace manticore {

/// Detector support.
namespace graybody {

/// Parameters required by flux().
struct FluxData {
  double Th,      ///< Core temperature.
         Sigmah,  ///< Core mass surface density.
         Tc,      ///< Halo temperature.
         Sigmac;  ///< Halo surface density.

  const Detector *d;  ///< Detector instance.

  const Graybody *g;  ///< Graybody instance.

  /// Single-temperature graybody intensity method.
  double (Graybody::*I)(double, double, double) const;

  /// Two-temperature graybody intensity method.
  double (Graybody::*I2)(double, double, double, double, double) const;
};

extern "C" {

/// Flux density integrand (one-component).
/// \param[in] nu  Frequency (Hz).
/// \param[in] fd  FluxData instance.
double flux(double nu, void *fd) {
  auto &p = *static_cast<const FluxData*>(fd);
  return (p.g->*(p.I))(nu, p.Th, p.Sigmah) * p.d->response(nu);
}

/// Flux density integrand (two-component).
/// \param[in] nu  Frequency (Hz).
/// \param[in] fd  FluxData instance.
double flux2(double nu, void *fd) {
  auto &p = *static_cast<const FluxData*>(fd);
  return (p.g->*(p.I2))(nu, p.Tc, p.Sigmac, p.Th, p.Sigmah) *
          p.d->response(nu);
}

}  // extern "C"

}  // namescape graybody


double Graybody::Itot(double (Graybody::*I)(double, double, double) const,
                      double T, double Sigma, const Detector *detect,
                      double sr) const
{
  graybody::FluxData fd = {T, Sigma, 0.0, 0.0, detect, this, I, nullptr};
  std::pair<double, double> freqRange = detect->freqRange();
  return sr * mu::kgauss_r(graybody::flux, &fd,
                           freqRange.first, freqRange.second, err_);
}


double Graybody::Itot2(
         double (Graybody::*I)(double, double, double, double, double) const,
         double Tc, double Sigmac, double Th, double Sigmah,
         const Detector *detect, double sr) const
{
  std::pair<double, double> freqRange = detect->freqRange();
  graybody::FluxData fd = {Th, Sigmah, Tc, Sigmac, detect, this, nullptr, I};
  return sr * mu::kgauss_r(graybody::flux2, &fd,
                           freqRange.first, freqRange.second, err_);
}

}  // namespace manticore