#include "MString.h"
#include <variant>

#if !defined(M__VARTYPE)
#define M__VARTYPE

using michlib::MString;

namespace vartype
{
enum class Vartype
{
 NONE,
 U,
 V,
 TEMP,
 SAL,
 CHL,
 MLD,
 SSH,
 W
};

template<Vartype vt_> struct VartypeCarrier
{
 static const Vartype vt = vt_;
};

using VartypeUnion =
    std::variant<VartypeCarrier<Vartype::NONE>, VartypeCarrier<Vartype::U>, VartypeCarrier<Vartype::V>, VartypeCarrier<Vartype::TEMP>, VartypeCarrier<Vartype::SAL>,
                 VartypeCarrier<Vartype::CHL>, VartypeCarrier<Vartype::MLD>, VartypeCarrier<Vartype::SSH>, VartypeCarrier<Vartype::W>>;

template<class T, Vartype vt>
concept HasVar = requires(T t) {
                  {
                   t.template Read<vt>(0)(0, 0)
                   } -> std::convertible_to<real>;
                  {
                   t.template Read<vt>(std::vector<size_t>())(0, 0)
                   } -> std::convertible_to<real>;
                 };
} // namespace vartype

template<class DT, vartype::Vartype vt> static constexpr bool isDataSupported = vartype::HasVar<DT, vt>;

class VarType: public vartype::VartypeUnion
{
 auto VT() const
 {
  return std::visit(
      [](auto v) -> auto{ return decltype(v)::vt; }, *this);
 }

 public:
 template<vartype::Vartype vt> VarType(vartype::VartypeCarrier<vt>&& vc): vartype::VartypeUnion(std::move(vc)) {}

 VarType(MString str)
 {
  str.ToLower();
  if(str == "u") *this = vartype::VartypeCarrier<vartype::Vartype::U>();
  if(str == "v") *this = vartype::VartypeCarrier<vartype::Vartype::V>();
  if(str == "t" || str == "temp" || str == "temperature") *this = vartype::VartypeCarrier<vartype::Vartype::TEMP>();
  if(str == "s" || str == "sal" || str == "salinity") *this = vartype::VartypeCarrier<vartype::Vartype::SAL>();
  if(str == "c" || str == "chl" || str == "chlorophyll") *this = vartype::VartypeCarrier<vartype::Vartype::CHL>();
  if(str == "mld") *this = vartype::VartypeCarrier<vartype::Vartype::MLD>();
  if(str == "ssh") *this = vartype::VartypeCarrier<vartype::Vartype::SSH>();
  if(str == "w") *this = vartype::VartypeCarrier<vartype::Vartype::W>();
 }

 MString Name() const
 {
  switch(VT())
  {
  case(vartype::Vartype::NONE): return "none";
  case(vartype::Vartype::U): return "U";
  case(vartype::Vartype::V): return "V";
  case(vartype::Vartype::TEMP): return "Temperature";
  case(vartype::Vartype::SAL): return "Salinity";
  case(vartype::Vartype::CHL): return "Chlorophyll";
  case(vartype::Vartype::MLD): return "Mixed layer depth";
  case(vartype::Vartype::SSH): return "Sea surface height";
  case(vartype::Vartype::W): return "W";
  }
  return "none";
 }

 bool                      Ok() const { return VT() != vartype::Vartype::NONE; }
 explicit                  operator bool() const { return Ok(); }
 bool                      operator==(const VarType& vt) const { return VT() == vt.VT(); }
 bool                      operator!=(const VarType& vt) const { return VT() != vt.VT(); }
 template<class Data> bool isSupported() const
 {
  return std::visit(
      [](const auto v) -> bool
      {
       if constexpr(isDataSupported<Data, decltype(v)::vt>)
        return true;
       else
        return false;
      },
      *this);
 }
};

#endif