#ifndef PYTHONIC_INCLUDE_TYPES_COMBINED_HPP
#define PYTHONIC_INCLUDE_TYPES_COMBINED_HPP

#include "pythonic/include/types/traits.hpp"
PYTHONIC_NS_BEGIN
namespace types
{
  template <class... Types>
  struct variant_functor;
}
PYTHONIC_NS_END

/* type inference stuff
*/

template <class... Types>
struct __combined;

template <class T>
struct __combined<T> {
  using type = T;
};

template <class T0, class T1, class T2, class... Types>
struct __combined<T0, T1, T2, Types...> {
  // This is less efficient that doing a binary split, but it's not equivalent
  // as the lhs dominates the rhs (a.k.a __combined is neither commutative nor
  // associative)
  using type = typename __combined<typename __combined<T0, T1>::type, T2,
                                   Types...>::type;
};

template <class T0, class T1>
struct __combined<T0, T1> {
  // callable -> functor
  template <class F0, class F1>
  static pythonic::types::variant_functor<F0, F1>
  get(std::integral_constant<bool, true>);

  // operator+ exists -> deduce type
  template <class F0, class F1>
  static decltype(std::declval<F0>() + std::declval<F1>())
  get(std::integral_constant<bool, false>);

  // operator+ does not exists -> pick first one, better than error
  // note that this is needed because broadcasting is too complex to be modeled
  // by our clumsy type inference scheme
  // so we sometime endup with __combined<indexable_container<...>, int> which
  // only makes sense when broadcasting
  // fortunately, broadcasting is only supported by ndarray, && we already
  // ignore __combined for ndarray
  // so the only thing to do in such situations is « ! throw an error »
  template <class F0, class F1>
  static F0 get(...);

  using type = typename std::conditional<
      std::is_same<T0, T1>::value, T0,
      decltype(get<T0, T1>(std::integral_constant<
          bool, pythonic::types::is_callable<T0>::value &&
                    pythonic::types::is_callable<T1>::value>()))>::type;
};

template <class T0, class T1>
struct __combined<const T0, T1> {
  using type = typename std::add_const<typename __combined<T0, T1>::type>::type;
};

template <class T0, class T1>
struct __combined<T0, const T1> {
  using type = typename std::add_const<typename __combined<T0, T1>::type>::type;
};

template <class T0, class T1>
struct __combined<T0 &, T1> {
  using type = typename __combined<T0, T1>::type;
};

template <class T0, class T1>
struct __combined<T0 &&, T1> {
  using type = typename __combined<T0, T1>::type;
};

template <class T0, class T1>
struct __combined<T0 const &, T1> {
  using type = typename __combined<T0, T1>::type;
};

template <class T0, class T1>
struct __combined<T0, T1 &> {
  using type = typename __combined<T0, T1>::type;
};

template <class T0, class T1>
struct __combined<T0, T1 &&> {
  using type = typename __combined<T0, T1>::type;
};

template <class T0, class T1>
struct __combined<T0, T1 const &> {
  using type = typename __combined<T0, T1>::type;
};

template <class T0, class T1>
struct __combined<const T0, T1 const &> {
  using type = typename __combined<T0, T1>::type;
};

template <class T0, class T1>
struct __combined<const T0, T1 &> {
  using type = typename __combined<T0, T1>::type;
};

template <class T0, class T1>
struct __combined<const T0, T1 &&> {
  using type = typename __combined<T0, T1>::type;
};

template <class T0, class T1>
struct __combined<T0 &, T1 const> {
  using type = typename __combined<T0, T1>::type;
};

template <class T0, class T1>
struct __combined<T0 &&, T1 const> {
  using type = typename __combined<T0, T1>::type;
};

template <class T0, class T1>
struct __combined<T0 const &, T1 const> {
  using type = typename __combined<T0, T1>::type;
};

template <class T0, class T1>
struct __combined<T0 &, T1 const &> {
  using type = typename __combined<T0, T1>::type;
};

template <class T0, class T1>
struct __combined<T0 &&, T1 const &> {
  using type = typename __combined<T0, T1>::type;
};

template <class T0, class T1>
struct __combined<T0 const &, T1 &> {
  using type = typename __combined<T0, T1>::type;
};

template <class T0, class T1>
struct __combined<T0 const &, T1 &&> {
  using type = typename __combined<T0, T1>::type;
};

template <class T0, class T1>
struct __combined<T0 &, T1 &> {
  using type = typename std::add_lvalue_reference<
      typename __combined<T0, T1>::type>::type;
};

template <class T0, class T1>
struct __combined<T0 &&, T1 &&> {
  using type = typename std::add_rvalue_reference<
      typename __combined<T0, T1>::type>::type;
};

template <class T0, class T1>
struct __combined<const T0, const T1> {
  using type = typename std::add_const<typename __combined<T0, T1>::type>::type;
};

template <class T0, class T1>
struct __combined<const T0 &, const T1 &> {
  using type = typename std::add_lvalue_reference<
      typename std::add_const<typename __combined<T0, T1>::type>::type>::type;
};

template <class T>
class container
{
public:
  using value_type =
      typename std::remove_cv<typename std::remove_reference<T>::type>::type;

private:
  container();
};

template <class K, class V>
class indexable_container
{
public:
  using key_type =
      typename std::remove_cv<typename std::remove_reference<K>::type>::type;
  using value_type =
      typename std::remove_cv<typename std::remove_reference<V>::type>::type;

private:
  indexable_container();
};

template <class T>
class dict_container
{
public:
  using value_type =
      typename std::remove_cv<typename std::remove_reference<T>::type>::type;

private:
  dict_container();
};

template <class T>
class indexable
{
public:
  using type =
      typename std::remove_cv<typename std::remove_reference<T>::type>::type;

private:
  indexable();
};

template <class T>
class indexable_dict
{
public:
  using type =
      typename std::remove_cv<typename std::remove_reference<T>::type>::type;

private:
  indexable_dict();
};

template <class K0, class V0, class K1, class V1>
struct __combined<indexable_container<K0, V0>, indexable_container<K1, V1>> {
  using type = indexable_container<typename __combined<K0, K1>::type,
                                   typename __combined<V0, V1>::type>;
};

template <class K, class V>
struct __combined<indexable<K>, indexable<V>> {
  using type = indexable<typename __combined<K, V>::type>;
};

template <class K, class V>
struct __combined<indexable<K>, container<V>> {
  using type = indexable_container<K, V>;
};

template <class V, class K>
struct __combined<container<V>, indexable<K>> {
  using type = indexable_container<K, V>;
};

template <class K, class V, class W>
struct __combined<indexable_container<K, V>, container<W>> {
  using type = indexable_container<K, typename __combined<V, W>::type>;
};

template <class V, class K, class W>
struct __combined<container<W>, indexable_container<K, V>> {
  using type = indexable_container<K, typename __combined<V, W>::type>;
};

template <class K1, class V1, class K2>
struct __combined<indexable_container<K1, V1>, indexable<K2>> {
  using type = indexable_container<typename __combined<K1, K2>::type, V1>;
};

template <class K1, class V1, class K2>
struct __combined<indexable<K2>, indexable_container<K1, V1>> {
  using type = indexable_container<typename __combined<K1, K2>::type, V1>;
};

template <class A, class B>
struct __combined<container<A>, container<B>> {
  using type = container<typename __combined<A, B>::type>;
};
/* special handling for functors
 * as it's based on a trait, template specialization cannot be used
 * so we rely on operator+ specialization
 * { */

template <class T, class... Types>
struct __combined<T, pythonic::types::variant_functor<Types...>> {
  using type = pythonic::types::variant_functor<T, Types...>;
};

template <class T, class... Types>
struct __combined<pythonic::types::variant_functor<Types...>, T> {
  using type = pythonic::types::variant_functor<T, Types...>;
};

template <class... Types0, class... Types1>
struct __combined<pythonic::types::variant_functor<Types0...>,
                  pythonic::types::variant_functor<Types1...>> {
  using type = pythonic::types::variant_functor<Types0..., Types1...>;
};

/* } */

/* mimic numpy behavior { */
#define SCALAR_COMBINER(Type)                                                  \
  template <>                                                                  \
  struct __combined<Type, Type> {                                              \
    using type = Type;                                                         \
  };
SCALAR_COMBINER(bool)
SCALAR_COMBINER(uint8_t)
SCALAR_COMBINER(int8_t)
SCALAR_COMBINER(uint16_t)
SCALAR_COMBINER(int16_t)
SCALAR_COMBINER(uint32_t)
SCALAR_COMBINER(int32_t)
SCALAR_COMBINER(uint64_t)
SCALAR_COMBINER(int64_t)
#undef SCALAR_COMBINER

#endif