#ifndef RFL_ATTRIBUTE_HPP_
#define RFL_ATTRIBUTE_HPP_

#include <algorithm>
#include <string_view>
#include <tuple>
#include <type_traits>
#include <utility>

#include "Literal.hpp"
#include "default.hpp"

namespace rfl {

  template <class T>
  struct Attribute {
    using Type           = T;
    using ReflectionType = T;

    Attribute() : value_(Type()) {}

    Attribute(const Type& _value) : value_(_value) {}

    Attribute(Type&& _value) noexcept : value_(std::move(_value)) {}

    Attribute(Attribute<T>&& _attr) noexcept = default;

    Attribute(const Attribute<Type>& _attr) = default;

    template <class U>
    Attribute(const Attribute<U>& _attr) : value_(_attr.get()) {}

    template <class U>
    Attribute(Attribute<U>&& _attr) : value_(_attr.get()) {}

    template <class U, typename std::enable_if<std::is_convertible_v<U, Type>, bool>::type = true>
    Attribute(const U& _value) : value_(_value) {}

    template <class U, typename std::enable_if<std::is_convertible_v<U, Type>, bool>::type = true>
    Attribute(U&& _value) noexcept : value_(std::forward<U>(_value)) {}

    template <class U, typename std::enable_if<std::is_convertible_v<U, Type>, bool>::type = true>
    Attribute(const Attribute<U>& _attr) : value_(_attr.value()) {}

    /// Assigns the underlying object to its default value.
    template <
      class U                                                                 = Type,
      typename std::enable_if<std::is_default_constructible_v<U>, bool>::type = true>
    Attribute(const Default& _default) : value_(Type()) {}

    ~Attribute() = default;

    /// Returns the underlying object.
    const Type& get() const { return value_; }

    /// Returns the underlying object.
    Type& operator()() { return value_; }

    /// Returns the underlying object.
    const Type& operator()() const { return value_; }

    /// Assigns the underlying object.
    auto& operator=(const Type& _value) {
      value_ = _value;
      return *this;
    }

    /// Assigns the underlying object.
    auto& operator=(Type&& _value) noexcept {
      value_ = std::move(_value);
      return *this;
    }

    /// Assigns the underlying object.
    template <class U, typename std::enable_if<std::is_convertible_v<U, Type>, bool>::type = true>
    auto& operator=(const U& _value) {
      value_ = _value;
      return *this;
    }

    /// Assigns the underlying object to its default value.
    template <
      class U                                                                 = Type,
      typename std::enable_if<std::is_default_constructible_v<U>, bool>::type = true>
    auto& operator=(const Default& _default) {
      value_ = Type();
      return *this;
    }

    /// Assigns the underlying object.
    Attribute<T>& operator=(const Attribute<T>& _attr) = default;

    /// Assigns the underlying object.
    Attribute<T>& operator=(Attribute<T>&& _attr) = default;

    /// Assigns the underlying object.
    template <class U>
    auto& operator=(const Attribute<U>& _attr) {
      value_ = _attr.get();
      return *this;
    }

    /// Assigns the underlying object.
    template <class U>
    auto& operator=(Attribute<U>&& _attr) {
      value_ = std::forward<T>(_attr.value_);
      return *this;
    }

    /// We want all parsers other than the XML parser to treat attributes like
    /// normal fields, so we just implement the reflection interface.
    const ReflectionType& reflection() const { return value_; }

    /// Assigns the underlying object.
    void set(const Type& _value) { value_ = _value; }

    /// Assigns the underlying object.
    void set(Type&& _value) { value_ = std::move(_value); }

    /// Returns the underlying object.
    Type& value() { return value_; }

    /// Returns the underlying object.
    const Type& value() const { return value_; }

    /// The underlying value.
    Type value_;
  };

} // namespace rfl

#endif