#pragma once

#include <memory>
#include "Test.hpp"

namespace smart_pointer {
class exception : std::exception {
    using base_class = std::exception;
    using base_class::base_class;
};

    template<
        typename T,
        typename Allocator
    >

        class SmartPointer {
        ENABLE_CLASS_TESTS;

         public:
            using value_type = T;

            explicit SmartPointer(value_type* p = nullptr) {
                if (p == nullptr) {
                    core = nullptr;
                } else {
                    core = new Core(p);
                }
            }

            SmartPointer(const SmartPointer& other) : core(other.core) {
                if (other.core != nullptr) core->count++;
            }

            SmartPointer(SmartPointer&& other) : core(other.core) {
                other = nullptr;
            }

            SmartPointer& operator=(const SmartPointer& other) {
                if (&other == this)
                    return *this;

                if (core != nullptr) {
                    core->count -= 1;
                    if (core->count == 0) {
                        delete core;
                    }
                }
                core = other.core;
                if (other.core != nullptr) {
                    core->count++;
                }

                return *this;
            }

            SmartPointer& operator=(SmartPointer&& other) {
                if (&other == this)
                    return *this;

                if (core != nullptr) {
                    core->count -= 1;
                    if (core->count == 0) {
                        delete core;
                    }
                }

                core = other.core;
                other.core = nullptr;

                return *this;
            }

            SmartPointer& operator=(value_type* p) {
                if (core != nullptr) {
                    core->count -= 1;
                    if (core->count == 0) {
                        delete core;
                    }
                }

                if (p != nullptr) {
                    core = new Core(p);
                } else {
                    core = nullptr;
                }
                return *this;
            }

            ~SmartPointer() {
            }

            value_type& operator*() {
                if (core != nullptr)
                    return *(core->p);
                throw smart_pointer::exception();
            }
            const value_type& operator*() const {
                if (core != nullptr)
                    return *(core->p);
                throw smart_pointer::exception();
            }

            value_type* operator->() const {
                if (core != nullptr)
                    return core->p;
                return nullptr;
            }

            value_type* get() const {
                if (core != nullptr)
                    return core->p;
                return nullptr;
            }

            operator bool() const {
                return core != nullptr;
            }

            template<typename U, typename AnotherAllocator>
            bool operator==(const SmartPointer<U,
                AnotherAllocator>& other) const {
                return (reinterpret_cast<void*>(this->get()) ==
                    reinterpret_cast<void*>(other.get()) ||
                    (!this && !other));
            }

            template<typename U, typename AnotherAllocator>
            bool operator!=(const SmartPointer<U,
                AnotherAllocator>& other) const {
                return !(reinterpret_cast<void*>(this->get()) ==
                    reinterpret_cast<void*>(other.get()) ||
                    (!this && !other));
            }

            std::size_t count_owners() const {
                if (core == nullptr) return 0;
                return core->count;
            }

         private:
            class Core {
             public:
                value_type* p;
                std::size_t count;

                explicit Core(value_type* ptr) : p(ptr), count(1) {}

                ~Core() {
                    Allocator a;
                    a.deallocate(p, sizeof(value_type));
                    p = nullptr;
                }

                value_type get() {
                    return *p;
                }
            };
            Core* core;
        };
}  // namespace smart_pointer