//
// Created by Patrick Maschek on 19.12.2023.
//

#ifndef CONST_CONTAINER_CONST_VEC_H_
#define CONST_CONTAINER_CONST_VEC_H_

#include <algorithm>
#include <initializer_list>
#include <iterator>
#include <utility>
#include "helper.h"

namespace cc {
	
	template<typename T, std::size_t N>
	class const_vector {

			static_assert(N > 0, "Capacity of const_vector has to be greater than 0");

        public:

            using value_type = T;
            using size_type = std::size_t;
            using difference_type = std::ptrdiff_t;
            using reference = value_type&;
            using const_reference = const value_type&;
            using pointer = value_type *;
            using const_pointer = const value_type *;
            using iterator = pointer;
            using const_iterator = const_pointer;
            using reverse_iterator = std::reverse_iterator<iterator>;
            using const_reverse_iterator = std::reverse_iterator<const_iterator>;

		protected:
			static constexpr const size_type _len = N;
			T _arr[N] = {};
			size_type _size = 0;

		public:

	        constexpr const_vector() noexcept = default;

			constexpr explicit const_vector(const value_type &value) noexcept;
	        constexpr const_vector(size_type count, const value_type &value) noexcept;

			constexpr const_vector(const value_type (&array)[N]) noexcept;
			template <std::size_t N2>
			constexpr explicit const_vector(const value_type (&array)[N2]);
			
			constexpr const_vector(std::initializer_list<value_type> values);

	        template<std::input_iterator InputIt>
	        constexpr const_vector(InputIt first, InputIt last);

			constexpr const_vector(const const_vector<value_type, N>& other) noexcept;
			template <std::size_t N2>
			constexpr const_vector(const const_vector<value_type, N2>& other);
			constexpr const_vector(const_vector&& other) noexcept;
			template <std::size_t N2>
			constexpr const_vector(const_vector<value_type, N2>&& other);

			constexpr ~const_vector() = default;    // elements in static array should be destroyed automatically

			constexpr const_vector<T, N>& operator=(const const_vector& other) noexcept;            // needed to handle *this = *this
            template <std::size_t N2>
            constexpr const_vector<T, N>& operator=(const const_vector<value_type, N2>& other);
			constexpr const_vector<T, N>& operator=(const_vector&& other) noexcept;
			template <std::size_t N2>
			constexpr const_vector<T, N>& operator=(const_vector<value_type, N2>&& other);
			//constexpr const_vector<T, N>& operator=(const value_type (&array)[N]) noexcept;       // not needed as functionally equivalent to templated overload, could be noexcept though
            template <std::size_t N2>
			constexpr const_vector<T, N>& operator=(const value_type (&array)[N2]);
			constexpr const_vector<T, N>& operator=(std::initializer_list<value_type> values);

			constexpr void assign(size_type count, const value_type& value) noexcept;
			template<std::input_iterator InputIt>
			constexpr void assign(InputIt first, InputIt last);
			constexpr void assign(std::initializer_list<value_type> values);

			constexpr reference at(size_type pos);
			constexpr const_reference at(size_type pos) const;

			constexpr T& operator[](size_type pos) { return _arr[pos]; }
			constexpr const T& operator[](size_type pos) const { return _arr[pos]; }

			[[nodiscard]] constexpr reference front() noexcept { return _arr[0]; }
			[[nodiscard]] constexpr const_reference front() const noexcept { return _arr[0]; }

			[[nodiscard]] constexpr reference back() noexcept { return _arr[_size - 1]; }
			[[nodiscard]] constexpr const_reference back() const noexcept { return _arr[_size - 1]; }

			[[nodiscard]] constexpr value_type * data() noexcept { return _arr; }
			[[nodiscard]] constexpr const value_type * data() const noexcept { return _arr; }

			[[nodiscard]] constexpr iterator begin() noexcept { return _arr; };
			[[nodiscard]] constexpr const_iterator begin() const noexcept { return _arr; };
			[[nodiscard]] constexpr const_iterator cbegin() const noexcept { return _arr; };

			[[nodiscard]] constexpr iterator end() noexcept { return _arr + _size; };
			[[nodiscard]] constexpr const_iterator end() const noexcept { return _arr + _size; };
			[[nodiscard]] constexpr const_iterator cend() const noexcept { return _arr + _size; };

			[[nodiscard]] constexpr reverse_iterator rbegin() noexcept { return std::reverse_iterator<iterator>(_arr + _size); };
			[[nodiscard]] constexpr const_reverse_iterator rbegin() const noexcept { return std::reverse_iterator<const_iterator>(_arr + _size); };
			[[nodiscard]] constexpr const_reverse_iterator crbegin() const noexcept { return std::reverse_iterator<const_iterator>(_arr + _size); };

			[[nodiscard]] constexpr reverse_iterator rend() noexcept { return std::reverse_iterator<iterator>(_arr); };
			[[nodiscard]] constexpr const_reverse_iterator rend() const noexcept { return std::reverse_iterator<const_iterator>(_arr); };
			[[nodiscard]] constexpr const_reverse_iterator crend() const noexcept { return std::reverse_iterator<const_iterator>(_arr); };

			[[nodiscard]] constexpr bool empty() const noexcept { return begin() == end(); }    // vector standard defines empty as this
			[[nodiscard]] constexpr size_type max_size() const noexcept { return _len; }
			[[nodiscard]] constexpr size_type capacity() const noexcept { return _len; }
			[[nodiscard]] constexpr size_type size() const noexcept { return _size; }

			constexpr void clear() { std::fill(begin(), end(), T()); }

			constexpr iterator insert(const_iterator pos, const T& value);
			constexpr iterator insert(const_iterator pos, T&& value);
			constexpr iterator insert(const_iterator pos, size_type count, const T& value);
			template<std::input_iterator InputIt>
			constexpr iterator insert(const_iterator pos, InputIt first, InputIt last);
			constexpr iterator insert(const_iterator pos, std::initializer_list<T> values);

			template<typename ...Args>
			constexpr iterator emplace(const_iterator pos, Args&&... args);

			constexpr iterator erase(const_iterator pos);
			constexpr iterator erase(const_iterator first, const_iterator last);

			constexpr void push_back(const T& value);
			constexpr void push_back(T&& value);

			template<typename ...Args>
			constexpr reference emplace_back(Args&&... args);

			constexpr void pop_back();

			template<std::size_t N2>
			constexpr void swap(const_vector<T, N2>& other);

			template <typename T2, std::size_t N2>
			friend class const_vector;

    };
	
	template<typename A>
	const_vector(A[]) -> const_vector<A, helper::array_size<A>>;

	template<typename ...T>
	const_vector(T...) -> const_vector<std::common_type_t<T...>, sizeof...(T)>;


	template<typename T1, typename T2, std::size_t N1, std::size_t N2>
	constexpr bool operator==(const const_vector<T1, N1>& lhs,
	                          const const_vector<T2, N2>& rhs)
	{
		return lhs.size() == rhs.size() && std::equal(lhs.begin(), lhs.end(), rhs.begin());
	}

	template<typename T1, typename T2, std::size_t N1, std::size_t N2>
	constexpr auto operator<=>(const const_vector<T1, N1>& lhs,
	                           const const_vector<T2, N2>& rhs)
	{
		return std::lexicographical_compare_three_way(lhs.begin(), lhs.end(), rhs.begin(), rhs.end(), std::compare_three_way());
	}

	template<typename T, std::size_t N1, std::size_t N2>
	constexpr void swap(const const_vector<T, N1>& lhs,
	                    const const_vector<T, N2>& rhs)
	{
		return lhs.swap(rhs);
	}

	template<typename T, std::size_t N, typename U>
	constexpr const_vector<T, N>::size_type erase(const_vector<T, N>& vec, const U& value)
	{
		auto it = std::remove(vec.begin(), vec.end(), value);
		auto r = vec.end() - it;
		vec.erase(it, vec.end());

		return r;
	}

	template<typename T, std::size_t N, typename Pred>
	constexpr const_vector<T, N>::size_type erase(const_vector<T, N>& vec, Pred pred)
	{
		auto it = std::remove_if(vec.begin(), vec.end(), pred);
		auto r = vec.end() - it;
		vec.erase(it, vec.end());

		return r;
	}


	template<typename T, std::size_t N>
	constexpr const_vector<T, N>::const_vector(const value_type &value) noexcept
		:	_size(N)
	{
		std::fill(std::begin(_arr), std::end(_arr), value);
	}

	template<typename T, std::size_t N>
    constexpr const_vector<T, N>::const_vector(size_type count, const value_type &value) noexcept
	{
		if (count > N) count = N;
		_size = count;
        std::fill(_arr, _arr + _size, value);
    }

	template<typename T, std::size_t N>
    constexpr const_vector<T, N>::const_vector(const value_type (&array)[N]) noexcept
		:	_size(N)
	{
		std::copy(std::begin(array), std::end(array), _arr);
    }

	template<typename T, std::size_t N>
	template<std::size_t N2>
    constexpr const_vector<T, N>::const_vector(const value_type (&array)[N2])
		:	_size(N2)
	{
		if (N < N2) throw std::invalid_argument("Size of array has to be smaller or equal to the capacity: " + std::to_string(N2) + ">=" + std::to_string(N));
		std::copy(std::begin(array), std::end(array), _arr);
    }

	template<typename T, std::size_t N>
	constexpr const_vector<T, N>::const_vector(std::initializer_list<value_type> values)
		:	_size(values.size())
	{
		if (values.size() > N) throw std::invalid_argument("Initializer list in assign has more elements than size" + std::to_string(values.size()) + ">=" + std::to_string(N));
		std::move(values.begin(), values.end(), _arr);
	}

	template<typename T, std::size_t N>
    template<std::input_iterator InputIt>
    constexpr const_vector<T, N>::const_vector(InputIt first, InputIt last)
		:   _size(std::distance(first, last))
	{
	    if (std::distance(first, last) > N) throw std::invalid_argument("tried inserting more elements than const_vector is in size");
	    std::copy(first, last, _arr);
	}

	template<typename T, std::size_t N>
	constexpr const_vector<T, N>::const_vector(const const_vector &other) noexcept
			:   _size(other._size)
	{
		std::copy(other.begin(), other.end(), _arr);
		_size = other._size;
	}

    template<typename T, std::size_t N>
    template<std::size_t N2>
    constexpr const_vector<T, N>::const_vector(const const_vector<const_vector::value_type, N2> &other)
		:   _size(other.size())
	{
		if (_len <= other.size()) throw std::invalid_argument("size of other has to be equal to or smaller than this");
		std::copy(other.begin(), other.end(), _arr);
	}

    template<typename T, std::size_t N>
    constexpr const_vector<T, N>::const_vector(const_vector &&other) noexcept
		:   _size(other._size)
	{
		std::move(other.begin(), other.end(), _arr);
    }

    template<typename T, std::size_t N>
    template<std::size_t N2>
    constexpr const_vector<T, N>::const_vector(const_vector<value_type, N2> &&other)
		:   _size(other._size)
	{
		if (_len <= other.size()) throw std::invalid_argument("size of other has to be equal to or smaller than this");
		std::move(other.begin(), other.end(), _arr);
    }

	template<typename T, std::size_t N>
	constexpr const_vector<T, N> &const_vector<T, N>::operator=(const const_vector &other) noexcept
	{
		if (this == &other) return *this;

		// event though assign may throw an exception noexcept for this operator should be fine,
		// as std::distance(other.begin(), other.end()) cannot be greater than the capacity,
		// because the signatures would have to differ
		assign(other.begin(), other.end());
		
		return *this;
	}

	template<typename T, std::size_t N>
	template<std::size_t N2>
	constexpr const_vector<T, N> &const_vector<T, N>::operator=(const const_vector<const_vector::value_type, N2> &other)
	{
        if (other.size() > _len) throw std::invalid_argument("size of other has to be equal to or smaller than this");

        // this is not necessary, as it should call the non templated operator=
        // (and throws an error without a cast)
		//if (this == &other) return *this;

		assign(other.begin(), other.end());

		return *this;
	}

	template<typename T, std::size_t N>
	constexpr const_vector<T, N> &const_vector<T, N>::operator=(const_vector &&other) noexcept
	{
        // cannot occur, otherwise signature would differ
		//static_assert(N == other._len, "Cannot assign const_vector to other with different size");
		//if (N != other._len) throw std::exception();

		clear();
		std::move(other.begin(), other.end(), _arr);
		_size = other._size;

		return *this;
	}

	template<typename T, std::size_t N>
	template<std::size_t N2>
	constexpr const_vector<T, N> &const_vector<T, N>::operator=(const_vector<value_type, N2> &&other)
	{
		if (other.size() > _len) throw std::invalid_argument("size of other has to be equal to or smaller than this");

		clear();
		std::move(other.begin(), other.end(), _arr);
		_size = other._size;

		return *this;
	}

	template<typename T, std::size_t N>
	template<std::size_t N2>
	constexpr const_vector<T, N> &const_vector<T, N>::operator=(const value_type (&array)[N2])
	{
		assign(std::begin(array), std::end(array));
		return *this;
	}

	template<typename T, std::size_t N>
	constexpr const_vector<T, N> &const_vector<T, N>::operator=(std::initializer_list<value_type> values)
	{
		assign(std::move(values));
		return *this;
	}

	template<typename T, std::size_t N>
	constexpr void const_vector<T, N>::assign(const_vector::size_type count, const value_type &value) noexcept
	{
		if (count > N) count = N;
		_size = count;

		std::fill(std::begin(_arr), std::end(_arr), value);
	}

	template<typename T, std::size_t N>
	template<std::input_iterator InputIt>
	constexpr void const_vector<T, N>::assign(InputIt first, InputIt last)
	{
		auto distance = std::distance(first, last);
		if (distance > N) throw std::invalid_argument("Iterator distance in assign surpasses size " + std::to_string(distance) + " >= " + std::to_string(N));
		_size = distance;
		std::copy(first, last, begin());
	}

	template<typename T, std::size_t N>
	constexpr void const_vector<T, N>::assign(std::initializer_list<value_type> values)
	{
		if (values.size() > N) throw std::invalid_argument("Initializer list in assign has more elements than size" + std::to_string(values.size()) + ">=" + std::to_string(N));
		_size = values.size();
		std::copy(values.begin(), values.end(), _arr);
	}

	template<typename T, std::size_t N>
	constexpr const_vector<T, N>::reference const_vector<T, N>::at(const_vector::size_type pos)
	{
		if (pos >= _size) throw std::out_of_range("Pos " + std::to_string(pos) + " is out of range");
		return _arr[pos];
	}

	template<typename T, std::size_t N>
	constexpr const_vector<T, N>::const_reference const_vector<T, N>::at(const_vector::size_type pos) const
	{
		if (pos >= _size) throw std::out_of_range("Pos " + std::to_string(pos) + " is out of range");
		return _arr[pos];
	}

	template<typename T, std::size_t N>
	constexpr const_vector<T, N>::iterator const_vector<T, N>::insert(const_vector::const_iterator pos, const T &value)
	{
		if (_size == N) throw std::exception();

		ptrdiff_t i = pos - _arr;
		std::move(_arr + i, _arr + _size, _arr + i + 1);
		_arr[i] = value;

		++_size;
		return pos;
	}

	template<typename T, std::size_t N>
	constexpr const_vector<T, N>::iterator const_vector<T, N>::insert(const_vector::const_iterator pos, T &&value)
	{
		if (_size == N) throw std::exception();

		ptrdiff_t i = pos - _arr;
		std::move(_arr + i, _arr + _size, _arr + i + 1);
		_arr[i] = std::move(value);

		++_size;
		return pos;
	}

	template<typename T, std::size_t N>
	constexpr const_vector<T, N>::iterator
	const_vector<T, N>::insert(const_vector::const_iterator pos, const_vector::size_type count, const T &value)
	{
		if (count == 0) return pos;
		if (_size + count >= N) throw std::exception();
		
		std::move(pos, _arr + _size, pos + count);
		std::fill(pos, pos + count, value);
		
		_size += count;
		return pos;
	}

	template<typename T, std::size_t N>
	template<std::input_iterator InputIt>
	constexpr const_vector<T, N>::iterator
	const_vector<T, N>::insert(const_vector::const_iterator pos, InputIt first, InputIt last)
	{
		auto count = std::distance(first, last);

		if (first == last) return pos;
		if (_size + count >= N) throw std::exception();


		std::move(pos, _arr + _size, pos + count);
		std::copy(first, last, pos);
		
		_size += count;
		return pos;
	}

	template<typename T, std::size_t N>
	constexpr const_vector<T, N>::iterator
	const_vector<T, N>::insert(const_vector::const_iterator pos, std::initializer_list<T> values)
	{
		return insert(pos, values.begin(), values.end());
	}

	template<typename T, std::size_t N>
	template<class... Args>
	constexpr const_vector<T, N>::iterator const_vector<T, N>::emplace(const_vector::const_iterator pos, Args &&... args)
	{
		if (_size == N) throw std::exception();

		T obj(std::forward<Args>(args)...);
		
		ptrdiff_t i = pos - _arr;
		std::move(_arr + i, _arr + _size, _arr + i + 1);
		_erase_no_move(pos);
		_arr[i] = std::move(obj);
		
		return pos;
	}

	template<typename T, std::size_t N>
	constexpr const_vector<T, N>::iterator const_vector<T, N>::erase(const_vector::const_iterator pos)
	{
		_erase_no_move(pos);
		std::move(pos + 1, end(), pos);
		--_size;

		return pos;
	}

	template<typename T, std::size_t N>
	constexpr const_vector<T, N>::iterator
	const_vector<T, N>::erase(const_vector::const_iterator first, const_vector::const_iterator last)
	{
		_erase_no_move(first, last);
		std::move(last + 1, end(), first);
		_size -= (last - first);
		
		return first;
	}

	template<typename T, std::size_t N>
	constexpr void const_vector<T, N>::push_back(const const_vector::value_type &value)
	{
		insert(end(), value);
	}

	template<typename T, std::size_t N>
	constexpr void const_vector<T, N>::push_back(T&& value)
	{
		insert(end(), value);
	}

	template<typename T, std::size_t N>
	template<typename ...Args>
	constexpr const_vector<T, N>::reference const_vector<T, N>::emplace_back(Args&&... args)
	{
		emplace(end(), std::forward(args)...);
	}

	template<typename T, std::size_t N>
	constexpr void const_vector<T, N>::pop_back()
	{
		_erase_no_move(end() - 1, end());
		--_size;
	}

	template<typename T, std::size_t N>
	template<std::size_t N2>
	constexpr void const_vector<T, N>::swap(const_vector<T, N2> &other)
	{
		if (_size > other._len || other._size > N) throw std::exception();

		cc::helper::swap_iter_range(begin(), end(), std::end(_arr), other.begin(), other.end(), std::end(other._arr));
		std::swap(_size, other._size);
	}

}; // cc

#endif //CONST_CONTAINER_CONST_VEC_H_