/**
	This file is a part of the rexy/r0nk/atlas project
	Copyright (C) 2020 rexy712

	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation, either version 3 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program.	If not, see <http://www.gnu.org/licenses/>.
*/

#ifndef REXY_MAT_HPP
#define REXY_MAT_HPP

#include <cstdlib> //size_t
#include <utility> //integer_sequence
#include <type_traits> //decay_t, is_same, integral_constant
#include "detail/math.hpp"

namespace math{

	template<typename T, size_t R, size_t C>
	class matrix_base
	{
		static_assert(C > 0, "Cannot have 0 columns matrix");
		static_assert(R > 0, "Cannot have 0 rows matrix");
	public:
		using value_type = T;
		using size_type = size_t;
		using pointer = value_type*;
		using const_pointer = const value_type*;
		using reference = value_type&;
		using const_reference = const value_type&;

		static constexpr size_type Columns = C;
		static constexpr size_type Rows = R;

	protected:
		value_type m_data[R*C];

	protected:
    template<size_t... Ss>
    constexpr matrix_base(std::integer_sequence<size_type,Ss...>);
	public:
		//Default construct as identity when square, zero otherwise
		constexpr matrix_base();

		//Range initializing constructors
		constexpr explicit matrix_base(detail::zero_initialize_t);
		constexpr explicit matrix_base(detail::no_initialize_t);

		//Value initializing constructors
		constexpr explicit matrix_base(value_type v);
		template<typename... Args>
		constexpr explicit matrix_base(Args&&... args);

		//Copying constructors
		constexpr matrix_base(const matrix_base&) = default;
		constexpr matrix_base(matrix_base&&) = default;
		template<typename U>
		constexpr matrix_base(const matrix_base<U,Columns,Rows>& m);
		~matrix_base() = default;

		constexpr matrix_base& operator=(const matrix_base&) = default;
		constexpr matrix_base& operator=(matrix_base&&) = default;
		template<typename U>
		constexpr matrix_base& operator=(const matrix_base<U,Columns,Rows>& m);

		//Getters/Setters
		constexpr auto operator[](size_type x);
		constexpr auto operator[](size_type x)const;
		constexpr reference get(size_type x, size_type y);
		constexpr const_reference get(size_type x, size_type y)const;
		constexpr reference get(size_type i);
		constexpr const_reference get(size_type i)const;

		constexpr size_type columns()const;
		constexpr size_type rows()const;
		constexpr size_type size()const;

		constexpr pointer raw();
		constexpr const_pointer raw()const;
		constexpr operator pointer();
		constexpr operator const_pointer()const;

	};

	template<typename T, size_t R, size_t C>
	class matrix : public matrix_base<T,R,C>
	{
	private:
		using base = matrix_base<T,R,C>;
	public:
		using value_type = typename base::value_type;
		using size_type = typename base::size_type;
		using pointer = typename base::pointer;
		using const_pointer = typename base::const_pointer;
		using reference = typename base::reference;
		using const_reference = typename base::const_reference;

	public:
		using base::base;

		constexpr matrix(const matrix&) = default;
		constexpr matrix(matrix&&) = default;
		~matrix() = default;

		//Assignement
		constexpr matrix& operator=(const matrix&) = default;
		constexpr matrix& operator=(matrix&&) = default;
		template<typename U>
		constexpr matrix& operator=(const matrix<U,R,C>& m);
	};

	template<typename T, size_t R>
	class matrix<T,R,R> : public matrix_base<T,R,R>
	{
	private:
		using base = matrix_base<T,R,R>;
	public:
		using value_type = typename base::value_type;
		using size_type = typename base::size_type;
		using pointer = typename base::pointer;
		using const_pointer = typename base::const_pointer;
		using reference = typename base::reference;
		using const_reference = typename base::const_reference;

	public:
		using base::base;

		constexpr matrix(const matrix&) = default;
		constexpr matrix(matrix&&) = default;
		constexpr explicit matrix(detail::id_initialize_t);
		~matrix() = default;

		//Assignement
		constexpr matrix& operator=(const matrix&) = default;
		constexpr matrix& operator=(matrix&&) = default;
		template<typename U>
		constexpr matrix& operator=(const matrix<U,R,R>& m);

		//square matrix arithmetic operations
		constexpr value_type determinate()const;
		constexpr value_type trace()const;
		constexpr matrix transpose()const;
		constexpr matrix inverse()const;
	};

	template<typename T, size_t R>
	constexpr T determinate(const matrix<T,R,R>& m);
	template<typename T, size_t R>
	constexpr matrix<T,R,R> inverse(const matrix<T,R,R>& m);

	template<typename T>
	matrix<T,2,2> rotation2d_pure(T angle);
	template<typename T>
	constexpr matrix<T,2,2> rotation2d_pure(T sin, T cos);
	template<typename T>
	constexpr matrix<T,2,2> scale2d(T x, T y);

	template<typename T>
	matrix<T,3,3> rotation2d(T angle);
	template<typename T>
	constexpr matrix<T,3,3> rotation2d(T sin, T cos);
	template<typename T>
	matrix<T,3,3> rotation2d(T x, T y, T z);

	template<typename T>
	matrix<T,4,4> fov_projection(T fov, T asp, T near, T far);
	template<typename T>
	matrix<T,4,4> fov_asymetric_projection(T fovl, T fovr, T fovb, T fovt, T asp, T near, T far);
	template<typename T>
	matrix<T,4,4> ortho_projection(T w, T h, T n, T f);
	template<typename T>
	matrix<T,4,4> ortho_asymetric_projection(T l, T r, T b, T t, T n, T f);
	template<typename T>
	constexpr matrix<T,4,4> rotation3d(T angle_x, T angle_y, T angle_z);
	template<typename T>
	constexpr matrix<T,4,4> translation3d(T x, T y, T z);
	template<typename T>
	constexpr matrix<T,4,4> scale3d(T x, T y, T z);

	namespace detail{

		template<typename T>
		struct is_matrix_helper {
			template<typename U, size_t R, size_t C>
			static std::true_type test(matrix_base<U,R,C>*);
			static std::false_type test(void*);

			static constexpr bool value = std::is_same<std::true_type,decltype(test(static_cast<std::decay_t<T>*>(nullptr)))>::value;
		};

	}

	template<typename... Ms>
	struct is_matrix {
		static constexpr bool value = (detail::is_matrix_helper<Ms>::value && ...);
	};

	namespace detail{

		template<typename M1, typename M2>
		struct are_same_size_matrix {
			using l = std::decay_t<M1>;
			using r = std::decay_t<M2>;
			static constexpr bool value = is_matrix<M1,M2>::value && l::Columns == r::Columns && l::Rows == r::Rows;
		};
		template<typename... Ms>
		using enable_if_matrix = std::enable_if_t<is_matrix<Ms...>::value,int>;

		template<typename M1, typename M2>
		using enable_if_eq_matrix = std::enable_if_t<are_same_size_matrix<M1,M2>::value,int>;

	}

	template<typename T, typename U, size_t R, size_t C>
	constexpr bool operator==(const matrix_base<T,R,C>& left, const matrix_base<U,R,C> right);
	template<typename T, typename U, size_t R, size_t C>
	constexpr bool operator!=(const matrix_base<T,R,C>& left, const matrix_base<U,R,C> right);

	template<typename T, typename U, size_t R1, size_t C1, size_t R2>
	constexpr auto operator*(const matrix<T,R1,C1>& left, const matrix<U,C1,R2>& right);
	template<typename T, typename U, size_t C, size_t R, std::enable_if_t<!is_matrix<U>::value,int> = 0>
	constexpr auto operator*(const matrix<T,R,C>& left, U&& right);
	template<typename T, typename U, size_t C, size_t R, std::enable_if_t<!is_matrix<U>::value,int> = 0>
	constexpr auto operator*(U&& left, const matrix<T,R,C>& right);
	template<typename T, typename U, size_t C, size_t R, std::enable_if_t<!is_matrix<U>::value,int> = 0>
	constexpr auto operator/(const matrix<T,R,C>& left, U&& right);
	template<typename T, typename U, size_t C, size_t R>
	constexpr auto operator+(const matrix<T,R,C>& left, const matrix<U,R,C>& right);
	template<typename T, typename U, size_t C, size_t R>
	constexpr auto operator-(const matrix<T,R,C>& left, const matrix<U,R,C>& right);
	template<typename T, typename U, size_t C, size_t R>
	constexpr auto operator-(const matrix<T,R,C>& left);

	template<typename T, typename U, size_t R>
	constexpr decltype(auto) operator*=(matrix<T,R,R>& left, const matrix<U,R,R>& right);
	template<typename T, typename U, size_t C, size_t R, std::enable_if_t<!is_matrix<U>::value,int> = 0>
	constexpr decltype(auto) operator*=(matrix<T,R,C>& left, U&& right);
	template<typename T, typename U, size_t C, size_t R, std::enable_if_t<!is_matrix<U>::value,int> = 0>
	constexpr decltype(auto) operator/=(matrix<T,R,C>& left, U&& right);
	template<typename T, typename U, size_t C, size_t R>
	constexpr decltype(auto) operator+=(matrix<T,R,C>& left, const matrix<U,R,C>& right);
	template<typename T, typename U, size_t C, size_t R>
	constexpr decltype(auto) operator-=(matrix<T,R,C>& left, const matrix<U,R,C>& right);

}

#include "mat.tpp"

#endif