/**
	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
#include <cmath> //sin, cos
#include "detail/math.hpp"
#include "detail/matrix.hpp"

namespace math{

	template<class T, size_t C, size_t R>
	class matrix : public detail::matrix_base<T,C,R>
	{
	private:
		using base = detail::matrix_base<T,C,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 detail::matrix_base<T,C,R>::matrix_base;
		using detail::matrix_base<T,C,R>::operator=;
	};

	template<class T>
	class matrix<T,3,3> : public detail::matrix_base<T,3,3>
	{
	private:
		using base = detail::matrix_base<T,3,3>;
	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 detail::matrix_base<T,3,3>::matrix_base;
		using detail::matrix_base<T,3,3>::operator=;

		template<class U = void>
		static constexpr matrix rotation(value_type angle){
			value_type c = std::cos(angle);
			value_type s = std::sin(angle);
			return rotation(s, c);
		}
		template<class U = void>
		static constexpr matrix rotation(value_type sin, value_type cos){
			return matrix(cos, -sin, 0,
			              sin,  cos, 0,
			              0,  0, 1);
		}
		static constexpr matrix rotation(value_type angle_x, value_type angle_y, value_type angle_z){
			//TODO
		}
	};

	namespace detail{

		template<class T>
		struct is_matrix_helper{
			template<class U, size_t W, size_t H>
			static std::true_type test(matrix<U,W,H>*);
			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<class... Ms>
	struct is_matrix{
		static constexpr bool value = (detail::is_matrix_helper<Ms>::value && ...);
	};

	namespace detail{

		template<class M1, class 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<class... Ms>
		using enable_if_matrix = std::enable_if_t<is_matrix<Ms...>::value,int>;

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

	}

	template<class T, class U, size_t W, size_t H>
	constexpr bool operator==(const matrix<T,W,H>& left, const matrix<U,W,H> right){
		for(size_t i = 0;i < left.size();++i){
			if(left.get(i) != right.get(i))
				return false;
		}
		return true;
	}
	template<class T, class U, size_t W, size_t H>
	constexpr bool operator!=(const matrix<T,W,H>& left, const matrix<U,W,H> right){
		return !(left == right);
	}

	template<class T, class U, size_t R1, size_t C1, size_t C2>
	constexpr auto operator*(const matrix<T,C1,R1>& left, const matrix<U,C2,C1>& right){
		using res_t = decltype(std::declval<T>() * std::declval<U>());
		matrix<res_t,C2,R1> res(no_initialize);
		size_t index = 0;
		for(size_t i = 0;i < right.rows();++i){
			for(size_t j = 0;j < left.rows();++j){
				for(size_t k = 0;k < left.columns();++k){
					res.get(index) += left[j][k] * right[i][k];
				}
				++index;
			}
		}
		return res;
	}
	template<class T, class U, size_t C, size_t R>
	constexpr auto operator*(const matrix<T,C,R>& left, U&& right){
		using res_t = decltype(std::declval<T>() * std::declval<U>());
		matrix<res_t,C,R> res(no_initialize);
		for(size_t i = 0;i < left.size();++i){
			res.get(i) = left.get(i) * std::forward<U>(right);
		}
		return res;
	}
	template<class T, class U, size_t C, size_t R>
	constexpr auto operator/(const matrix<T,C,R>& left, U&& right){
		using res_t = decltype(std::declval<T>() / std::declval<U>());
		matrix<res_t,C,R> res(no_initialize);
		for(size_t i = 0;i < left.size();++i){
			res.get(i) = left.get(i) / std::forward<U>(right);
		}
		return res;
	}
	template<class T, class U, size_t C, size_t R>
	constexpr auto operator+(const matrix<T,C,R>& left, const matrix<U,C,R>& right){
		using res_t = decltype(std::declval<T>() + std::declval<U>());
		matrix<res_t,C,R> res(no_initialize);
		for(size_t i = 0;i < left.size();++i){
			res.get(i) = left.get(i) + right.get(i);
		}
		return res;
	}
	template<class T, class U, size_t C, size_t R>
	constexpr auto operator-(const matrix<T,C,R>& left, const matrix<U,C,R>& right){
		using res_t = decltype(std::declval<T>() - std::declval<U>());
		matrix<res_t,C,R> res(no_initialize);
		for(size_t i = 0;i < left.size();++i){
			res.get(i) = left.get(i) - right.get(i);
		}
		return res;
	}
	template<class T, class U, size_t C, size_t R>
	constexpr auto operator-(const matrix<T,C,R>& left){
		using res_t = decltype(std::declval<T>() - std::declval<U>());
		matrix<res_t,C,R> res(no_initialize);
		for(size_t i = 0;i < left.size();++i){
			res.get(i) = -left.get(i);
		}
		return res;
	}


	template<class T, class U, size_t R1, size_t C1, size_t C2>
	constexpr decltype(auto) operator*=(matrix<T,C1,R1>& left, const matrix<U,C2,C1>& right){
		//have to evaluate entire expression first since matrix multiplication depends on reusing many elements
		//cannot be expression templatized, TODO
		return (left = (left * right));
	}
	template<class T, class U, size_t C, size_t R>
	constexpr decltype(auto) operator*=(matrix<T,C,R>& left, U&& right){
		for(size_t i = 0;i < left.size();++i){
			left.get(i) = left.get(i) * std::forward<U>(right);
		}
		return left;
	}
	template<class T, class U, size_t C, size_t R>
	constexpr decltype(auto) operator/=(matrix<T,C,R>& left, U&& right){
		for(size_t i = 0;i < left.size();++i){
			left.get(i) = left.get(i) / std::forward<U>(right);
		}
		return left;
	}
	template<class T, class U, size_t C, size_t R>
	constexpr decltype(auto) operator+=(matrix<T,C,R>& left, const matrix<U,C,R>& right){
		for(size_t i = 0;i < left.size();++i){
			left.get(i) = left.get(i) + right.get(i);
		}
		return left;
	}
	template<class T, class U, size_t C, size_t R>
	constexpr decltype(auto) operator-=(matrix<T,C,R>& left, const matrix<U,C,R>& right){
		for(size_t i = 0;i < left.size();++i){
			left.get(i) = left.get(i) - right.get(i);
		}
		return left;
	}

}

#endif