// -*- c++ -*-
#pragma once

#include <utility>
#include <valarray>
#include <stdexcept>

template<typename T, std::size_t W, std::size_t H>
class Matrix
{
public:
	Matrix()
		: data(T{}, W * H)
	{
	}

	Matrix(Matrix<T, W, H>&& other)
	{
		*this = std::move(other);
	}

	Matrix(const Matrix<T, W, H>& other)
	{
		*this = other;
	}

	Matrix& operator=(Matrix<T, W, H>&& other)
	{
		data = std::move(other.data);
		return *this;
	}

	Matrix& operator=(const Matrix<T, W, H>& other)
	{
		data = other.data;
		return *this;
	}

	T& m(std::size_t x, std::size_t y)
	{
		if(x >= W || y >= H) throw std::out_of_range("Subscript out of range.");
		return data[x + y * W];
	}

	const T& m(std::size_t x, std::size_t y) const
	{
		if(x >= W || y >= H) throw std::out_of_range("Subscript out of range.");
		return data[x + y * W];
	}

	Matrix<T, W, H> operator+(const Matrix<T, W, H>& other) const
	{
		Matrix m(*this);
		m.data += other.data;
		return m;
	}

	Matrix<T, W, H> operator+(T val)
	{
		Matrix<T, W, H> m(*this);
		m.data += val;
		return m;
	}

	Matrix<T, W, H> operator-(const Matrix<T, W, H>& other) const
	{
		Matrix<T, W, H> m(*this);
		m.data -= other.data;
		return m;
	}

	Matrix <T, W, H>operator-(T val)
	{
		Matrix<T, W, H> m(*this);
		m.data -= val;
		return m;
	}

	Matrix<T, W, H> operator%(const Matrix<T, W, H>& other) const
	{
		Matrix<T, W, H> m(*this);
		m.data %= other.data;
		return m;
	}

	Matrix<T, W, H> operator%(T val)
	{
		Matrix m(*this);
		m.data %= val;
		return m;
	}

	template<std::size_t N>
	Matrix<T, W, N> operator*(const Matrix<T, H, N>& other) const
	{
		Matrix<T, W, N> out;
		for(std::size_t i = 0; i < W; ++i)
		{
			for(std::size_t j = 0; j < N; ++j)
			{
				out.m(i,j) = {};
				for(std::size_t k = 0; k < H; ++k)
				{
					out.m(i,j) += m(i, j) * other.m(k, j);
				}
			}
		}

		return out;
	}

	Matrix<T, W, H> operator*(T val)
	{
		Matrix<T, W, H> m(*this);
		m.data *= val;
		return m;
	}

	template<std::size_t N>
	Matrix<T, W, N> operator/(const Matrix<T, H, N>& other) const
	{
		Matrix<T, W, N> out;
		for(std::size_t i = 0; i < W; ++i)
		{
			for(std::size_t j = 0; j < N; ++j)
			{
				out.m(i,j) = {};
				for(std::size_t k = 0; k < H; ++k)
				{
					out.m(i,j) += m(i, j) / other.m(k, j);
				}
			}
		}

		return out;
	}

	Matrix<T, W, H> operator/(T val) const
	{
		Matrix<T, W, H> m(*this);
		m.data /= val;
		return m;
	}

	struct pos_t
	{
		std::size_t x;
		std::size_t y;
	};

	void Move(pos_t from, pos_t to)
	{
		m(to.x, to.x) = m(from.x, from.x);
		m(from.x, from.y) = {};
	}

	std::vector<T> Row(std::size_t n) const
	{
		if(n >= H) throw std::out_of_range("Subscript out of range.");
		std::vector<T> out;
		for(std::size_t x = 0; x < W; ++x)
		{
			out.push_back(m(x, n));
		}
		return out;
	}

	std::vector<T> Column(std::size_t n) const
	{
		if(n >= W) throw std::out_of_range("Subscript out of range.");
		std::vector<T> out;
		for(std::size_t y = 0; y < H; ++y)
		{
			out.push_back(m(n, y));
		}
		return out;
	}

private:
	// Invariant; at all times data contains w * h initialized data members
	std::valarray<T> data; // default initialized to empty
};