#include "array"
#include "boost/array.hpp"
#include "boost/coroutine/all.hpp"
#include "functional"
#include "iostream"

namespace detail {

template <
	template <class Value_T, size_t Length> class Container_T,
	class Value_T,
	size_t Length,
	size_t Index
> class print_impl
{
public:
	static void print(const Container_T<Value_T, Length>& current)
	{
		print_impl<Container_T, Value_T, Length, Index - 1>::print(current);
		std::cout << current[Index] << " ";
	}
};

template <
	template <class Value_T, size_t Length> class Container_T,
	class Value_T,
	size_t Length
> class print_impl<Container_T, Value_T, Length, 0>
{
public:
	static void print(const Container_T<Value_T, Length>& current)
	{
		std::cout << current[0] << " ";
	}
};

} // namespace detail


template <
	template <class Value_T, size_t Length> class Container_T,
	class Value_T,
	size_t Length
> void print(const Container_T<Value_T, Length>& current)
{
	detail::print_impl<
		Container_T,
		Value_T,
		Length,
		Length - 1
	>::print(current);
	std::cout << std::endl;
}


namespace detail {

//! iterates over values in dimension Index
template <
	template <class Value_T, size_t Length> class Container_T,
	class Value_T,
	size_t Length,
	size_t Index
> class volume_iterator_impl
{
public:
	static void iterate(
		typename boost::coroutines::coroutine<
			Container_T<Value_T, Length>
		>::push_type& sink,
		Container_T<Value_T, Length>& current,
		const Container_T<Value_T, Length>& start,
		const Container_T<Value_T, Length>& end,
		const Container_T<Value_T, Length>& increment
	) {
		for(
			current[Index] = start[Index] + increment[Index] / Value_T(2);
			current[Index] < end[Index];
			current[Index] += increment[Index]
		) {
			volume_iterator_impl<
				Container_T,
				Value_T,
				Length,
				Index - 1
			>::iterate(
				sink,
				current,
				start,
				end,
				increment
			);
		}
	}
};

//! iterates over values of the last dimension
template <
	template <class Value_T, size_t Length> class Container_T,
	class Value_T,
	size_t Length
> class volume_iterator_impl<Container_T, Value_T, Length, 0>
{
public:
	static void iterate(
		typename boost::coroutines::coroutine<
			Container_T<Value_T, Length>
		>::push_type& sink,
		Container_T<Value_T, Length>& current,
		const Container_T<Value_T, Length>& start,
		const Container_T<Value_T, Length>& end,
		const Container_T<Value_T, Length>& increment
	) {
		for(
			current[0] = start[0] + increment[0] / Value_T(2);
			current[0] < end[0];
			current[0] += increment[0]
		) {
			sink(current);
		}
	}
};

} // namespace detail


template <
	template <class Value_T, size_t Length> class Container_T,
	class Value_T,
	size_t Length
> typename boost::coroutines::coroutine<
	Container_T<Value_T, Length>
>::pull_type volume_iterator(
	const Container_T<Value_T, Length>& start,
	const Container_T<Value_T, Length>& end,
	const size_t samples
) {
	Container_T<Value_T, Length> increment;

	for (size_t i = 0; i < Length; i++) {
		increment[i] = (end[i] - start[i]) / samples;
	}

	return
		typename boost::coroutines::coroutine<
			Container_T<Value_T, Length>
		>::pull_type(
			std::bind(
				&detail::volume_iterator_impl<
					Container_T,
					Value_T,
					Length,
					Length - 1
				>::iterate,
				std::placeholders::_1,
				Container_T<Value_T, Length>(),
				start,
				end,
				increment
			)
		);
}

int main()
{
	const size_t samples = 2;
	std::cout << "Number of samples per dimension: " << samples
		<< std::endl << std::endl;

	std::cout << "std::array<double, 1>:" << std::endl;
	{
		std::array<double, 1> start, end;

		for (size_t i = 0; i < start.size(); i++) {
			end[i] = (i + 1);
			start[i] = -end[i];
		}

		std::cout << "start: ";
		print(start);
		std::cout << "end: ";
		print(end);

		std::cout << "iteration:" << std::endl;
		for (const auto& i: volume_iterator(start, end, samples)) {
			print(i);
		}

		std::cout << std::endl;
	}

	std::cout << "std::array<double, 3>:" << std::endl;
	{
		std::array<double, 3> start, end;

		for (size_t i = 0; i < start.size(); i++) {
			end[i] = 2 * (i + 1);
			start[i] = -end[i];
		}

		std::cout << "start: ";
		print(start);
		std::cout << "end: ";
		print(end);

		std::cout << "iteration:" << std::endl;
		for (const auto& i: volume_iterator(start, end, samples)) {
			print(i);
		}

		std::cout << std::endl;
	}

	std::cout << "boost::array<double, 2>:" << std::endl;
	{
		boost::array<double, 2> start, end;

		for (size_t i = 0; i < start.size(); i++) {
			end[i] = (i + 2) * (i + 2);
			start[i] = -end[i];
		}

		std::cout << "start: ";
		print(start);
		std::cout << "end: ";
		print(end);

		std::cout << "iteration:" << std::endl;
		for (const auto& i: volume_iterator(start, end, samples)) {
			print(i);
		}

		std::cout << std::endl;
	}

	return 0;
}