#include <type_traits>

#include <function_ref.hpp>

#include "engine/displacement.hpp"

namespace devilution {

/**
 * CrawlTable specifies X- and Y-coordinate deltas from a missile target coordinate.
 *
 * n=4
 *
 *    y
 *    ^
 *    |  1
 *    | 3#4
 *    |  2
 *    +-----> x
 *
 * n=16
 *
 *    y
 *    ^
 *    |  314
 *    | B7 8C
 *    | F # G
 *    | D9 AE
 *    |  526
 *    +-------> x
 */

bool DoCrawl(unsigned radius, tl::function_ref<bool(Displacement)> function);
bool DoCrawl(unsigned minRadius, unsigned maxRadius, tl::function_ref<bool(Displacement)> function);

template <typename F>
auto Crawl(unsigned radius, F function) -> std::invoke_result_t<decltype(function), Displacement>
{
	std::invoke_result_t<decltype(function), Displacement> result;
	DoCrawl(radius, [&result, &function](Displacement displacement) -> bool {
		result = function(displacement);
		return !result;
	});
	return result;
}

template <typename F>
auto Crawl(unsigned minRadius, unsigned maxRadius, F function) -> std::invoke_result_t<decltype(function), Displacement>
{
	std::invoke_result_t<decltype(function), Displacement> result;
	DoCrawl(minRadius, maxRadius, [&result, &function](Displacement displacement) -> bool {
		result = function(displacement);
		return !result;
	});
	return result;
}

} // namespace devilution