#pragma once
#include "core-library/views/view-closure.h"

#include <ranges>

namespace core {

template<std::ranges::forward_range Range>
    requires requires(Range&& range) {
	    *std::begin(range) == ' '; // Comparable with char literals.
    }
class trim_view : public std::ranges::view_interface<trim_view<Range>>
{
public:
	constexpr explicit trim_view(Range range)
	: m_range(std::move(range))
	{
	}

	static constexpr bool is_space(auto&& c)
	{
		return c == ' ' || c == '\t' || c == '\r' || c == '\n' || c == '\0';
	}

	constexpr auto begin()
	{
		auto it = std::begin(m_range);
		while (it != std::end(m_range) && is_space(*it))
			++it;

		return it;
	}

	constexpr auto end()
	{
		auto nonspace_end = std::end(m_range);

		for (auto it = std::begin(m_range); it != std::end(m_range);)
		{
			if (!is_space(*it++))
				nonspace_end = it;
		}

		return nonspace_end;
	}

private:
	Range m_range{};
};

constexpr view_closure<trim_view> trim{};

}