module;

#include <cstddef>
#include <string>
#include <optional>

export module jlx:source_stream;

namespace jlx {
	export template<typename CharT>
	class source_stream {
		public:
			using char_traits = std::char_traits<CharT>;
			using str = std::basic_string<CharT, char_traits>;
		protected:
			str::size_type pos = 0;
			std::size_t line = 1;
			std::size_t col = 0;
			const str input;
		public:
			source_stream(const str input) : input(std::move(input)){
				
			}

			std::optional<CharT> next() {
				if (pos >= input.length()) {
					return std::nullopt;
				}
				auto ch = input.at(pos++);
				if(char_traits::to_int_type(ch) == 10) {
					line += 1;
					col = 0;
				} else {
					col++;
				}
				return ch;
			}

			std::optional<CharT> peek() const {
				if (pos >= input.length()) {
					return std::nullopt;
				}

				return input.at(pos);
			}

			bool eof() {
				return pos >= input.length();
			}

			size_t current_line() const {
				return line;
			}

			size_t current_col() const {
				return col;
			}
	};
}