#include <exception>
#include <filesystem>
#include <format>
#include <iostream>
#include <string>
#include <regex>
#include <ranges>
#include <vector>
#include <fstream>

namespace fs = std::filesystem;

int main(int argc, char* argv[]) try {
    std::vector<std::string> args(argv + 1, argv + argc);

    const std::regex link_regex{R"(\[[^\]]*\]\(([^)]*)\))"};

    if (args.size() != 1) {
        std::cerr << "only one argument expected\n";
        return 1;
    }

    for (const auto& entry : fs::recursive_directory_iterator(args[0])) {
        if (entry.is_regular_file()) {
            const auto entry_path = entry.path();

            if (entry_path.extension() == ".md") {
                std::ifstream document(entry_path);

                if (!document.good()) {
                    std::cerr << "something bad happened" << std::endl;
                }

                std::string line;

                while (std::getline(document, line)) {
                    const auto links = std::sregex_iterator(line.begin(), line.end(), link_regex);
                    const auto end = std::sregex_iterator();

                    for (auto it = links; it != end; ++it) {
                        const auto link = it->str(1);

                        // TODO
                    }
                }
            }
        }
    }


} catch (std::exception& e) {
    std::cerr << e.what() << std::endl;
    return 1;
} catch (...) {
    std::cerr << "unexpected exception" << std::endl;
    return 1;
}