module;

export module mcpplibs.cmdline:parse;

import std;

namespace mcpplibs::cmdline::detail {

export struct OptionValue {

int count = 0; // flag 出现次数（如 -v -v -v）

std::vector<std::string> values; // 带值选项的值，multiple 时多个

[[nodiscard]] std::string value() const {

return values.empty() ? std::string{} : values.back();

}

[[nodiscard]] std::string value_or(std::string_view default_value) const {

return values.empty() ? std::string{default_value} : values.back();

}

[[nodiscard]] bool is_set() const { return count > 0 || !values.empty(); }

};

export struct ParseError {

enum Kind : std::uint8_t { help, version, error };

Kind kind = error;

std::string message;

bool is_error() const { return kind == error; }

static ParseError make_help() { return {.kind = help}; }

static ParseError make_version() { return {.kind = version}; }

friend std::ostream& operator<<(std::ostream& os, const ParseError& e) {

return os << e.message;

}

};

export struct ParsedArgs {

std::map<std::string, OptionValue, std::less<>> opts;

std::vector<std::string> positionals;

std::vector<std::string> positional_names_;

std::string subcommand_name_;

std::unique_ptr<ParsedArgs> subcommand_matches;

[[nodiscard]] std::optional<std::reference_wrapper<const OptionValue>> option(std::string_view name) const {

}

[[nodiscard]] OptionValue option_or_empty(std::string_view name) const {

auto opt = option(name);

return opt ? opt->get() : OptionValue{};

}

[[nodiscard]] bool is_flag_set(std::string_view name) const {

return option_or_empty(name).is_set();

}

[[nodiscard]] std::optional<std::string> value(std::string_view name) const {

}

[[nodiscard]] std::string positional(std::size_t index) const {

return index < positionals.size() ? positionals[index] : std::string{};

}

[[nodiscard]] std::string positional_or(std::size_t index, std::string_view default_value) const {

return index < positionals.size() ? positionals[index] : std::string{default_value};

}

[[nodiscard]] std::size_t positional_count() const { return positionals.size(); }

[[nodiscard]] bool has_subcommand() const { return !subcommand_name_.empty(); }

[[nodiscard]] std::string_view subcommand_name() const { return std::string_view(subcommand_name_); }

[[nodiscard]] std::optional<std::reference_wrapper<const ParsedArgs>> subcommand() const {

if (subcommand_matches) return std::cref(*subcommand_matches);

return std::nullopt;

}

};

export using ParseResult = std::expected<ParsedArgs, ParseError>;

} // namespace mcpplibs::cmdline::detail