/*
 * This source code is released into the public domain.
 */

module;

#include <memory>
#include <ranges>
#include <string>
#include <vector>

export module nihil.posix:argv;

namespace nihil {

/*
 * argv: stores a null-terminated array of nul-terminated C strings.
 * argv::data() is suitable for passing to ::execv().
 *
 * Create an argv using argv::from_range(), which takes a range of
 * string-like objects.
 */

export struct argv {
	/*
	 * Create a new argv from a range.
	 */
	argv(std::from_range_t, std::ranges::range auto &&args)
	{
		for (auto &&arg : args)
			add_arg(std::string_view(arg));

		m_args.push_back(nullptr);
	}

	/*
	 * Create an argv from an initializer list.
	 */
	template<typename T>
	explicit argv(std::initializer_list<T> &&args)
		: argv(std::from_range, std::forward<decltype(args)>(args))
	{
	}

	// Movable.
	argv(argv &&) noexcept;
	auto operator=(this argv &, argv &&other) -> argv &;

	// Not copyable.  TODO: for completeness, it probably should be.
	argv(argv const &) = delete;
	auto operator=(this argv &, argv const &other) -> argv& = delete;

	~argv();

	// Access the stored arguments.
	[[nodiscard]] auto data(this argv const &self) -> char const * const *;
	[[nodiscard]] auto data(this argv &self) -> char * const *;
	[[nodiscard]] auto size(this argv const &self);

	// Range access
	[[nodiscard]] auto begin(this argv const &self);
	[[nodiscard]] auto end(this argv const &self);

private:
	// Use the from_range() factory method to create new instances.
	argv();

	// The argument pointers, including the null terminator.
	// This can't be a vector<unique_ptr> because we need an array of
	// char pointers to pass to exec.
	std::vector<char *> m_args;

	// Add a new argument to the array.
	auto add_arg(this argv &self, std::string_view arg) -> void;
};

} // namespace nihil