use std::{fs::File, io::Result, path::Path};

use nix::unistd;

use super::ToIOResult;

pub struct SetEUID(unistd::Uid);

impl Drop for SetEUID {
	fn drop(&mut self) {
		unistd::seteuid(self.0).expect("failed to reset effective UID");
	}
}

pub fn seteuid(uid: unistd::Uid) -> Result<SetEUID> {
	let old_uid = unistd::geteuid();
	unistd::seteuid(uid).to_io_result()?;
	Ok(SetEUID(old_uid))
}

pub struct SetEGID(unistd::Gid);

impl Drop for SetEGID {
	fn drop(&mut self) {
		unistd::setegid(self.0).expect("failed to reset effective GID");
	}
}

pub fn setegid(gid: unistd::Gid) -> Result<SetEGID> {
	let old_gid = unistd::getegid();
	unistd::setegid(gid).to_io_result()?;
	Ok(SetEGID(old_gid))
}

pub fn create_as<P: AsRef<Path>>(
	path: P,
	uid: Option<unistd::Uid>,
	gid: Option<unistd::Gid>,
) -> Result<File> {
	let _setegid = gid.map(setegid).transpose()?;
	let _seteuid = uid.map(seteuid).transpose()?;

	File::create(path)
}