use std::io;

use nix::{
	mount::{self, MsFlags},
	sched::{self, CloneFlags},
};
use serde::{Deserialize, Serialize};

fn mount_buildtmp() -> nix::Result<()> {
	mount::mount::<_, _, _, str>(
		Some("buildtmp"),
		"build/tmp",
		Some("tmpfs"),
		MsFlags::empty(),
		None,
	)
}

#[derive(Debug, Deserialize, Serialize)]
pub enum Error {
	Code(i32),
	String(String),
}

impl From<nix::Error> for Error {
	fn from(error: nix::Error) -> Self {
		match error {
			nix::Error::Sys(code) => Error::Code(code as i32),
			_ => Error::String(error.to_string()),
		}
	}
}

impl From<Error> for io::Error {
	fn from(error: Error) -> Self {
		match error {
			Error::Code(code) => io::Error::from_raw_os_error(code),
			Error::String(string) => io::Error::new(io::ErrorKind::Other, string),
		}
	}
}

pub fn runc_initialize() -> Result<(), Error> {
	sched::unshare(CloneFlags::CLONE_NEWUSER | CloneFlags::CLONE_NEWNS)?;
	mount_buildtmp()?;
	Ok(())
}