use std::os::fd::{AsRawFd, OwnedFd, RawFd};
use std::os::unix::ffi::OsStrExt;
use std::sync::Arc;
use std::{ffi::CString, io, path::Path};

pub(crate) type ArcFd = Arc<dyn AsRawFd + Send + Sync + 'static>;

/// Raw file descriptor trait for io-uring operations.
///
/// `Arc<dyn AsRawFd>` does not satisfy `AsRawFd` because the blanket impl
/// for `Arc<T>` requires `T: Sized`. This trait bridges that gap so both
/// `OwnedFd` and `ArcFd` can be used generically with `Op::read_at`.
pub(crate) trait UringFd: Send + Sync + 'static {
    fn as_raw_fd(&self) -> RawFd;
}

impl UringFd for OwnedFd {
    fn as_raw_fd(&self) -> RawFd {
        AsRawFd::as_raw_fd(self)
    }
}

impl UringFd for ArcFd {
    fn as_raw_fd(&self) -> RawFd {
        (**self).as_raw_fd()
    }
}

pub(crate) fn cstr(p: &Path) -> io::Result<CString> {
    Ok(CString::new(p.as_os_str().as_bytes())?)
}