/// An allocated pty
pub struct Pty(crate::sys::Pty);

impl Pty {
    /// Allocate and return a new pty.
    ///
    /// # Errors
    /// Returns an error if the pty failed to be allocated.
    pub fn new() -> crate::Result<Self> {
        Ok(Self(crate::sys::Pty::open()?))
    }

    /// Change the terminal size associated with the pty.
    ///
    /// # Errors
    /// Returns an error if we were unable to set the terminal size.
    pub fn resize(&self, size: crate::Size) -> crate::Result<()> {
        self.0.set_term_size(size)
    }

    /// Opens a file descriptor for the other end of the pty, which should be
    /// attached to the child process running in it. See
    /// [`Command::spawn`](crate::blocking::Command::spawn).
    ///
    /// # Errors
    /// Returns an error if the device node to open could not be determined,
    /// or if the device node could not be opened.
    pub fn pts(&self) -> crate::Result<Pts> {
        Ok(Pts(self.0.pts()?))
    }
}

impl std::os::unix::io::AsRawFd for Pty {
    fn as_raw_fd(&self) -> std::os::unix::io::RawFd {
        self.0 .0.as_raw_fd()
    }
}

impl std::io::Read for Pty {
    fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
        self.0 .0.read(buf)
    }
}

impl std::io::Write for Pty {
    fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
        self.0 .0.write(buf)
    }

    fn flush(&mut self) -> std::io::Result<()> {
        self.0 .0.flush()
    }
}

impl std::io::Read for &Pty {
    fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
        (&self.0 .0).read(buf)
    }
}

impl std::io::Write for &Pty {
    fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
        (&self.0 .0).write(buf)
    }

    fn flush(&mut self) -> std::io::Result<()> {
        (&self.0 .0).flush()
    }
}

/// The child end of the pty
///
/// See [`Pty::pts`] and [`Command::spawn`](crate::blocking::Command::spawn)
pub struct Pts(pub(crate) crate::sys::Pts);