use std::fs::File;
use std::io::{IoSlice, IoSliceMut, Read, Seek, SeekFrom, Write};

#[open_coroutine::main(event_loop_size = 1, max_size = 1)]
pub fn main() -> std::io::Result<()> {
    const HELLO: &str = "Hello World!";

    // Write
    let mut tmpfile: File = tempfile::tempfile()?;
    assert_eq!(HELLO.len(), tmpfile.write(HELLO.as_ref())?);
    // Seek to start
    tmpfile.seek(SeekFrom::Start(0))?;
    // Read
    let mut buf = String::new();
    assert_eq!(HELLO.len(), tmpfile.read_to_string(&mut buf)?);
    assert_eq!(HELLO, buf);

    // Seek to start
    tmpfile.seek(SeekFrom::Start(0))?;

    // Write multiple
    let ioslices = [IoSlice::new(HELLO.as_ref()), IoSlice::new(HELLO.as_ref())];
    assert_eq!(HELLO.len() * 2, tmpfile.write_vectored(&ioslices)?);
    // Seek to start
    tmpfile.seek(SeekFrom::Start(0))?;
    // Read multiple
    let mut buf1 = [0; HELLO.len()];
    let mut buf2 = [0; HELLO.len()];
    let mut ioslicemuts = [IoSliceMut::new(&mut buf1), IoSliceMut::new(&mut buf2)];
    assert_eq!(HELLO.len() * 2, tmpfile.read_vectored(&mut ioslicemuts)?);
    assert_eq!(HELLO, unsafe { std::str::from_utf8_unchecked(&mut buf1) });
    assert_eq!(HELLO, unsafe { std::str::from_utf8_unchecked(&mut buf2) });

    Ok(())
}