use more_asserts::assert_gt;
use std::{env, process};
use wasi::wasi_unstable;
use wasi_tests::open_scratch_directory;
use wasi_tests::utils::{cleanup_file, close_fd, create_file};
use wasi_tests::wasi_wrappers::{wasi_fd_read, wasi_fd_write, wasi_path_open};

unsafe fn test_file_unbuffered_write(dir_fd: wasi_unstable::Fd) {
    // Create file
    create_file(dir_fd, "file");

    // Open file for reading
    let mut fd_read = wasi_unstable::Fd::max_value() - 1;
    let mut status = wasi_path_open(
        dir_fd,
        0,
        "file",
        0,
        wasi_unstable::RIGHT_FD_READ,
        0,
        0,
        &mut fd_read,
    );
    assert_eq!(
        status,
        wasi_unstable::raw::__WASI_ESUCCESS,
        "opening a file"
    );
    assert_gt!(
        fd_read,
        libc::STDERR_FILENO as wasi_unstable::Fd,
        "file descriptor range check",
    );

    // Open the same file but for writing
    let mut fd_write = wasi_unstable::Fd::max_value() - 1;
    status = wasi_path_open(
        dir_fd,
        0,
        "file",
        0,
        wasi_unstable::RIGHT_FD_WRITE,
        0,
        0,
        &mut fd_write,
    );
    assert_eq!(
        status,
        wasi_unstable::raw::__WASI_ESUCCESS,
        "opening a file"
    );
    assert_gt!(
        fd_write,
        libc::STDERR_FILENO as wasi_unstable::Fd,
        "file descriptor range check",
    );

    // Write to file
    let contents = &[1u8];
    let ciovec = wasi_unstable::CIoVec {
        buf: contents.as_ptr() as *const libc::c_void,
        buf_len: contents.len(),
    };
    let mut nwritten = 0;
    status = wasi_fd_write(fd_write, &[ciovec], &mut nwritten);
    assert_eq!(
        status,
        wasi_unstable::raw::__WASI_ESUCCESS,
        "writing byte to file"
    );
    assert_eq!(nwritten, 1, "nwritten bytes check");

    // Read from file
    let contents = &mut [0u8; 1];
    let iovec = wasi_unstable::IoVec {
        buf: contents.as_mut_ptr() as *mut libc::c_void,
        buf_len: contents.len(),
    };
    let mut nread = 0;
    status = wasi_fd_read(fd_read, &[iovec], &mut nread);
    assert_eq!(
        status,
        wasi_unstable::raw::__WASI_ESUCCESS,
        "reading bytes from file"
    );
    assert_eq!(nread, 1, "nread bytes check");
    assert_eq!(contents, &[1u8], "written bytes equal read bytes");

    // Clean up
    close_fd(fd_write);
    close_fd(fd_read);
    cleanup_file(dir_fd, "file");
}
fn main() {
    let mut args = env::args();
    let prog = args.next().unwrap();
    let arg = if let Some(arg) = args.next() {
        arg
    } else {
        eprintln!("usage: {} <scratch directory>", prog);
        process::exit(1);
    };

    // Open scratch directory
    let dir_fd = match open_scratch_directory(&arg) {
        Ok(dir_fd) => dir_fd,
        Err(err) => {
            eprintln!("{}", err);
            process::exit(1)
        }
    };

    // Run the tests.
    unsafe { test_file_unbuffered_write(dir_fd) }
}