use std::{env, fs::File, io::Write, time};

fn write_buf_un(w: &mut impl Write) -> Result<(), std::io::Error> {
    let buf: [u8; 10] = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
    w.write_all(&buf)?;
    Ok(())
}

#[inline]
fn write_buf(w: &mut impl Write) -> Result<(), std::io::Error> {
    let mut buf = [0u8; 10];
    buf[0] = 0;
    buf[1] = 1;
    buf[2] = 2;
    buf[3] = 3;
    buf[4] = 4;
    buf[5] = 5;
    buf[6] = 6;
    buf[7] = 7;
    buf[8] = 8;
    buf[9] = 9;
    w.write_all(&buf)?;
    Ok(())
}

fn write_many(w: &mut impl Write) -> Result<(), std::io::Error> {
    w.write_all(&[0])?;
    w.write_all(&[1])?;
    w.write_all(&[2])?;
    w.write_all(&[3])?;
    w.write_all(&[4])?;
    w.write_all(&[5])?;
    w.write_all(&[6])?;
    w.write_all(&[7])?;
    w.write_all(&[8])?;
    w.write_all(&[9])?;
    Ok(())
}

fn main() {
    let args: Vec<String> = env::args().collect();

    match args[1].as_ref() {
        "1" => {
            _ = std::fs::remove_file("/tmp/write_buf_1");
            let mut file = File::create("/tmp/write_buf_1").unwrap();
            let now = time::Instant::now();
            while now.elapsed().as_secs() < 1u64 {
                write_buf(&mut file).expect("written");
            }
        }
        "2" => {
            _ = std::fs::remove_file("/tmp/write_many_1");
            let mut file = File::create("/tmp/write_many_1").unwrap();
            let now = time::Instant::now();
            while now.elapsed().as_secs() < 1u64 {
                write_many(&mut file).expect("written");
            }
        }
        "3" => {
            _ = std::fs::remove_file("/tmp/write_many_buf_1");
            let file = File::create("/tmp/write_many_buf_1").unwrap();
            let mut w = std::io::BufWriter::new(file);
            let now = time::Instant::now();
            while now.elapsed().as_secs() < 1u64 {
                write_many(&mut w).expect("written");
            }
        }
        "4" => {
            _ = std::fs::remove_file("/tmp/write_buf_buf_1");
            let file = File::create("/tmp/write_buf_buf_1").unwrap();
            let mut w = std::io::BufWriter::new(file);
            let now = time::Instant::now();
            while now.elapsed().as_secs() < 1u64 {
                write_buf(&mut w).expect("written");
            }
        }
        "5" => {
            _ = std::fs::remove_file("/tmp/write_buf_buf_un_1");
            let file = File::create("/tmp/write_buf_buf_un_1").unwrap();
            let mut w = std::io::BufWriter::new(file);
            let now = time::Instant::now();
            while now.elapsed().as_secs() < 1u64 {
                write_buf_un(&mut w).expect("written");
            }
        }
        _ => println!("expect 1,2,3,1"),
    }
}