main.rs

use tokio::io::{self, AsyncWriteExt};
use tokio::runtime::Runtime;
use tokio::fs;
use tokio::signal::ctrl_c;
use tokio::time::delay_for;
use chrono::{DateTime, Local};
use futures::select;
use std::time::Duration;
use futures::future::FutureExt;
fn main() {
    let mut rt = Runtime::new().unwrap();
    rt.block_on(async{
        timer_loop(Duration::from_secs(30), Duration::from_secs(10)).await.unwrap()
    })
}

async fn timer_loop(work_pause : Duration, break_pause : Duration) -> io::Result<()>{
    let mut current_file_task = None;
    loop{
        let mut time = Local::now();
        println!("Starting to work!");
        let was_interrupted = select!{
            _ = delay_for(work_pause).fuse() => false,
            x = ctrl_c().fuse() => {x?; true}, 
        };
        match current_file_task{
            Some(x) => x.await??,
            None => (),
        }
        if was_interrupted{
            println!("Timer was stopped when we were working");
            write_to_file(time, Local::now()).await?;
            break;
        }
        current_file_task = Some(tokio::spawn(write_to_file(time, Local::now())));
        time = Local::now();
        println!("Starting the pause!");
        let was_interrupted = select!{
            _ = delay_for(break_pause).fuse() => false,
            x = ctrl_c().fuse() => {x?; true}, 
        };
        match current_file_task{
            Some(x) => x.await??,
            None => (),
        }
        if was_interrupted{
            println!("Timer was stopped during the pause");
            write_to_file(time, Local::now()).await?;
            break;
        }
        current_file_task = Some(tokio::spawn(write_to_file(time, Local::now())));
    }
    Ok(())
}


async fn write_to_file(start : DateTime<Local>, end : DateTime<Local>) -> io::Result<()>{
    let mut file = fs::OpenOptions::new()
            .create(true)
            .append(true)
            .open("pom.txt").await?;
    let data = format!("{} -- {}\n", start.format("%H:%M:%S"), end.format("%H:%M:%S, %a %Y-%m-%d"));
    file.write_all(data.as_bytes()).await?;
    Ok(())
}