use std::fs;
use std::time::Instant;

#[tokio::main]
async fn main() {
    println!("Hello, world!");

    let path = "/usr/bin";

    let start = Instant::now();
    list_files_async(path).await;
    let async_duration = start.elapsed();
    println!("Async time: {:?}", async_duration);

    let start = Instant::now();
    list_files_sync(path);
    let sync_duration = start.elapsed();
    println!("Sync time: {:?}", sync_duration);
}

async fn list_files_async(path: &str) {
    let mut total_size = 0;
    let mut entries = tokio::fs::read_dir(path).await.unwrap();
    let mut tasks = Vec::new();

    while let Some(entry) = entries.next_entry().await.unwrap() {
        let task = tokio::spawn(async move { entry.metadata().await.unwrap().len() });
        tasks.push(task);
    }

    for task in tasks {
        total_size += task.await.unwrap();
    }
    println!("Async total_size: {}", total_size);
}

fn list_files_sync(path: &str) {
    let mut total_size = 0;
    for entry in fs::read_dir(path).unwrap() {
        let entry = entry.unwrap();
        let file_size = entry.metadata().unwrap().len();
        total_size += file_size;
    }
    println!("Sync total_size: {}", total_size);
}