use alloc::format;
use alloc::vec::Vec;

use crate::{
    percpu::get_all_stats,
    sync::CleanLockToken,
    syscall::error::{Error, Result, ENOENT},
};

/// Format one per-CPU stat line compatible with Linux `/proc/stat`:
/// `user nice system idle iowait irq softirq steal`.
///
/// Redox's scheduler tracks user, nice, kernel, idle, and irq. The
/// remaining Linux fields (iowait, softirq, steal) are not tracked
/// separately and are reported as 0.
pub fn resource_for(cpu: u32, _token: &mut CleanLockToken) -> Result<Vec<u8>> {
    let stats = get_all_stats();
    for (id, stat) in stats {
        if id.get() == cpu {
            let line = format!(
                "{} {} {} {} {} 0 0 0\n",
                stat.user, stat.nice, stat.kernel, stat.idle, stat.irq
            );
            return Ok(line.into_bytes());
        }
    }
    Err(Error::new(ENOENT))
}