use std::time::Duration;

pub fn pct(sorted: &mut [Duration], p: f64) -> f64 {
    if sorted.is_empty() {
        return 0.0;
    }
    sorted.sort_unstable();
    let i = ((sorted.len() as f64 - 1.0) * p).round() as usize;
    sorted[i].as_secs_f64() * 1000.0
}

pub const CPU_BUDGET: Duration = Duration::from_micros(8_333);

pub fn summarise(name: &str, samples: &[Duration]) {
    let mut v = samples.to_vec();
    let over_budget = v.iter().filter(|d| **d > CPU_BUDGET).count();
    println!(
        "  {name:16} n={:<5} p50 {:.2}ms  p90 {:.2}ms  p99 {:.2}ms  worst {:.2}ms  \
         over-8.3ms {over_budget}",
        v.len(),
        pct(&mut v, 0.5),
        pct(&mut v, 0.9),
        pct(&mut v, 0.99),
        pct(&mut v, 1.0),
    );
}

pub fn pct_u64(v: &mut [u64], p: f64) -> u64 {
    if v.is_empty() {
        return 0;
    }
    v.sort_unstable();
    v[(((v.len() - 1) as f64) * p).round() as usize]
}