"""Sender + receiver CPU per (experiment, solution): mean and sample SD in %."""
from pathlib import Path

import pandas as pd


METRICS = {
    "sender-cpu":   "cpu_sender",
    "receiver-cpu": "cpu_receiver",
}


def compute(derived: Path) -> tuple[dict[str, str], list[Path]]:
    out: dict[str, str] = {}
    sources: list[Path] = []
    for exp_dir in sorted(p for p in derived.iterdir() if p.is_dir()):
        runs = exp_dir / "runs.csv"
        if not runs.exists():
            continue
        sources.append(runs)
        df = pd.read_csv(runs)
        for sol, sub in df.groupby("solution", sort=True):
            for metric, col in METRICS.items():
                x = sub[col].to_numpy()
                base = f"{exp_dir.name}/{metric}/{sol}"
                out[f"{base}/mean-pct"] = f"{x.mean():.2f}"
                out[f"{base}/sd-pct"]   = f"{x.std(ddof=1):.2f}"
    return out, sources