"""Cross-run comparison table (markdown) from files each run writes."""
from __future__ import annotations

import json
from pathlib import Path


def _load(p: Path):
    return json.loads(p.read_text()) if p.exists() else None


def run_row(run: str | Path) -> dict:
    run = Path(run)
    s = _load(run / "summary.json") or {}
    g = _load(run / "games.json") or {}
    b = _load(run / "benchmark.json") or []
    cal = s.get("test_calibrated", {})
    row = {"run": run.name, "model": (_load(run / "env.json") or {}).get("task", ""),
           "params": s.get("params_human"), "acc": cal.get("accuracy"), "ece": cal.get("ece"),
           "ece_raw": s.get("test_raw", {}).get("ece"), "nll": cal.get("nll"), "brier": cal.get("brier"),
           "avg_score": g.get("avg_score"), "median": g.get("median_score"), "max": g.get("max_score"),
           "win": g.get("win_rate"), "fatal": g.get("fatal_move_rate"),
           "train_min": round(s["train_seconds"] / 60, 1) if s.get("train_seconds") else None,
           "cost": (s.get("cost") or {}).get("actual_cost", (s.get("cost") or {}).get("estimated_cost"))}
    for r in b:
        kind = "int8" if ".int8." in r["model"] else ("onnx" if r["model"].endswith(".onnx") else "torch")
        row[f"{kind}_mb"] = r["file_size_mb"]
        row[f"{kind}_p50"] = r["latency"]["end_to_end"]["p50_ms"]
        row[f"{kind}_p99"] = r["latency"]["end_to_end"]["p99_ms"]
        row[f"{kind}_dps"] = r["latency"]["max_decisions_per_sec_batch1"]
    return row


COLUMNS = [("run", "run"), ("params", "params"), ("onnx_mb", "onnx MB"), ("int8_mb", "int8 MB"),
           ("onnx_p50", "p50 ms"), ("onnx_p99", "p99 ms"), ("onnx_dps", "dec/s"), ("acc", "acc"),
           ("ece_raw", "ECE raw"), ("ece", "ECE"), ("brier", "Brier"), ("avg_score", "avg score"),
           ("median", "median"), ("max", "max"), ("win", "win"), ("fatal", "fatal-move"),
           ("train_min", "train min"), ("cost", "cost €")]


def _fmt(v, key):
    if v is None:
        return "-"
    if key in ("acc", "win"):
        return f"{v:.1%}"
    if key == "fatal":
        return f"{v:.3%}"
    if key in ("ece", "ece_raw", "brier", "nll"):
        return f"{v:.4f}"
    if isinstance(v, float):
        return f"{v:.2f}" if v < 100 else f"{v:,.0f}"
    return str(v)


def compare_runs(runs, out: str | None = None) -> str:
    rows = [run_row(r) for r in runs]
    cols = [(k, h) for k, h in COLUMNS if any(r.get(k) is not None for r in rows)]
    lines = ["| " + " | ".join(h for _, h in cols) + " |", "|" + "---|" * len(cols)]
    for r in rows:
        lines.append("| " + " | ".join(_fmt(r.get(k), k) for k, _ in cols) + " |")
    table = "\n".join(lines)
    if out:
        Path(out).write_text(table + "\n")
    return table