#!/usr/bin/env python3
"""Stats for controller-like outputs (Type 2)."""

import argparse
import csv
import gzip
import json
from pathlib import Path
from typing import Dict, List


def parse_args():
    base_dir = Path(__file__).resolve().parent
    parser = argparse.ArgumentParser(description="Controller output stats.")
    parser.add_argument("--generated", default=str(base_dir / "results" / "generated.csv"))
    parser.add_argument("--reference", default=str(base_dir / "config.json"))
    parser.add_argument("--features", default="", help="comma-separated list")
    parser.add_argument("--config", default=str(base_dir / "config.json"))
    parser.add_argument("--out", default=str(base_dir / "results" / "controller_stats.json"))
    parser.add_argument("--max-rows", type=int, default=200000)
    return parser.parse_args()


def resolve_reference_glob(ref_arg: str) -> str:
    ref_path = Path(ref_arg)
    if ref_path.suffix == ".json":
        cfg = json.loads(ref_path.read_text(encoding="utf-8"))
        data_glob = cfg.get("data_glob") or cfg.get("data_path") or ""
        if not data_glob:
            raise SystemExit("reference config has no data_glob/data_path")
        combined = ref_path.parent / data_glob
        if "*" in str(combined) or "?" in str(combined):
            return str(combined)
        return str(combined.resolve())
    return str(ref_path)


def read_series(path: Path, cols: List[str], max_rows: int) -> Dict[str, List[float]]:
    vals = {c: [] for c in cols}
    opener = gzip.open if str(path).endswith(".gz") else open
    with opener(path, "rt", newline="") as fh:
        reader = csv.DictReader(fh)
        for i, row in enumerate(reader):
            for c in cols:
                try:
                    vals[c].append(float(row[c]))
                except Exception:
                    pass
            if max_rows > 0 and i + 1 >= max_rows:
                break
    return vals


def stats(series: List[float], vmin: float, vmax: float):
    if not series:
        return {"saturation_ratio": None, "change_rate": None, "step_median": None}
    # saturation ratio near bounds (1% of range)
    rng = vmax - vmin
    tol = 0.01 * rng if rng > 0 else 0.0
    sat = sum(1 for v in series if v <= vmin + tol or v >= vmax - tol) / len(series)
    # change rate
    changes = 0
    steps = []
    prev = series[0]
    for v in series[1:]:
        if v != prev:
            changes += 1
            steps.append(abs(v - prev))
        prev = v
    change_rate = changes / max(len(series) - 1, 1)
    steps.sort()
    step_median = steps[len(steps) // 2] if steps else None
    return {"saturation_ratio": sat, "change_rate": change_rate, "step_median": step_median}


def main():
    args = parse_args()
    features = [f.strip() for f in args.features.split(",") if f.strip()]
    if not features and Path(args.config).exists():
        cfg = json.loads(Path(args.config).read_text(encoding="utf-8"))
        features = cfg.get("type2_features", []) or []
    if not features:
        raise SystemExit("no features specified for controller_stats")

    # generated
    gen_vals = read_series(Path(args.generated), features, args.max_rows)

    # reference
    ref_glob = resolve_reference_glob(args.reference)
    ref_paths = sorted(Path(ref_glob).parent.glob(Path(ref_glob).name))
    if not ref_paths:
        raise SystemExit(f"no reference files matched: {ref_glob}")
    real_vals = {c: [] for c in features}
    for p in ref_paths:
        vals = read_series(p, features, args.max_rows)
        for c in features:
            real_vals[c].extend(vals[c])

    out = {"features": features, "generated": {}, "reference": {}}
    for c in features:
        rv = real_vals[c]
        if not rv:
            continue
        vmin, vmax = min(rv), max(rv)
        out["generated"][c] = stats(gen_vals[c], vmin, vmax)
        out["reference"][c] = stats(rv, vmin, vmax)

    out_path = Path(args.out)
    out_path.parent.mkdir(parents=True, exist_ok=True)
    out_path.write_text(json.dumps(out, indent=2), encoding="utf-8")
    print("wrote", out_path)


if __name__ == "__main__":
    main()