#!/usr/bin/env python3
"""Compute program-style stats (dwell, change count, step size) for selected features."""

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="Program stats for setpoints/demands.")
    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; empty = auto from eval")
    parser.add_argument("--config", default=str(base_dir / "config.json"))
    parser.add_argument("--out", default=str(base_dir / "results" / "program_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
        # avoid resolve on glob patterns
        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 dwell_and_steps(series: List[float]):
    if not series:
        return {
            "num_changes": 0,
            "mean_dwell": None,
            "median_dwell": None,
            "mean_step": None,
            "median_step": None,
        }
    changes = 0
    dwells = []
    steps = []
    current = series[0]
    dwell = 1
    for v in series[1:]:
        if v == current:
            dwell += 1
            continue
        changes += 1
        dwells.append(dwell)
        steps.append(abs(v - current))
        current = v
        dwell = 1
    dwells.append(dwell)

    def mean(x):
        return sum(x) / len(x) if x else None

    def median(x):
        if not x:
            return None
        xs = sorted(x)
        mid = len(xs) // 2
        return xs[mid] if len(xs) % 2 == 1 else 0.5 * (xs[mid - 1] + xs[mid])

    return {
        "num_changes": changes,
        "mean_dwell": mean(dwells),
        "median_dwell": median(dwells),
        "mean_step": mean(steps),
        "median_step": median(steps),
    }


def main():
    args = parse_args()
    out_path = Path(args.out)

    eval_path = Path("results") / "eval.json"
    auto_feats = []
    if eval_path.exists():
        data = json.loads(eval_path.read_text(encoding="utf-8"))
        ks = data.get("continuous_ks", {})
        auto_feats = [k for k, v in ks.items() if v >= 0.6]

    features = [f.strip() for f in args.features.split(",") if f.strip()] or auto_feats
    if not features and Path(args.config).exists():
        cfg = json.loads(Path(args.config).read_text(encoding="utf-8"))
        features = cfg.get("type1_features", []) or []
    if not features:
        raise SystemExit("no features specified and no eval.json with ks>=0.6")

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

    # reference series (aggregate across files)
    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:
        out["generated"][c] = dwell_and_steps(gen_vals[c])
        out["reference"][c] = dwell_and_steps(real_vals[c])

    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()