"""Shared helpers: settings, paths, logging, deterministic seeds."""
from __future__ import annotations
import hashlib, json, logging, os, random, sys, time
from pathlib import Path
import numpy as np
import yaml

ROOT = Path(__file__).resolve().parents[1]
SETTINGS = yaml.safe_load((ROOT / "config" / "settings.yaml").read_text())
SEED = int(SETTINGS["seed"])
TZ = SETTINGS.get("timezone_display", "America/Toronto")

def path(key: str) -> Path:
    p = ROOT / SETTINGS["paths"][key]
    p.mkdir(parents=True, exist_ok=True)
    return p

def snapshot_db() -> Path:
    return ROOT / SETTINGS["snapshot"]["path"]

def verify_snapshot() -> str:
    h = hashlib.sha256()
    with open(snapshot_db(), "rb") as f:
        for chunk in iter(lambda: f.read(1 << 20), b""):
            h.update(chunk)
    digest = h.hexdigest()
    if digest != SETTINGS["snapshot"]["sha256"]:
        raise SystemExit(f"snapshot sha256 mismatch: {digest}")
    return digest

def seed_everything(seed: int = SEED) -> None:
    random.seed(seed); np.random.seed(seed)
    os.environ["PYTHONHASHSEED"] = str(seed)

def get_logger(name: str) -> logging.Logger:
    log = logging.getLogger(name)
    if not log.handlers:
        fmt = logging.Formatter("%(asctime)s %(levelname)s %(name)s: %(message)s", "%Y-%m-%dT%H:%M:%S")
        sh = logging.StreamHandler(sys.stdout); sh.setFormatter(fmt); log.addHandler(sh)
        fh = logging.FileHandler(path("logs") / "pipeline.log"); fh.setFormatter(fmt); log.addHandler(fh)
        log.setLevel(logging.INFO)
    return log

def ledger(phase: str, action: str, result: str) -> None:
    """Append a machine-readable line to the structured run ledger."""
    rec = {"utc": time.strftime("%Y-%m-%dT%H:%M:%SZ", time.gmtime()), "phase": phase, "action": action, "result": result}
    with open(path("logs") / "run_ledger.jsonl", "a") as f:
        f.write(json.dumps(rec, ensure_ascii=False) + "\n")

def write_manifest(name: str, files: list[Path], extra: dict | None = None) -> None:
    man = {"name": name, "utc": time.strftime("%Y-%m-%dT%H:%M:%SZ", time.gmtime()), "seed": SEED,
           "snapshot": SETTINGS["snapshot"]["id"], "files": {}}
    for f in files:
        f = Path(f)
        if f.exists():
            man["files"][str(f.relative_to(ROOT))] = {"bytes": f.stat().st_size,
                "sha256": hashlib.sha256(f.read_bytes()).hexdigest() if f.stat().st_size < 400_000_000 else None}
    if extra: man.update(extra)
    (path("logs") / f"manifest_{name}.json").write_text(json.dumps(man, indent=2, ensure_ascii=False))