import os
from datetime import datetime
from pathlib import Path
from zoneinfo import ZoneInfo

_TZ = ZoneInfo("Europe/Zurich")

_ROOT    = Path(__file__).resolve().parent.parent
DATA_DIR = Path(os.getenv("DATA_DIR", str(_ROOT / "data")))
_LOG_FILE = DATA_DIR / "logs" / "operations.log"


def app_log(msg: str, debug: bool = False) -> None:
    """Écrit une entrée dans operations.log.

    PROD (debug=False) : [HH:MM:SS] msg   — ligne non indentée, visible en mode PROD
    DEBUG (debug=True) : [HH:MM:SS]   msg — ligne indentée, visible seulement en mode DEBUG
    """
    ts = datetime.now(tz=_TZ).strftime("%H:%M:%S")
    indent = "  " if debug else ""
    line = f"[{ts}] {indent}{msg}"
    try:
        _LOG_FILE.parent.mkdir(parents=True, exist_ok=True)
        with _LOG_FILE.open("a", encoding="utf-8") as f:
            f.write(line + "\n")
    except Exception:
        pass