"""Central textual audit log for user-driven warehouse operations."""

from __future__ import annotations

import json
import logging
from pathlib import Path
from typing import Any

from user_session import UserSession


AUDIT_LOG_PATH = Path(__file__).with_name("warehouse_audit.log")
_LOGGER = logging.getLogger("warehouse_audit")
_LOGGER_CONFIGURED = False


def _configure_logger() -> None:
    """Configure the append-only textual audit logger once."""

    global _LOGGER_CONFIGURED
    if _LOGGER_CONFIGURED:
        return

    _LOGGER.setLevel(logging.INFO)
    _LOGGER.propagate = False
    handler = logging.FileHandler(AUDIT_LOG_PATH, encoding="utf-8")
    handler.setFormatter(logging.Formatter("%(asctime)s | %(message)s"))
    _LOGGER.addHandler(handler)
    _LOGGER_CONFIGURED = True


def _user_label(session: UserSession | None) -> str:
    """Render the user identity consistently in the audit trail."""

    if session is None:
        return "anonymous"
    return f"{session.login or 'anonymous'}#{session.operator_id}"


def _payload(
    *,
    session: UserSession | None,
    module: str,
    action: str,
    outcome: str,
    target: str = "",
    details: dict[str, Any] | None = None,
) -> str:
    """Serialize one audit event as a compact text line."""

    base = {
        "user": _user_label(session),
        "module": module,
        "action": action,
        "outcome": outcome,
        "target": target,
        "details": details or {},
    }
    return json.dumps(base, ensure_ascii=False, default=str)


def log_user_action(
    session: UserSession | None,
    *,
    module: str,
    action: str,
    outcome: str,
    target: str = "",
    details: dict[str, Any] | None = None,
) -> None:
    """Write one user action event to the textual audit file."""

    _configure_logger()
    _LOGGER.info(
        _payload(
            session=session,
            module=module,
            action=action,
            outcome=outcome,
            target=target,
            details=details,
        )
    )


def log_session_event(
    session: UserSession | None,
    *,
    action: str,
    outcome: str,
    details: dict[str, Any] | None = None,
) -> None:
    """Write one session lifecycle event to the textual audit file."""

    log_user_action(
        session,
        module="session",
        action=action,
        outcome=outcome,
        details=details,
    )