"""System metrics handler.

Returns CPU load, memory usage, and per-interface network traffic stats.
"""

from __future__ import annotations

import logging
from typing import Any

from daemon.iface import GET_SYSTEM_METRICS
from daemon.server import registry
from lib.state import state as state_store

logger = logging.getLogger(__name__)


@registry.register(GET_SYSTEM_METRICS)
def system_metrics(_request: Any, _body: Any) -> dict[str, Any]:
    """Return system-wide metrics.

    Reads from pre-collected state (CPU load, memory, network traffic).

    Returns:
        Dict with load, memory, swap, and traffic data.
    """
    sys_state = state_store.get("system")
    if sys_state is None:
        return {
            "load": {"load1": 0.0, "load5": 0.0, "load15": 0.0},
            "memory": {"total": 0, "available": 0, "used": 0, "used_pct": 0},
            "swap": {"total": 0, "used": 0, "used_pct": 0},
            "traffic": {},
        }
    return sys_state