"""Global counters & simple rate samples."""

from __future__ import annotations

import time
from collections import defaultdict
from dataclasses import dataclass, field
from threading import Lock
from typing import Any


@dataclass
class Stats:
    """Thread/async-safe counter container.

    Counters are plain integers keyed by name. Gauges hold instantaneous
    numeric values. Queue depth samples are reported via ``set_gauge``.
    """

    counters: dict[str, int] = field(default_factory=lambda: defaultdict(int))
    gauges: dict[str, float] = field(default_factory=dict)
    started_at: float = field(default_factory=time.time)
    _lock: Lock = field(default_factory=Lock, repr=False)

    def incr(self, name: str, n: int = 1) -> None:
        with self._lock:
            self.counters[name] += n

    def set_gauge(self, name: str, value: float) -> None:
        with self._lock:
            self.gauges[name] = value

    def snapshot(self) -> dict[str, Any]:
        with self._lock:
            now = time.time()
            return {
                "uptime_sec": round(now - self.started_at, 3),
                "started_at": self.started_at,
                "counters": dict(self.counters),
                "gauges": dict(self.gauges),
            }


__all__ = ["Stats"]