"""Thread-safe object counter.

Ported from net.i2p.util.ObjectCounter.
"""

from __future__ import annotations

import threading


class ObjectCounter:
    """Thread-safe counter for named keys."""

    def __init__(self) -> None:
        self._lock = threading.Lock()
        self._counts: dict[str, int] = {}

    def increment(self, key: str) -> int:
        with self._lock:
            self._counts[key] = self._counts.get(key, 0) + 1
            return self._counts[key]

    def decrement(self, key: str) -> int:
        with self._lock:
            val = self._counts.get(key, 0) - 1
            self._counts[key] = max(0, val)
            return self._counts[key]

    def count(self, key: str) -> int:
        with self._lock:
            return self._counts.get(key, 0)

    def total(self) -> int:
        with self._lock:
            return sum(self._counts.values())