import asyncio
from collections import defaultdict


class MetricsRegistry:
    def __init__(self) -> None:
        self._lock = asyncio.Lock()
        self.requests_total = 0
        self.errors_total = 0
        self.latency_total_ms = 0.0
        self.requests_by_path: dict[str, int] = defaultdict(int)

    async def record(self, path: str, status_code: int, latency_ms: float) -> None:
        async with self._lock:
            self.requests_total += 1
            self.requests_by_path[path] += 1
            self.latency_total_ms += latency_ms
            if status_code >= 500:
                self.errors_total += 1

    async def snapshot(self) -> dict:
        async with self._lock:
            average = (
                self.latency_total_ms / self.requests_total
                if self.requests_total
                else 0.0
            )
            return {
                "requests_total": self.requests_total,
                "requests_by_path": dict(self.requests_by_path),
                "errors_total": self.errors_total,
                "average_latency_ms": round(average, 3),
            }


metrics = MetricsRegistry()