from __future__ import annotations

import time
from threading import Lock
from typing import Optional

_lock = Lock()
_prices: dict[str, tuple[float, float]] = {}


def prime(symbol: str, price_usd: float, ttl_sec: float = 300) -> None:
    if not price_usd or price_usd <= 0:
        return
    key = symbol.upper()
    with _lock:
        _prices[key] = (price_usd, time.time() + ttl_sec)


def get(symbol: str) -> Optional[float]:
    key = symbol.upper()
    with _lock:
        row = _prices.get(key)
    if not row:
        return None
    price, expires = row
    if expires <= time.time():
        return None
    return price


def snapshot() -> dict[str, float]:
    now = time.time()
    with _lock:
        return {k: v[0] for k, v in _prices.items() if v[1] > now}