"""Bounded retry with exponential backoff + jitter."""
from __future__ import annotations

import random
import time
from typing import Callable, Optional, Tuple, Type


def retry(
    fn: Callable,
    *,
    max_attempts: int = 3,
    base_delay: float = 0.1,
    max_delay: float = 10.0,
    retryable: Tuple[Type[BaseException], ...] = (Exception,),
    sleep: Callable[[float], None] = time.sleep,
    rng: Optional[random.Random] = None,
) -> object:
    if max_attempts < 1:
        raise ValueError("max_attempts must be >= 1")
    if base_delay < 0 or max_delay < 0:
        raise ValueError("delays must be >= 0")
    r = rng if rng is not None else random.Random()
    last_exc = None
    for attempt in range(max_attempts):
        try:
            return fn()
        except retryable as e:
            last_exc = e
            if attempt == max_attempts - 1:
                break
            exp = min(max_delay, base_delay * (2 ** attempt))
            delay = r.uniform(0, exp) if exp > 0 else 0.0
            sleep(delay)
        except BaseException:
            raise
    assert last_exc is not None
    raise last_exc