"""Unit tests for the token-bucket rate limiter."""

from __future__ import annotations

import asyncio

import pytest

from contract_check.core.rate_limit import MemoryRateLimiter


@pytest.fixture
def limiter() -> MemoryRateLimiter:
    return MemoryRateLimiter()


async def test_memory_rate_limiter_allows_first_requests(limiter: MemoryRateLimiter) -> None:
    # With limit=3, the first 3 requests should be allowed immediately.
    results = [await limiter.allow("key-a", 3) for _ in range(3)]
    assert all(r.allowed for r in results)
    assert all(r.retry_after_sec is None for r in results)


async def test_memory_rate_limiter_blocks_excess(limiter: MemoryRateLimiter) -> None:
    # First 3 allowed, 4th blocked with a retry_after hint.
    for _ in range(3):
        assert (await limiter.allow("key-b", 3)).allowed

    blocked = await limiter.allow("key-b", 3)
    assert not blocked.allowed
    assert blocked.retry_after_sec is not None
    assert 0 < blocked.retry_after_sec <= 1


async def test_memory_rate_limiter_replenishes_after_time(limiter: MemoryRateLimiter) -> None:
    # Burn the bucket dry.
    for _ in range(3):
        assert (await limiter.allow("key-c", 3)).allowed
    assert not (await limiter.allow("key-c", 3)).allowed

    # Wait long enough for one token to refill at 3 tokens/second.
    await asyncio.sleep(0.5)
    assert (await limiter.allow("key-c", 3)).allowed


async def test_memory_rate_limiter_keys_are_isolated(limiter: MemoryRateLimiter) -> None:
    assert (await limiter.allow("key-1", 1)).allowed
    assert not (await limiter.allow("key-1", 1)).allowed
    assert (await limiter.allow("key-2", 1)).allowed


async def test_memory_rate_limiter_zero_limit_is_allowed(limiter: MemoryRateLimiter) -> None:
    # RedisRateLimiter treats non-positive limits as misconfigured and allows.
    assert (await limiter.allow("key-z", 0)).allowed