"""Per-session sliding-window rate limiting for light optimization."""

from fastapi import FastAPI
from fastapi.testclient import TestClient
from fastapi.responses import JSONResponse

from app.fsm import FSMError
from app.optimization_models import OptimizationRunView
from app.rate_limit import SlidingWindowRateLimiter
from app.resume_routes import register_resume_routes


class FakeClock:
    def __init__(self) -> None:
        self.now = 1000.0

    def __call__(self) -> float:
        return self.now


def test_allows_up_to_limit_then_rejects() -> None:
    clock = FakeClock()
    limiter = SlidingWindowRateLimiter(limit=3, window_seconds=3600, clock=clock)

    assert limiter.allow("s1") is True
    assert limiter.allow("s1") is True
    assert limiter.allow("s1") is True
    assert limiter.allow("s1") is False


def test_window_slides_and_allows_again() -> None:
    clock = FakeClock()
    limiter = SlidingWindowRateLimiter(limit=2, window_seconds=3600, clock=clock)

    assert limiter.allow("s1") is True
    assert limiter.allow("s1") is True
    assert limiter.allow("s1") is False

    clock.now += 3601
    assert limiter.allow("s1") is True


def test_sessions_are_independent() -> None:
    limiter = SlidingWindowRateLimiter(
        limit=1, window_seconds=3600, clock=FakeClock()
    )

    assert limiter.allow("s1") is True
    assert limiter.allow("s2") is True
    assert limiter.allow("s1") is False


def test_light_route_returns_429_without_calling_optimizer_when_limited() -> None:
    view = OptimizationRunView(
        id="r1",
        mode="light",
        status="proposal_pending",
        entry_id="e1",
    )

    class StubAgent:
        def __init__(self) -> None:
            self.calls = 0

        def optimize_light(
            self, session_id: str, request: object
        ) -> OptimizationRunView:
            self.calls += 1
            return view

    application = FastAPI()

    @application.exception_handler(FSMError)
    async def handle_fsm_error(_request: object, exc: FSMError) -> JSONResponse:
        return JSONResponse(status_code=exc.status_code, content={"detail": exc.message})
    application.state.light_opt_limiter = SlidingWindowRateLimiter(
        limit=2, window_seconds=3600
    )
    agent = StubAgent()
    register_resume_routes(application, agent, "/ai-api/resume-agent")
    client = TestClient(application, raise_server_exceptions=False)
    url = "/ai-api/resume-agent/sessions/s1/resume/optimize/light"

    assert client.post(url, json={"entry_id": "e1"}).status_code == 200
    assert client.post(url, json={"entry_id": "e1"}).status_code == 200
    blocked = client.post(url, json={"entry_id": "e1"})

    assert blocked.status_code == 429
    assert blocked.json()["detail"] == "操作过于频繁，请稍后再试（轻度优化每小时最多 20 次）。"
    assert agent.calls == 2