"""AliCloud International ``list_billing_daily`` NextToken pagination guards.

Regression (#1655): ``DescribeInstanceBill`` pagination broke only when
``NextToken`` came back falsy. A degenerate BSS response returning a stable,
non-empty ``NextToken`` would loop forever, hanging the worker. The fix adds a
same-token termination guard plus a page-count ceiling that raise rather than
spin.
"""
from __future__ import annotations

from datetime import date
from unittest.mock import AsyncMock, patch

import pytest

from app.integrations.driver_base import CloudScopeRef
from app.integrations.drivers.alicloud_intl_cloud import AlicloudIntlCloudDriver


class _StubIntlDriver(AlicloudIntlCloudDriver):
    """Bypass ``__init__`` so we can drive ``list_billing_daily`` directly."""

    def __init__(self) -> None:
        self.integration_id = "test-alicloud-intl"
        # Pin FX so ``list_billing_daily`` never touches the DB / platform
        # settings for ``resolve_cny_per_usd``.
        self.config = {"cny_per_usd": 7.2}


def _scope() -> CloudScopeRef:
    return CloudScopeRef(scope_type="aliyun_account", external_id="500001")


@pytest.mark.asyncio
async def test_list_billing_daily_raises_on_stable_next_token() -> None:
    drv = _StubIntlDriver()

    # Every page returns the SAME non-empty NextToken → infinite loop pre-fix.
    async def _fake_acs3(*_a, **_kw):
        return {
            "Data": {
                "Items": [],
                "NextToken": "STUCK-TOKEN",
            },
        }

    with patch.object(
        AlicloudIntlCloudDriver, "_master_account_id",
        new=AsyncMock(return_value="500000"),
    ), patch.object(
        AlicloudIntlCloudDriver, "_acs3_call", side_effect=_fake_acs3,
    ), pytest.raises(RuntimeError, match="NextToken did not advance"):
        await drv.list_billing_daily(
            date(2026, 7, 1), date(2026, 7, 1), scope=_scope(),
        )


@pytest.mark.asyncio
async def test_list_billing_daily_terminates_on_empty_next_token() -> None:
    """Sanity guard: the normal happy path (NextToken falsy on the last page)
    still terminates and returns a result."""
    drv = _StubIntlDriver()
    pages = [
        {"Data": {"Items": [], "NextToken": "page-2"}},
        {"Data": {"Items": [], "NextToken": ""}},  # terminal
    ]
    calls = {"n": 0}

    async def _fake_acs3(*_a, **_kw):
        page = pages[calls["n"]]
        calls["n"] += 1
        return page

    with patch.object(
        AlicloudIntlCloudDriver, "_master_account_id",
        new=AsyncMock(return_value="500000"),
    ), patch.object(
        AlicloudIntlCloudDriver, "_acs3_call", side_effect=_fake_acs3,
    ):
        out = await drv.list_billing_daily(
            date(2026, 7, 1), date(2026, 7, 1), scope=_scope(),
        )
    assert calls["n"] == 2
    assert len(out) == 1  # one CloudDailyCost row for the single day