from datetime import datetime
from decimal import Decimal
from types import MappingProxyType

import pytest

from app.api.schemas.risk import RiskAlertPageQuery, RiskEvidencePageQuery
from app.core.contracts import RequestContext
from app.core.errors import GenericResourceNotFoundError, InvalidCursorError
from app.core.risk_cursor import cursor_binding, decode_offset_cursor, encode_offset_cursor
from app.repository.fund_query_repository import CustomerScope, FundPage, FundRecord
from app.service.risk_query_service import RiskQueryService, scope_from_context


class FakeRepository:
    def __init__(self) -> None:
        self.page = FundPage(
            entity="risk_alert",
            items=(
                FundRecord(
                    entity="risk_alert",
                    values=MappingProxyType(
                        {
                            "alert_no": "ALERT-001",
                            "customer_id": 9,
                            "risk_level": "高",
                            "amount": Decimal("100.00"),
                            "created_at": datetime(2026, 9, 10, 8, 0),
                            "rule_codes": ("RW-007",),
                        }
                    ),
                ),
            ),
            limit=5,
            offset=0,
            next_offset=5,
        )

    async def overview(self) -> dict:
        return {
            "total": 2,
            "levels": {"低": 1, "中": 0, "高": 1},
            "pending": 1,
            "overdue": 0,
            "high_priority": list(self.page.items),
        }

    async def list_alerts(self, **_kwargs) -> FundPage:
        return self.page

    async def get_alert_detail(self, _alert_no: str) -> FundRecord | None:
        return None


def context(**updates) -> RequestContext:
    values = {
        "user_id": "990000002",
        "trace_id": "trace",
        "permissions": ("risk:alert:read",),
        "data_scope": "all",
    }
    values.update(updates)
    return RequestContext(**values)


def test_cursor_round_trip_and_invalid_values() -> None:
    binding = cursor_binding(user_id="990000002", filters={"keyword": None})
    assert (
        decode_offset_cursor(encode_offset_cursor(20, binding=binding), binding=binding) == 20
    )
    assert decode_offset_cursor(None, binding=binding) == 0
    with pytest.raises(InvalidCursorError):
        decode_offset_cursor("not-a-cursor", binding=binding)
    with pytest.raises(InvalidCursorError):
        decode_offset_cursor(encode_offset_cursor(1, binding=binding) + "x", binding=binding)


def test_query_schema_enforces_business_page_sizes() -> None:
    assert RiskAlertPageQuery(limit=5).limit == 5
    assert RiskEvidencePageQuery(limit=10).limit == 10
    with pytest.raises(ValueError):
        RiskAlertPageQuery(limit=6)
    with pytest.raises(ValueError):
        RiskEvidencePageQuery(limit=11)


def test_scope_from_context_is_fail_closed() -> None:
    assert scope_from_context(context()).is_unrestricted
    assert scope_from_context(context(data_scope="self")).is_denied
    scope = scope_from_context(
        context(data_scope="own_customers", customer_ids=("9", "10"))
    )
    assert scope == CustomerScope.for_customers({9, 10})


@pytest.mark.asyncio
async def test_overview_maps_levels_and_serializes_high_priority() -> None:
    service = RiskQueryService(None, repository=FakeRepository())

    result = await service.overview(context())

    assert result["levels"] == {"高风险": 1, "中风险": 0, "低风险": 1}
    assert result["high_priority"][0]["customer_id"] == "9"
    assert result["high_priority"][0]["amount"] == "100.00"
    assert result["high_priority"][0]["created_at"] == "2026-09-10T08:00:00Z"


@pytest.mark.asyncio
async def test_alert_page_returns_opaque_cursor() -> None:
    service = RiskQueryService(None, repository=FakeRepository())
    query = RiskAlertPageQuery(limit=5)

    result = await service.list_alerts(context(), query)

    assert result["has_more"] is True
    binding = RiskQueryService._binding(context(), query)
    assert decode_offset_cursor(result["next_cursor"], binding=binding) == 5
    assert result["items"][0]["rule_codes"] == ["RW-007"]


def test_cursor_is_bound_to_user_and_filters() -> None:
    """§3.8：游标绑定用户与查询条件，换个人或换个筛选条件都必须失效。"""
    query = RiskAlertPageQuery(limit=5)
    raw = encode_offset_cursor(5, binding=RiskQueryService._binding(context(), query))

    assert decode_offset_cursor(raw, binding=RiskQueryService._binding(context(), query)) == 5

    with pytest.raises(InvalidCursorError):
        decode_offset_cursor(
            raw,
            binding=RiskQueryService._binding(context(user_id="990000003"), query),
        )
    with pytest.raises(InvalidCursorError):
        other_filter = RiskAlertPageQuery(limit=5, keyword="张三")
        decode_offset_cursor(
            raw,
            binding=RiskQueryService._binding(context(), other_filter),
        )
    # data_scope 收紧后旧游标同样失效
    with pytest.raises(InvalidCursorError):
        decode_offset_cursor(
            raw,
            binding=RiskQueryService._binding(
                context(data_scope="own_customers", customer_ids=("9",)), query
            ),
        )


def test_cursor_ignores_page_size_and_other_filters_do_not_collide() -> None:
    """翻页时改 limit 不该让游标失效；不同证据类型之间不能互相串用游标。"""
    base = RiskEvidencePageQuery(limit=10)
    binding = RiskQueryService._binding(context(), base, "customers")

    again = RiskQueryService._binding(context(), RiskEvidencePageQuery(limit=10), "customers")
    other = RiskQueryService._binding(context(), RiskEvidencePageQuery(limit=10), "products")
    assert binding == again
    assert binding != other


@pytest.mark.asyncio
async def test_missing_alert_detail_is_hidden() -> None:
    service = RiskQueryService(None, repository=FakeRepository())

    with pytest.raises(GenericResourceNotFoundError):
        await service.get_alert_detail(context(), "ALERT-NOT-FOUND")