"""单据编号生成器的跨位宽正确性（no_generator）。

守：当日序号超过 4 位宽度（9999→10000）后，VARCHAR 字典序排序会失效
（"-10000" < "-9999"，'1'<'9'）——MAX 检索若按纯字典序，seq 会恒重算出
同一号码，每笔建单都撞唯一键。修复口径：长度优先、同级按字典序
（同前缀下长度大即数值大；同长时字典序与数值序一致）。
"""

import pytest
from sqlalchemy import select

from app.core.constants import NO_PREFIX_BUSINESS
from app.core.db import get_session_factory
from app.models import Business, Customer
from app.services.no_generator import next_no, today_prefix

pytestmark = pytest.mark.integration


def _insert_business_nos(nos: list[str]) -> None:
    """直插同日前缀的业务编号行（仅编号用于 MAX 检索；其余列取默认/可空）。

    直插绕过服务层（服务层走完整创建链太重），业务行为挂在 t_ 客户名下，
    由 integration/conftest 兜底清理（YW% 单据 + t\\_% 客户）。
    """
    factory = get_session_factory()
    with factory() as session:
        customer = Customer(
            company_name="t_no_generator_client",
            owner_name="t_no_generator_owner",
            customer_type="enterprise",
        )
        session.add(customer)
        session.flush()
        session.add_all(Business(business_no=no, customer_id=customer.id) for no in nos)
        session.commit()


class TestMaxCrossWidth:
    """MAX 检索在同日前缀下跨位宽取最大序号。"""

    def test_序号破四位宽后仍按数值取最大(self) -> None:
        """4 位与 5 位并存："-9999" 字典序大于 "-10000"，纯字典序会取错。"""
        prefix = today_prefix(NO_PREFIX_BUSINESS)
        _insert_business_nos([f"{prefix}9999", f"{prefix}10000"])
        factory = get_session_factory()
        with factory() as session:
            no = next_no(
                session, model=Business, column_name="business_no", prefix=NO_PREFIX_BUSINESS
            )
        assert no == f"{prefix}10001"

    def test_同位宽内字典序与数值序一致仍取最大(self) -> None:
        """同宽多行（修复的排序不破坏原行为）：是长度优先而非只按长度取首行。"""
        prefix = today_prefix(NO_PREFIX_BUSINESS)
        _insert_business_nos([f"{prefix}0099", f"{prefix}8499", f"{prefix}8500"])
        factory = get_session_factory()
        with factory() as session:
            no = next_no(
                session, model=Business, column_name="business_no", prefix=NO_PREFIX_BUSINESS
            )
        assert no == f"{prefix}8501"

    def test_无当日编号时从1起编(self) -> None:
        """当日无同前缀行（昨日编号不被 like 命中）：从 0001 起，不受历史天数影响。

        当日若已有其他用例留下的同前缀编号（用例间无隔离库），跳过——
        空表场景由每次 `down -v` 重建后的首个用例覆盖。
        """
        prefix = today_prefix(NO_PREFIX_BUSINESS)
        factory = get_session_factory()
        with factory() as session:
            existing = session.execute(
                select(Business.id).where(Business.business_no.like(f"{prefix}%")).limit(1)
            ).scalar()
        if existing is not None:
            pytest.skip(f"当日已有同前缀编号 {existing}，空表场景跳过")
        with factory() as session:
            no = next_no(
                session, model=Business, column_name="business_no", prefix=NO_PREFIX_BUSINESS
            )
        assert no == f"{prefix}0001"