"""P0 #1 批次/效期管理集成测试。

覆盖：批次入库聚合、FEFO 跨批次分摊、批次不足拒绝、近效期预警去重、
采购带批次入库、非批次商品路径不受影响。
"""

import pytest
from datetime import date, timedelta
from decimal import Decimal
from model_bakery import baker

from apps.catalog.models import Product
from apps.inventory import services as inv_services
from apps.inventory.models import Stock, StockBatch, StockMovement
from apps.notify.models import Notification, AlertRule
from apps.notify import services as notify_services
from apps.purchase import services as purchase_services
from apps.partner.models import Supplier


@pytest.fixture
def warehouse(db, tenant):
    return baker.make(Warehouse := __import__(
        "apps.inventory.models", fromlist=["Warehouse"]
    ).Warehouse, tenant=tenant, code="WH01", name="主仓")


@pytest.fixture
def batch_product(db, tenant):
    return baker.make(
        Product, tenant=tenant, code="MILK01", name="鲜牛奶",
        is_batch_managed=True, shelf_life_days=7,
        sale_price=Decimal("50"), cost_price=Decimal("30"),
    )


@pytest.fixture
def normal_product(db, tenant):
    return baker.make(Product, tenant=tenant, code="P001", name="普通商品")


def test_batch_inbound_requires_batch_no(tenant, warehouse, batch_product):
    with pytest.raises(ValueError):
        inv_services.inbound(
            tenant=tenant, warehouse=warehouse, product=batch_product,
            quantity=Decimal("10"),
        )


def test_batch_inbound_updates_batch_and_stock(tenant, warehouse, batch_product):
    inv_services.inbound(
        tenant=tenant, warehouse=warehouse, product=batch_product,
        quantity=Decimal("10"), unit_cost=Decimal("30"),
        batch_no="B20260901", production_date=date(2026, 9, 1),
        expiry_date=date(2026, 9, 8),
    )
    stock = Stock.objects.get(tenant=tenant, warehouse=warehouse, product=batch_product)
    batch = StockBatch.objects.get(
        tenant=tenant, warehouse=warehouse, product=batch_product, batch_no="B20260901"
    )
    assert stock.on_hand == Decimal("10")
    assert batch.on_hand == Decimal("10")
    assert batch.expiry_date == date(2026, 9, 8)


def test_batch_inbound_auto_expiry_from_shelf_life(tenant, warehouse, batch_product):
    inv_services.inbound(
        tenant=tenant, warehouse=warehouse, product=batch_product,
        quantity=Decimal("5"), batch_no="B1",
        production_date=date(2026, 9, 1),
    )
    batch = StockBatch.objects.get(batch_no="B1")
    assert batch.expiry_date == date(2026, 9, 1) + timedelta(days=7)


def test_outbound_fefo_allocates_nearest_expiry_first(tenant, warehouse, batch_product):
    inv_services.inbound(
        tenant=tenant, warehouse=warehouse, product=batch_product,
        quantity=Decimal("10"), batch_no="B_LATE", expiry_date=date(2026, 12, 31),
    )
    inv_services.inbound(
        tenant=tenant, warehouse=warehouse, product=batch_product,
        quantity=Decimal("10"), batch_no="B_SOON", expiry_date=date(2026, 10, 1),
    )
    result = inv_services.outbound(
        tenant=tenant, warehouse=warehouse, product=batch_product,
        quantity=Decimal("12"), source_type="sale", source_ref="XS001",
    )
    soon = StockBatch.objects.get(batch_no="B_SOON")
    late = StockBatch.objects.get(batch_no="B_LATE")
    assert soon.on_hand == Decimal("0")      # 近效期先出清
    assert late.on_hand == Decimal("8")
    assert result.movement.batch_detail == [
        {"batch_no": "B_SOON", "quantity": "10.0000", "expiry_date": "2026-10-01"},
        {"batch_no": "B_LATE", "quantity": "2.0000", "expiry_date": "2026-12-31"},
    ]
    stock = Stock.objects.get(product=batch_product)
    assert stock.on_hand == Decimal("8")


def test_outbound_batch_insufficient_rejects(tenant, warehouse, batch_product):
    inv_services.inbound(
        tenant=tenant, warehouse=warehouse, product=batch_product,
        quantity=Decimal("5"), batch_no="B1", expiry_date=date(2026, 12, 31),
    )
    from apps.inventory.services import InsufficientStock
    with pytest.raises(InsufficientStock):
        inv_services.outbound(
            tenant=tenant, warehouse=warehouse, product=batch_product,
            quantity=Decimal("6"),
        )


def test_normal_product_unchanged(tenant, warehouse, normal_product):
    """非批次商品路径回归：无批次账产生，行为与改造前一致。"""
    inv_services.inbound(
        tenant=tenant, warehouse=warehouse, product=normal_product,
        quantity=Decimal("10"), unit_cost=Decimal("5"),
    )
    inv_services.outbound(
        tenant=tenant, warehouse=warehouse, product=normal_product,
        quantity=Decimal("4"),
    )
    assert StockBatch.objects.filter(product=normal_product).count() == 0
    stock = Stock.objects.get(product=normal_product)
    assert stock.on_hand == Decimal("6")


def test_batch_expiry_alert_dedup(tenant, warehouse, batch_product):
    AlertRule.objects.create(
        tenant=tenant, code="exp30", name="近效期30天",
        rule_type="batch_expiry", threshold=30, is_enabled=True,
    )
    inv_services.inbound(
        tenant=tenant, warehouse=warehouse, product=batch_product,
        quantity=Decimal("10"), batch_no="B1",
        expiry_date=date.today() + timedelta(days=10),
    )
    count1 = notify_services.check_batch_expiry_alerts(tenant)
    count2 = notify_services.check_batch_expiry_alerts(tenant)  # 当日去重
    assert count1 == 1
    assert count2 == 0
    n = Notification.objects.filter(
        tenant=tenant, extra_data__batch_no__isnull=True
    ).first()
    assert Notification.objects.filter(tenant=tenant, category="warning").count() == 1
    assert "B1" in n.content


def test_run_all_includes_batch_alerts(tenant, warehouse, batch_product):
    res = notify_services.run_all_alert_checks(tenant)
    assert "batch_expiry_alerts_count" in res


def test_purchase_bill_with_batch_end_to_end(tenant, warehouse, batch_product):
    supplier = baker.make(Supplier, tenant=tenant, code="S001", name="奶厂")
    bill = purchase_services.create_purchase_bill(
        tenant=tenant, supplier=supplier, warehouse=warehouse,
        lines=[{
            "product": batch_product, "quantity": 20, "unit_price": 30,
            "batch_no": "PB001",
            "production_date": date.today(),
            "expiry_date": date.today() + timedelta(days=7),
        }],
    )
    purchase_services.confirm_purchase_bill(bill)
    batch = StockBatch.objects.get(batch_no="PB001")
    assert batch.on_hand == Decimal("20")
    assert batch.production_date == date.today()