from decimal import Decimal
from typing import List, Dict, Any

from django.contrib.auth import get_user_model
from django.test import TestCase, override_settings
from django.utils import timezone
from unittest.mock import patch, MagicMock

from basic_info import models as basic_models
from stock import models as stock_models
from business import models as business_models, services, tasks


def create_basic_fixtures():
    merchant = basic_models.Merchant.objects.create(
        name='测试商户',
        type=basic_models.MerchantTypeEnum.FACTORY,
    )
    supplier = basic_models.Supplier.objects.create(
        merchant=merchant,
        name='测试供应商',
    )
    warehouse = basic_models.WareHouse.objects.create(
        merchant=merchant,
        name='主仓',
        mode=basic_models.WareHouseModeEnum.RESTRICT_IN,
    )
    category = basic_models.ProductCategory.objects.create(
        merchant=merchant,
        name='面料',
        product_prefix='FAB',
    )
    product = basic_models.Product.objects.create(
        merchant=merchant,
        category=category,
        name='测试面料',
        human_id='FAB-001',
        unit=basic_models.ProductUnitEnum.METER,
    )
    return merchant, supplier, warehouse, product


class PurchaseOrderServiceTestCase(TestCase):
    def setUp(self):
        self.merchant, self.supplier, self.warehouse, self.product = create_basic_fixtures()
        User = get_user_model()
        self.user = User.objects.create_user(username='creator', password='pass123')
        self.items: List[Dict[str, Any]] = [
            {'product_id': self.product.id, 'quantities': ['10.00', '5.00']},
        ]

    def test_create_purchase_order_triggers_task(self):
        with patch('business.services.create_purchase_order_stock_entries.delay') as mock_delay:
            purchase_order = services.create_purchase_order(
                merchant=self.merchant,
                supplier=self.supplier,
                order_date=timezone.now().date(),
                total_amount=Decimal('100.00'),
                warehouse_id=self.warehouse.id,
                items=self.items,
                remarks='自动化测试',
                created_by=self.user,
            )

        self.assertIsInstance(purchase_order, business_models.PurchaseOrder)
        mock_delay.assert_called_once_with(
            purchase_order_id=purchase_order.id,
            warehouse_id=self.warehouse.id,
            items=self.items,
            created_by_id=self.user.id,
        )

    def test_create_purchase_order_without_items_raises(self):
        with self.assertRaises(ValueError):
            services.create_purchase_order(
                merchant=self.merchant,
                supplier=self.supplier,
                order_date=timezone.now().date(),
                total_amount=Decimal('50.00'),
                warehouse_id=self.warehouse.id,
                items=[],
            )


@override_settings(
    CELERY_TASK_ALWAYS_EAGER=True,
    CELERY_TASK_EAGER_PROPAGATES=True,
)
class PurchaseOrderStockTaskTestCase(TestCase):
    def setUp(self):
        self.merchant, self.supplier, self.warehouse, self.product = create_basic_fixtures()
        User = get_user_model()
        self.user = User.objects.create_user(username='task-user', password='pass123')
        self.purchase_order = business_models.PurchaseOrder.objects.create(
            merchant=self.merchant,
            supplier=self.supplier,
            order_date=timezone.now().date(),
            total_amount=Decimal('100.00'),
        )
        self.items = [{'product_id': self.product.id, 'quantities': ['8.00']}]

    def test_task_calls_stock_flow_service(self):
        with patch('business.tasks.StockFlowService') as mock_flow_cls:
            mock_instance = mock_flow_cls.return_value
            mock_instance.stock_in.return_value = (MagicMock(id=321), [], 2)

            async_result = tasks.create_purchase_order_stock_entries.delay(
                purchase_order_id=self.purchase_order.id,
                warehouse_id=self.warehouse.id,
                items=self.items,
                created_by_id=self.user.id,
            )
            payload = async_result.get(timeout=5)

        mock_flow_cls.assert_called_once_with(merchant=self.merchant, created_by=self.user)
        mock_instance.stock_in.assert_called_once_with(
            warehouse_id=self.warehouse.id,
            source_type=stock_models.StockChangeSourceEnum.PURCHASE,
            source_id=self.purchase_order.id,
            items=self.items,
        )
        self.assertEqual(payload['purchase_order_id'], self.purchase_order.id)
        self.assertEqual(payload['stock_change_record_id'], 321)
from django.test import TestCase

# Create your tests here.