package service

import (
	"fmt"
	"testing"
	"time"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"

	"github.com/wangjia/jiu/backend/internal/model"
	"github.com/wangjia/jiu/backend/testutil"
)


func TestStockService_ApproveStockIn_Success(t *testing.T) {
	db := testutil.SetupTestDB()
	shop := testutil.CreateTestShop(db, "STOCK001")
	warehouse := testutil.CreateTestWarehouse(db, shop.ID, "Main Warehouse")
	product := testutil.CreateTestProduct(db, shop.ID, "Beer")
	user := testutil.CreateTestUser(db, shop.ID, "admin", "pass", "admin")

	// 创建入库单
	order := model.StockInOrder{
		TenantBase:  model.TenantBase{ShopID: shop.ID},
		OrderNo:     "IN20240101000001",
		WarehouseID: warehouse.ID,
		OperatorID:  user.ID,
		Status:      "pending",
		OrderDate:   model.Date{Time: time.Now()},
		Items: []model.StockInItem{
			{
				ShopID:   shop.ID,
				ProductID: product.ID,
				Quantity:  10,
				UnitPrice: 5.0,
				TotalPrice: 50.0,
			},
		},
	}
	require.NoError(t, db.Create(&order).Error)

	svc := NewStockService(db)
	err := svc.ApproveStockIn(shop.ID, order.ID, user.ID)
	require.NoError(t, err)

	// 验证单据状态
	var updated model.StockInOrder
	db.First(&updated, order.ID)
	assert.Equal(t, "approved", updated.Status)

	// 验证库存
	var inv model.Inventory
	db.Where("shop_id = ? AND warehouse_id = ? AND product_id = ?",
		shop.ID, warehouse.ID, product.ID).First(&inv)
	assert.Equal(t, float64(10), inv.Quantity)

	// 验证库存流水
	var logs []model.InventoryLog
	db.Where("shop_id = ? AND product_id = ?", shop.ID, product.ID).Find(&logs)
	require.Len(t, logs, 1)
	assert.Equal(t, "in", logs[0].Direction)
	assert.Equal(t, float64(10), logs[0].Quantity)
	assert.Equal(t, float64(0), logs[0].QtyBefore)
	assert.Equal(t, float64(10), logs[0].QtyAfter)
}

func TestStockService_ApproveStockIn_NotPending(t *testing.T) {
	db := testutil.SetupTestDB()
	shop := testutil.CreateTestShop(db, "STOCK002")
	warehouse := testutil.CreateTestWarehouse(db, shop.ID, "Warehouse")
	_ = testutil.CreateTestProduct(db, shop.ID, "Wine")
	user := testutil.CreateTestUser(db, shop.ID, "admin", "pass", "admin")

	order := model.StockInOrder{
		TenantBase:  model.TenantBase{ShopID: shop.ID},
		OrderNo:     "IN20240101000002",
		WarehouseID: warehouse.ID,
		OperatorID:  user.ID,
		Status:      "draft", // 非 pending 状态
		OrderDate:   model.Date{Time: time.Now()},
	}
	require.NoError(t, db.Create(&order).Error)

	svc := NewStockService(db)
	err := svc.ApproveStockIn(shop.ID, order.ID, user.ID)
	assert.Error(t, err)
	assert.Contains(t, err.Error(), "not in pending status")
}

func TestStockService_ApproveStockOut_Success(t *testing.T) {
	db := testutil.SetupTestDB()
	shop := testutil.CreateTestShop(db, "STOCK003")
	warehouse := testutil.CreateTestWarehouse(db, shop.ID, "Warehouse")
	product := testutil.CreateTestProduct(db, shop.ID, "Whiskey")
	user := testutil.CreateTestUser(db, shop.ID, "admin", "pass", "admin")

	// 先入库
	inv := model.Inventory{
		ShopID:     shop.ID,
		WarehouseID: &warehouse.ID,
		ProductID:   &product.ID,
		Quantity:    20,
	}
	require.NoError(t, db.Create(&inv).Error)

	// 创建出库单
	order := model.StockOutOrder{
		TenantBase:  model.TenantBase{ShopID: shop.ID},
		OrderNo:     "OUT20240101000001",
		WarehouseID: warehouse.ID,
		OperatorID:  user.ID,
		Status:      "pending",
		OrderDate:   model.Date{Time: time.Now()},
		Items: []model.StockOutItem{
			{
				ShopID:   shop.ID,
				ProductID: product.ID,
				Quantity:  5,
				UnitPrice: 10.0,
				TotalPrice: 50.0,
			},
		},
	}
	require.NoError(t, db.Create(&order).Error)

	svc := NewStockService(db)
	err := svc.ApproveStockOut(shop.ID, order.ID, user.ID)
	require.NoError(t, err)

	// 验证库存减少
	var updatedInv model.Inventory
	db.First(&updatedInv, inv.ID)
	assert.Equal(t, float64(15), updatedInv.Quantity)

	// 验证单据状态
	var updatedOrder model.StockOutOrder
	db.First(&updatedOrder, order.ID)
	assert.Equal(t, "approved", updatedOrder.Status)
}

func TestStockService_ApproveStockOut_InsufficientStock(t *testing.T) {
	db := testutil.SetupTestDB()
	shop := testutil.CreateTestShop(db, "STOCK004")
	warehouse := testutil.CreateTestWarehouse(db, shop.ID, "Warehouse")
	product := testutil.CreateTestProduct(db, shop.ID, "Vodka")
	user := testutil.CreateTestUser(db, shop.ID, "admin", "pass", "admin")

	// 库存只有 3
	inv := model.Inventory{
		ShopID:     shop.ID,
		WarehouseID: &warehouse.ID,
		ProductID:   &product.ID,
		Quantity:    3,
	}
	require.NoError(t, db.Create(&inv).Error)

	// 要出库 10
	order := model.StockOutOrder{
		TenantBase:  model.TenantBase{ShopID: shop.ID},
		OrderNo:     "OUT20240101000002",
		WarehouseID: warehouse.ID,
		OperatorID:  user.ID,
		Status:      "pending",
		OrderDate:   model.Date{Time: time.Now()},
		Items: []model.StockOutItem{
			{
				ShopID:   shop.ID,
				ProductID: product.ID,
				Quantity:  10,
			},
		},
	}
	require.NoError(t, db.Create(&order).Error)

	svc := NewStockService(db)
	err := svc.ApproveStockOut(shop.ID, order.ID, user.ID)
	assert.Error(t, err)
	assert.ErrorIs(t, err, ErrInsufficientStock)
}

func TestStockService_ApproveStockOut_ProductNotInInventory(t *testing.T) {
	db := testutil.SetupTestDB()
	shop := testutil.CreateTestShop(db, "STOCK005")
	warehouse := testutil.CreateTestWarehouse(db, shop.ID, "Warehouse")
	product := testutil.CreateTestProduct(db, shop.ID, "Rum")
	user := testutil.CreateTestUser(db, shop.ID, "admin", "pass", "admin")

	// 没有创建库存记录
	order := model.StockOutOrder{
		TenantBase:  model.TenantBase{ShopID: shop.ID},
		OrderNo:     "OUT20240101000003",
		WarehouseID: warehouse.ID,
		OperatorID:  user.ID,
		Status:      "pending",
		OrderDate:   model.Date{Time: time.Now()},
		Items: []model.StockOutItem{
			{
				ShopID:   shop.ID,
				ProductID: product.ID,
				Quantity:  5,
			},
		},
	}
	require.NoError(t, db.Create(&order).Error)

	svc := NewStockService(db)
	err := svc.ApproveStockOut(shop.ID, order.ID, user.ID)
	assert.Error(t, err)
	assert.ErrorIs(t, err, ErrInsufficientStock)
}

func TestStockService_GenerateOrderNo(t *testing.T) {
	db := testutil.SetupTestDB()
	shop := testutil.CreateTestShop(db, "STOCK006")

	svc := NewStockService(db)
	no, err := svc.GenerateOrderNo(shop.ID, "stock_in")
	require.NoError(t, err)
	assert.NotEmpty(t, no)
	// 单号格式: prefix + date + 6位序号
	assert.Contains(t, no, "RK")

	// 第二次生成序号应递增
	no2, err := svc.GenerateOrderNo(shop.ID, "stock_in")
	require.NoError(t, err)
	assert.NotEqual(t, no, no2)
}

// TestStockService_GenerateOrderNo_Sequential 验证顺序调用生成唯一递增单号
// 注：并发安全由 MySQL 的事务锁保证，SQLite in-memory 不模拟此场景
func TestStockService_GenerateOrderNo_Sequential(t *testing.T) {
	db := testutil.SetupTestDB()
	shop := testutil.CreateTestShop(db, "STOCK007")

	svc := NewStockService(db)

	const count = 5
	seen := map[string]bool{}

	for i := 0; i < count; i++ {
		no, err := svc.GenerateOrderNo(shop.ID, "stock_in")
		require.NoError(t, err)
		assert.NotEmpty(t, no)
		assert.False(t, seen[no], fmt.Sprintf("duplicate order no: %s", no))
		seen[no] = true
	}

	assert.Len(t, seen, count, "should generate exactly %d unique order numbers", count)
}

func TestStockService_MultipleStockIn_AccumulatesInventory(t *testing.T) {
	db := testutil.SetupTestDB()
	shop := testutil.CreateTestShop(db, "STOCK008")
	warehouse := testutil.CreateTestWarehouse(db, shop.ID, "Warehouse")
	product := testutil.CreateTestProduct(db, shop.ID, "Gin")
	user := testutil.CreateTestUser(db, shop.ID, "admin", "pass", "admin")

	svc := NewStockService(db)

	// 第一次入库
	order1 := model.StockInOrder{
		TenantBase:  model.TenantBase{ShopID: shop.ID},
		OrderNo:     "IN001",
		WarehouseID: warehouse.ID,
		OperatorID:  user.ID,
		Status:      "pending",
		OrderDate:   model.Date{Time: time.Now()},
		Items: []model.StockInItem{
			{ShopID: shop.ID, ProductID: product.ID, Quantity: 10},
		},
	}
	require.NoError(t, db.Create(&order1).Error)
	require.NoError(t, svc.ApproveStockIn(shop.ID, order1.ID, user.ID))

	// 第二次入库
	order2 := model.StockInOrder{
		TenantBase:  model.TenantBase{ShopID: shop.ID},
		OrderNo:     "IN002",
		WarehouseID: warehouse.ID,
		OperatorID:  user.ID,
		Status:      "pending",
		OrderDate:   model.Date{Time: time.Now()},
		Items: []model.StockInItem{
			{ShopID: shop.ID, ProductID: product.ID, Quantity: 5},
		},
	}
	require.NoError(t, db.Create(&order2).Error)
	require.NoError(t, svc.ApproveStockIn(shop.ID, order2.ID, user.ID))

	// 总库存应该是 15（两个批次之和）
	var totalQty float64
	db.Model(&model.Inventory{}).
		Where("shop_id = ? AND warehouse_id = ? AND product_id = ? AND deleted_at IS NULL",
			shop.ID, &warehouse.ID, &product.ID).
		Select("COALESCE(SUM(quantity), 0)").Scan(&totalQty)
	assert.Equal(t, float64(15), totalQty)
}