package handler

import (
	"fmt"
	"log"
	"net/http"
	"strconv"
	"strings"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/google/uuid"
	"github.com/shakinm/xlsReader/xls"
	"github.com/xuri/excelize/v2"
	"gorm.io/gorm"

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

type ImportHandler struct {
	db *gorm.DB
}

func NewImportHandler(db *gorm.DB) *ImportHandler {
	return &ImportHandler{db: db}
}

// ImportProducts POST /api/v1/import/products
// 支持 .xlsx / .csv，列顺序：名称,系列,规格,单位,品牌,最低库存,备注
func (h *ImportHandler) ImportProducts(c *gin.Context) {
	shopID := middleware.GetShopID(c)

	rows, err := parseUploadedExcel(c)
	if err != nil || len(rows) < 2 {
		c.JSON(http.StatusBadRequest, gin.H{"error": "empty or invalid sheet"})
		return
	}

	var products []model.Product
	var errRows []map[string]interface{}

	for i, row := range rows[1:] { // 跳过表头
		if len(row) < 1 || strings.TrimSpace(row[0]) == "" {
			continue
		}
		p := model.Product{
			TenantBase: model.TenantBase{ShopID: shopID},
		}
		p.Name = cell(row, 0)
		p.Series = cell(row, 1)
		p.Spec = cell(row, 2)
		p.Unit = cell(row, 3)
		p.Brand = cell(row, 4)
		p.Remark = cell(row, 6)

		if p.Name == "" {
			errRows = append(errRows, map[string]interface{}{"row": i + 2, "error": "name is empty"})
			continue
		}
		products = append(products, p)
	}

	if len(products) == 0 {
		c.JSON(http.StatusBadRequest, gin.H{"error": "no valid rows", "errors": errRows})
		return
	}

	if err := h.db.CreateInBatches(&products, 100).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	c.JSON(http.StatusOK, gin.H{
		"imported": len(products),
		"errors":   errRows,
	})
}

// ImportProductCodes POST /api/v1/import/product-codes
// 列顺序：商品名称,商品编码（按名称匹配商品并更新编码）
func (h *ImportHandler) ImportProductCodes(c *gin.Context) {
	shopID := middleware.GetShopID(c)

	rows, err := parseUploadedExcel(c)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}

	total, imported, skipped := 0, 0, 0
	for _, row := range rows[1:] {
		name := cell(row, 0)
		code := cell(row, 1)
		if name == "" || code == "" {
			continue
		}
		total++
		var p model.Product
		if h.db.Where("shop_id = ? AND name = ? AND deleted_at IS NULL", shopID, name).First(&p).Error != nil {
			skipped++
			continue
		}
		if h.db.Model(&p).Update("code", code).Error == nil {
			imported++
		}
	}
	c.JSON(http.StatusOK, gin.H{"total": total, "imported": imported, "skipped": skipped})
}

// ImportPartners POST /api/v1/import/partners
// 列顺序（来往单位.xls）：编号,类型,状态,名称,电话,卡号,初始金额,单位,地址,...,备注
func (h *ImportHandler) ImportPartners(c *gin.Context) {
	shopID := middleware.GetShopID(c)

	rows, err := parseUploadedExcel(c)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}

	total, imported, skipped := 0, 0, 0
	for _, row := range rows[1:] {
		name := cell(row, 3)
		if name == "" {
			continue
		}
		total++
		var existing model.Partner
		if h.db.Where("shop_id = ? AND name = ? AND deleted_at IS NULL", shopID, name).First(&existing).Error == nil {
			skipped++
			continue
		}
		balance, _ := strconv.ParseFloat(cell(row, 6), 64)
		status := "enabled"
		if cell(row, 2) == "禁用" {
			status = "disabled"
		}
		p := model.Partner{
			TenantBase:  model.TenantBase{ShopID: shopID},
			Code:        cell(row, 0),
			Type:        parsePartnerType(cell(row, 1)),
			Status:      status,
			Name:        name,
			Phone:       cell(row, 4),
			BankAccount: cell(row, 5),
			Balance:     balance,
			Address:     cell(row, 8),
			Remark:      cell(row, 11),
		}
		if h.db.Create(&p).Error == nil {
			imported++
		}
	}

	c.JSON(http.StatusOK, gin.H{"total": total, "imported": imported, "skipped": skipped})
}

// ImportProductNames POST /api/v1/import/product-names
// 列顺序（商品名称.xls）：选项编号,选项名称,备注
func (h *ImportHandler) ImportProductNames(c *gin.Context) {
	shopID := middleware.GetShopID(c)
	rows, err := parseUploadedExcel(c)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}

	total, imported, skipped := 0, 0, 0
	for _, row := range rows[1:] {
		name := cell(row, 1)
		if name == "" {
			continue
		}
		total++
		var existing model.ProductNameOption
		if h.db.Where("shop_id = ? AND name = ? AND deleted_at IS NULL", shopID, name).First(&existing).Error == nil {
			skipped++
			continue
		}
		opt := model.ProductNameOption{
			TenantBase: model.TenantBase{ShopID: shopID},
			Code:       cell(row, 0),
			Name:       name,
			Remark:     cell(row, 2),
		}
		if h.db.Create(&opt).Error == nil {
			imported++
		}
	}
	c.JSON(http.StatusOK, gin.H{"total": total, "imported": imported, "skipped": skipped})
}

// ImportProductSeries POST /api/v1/import/product-series
// 列顺序（商品系列.xls）：选项编号,选项名称,备注
func (h *ImportHandler) ImportProductSeries(c *gin.Context) {
	shopID := middleware.GetShopID(c)
	rows, err := parseUploadedExcel(c)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}

	total, imported, skipped := 0, 0, 0
	for _, row := range rows[1:] {
		name := cell(row, 1)
		if name == "" {
			continue
		}
		total++
		var existing model.ProductSeriesOption
		if h.db.Where("shop_id = ? AND name = ? AND deleted_at IS NULL", shopID, name).First(&existing).Error == nil {
			skipped++
			continue
		}
		opt := model.ProductSeriesOption{
			TenantBase: model.TenantBase{ShopID: shopID},
			Code:       cell(row, 0),
			Name:       name,
			Remark:     cell(row, 2),
		}
		if h.db.Create(&opt).Error == nil {
			imported++
		}
	}
	c.JSON(http.StatusOK, gin.H{"total": total, "imported": imported, "skipped": skipped})
}

// ImportProductSpecs POST /api/v1/import/product-specs
// 列顺序（商品规格.xls）：选项编号,选项名称,单品数量,备注
func (h *ImportHandler) ImportProductSpecs(c *gin.Context) {
	shopID := middleware.GetShopID(c)
	rows, err := parseUploadedExcel(c)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}

	total, imported, skipped := 0, 0, 0
	for _, row := range rows[1:] {
		name := cell(row, 1)
		if name == "" {
			continue
		}
		total++
		var existing model.ProductSpecOption
		if h.db.Where("shop_id = ? AND name = ? AND deleted_at IS NULL", shopID, name).First(&existing).Error == nil {
			skipped++
			continue
		}
		qty, _ := strconv.Atoi(strings.TrimSuffix(cell(row, 2), ".0")) // "12" 或 "12.0"
		if qty == 0 {
			qtyF, _ := strconv.ParseFloat(cell(row, 2), 64)
			qty = int(qtyF)
		}
		opt := model.ProductSpecOption{
			TenantBase: model.TenantBase{ShopID: shopID},
			Code:       cell(row, 0),
			Name:       name,
			Quantity:   qty,
			Remark:     cell(row, 3),
		}
		if h.db.Create(&opt).Error == nil {
			imported++
		}
	}
	c.JSON(http.StatusOK, gin.H{"total": total, "imported": imported, "skipped": skipped})
}

// ImportStockIn POST /api/v1/import/stock-in
// 支持老系统打印格式（每文件一张入库单）
func (h *ImportHandler) ImportStockIn(c *gin.Context) {
	shopID := middleware.GetShopID(c)
	userID := middleware.GetUserID(c)
	rows, err := parseUploadedExcel(c)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}
	if len(rows) < 7 {
		c.JSON(http.StatusBadRequest, gin.H{"error": "文件行数不足，请检查格式"})
		return
	}

	// 解析单据头
	partnerName := strings.TrimPrefix(cell(rows[3], 0), "来往单位名称：")
	dateStr := strings.TrimPrefix(cell(rows[3], 7), "单据日期：")
	orderNo := strings.TrimPrefix(cell(rows[3], 18), "NO.")

	if orderNo == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "未找到单据号，请检查文件格式"})
		return
	}

	// 检查重复
	var existing model.StockInOrder
	if h.db.Where("shop_id = ? AND order_no = ?", shopID, orderNo).First(&existing).Error == nil {
		c.JSON(http.StatusOK, gin.H{"order_no": orderNo, "skipped": true, "message": "单据已存在，已跳过"})
		return
	}

	// 解析日期
	orderDate := parseDate(dateStr)

	// 往来单位
	partnerID := findOrCreatePartner(h.db, shopID, partnerName, "supplier")

	// 默认仓库
	var wh model.Warehouse
	if h.db.Where("shop_id = ? AND is_default = 1", shopID).First(&wh).Error != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "请先在系统设置中设置默认仓库"})
		return
	}

	// 解析明细
	var items []model.StockInItem
	var totalAmount float64
	for _, row := range rows[6:] {
		if cell(row, 0) == "" || strings.HasPrefix(cell(row, 0), "单据总计") {
			break
		}
		productName := cell(row, 1)
		if productName == "" {
			continue
		}
		series := cell(row, 5)
		spec := cell(row, 6)
		qty, _ := strconv.ParseFloat(cell(row, 9), 64)
		price, _ := strconv.ParseFloat(cell(row, 11), 64)
		batchNo := cell(row, 16)

		prod, err := findOrCreateProductFn(h.db, shopID, "", productName, series, spec)
		if err != nil {
			continue
		}
		total := qty * price
		totalAmount += total
		items = append(items, model.StockInItem{
			ShopID:     shopID,
			ProductID:  prod.ID,
			Quantity:   qty,
			CostPrice:  price,
			CostAmount: total,
			BatchNo:    batchNo,
		})
	}

	if len(items) == 0 {
		c.JSON(http.StatusBadRequest, gin.H{"error": "未解析到有效明细行"})
		return
	}

	order := model.StockInOrder{
		TenantBase:  model.TenantBase{ShopID: shopID},
		OrderNo:     orderNo,
		Type:        "purchase",
		WarehouseID: wh.ID,
		PartnerID:   partnerID,
		OperatorID:  userID,
		Status:      "draft",
		OrderDate:   orderDate,
		CostTotal:   totalAmount,
	}

	if err := h.db.Create(&order).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	for i := range items {
		items[i].OrderID = order.ID
	}
	if err := h.db.CreateInBatches(&items, 50).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	c.JSON(http.StatusOK, gin.H{"order_no": orderNo, "items": len(items)})
}

// ImportStockOut POST /api/v1/import/stock-out
// 支持老系统打印格式（每文件一张出库单）
func (h *ImportHandler) ImportStockOut(c *gin.Context) {
	shopID := middleware.GetShopID(c)
	userID := middleware.GetUserID(c)
	rows, err := parseUploadedExcel(c)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}
	if len(rows) < 7 {
		c.JSON(http.StatusBadRequest, gin.H{"error": "文件行数不足，请检查格式"})
		return
	}

	// 出库单日期在 col8（比入库单多一个空列）
	partnerName := strings.TrimPrefix(cell(rows[3], 0), "来往单位名称：")
	dateStr := strings.TrimPrefix(cell(rows[3], 8), "单据日期：")
	orderNo := strings.TrimPrefix(cell(rows[3], 18), "NO.")

	if orderNo == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "未找到单据号，请检查文件格式"})
		return
	}

	var existing model.StockOutOrder
	if h.db.Where("shop_id = ? AND order_no = ?", shopID, orderNo).First(&existing).Error == nil {
		c.JSON(http.StatusOK, gin.H{"order_no": orderNo, "skipped": true, "message": "单据已存在，已跳过"})
		return
	}

	orderDate := parseDate(dateStr)
	partnerID := findOrCreatePartner(h.db, shopID, partnerName, "customer")

	var wh model.Warehouse
	if h.db.Where("shop_id = ? AND is_default = 1", shopID).First(&wh).Error != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "请先在系统设置中设置默认仓库"})
		return
	}

	var items []model.StockOutItem
	var totalAmount float64
	for _, row := range rows[6:] {
		if cell(row, 0) == "" || strings.HasPrefix(cell(row, 0), "单据总计") {
			break
		}
		productName := cell(row, 1)
		if productName == "" {
			continue
		}
		series := cell(row, 5)
		spec := cell(row, 6)
		qty, _ := strconv.ParseFloat(cell(row, 9), 64)
		price, _ := strconv.ParseFloat(cell(row, 11), 64)

		prod, err := findOrCreateProductFn(h.db, shopID, "", productName, series, spec)
		if err != nil {
			continue
		}
		total := qty * price
		totalAmount += total
		items = append(items, model.StockOutItem{
			ShopID:     shopID,
			ProductID:  prod.ID,
			Quantity:   qty,
			CostPrice:  price,
			CostAmount: total,
		})
	}

	if len(items) == 0 {
		c.JSON(http.StatusBadRequest, gin.H{"error": "未解析到有效明细行"})
		return
	}

	order := model.StockOutOrder{
		TenantBase:  model.TenantBase{ShopID: shopID},
		OrderNo:     orderNo,
		Type:        "sale",
		WarehouseID: wh.ID,
		PartnerID:   partnerID,
		OperatorID:  userID,
		Status:      "draft",
		OrderDate:   orderDate,
		// 导入单沿旧行为：合计=源金额（明细 sale_price=0 待定价，确认售价后按差额调整）
		SaleTotal: totalAmount,
	}

	if err := h.db.Create(&order).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	for i := range items {
		items[i].OrderID = order.ID
	}
	if err := h.db.CreateInBatches(&items, 50).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	c.JSON(http.StatusOK, gin.H{"order_no": orderNo, "items": len(items)})
}

// ImportInventory POST /api/v1/import/inventory
// 列顺序：商品编号,商品名称,系列,规格,单位,库存数量,单价,金额,生产日期,批次,分类,所在仓库,入库日期,供应商,上次盘点,备注
func (h *ImportHandler) ImportInventory(c *gin.Context) {
	shopID := middleware.GetShopID(c)

	rows, err := parseUploadedExcel(c)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}

	type importResult struct {
		total    int
		imported int
		updated  int
		skipped  int
		errors   []string
	}
	var res importResult

	// 预加载仓库（1 次查询）
	var warehouses []model.Warehouse
	h.db.Where("shop_id = ? AND deleted_at IS NULL", shopID).Find(&warehouses)
	warehouseByName := make(map[string]uint64, len(warehouses))
	for _, wh := range warehouses {
		warehouseByName[wh.Name] = wh.ID
	}
	findWarehouse := func(name string) *uint64 {
		if name == "" {
			return nil
		}
		if id, ok := warehouseByName[name]; ok {
			return &id
		}
		return nil
	}

	// 预加载商品（1 次查询）
	var allProducts []model.Product
	h.db.Where("shop_id = ? AND deleted_at IS NULL", shopID).Find(&allProducts)
	productByCode := make(map[string]*model.Product, len(allProducts))
	productByNSS := make(map[string]*model.Product, len(allProducts))
	for i := range allProducts {
		p := &allProducts[i]
		if p.Code != "" {
			productByCode[p.Code] = p
		}
		productByNSS[p.Name+"|"+p.Series+"|"+p.Spec] = p
	}

	// 预加载已有导入库存（1 次查询）
	// 同时建两套索引：编号索引 + 名称|系列|规格索引，供后续双路查找
	var allInvs []model.Inventory
	h.db.Where("shop_id = ? AND stock_in_item_id IS NULL AND deleted_at IS NULL", shopID).Find(&allInvs)
	invByCode := make(map[string]*model.Inventory, len(allInvs)) // key: productCode|warehouseID
	invByNSS := make(map[string]*model.Inventory, len(allInvs))  // key: name|series|spec|warehouseID
	for i := range allInvs {
		inv := &allInvs[i]
		whID := uint64(0)
		if inv.WarehouseID != nil {
			whID = *inv.WarehouseID
		}
		if inv.ProductCode != "" {
			invByCode[fmt.Sprintf("%s|%d", inv.ProductCode, whID)] = inv
		}
		nssKey := fmt.Sprintf("%s|%s|%s|%d", inv.ProductName, inv.Series, inv.Spec, whID)
		invByNSS[nssKey] = inv
	}
	lookupInv := func(productCode, name, series, spec string, whID uint64) *model.Inventory {
		// 有商品编号时，仅按「编号|仓库」唯一匹配，绝不回退到名称匹配：
		// 同一款酒的不同批次/年份是不同的商品编号，名称相同但属于独立库存记录，
		// 回退名称匹配会把它们错误合并成一条（3264 行被压成 1134 行）。
		if productCode != "" {
			return invByCode[fmt.Sprintf("%s|%d", productCode, whID)]
		}
		return invByNSS[fmt.Sprintf("%s|%s|%s|%d", name, series, spec, whID)]
	}

	// Dynamic column detection from header row
	colProductCode, colProductName, colSeries, colSpec, colUnit := 0, 1, 2, 3, 4
	colQty, colPrice, colProductionDate, colBatchNo, colWarehouse, colSupplier, colRemark := 5, 6, 8, 9, 11, 13, 15
	colStockInDate := 12
	if len(rows) > 0 {
		log.Printf("[import-inv] header row (%d cols): %v", len(rows[0]), rows[0])
		for j, h := range rows[0] {
			switch strings.TrimSpace(h) {
			case "商品编号", "商品编码", "编号", "编码", "商品条码":
				colProductCode = j
			case "商品名称", "品名", "名称", "货品名称":
				colProductName = j
			case "系列", "品牌系列":
				colSeries = j
			case "规格", "规格型号":
				colSpec = j
			case "单位":
				colUnit = j
			case "库存数量", "数量", "库存":
				colQty = j
			case "单价", "进价", "采购单价":
				colPrice = j
			case "生产日期", "生产年月":
				colProductionDate = j
			case "批次", "批次号", "批次/编号/物流码":
				colBatchNo = j
			case "入库日期", "入库时间", "入库日":
				colStockInDate = j
			case "所在仓库", "仓库", "库位":
				colWarehouse = j
			case "供应商", "供应商名称":
				colSupplier = j
			case "备注":
				colRemark = j
			}
		}
	}
	log.Printf("[import-inv] total rows=%d, colProductName=%d, colProductCode=%d, colQty=%d",
		len(rows), colProductName, colProductCode, colQty)

	// 如果没有匹配到任何列头，返回诊断信息
	detectedHeader := strings.Join(rows[0], " | ")

	var logsToCreate []model.InventoryLog

	for i, row := range rows[1:] {
		productName := cell(row, colProductName)
		if i < 5 {
			log.Printf("[import-inv] row[%d] len=%d | productName=%q productCode=%q qty=%q",
				i+2, len(row), productName, cell(row, colProductCode), cell(row, colQty))
		}
		if productName == "" {
			continue // 空行（文件末尾填充行），不计入 total
		}

		productCode := cell(row, colProductCode)
		series := cell(row, colSeries)
		spec := cell(row, colSpec)
		unit := cell(row, colUnit)
		qtyStr := cell(row, colQty)
		priceStr := cell(row, colPrice)
		productionDateStr := cell(row, colProductionDate)
		batchNo := cell(row, colBatchNo)
		warehouseName := cell(row, colWarehouse)
		supplierName := cell(row, colSupplier)
		remark := cell(row, colRemark)
		stockInDateStr := cell(row, colStockInDate)

		qty, _ := strconv.ParseFloat(qtyStr, 64)
		if qty <= 0 {
			qty = 1
		}
		price, _ := strconv.ParseFloat(priceStr, 64)

		res.total++ // 有商品名称的行才计入总数

		// 从缓存查商品，找不到才创建。
		// 有商品编号时：只按编号匹配，绝不回退「名称|系列|规格」合并——同名不同编号
		// 是不同的特有产品/序列号，回退名称会把它们错并到同一 product（历史 bug 根因）。
		var prod *model.Product
		if productCode != "" {
			prod = productByCode[productCode]
		} else {
			prod = productByNSS[productName+"|"+series+"|"+spec]
		}
		if prod == nil {
			newProd, createErr := findOrCreateProductFn(h.db, shopID, productCode, productName, series, spec)
			if createErr != nil {
				res.errors = append(res.errors, fmt.Sprintf("行%d: 商品创建失败: %s", i+2, createErr.Error()))
				continue
			}
			allProducts = append(allProducts, newProd)
			prod = &allProducts[len(allProducts)-1]
			if prod.Code != "" {
				productByCode[prod.Code] = prod
			}
			productByNSS[prod.Name+"|"+prod.Series+"|"+prod.Spec] = prod
		}
		if unit != "" && prod.Unit == "" {
			h.db.Model(prod).Update("unit", unit)
			prod.Unit = unit
		}

		// 解析生产日期
		var productionDate *model.Date
		if productionDateStr != "" {
			d := parseDate(productionDateStr)
			productionDate = &d
		}

		// 解析入库日期：用 Excel 里的值作为库存记录的入库时间(CreatedAt)，
		// 解析失败或为空时回退到当前时间。
		stockInTime, _ := parseTimeWithFallback(stockInDateStr, time.Now())

		whIDPtr := findWarehouse(warehouseName)

		var unitPricePtr *float64
		if price != 0 {
			unitPricePtr = &price
		}

		whIDVal := uint64(0)
		if whIDPtr != nil {
			whIDVal = *whIDPtr
		}

		existing := lookupInv(productCode, prod.Name, prod.Series, prod.Spec, whIDVal)

		if existing != nil {
			// 去重/增量更新：逐字段对比 Excel 行与库内现有记录，
			// 仅把「不一致」的字段放进 updates；全部一致则跳过不写库。
			updates := map[string]interface{}{}

			if existing.Quantity != qty {
				updates["quantity"] = qty
			}
			if existing.ProductName != prod.Name {
				updates["product_name"] = prod.Name
			}
			if existing.Series != prod.Series {
				updates["series"] = prod.Series
			}
			if existing.Spec != prod.Spec {
				updates["spec"] = prod.Spec
			}
			if existing.Unit != prod.Unit {
				updates["unit"] = prod.Unit
			}
			if existing.WarehouseName != warehouseName {
				updates["warehouse_name"] = warehouseName
			}
			if existing.SupplierName != supplierName {
				updates["supplier_name"] = supplierName
			}
			if existing.Remark != remark {
				updates["remark"] = remark
			}
			if existing.BatchNo != batchNo {
				updates["batch_no"] = batchNo
			}
			// 单价：仅当 Excel 提供了非零单价且与现有不同才更新
			if unitPricePtr != nil {
				if existing.UnitPrice == nil || *existing.UnitPrice != *unitPricePtr {
					updates["unit_price"] = *unitPricePtr
				}
			}
			// 生产日期：仅当 Excel 提供了值且与现有不同才更新
			if productionDate != nil {
				if existing.ProductionDate == nil ||
					!existing.ProductionDate.Time.Equal(productionDate.Time) {
					updates["production_date"] = productionDate
				}
			}
			// 入库时间(created_at)：与现有不同才更新
			if !existing.CreatedAt.Equal(stockInTime) {
				updates["created_at"] = stockInTime
			}

			if len(updates) == 0 {
				// 所有字段都一致，跳过（不写库、不写流水）
				res.skipped++
				continue
			}

			qtyBefore := existing.Quantity
			if err := h.db.Model(existing).Updates(updates).Error; err != nil {
				res.errors = append(res.errors, fmt.Sprintf("行%d: 库存更新失败: %s", i+2, err.Error()))
				continue
			}
			// 仅在库存数量变化时才记一笔流水（用更新前的数量作为 QtyBefore）
			if _, ok := updates["quantity"]; ok {
				logsToCreate = append(logsToCreate, model.InventoryLog{
					ShopID: shopID, WarehouseID: whIDVal, ProductID: prod.ID,
					Direction: "in", Quantity: qty, QtyBefore: qtyBefore, QtyAfter: qty,
					RefType: "import", RefID: 0,
				})
			}
			// 同步缓存，避免同文件后续行重复比对到旧值
			existing.Quantity = qty
			existing.ProductName = prod.Name
			existing.Series = prod.Series
			existing.Spec = prod.Spec
			existing.Unit = prod.Unit
			existing.WarehouseName = warehouseName
			existing.SupplierName = supplierName
			existing.Remark = remark
			existing.BatchNo = batchNo
			if _, ok := updates["unit_price"]; ok {
				existing.UnitPrice = unitPricePtr
			}
			if _, ok := updates["production_date"]; ok {
				existing.ProductionDate = productionDate
			}
			if _, ok := updates["created_at"]; ok {
				existing.CreatedAt = stockInTime
			}
			res.updated++
		} else {
			productIDCopy := prod.ID
			inv := model.Inventory{
				ShopID:         shopID,
				WarehouseID:    whIDPtr,
				ProductID:      &productIDCopy,
				StockInItemID:  nil,
				Quantity:       qty,
				ProductCode:    productCode, // 行自身的商品编号（每条库存记录唯一），而非商品目录编号
				ProductName:    prod.Name,
				Series:         prod.Series,
				Spec:           prod.Spec,
				Unit:           prod.Unit,
				WarehouseName:  warehouseName,
				UnitPrice:      unitPricePtr,
				ProductionDate: productionDate,
				BatchNo:        batchNo,
				SupplierName:   supplierName,
				Remark:         remark,
				CreatedAt:      stockInTime, // 用 Excel「入库日期」作为入库时间
			}
			if err := h.db.Create(&inv).Error; err != nil {
				res.errors = append(res.errors, fmt.Sprintf("行%d: 库存写入失败: %s", i+2, err.Error()))
				continue
			}
			// 写入两套缓存，防止同文件后续行重复插入
			if inv.ProductCode != "" {
				invByCode[fmt.Sprintf("%s|%d", inv.ProductCode, whIDVal)] = &inv
			}
			invByNSS[fmt.Sprintf("%s|%s|%s|%d", inv.ProductName, inv.Series, inv.Spec, whIDVal)] = &inv
			logsToCreate = append(logsToCreate, model.InventoryLog{
				ShopID: shopID, WarehouseID: whIDVal, ProductID: prod.ID,
				Direction: "in", Quantity: qty, QtyBefore: 0, QtyAfter: qty,
				RefType: "import", RefID: 0,
			})
			res.imported++
		}
	}

	// 批量写流水
	if len(logsToCreate) > 0 {
		h.db.CreateInBatches(&logsToCreate, 100)
	}

	// total=0 说明列格式不匹配，没有解析到任何有效行
	if res.total == 0 {
		res.errors = append(res.errors,
			fmt.Sprintf("未解析到任何有效行，可能列格式不匹配。识别到的表头：%s", detectedHeader))
	}

	log.Printf("[import-inv] RESULT: total=%d imported=%d updated=%d skipped=%d errors=%d",
		res.total, res.imported, res.updated, res.skipped, len(res.errors))

	c.JSON(http.StatusOK, gin.H{
		"total":    res.total,
		"imported": res.imported,
		"updated":  res.updated,
		"skipped":  res.skipped,
		"errors":   res.errors,
	})
}

// ── 内部辅助函数 ─────────────────────────────────────────────

func parseUploadedExcel(c *gin.Context) ([][]string, error) {
	file, err := c.FormFile("file")
	if err != nil {
		return nil, fmt.Errorf("file required")
	}
	f, err := file.Open()
	if err != nil {
		return nil, err
	}
	defer f.Close()

	// 读取前 4 字节检测 OLE2 格式（D0 CF 11 E0 = 老式 .xls BIFF）
	var magic [4]byte
	f.Read(magic[:])
	f.Seek(0, 0)
	isOLE := magic[0] == 0xD0 && magic[1] == 0xCF && magic[2] == 0x11 && magic[3] == 0xE0

	var rows [][]string

	if isOLE {
		// 老格式 BIFF (.xls)。注意：extrame/xls 对部分真实导出文件会错读单元格
		// （字符串整列丢失、数字被当成日期序列号），导致 3000 行只解析出几百行。
		// 改用 shakinm/xlsReader，可正确读取共享字符串表与数值。
		wb, xlErr := xls.OpenReader(f)
		if xlErr != nil {
			return nil, fmt.Errorf("invalid xls file: %s", xlErr.Error())
		}
		sheet, shErr := wb.GetSheet(0)
		if shErr != nil || sheet == nil {
			return nil, fmt.Errorf("no sheet found")
		}
		numRows := sheet.GetNumberRows()
		if numRows < 1 {
			return nil, fmt.Errorf("empty or invalid sheet")
		}
		// 列数以表头行为准
		header, _ := sheet.GetRow(0)
		numCols := len(header.GetCols())
		if numCols == 0 {
			numCols = 20
		}
		for r := 0; r < numRows; r++ {
			row, _ := sheet.GetRow(r)
			cells := make([]string, numCols)
			if row != nil {
				for col := 0; col < numCols; col++ {
					if cd, cErr := row.GetCol(col); cErr == nil && cd != nil {
						cells[col] = strings.TrimSpace(cd.GetString())
					}
				}
			}
			// 保留空行，让调用方自行跳过
			rows = append(rows, cells)
		}
	} else {
		// xlsx / xlsm（ZIP 格式）
		xl, xlErr := excelize.OpenReader(f)
		if xlErr != nil {
			return nil, fmt.Errorf("invalid xlsx file: %s", xlErr.Error())
		}
		rows, err = xl.GetRows(xl.GetSheetName(0))
		if err != nil {
			return nil, fmt.Errorf("cannot read sheet: %s", err.Error())
		}
	}

	if len(rows) < 2 {
		return nil, fmt.Errorf("empty or invalid sheet")
	}
	log.Printf("[import] parseUploadedExcel: file=%s rows=%d (incl. header)", file.Filename, len(rows))
	return rows, nil
}

func findOrCreateProductFn(db *gorm.DB, shopID uint64, code, name, series, spec string) (model.Product, error) {
	var p model.Product
	if code != "" {
		// 有编号：按「编号」唯一匹配/创建（编号即特有产品序列号），
		// 绝不按「名称|系列|规格」合并——同名不同编号是不同商品。
		if db.Where("shop_id = ? AND code = ? AND deleted_at IS NULL", shopID, code).First(&p).Error == nil {
			return p, nil
		}
	} else {
		// 无编号：退回「名称|系列|规格」匹配（供 ImportStockIn/Out 等无编号场景）。
		if db.Where("shop_id = ? AND name = ? AND series = ? AND spec = ? AND deleted_at IS NULL",
			shopID, name, series, spec).First(&p).Error == nil {
			return p, nil
		}
	}
	p = model.Product{
		TenantBase: model.TenantBase{ShopID: shopID},
		PublicID:   uuid.New().String(),
		Code:       code,
		Name:       name,
		Series:     series,
		Spec:       spec,
		Unit:       "瓶",
	}
	return p, db.Create(&p).Error
}

func findOrCreatePartner(db *gorm.DB, shopID uint64, name, ptype string) *uint64 {
	if name == "" {
		return nil
	}
	var p model.Partner
	if db.Where("shop_id = ? AND name = ? AND deleted_at IS NULL", shopID, name).First(&p).Error == nil {
		id := p.ID
		return &id
	}
	p = model.Partner{
		TenantBase: model.TenantBase{ShopID: shopID},
		Name:       name,
		Type:       ptype,
		Status:     "enabled",
	}
	if db.Create(&p).Error != nil {
		return nil
	}
	id := p.ID
	return &id
}

func parseDate(s string) model.Date {
	t, err := time.ParseInLocation("2006-01-02", s, time.Local)
	if err != nil {
		return model.Date{Time: time.Now()}
	}
	return model.Date{Time: t}
}

// parseTimeWithFallback 解析「入库日期」等列的时间值。
// 兼容：yyyy-MM-dd、yyyy-MM-dd HH:mm:ss、yyyy/MM/dd、Excel 序列号。
// 解析失败或为空时返回 fallback（通常为 time.Now()），ok=false。
func parseTimeWithFallback(s string, fallback time.Time) (t time.Time, ok bool) {
	s = strings.TrimSpace(s)
	if s == "" {
		return fallback, false
	}
	layouts := []string{
		"2006-01-02 15:04:05",
		"2006-01-02T15:04:05",
		"2006-01-02 15:04",
		"2006-01-02",
		"2006/01/02 15:04:05",
		"2006/01/02",
	}
	for _, layout := range layouts {
		if parsed, err := time.ParseInLocation(layout, s, time.Local); err == nil {
			return parsed, true
		}
	}
	// Excel 序列号（自 1899-12-30 起的天数，可带小数表示时间）
	if serial, err := strconv.ParseFloat(s, 64); err == nil && serial > 0 && serial < 100000 {
		base := time.Date(1899, 12, 30, 0, 0, 0, 0, time.Local)
		days := int(serial)
		frac := serial - float64(days)
		parsed := base.AddDate(0, 0, days).Add(time.Duration(frac * 24 * float64(time.Hour)))
		return parsed, true
	}
	return fallback, false
}

func parsePartnerType(raw string) string {
	hasCust := strings.Contains(raw, "客户")
	hasSupp := strings.Contains(raw, "供应商")
	switch {
	case hasCust && hasSupp:
		return "supplier,customer"
	case hasCust:
		return "customer"
	default:
		return "supplier"
	}
}

func cell(row []string, idx int) string {
	if idx >= len(row) {
		return ""
	}
	return strings.TrimSpace(row[idx])
}