package service

import (
	"fmt"
	"strings"
	"time"

	"github.com/xuri/excelize/v2"
	"gorm.io/gorm"

	"psi/database"
	"psi/models"
	"psi/models/request"
)

// LocationImportService 库位导入服务
type LocationImportService struct{}

// LOCATION_IMPORT_COLUMNS 库位导入表格列（仅1列）
var LOCATION_IMPORT_COLUMNS = []string{"库位编码"}

// LocationImportResult 导入结果
type LocationImportResult struct {
	SuccessCount int
	FailCount    int
	FailList     []string
	Message      string
}

// AddFail 添加失败记录
func (r *LocationImportResult) AddFail(reason string) {
	r.FailCount++
	r.FailList = append(r.FailList, reason)
}

// ParseLocationImportExcel 解析Excel文件为库位行数据
func (s *LocationImportService) ParseLocationImportExcel(fileBytes []byte) ([]request.LocationImportRow, error) {
	f, err := excelize.OpenReader(strings.NewReader(string(fileBytes)))
	if err != nil {
		return nil, fmt.Errorf("无法打开Excel文件: %v", err)
	}
	defer f.Close()

	rows, err := f.GetRows(f.GetSheetName(0))
	if err != nil {
		return nil, fmt.Errorf("读取Sheet失败: %v", err)
	}

	if len(rows) < 2 {
		return nil, fmt.Errorf("Excel至少需要表头+1行数据")
	}

	// 校验表头
	header := rows[0]
	if len(header) < len(LOCATION_IMPORT_COLUMNS) {
		return nil, fmt.Errorf("表头列数不足，期望%d列(库位编码)，实际%d列", len(LOCATION_IMPORT_COLUMNS), len(header))
	}

	var result []request.LocationImportRow
	for i := 1; i < len(rows); i++ {
		row := rows[i]
		code := strings.TrimSpace(getCell(row, 0))
		if code == "" {
			continue
		}
		result = append(result, request.LocationImportRow{Code: code})
	}

	return result, nil
}

// getCell 安全获取单元格值
func getCell(row []string, idx int) string {
	if idx < len(row) {
		return row[idx]
	}
	return ""
}

// ImportLocationsFromExcel 从Excel导入库位（事务内批量创建）
func (s *LocationImportService) ImportLocationsFromExcel(userID, warehouseID int64, rows []request.LocationImportRow) (*LocationImportResult, error) {
	databaseConn, err := database.GetTenantDB(userID)
	if err != nil {
		return nil, fmt.Errorf("获取数据库连接失败: %v", err)
	}

	result := &LocationImportResult{}

	err = databaseConn.Transaction(func(tx *gorm.DB) error {
		now := time.Now().Unix()

		for _, row := range rows {
			code := strings.TrimSpace(row.Code)
			if code == "" {
				result.AddFail("库位编码为空")
				continue
			}

			// 检查同仓库下是否已存在
			var existing models.Location
			if err := tx.Where("warehouse_id = ? AND code = ? AND is_del = ?", warehouseID, code, 0).First(&existing).Error; err == nil {
				result.AddFail(fmt.Sprintf("%s: 库位已存在", code))
				continue
			}

			loc := models.Location{
				WarehouseID: warehouseID,
				Code:        code,
				Type:        1, // 存储库位
				Capacity:    255,
				Sort:        0,
				Status:      1, // 启用
				CreatedAt:   now,
				UpdatedAt:   now,
				IsDel:       0,
			}
			if err := tx.Create(&loc).Error; err != nil {
				result.AddFail(fmt.Sprintf("%s: 创建失败: %v", code, err))
				continue
			}

			result.SuccessCount++
		}

		return nil
	})

	if err != nil {
		return nil, fmt.Errorf("导入库位事务失败: %v", err)
	}

	if result.FailCount > 0 {
		result.Message = fmt.Sprintf("成功 %d 条，失败 %d 条。失败明细: %s",
			result.SuccessCount, result.FailCount, strings.Join(result.FailList, "; "))
	} else {
		result.Message = fmt.Sprintf("全部成功，共 %d 条", result.SuccessCount)
	}

	return result, nil
}