如何利用Go语言开发点餐系统的报表生成功能

router.POST("/order", func(c *gin.Context) {
    var order Order
    if err := c.BindJSON(&order); err != nil {
        c.jsON(http.StatusBadRequest, gin.H{"error": err.Error()})
        return
    }
    
    // 将订单数据存入数据库
    db.Create(&order)
    
    c.JSON(http.StatusOK, gin.H{"message": "Order success"})
})

func GetDishSalesCount() (map[string]int, error) {
    rows, err := db.Raw("SELECT dish, COUNT(*) as count FROM orders GROUP BY dish").Rows()
    if err != nil {
        return nil, err
    }
    
    result := make(map[string]int)
    defer rows.Close()
    for rows.Next() {
        var dish string
        var count int
        rows.Scan(&dish, &count)
        result[dish] = count
    }
    
    return result, nil
}

func GenerateReport(data map[string]int) error {
    f := excelize.NewFile()
    f.SetCellValue("Sheet1", "A1", "菜品")
    f.SetCellValue("Sheet1", "B1", "销售数量")
    
    row := 2
    for dish, count := range data {
        f.SetCellValue("Sheet1", fmt.Sprintf("A%d", row), dish)
        f.SetCellValue("Sheet1", fmt.Sprintf("B%d", row), count)
        row++
    }
    
    if err := f.SaveAs("report.xlsx"); err != nil {
        return err
    }
    
    return nil
}