package model

import (
	"math"
	"time"
)

// Consumable 耗材
type Consumable struct {
	ID          string     `gorm:"type:uuid;primaryKey;default:gen_random_uuid()" json:"id"`
	Name        string     `gorm:"size:64" json:"name"`
	Category    string     `gorm:"size:32;index" json:"category"` // lamp_reagent/lamp_consumable/disinfectant/other
	Spec        *string    `gorm:"size:128" json:"spec,omitempty"`
	Quantity    float64    `gorm:"type:float" json:"quantity"`
	Unit        *string    `gorm:"size:32" json:"unit,omitempty"`
	MinQuantity float64    `gorm:"column:min_quantity;type:float" json:"minQuantity"`
	ExpiryDate  *time.Time `gorm:"column:expiry_date;type:timestamptz" json:"expiryDate,omitempty"`
	Supplier    *string    `gorm:"size:128" json:"supplier,omitempty"`
	Note        *string    `gorm:"type:text" json:"note,omitempty"`
	CreatedAt   time.Time  `gorm:"type:timestamptz" json:"createdAt"`
	UpdatedAt   time.Time  `gorm:"type:timestamptz" json:"updatedAt"`
}

func (Consumable) TableName() string { return "consumables" }

// LowStockAlert 库存低于安全阈值
func (c Consumable) LowStockAlert() bool {
	return c.Quantity < c.MinQuantity
}

// ExpiringAlert 效期在 days 天内到期（含已过期）
func (c Consumable) ExpiringAlert(days int) bool {
	if c.ExpiryDate == nil {
		return false
	}
	return !c.ExpiryDate.After(time.Now().Add(time.Duration(days) * 24 * time.Hour))
}

// PurchaseSuggestion 建议采购量（低于安全阈值时补足差额，向上取整）
func (c Consumable) PurchaseSuggestion() float64 {
	if !c.LowStockAlert() {
		return 0
	}
	return math.Ceil(c.MinQuantity - c.Quantity)
}