kknongchang_2506/app/Module/Shop/Models/ShopPromotion.php

<?php

namespace App\Module\Shop\Models;

use Illuminate\Database\Eloquent\Relations\BelongsToMany;
use Illuminate\Database\Eloquent\Relations\HasMany;
use UCore\ModelCore;

/**
 * 商店促销活动模型
 *
 * field start 
 * field end
 */
class ShopPromotion extends ModelCore
{
    /**
     * 与模型关联的表名
     *
     * @var string
     */
    protected $table = 'shop_promotions';

    /**
     * 可批量赋值的属性
     *
     * @var array
     */
    protected $fillable = [
        'name',
        'description',
        'banner',
        'discount_type',
        'discount_value',
        'is_active',
        'sort_order',
        'start_time',
        'end_time',
    ];

    /**
     * 应该被转换为日期的属性
     *
     * @var array
     */
    protected $dates = [
        'start_time',
        'end_time',
        'created_at',
        'updated_at',
    ];

    /**
     * 应该被转换为原生类型的属性
     *
     * @var array
     */
    protected $casts = [
        'is_active' => 'boolean',
    ];

    /**
     * 折扣类型：固定折扣
     */
    const DISCOUNT_TYPE_FIXED = 1;

    /**
     * 折扣类型：百分比折扣
     */
    const DISCOUNT_TYPE_PERCENTAGE = 2;

    /**
     * 获取折扣类型文本
     *
     * @return string
     */
    public function getDiscountTypeTextAttribute(): string
    {
        return match ($this->discount_type) {
            self::DISCOUNT_TYPE_FIXED => '固定折扣',
            self::DISCOUNT_TYPE_PERCENTAGE => '百分比折扣',
            default => '未知',
        };
    }

    /**
     * 获取该促销活动关联的商品
     *
     * @return BelongsToMany
     */
    public function items(): BelongsToMany
    {
        return $this->belongsToMany(
            ShopItem::class,
            'shop_promotion_items',
            'promotion_id',
            'shop_item_id'
        )->withPivot('custom_discount_value')
        ->withTimestamps();
    }

    /**
     * 获取促销活动的商品关联记录
     *
     * @return HasMany
     */
    public function promotionItems(): HasMany
    {
        return $this->hasMany(ShopPromotionItem::class, 'promotion_id');
    }

    /**
     * 检查促销活动是否有效
     *
     * @return bool
     */
    public function isValid(): bool
    {
        if (!$this->is_active) {
            return false;
        }

        $now = now();
        if ($this->start_time && $now < $this->start_time) {
            return false;
        }

        if ($this->end_time && $now > $this->end_time) {
            return false;
        }

        return true;
    }

    /**
     * 计算折扣后的价格
     *
     * @param int $originalPrice 原价
     * @param int|null $customDiscountValue 自定义折扣值
     * @return int 折扣后的价格
     */
    public function calculateDiscountedPrice(int $originalPrice, ?int $customDiscountValue = null): int
    {
        $discountValue = $customDiscountValue ?? $this->discount_value;

        if ($this->discount_type === self::DISCOUNT_TYPE_FIXED) {
            return max(0, $originalPrice - $discountValue);
        } elseif ($this->discount_type === self::DISCOUNT_TYPE_PERCENTAGE) {
            return (int)($originalPrice * (100 - $discountValue) / 100);
        }

        return $originalPrice;
    }
}