<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\BelongsTo;

/**
 * 商品价格模型（同一商品按客户等级定价，联合键 product_id + level_id）
 */
class ProductPriceModel extends Model
{
    use HasFactory;

    protected $table = 'product_price';
    protected $primaryKey = 'id';

    protected $fillable = [
        'product_id',
        'level_id',
        'price',
    ];

    protected $casts = [
        'product_id' => 'integer',
        'level_id' => 'integer',
        'price' => 'decimal:2',
    ];

    /**
     * 所属商品
     */
    public function product(): BelongsTo
    {
        return $this->belongsTo(ProductModel::class, 'product_id', 'id');
    }

    /**
     * 所属客户等级
     */
    public function level(): BelongsTo
    {
        return $this->belongsTo(CustomerLevelModel::class, 'level_id', 'id');
    }

    /**
     * 按商品 + 等级筛选价格
     */
    public function scopeForProductLevel($query, int $productId, int $levelId)
    {
        return $query->where('product_id', $productId)->where('level_id', $levelId);
    }
}