Horux_back/app/Models/InvoiceLine.php

<?php

namespace App\Models;

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

class InvoiceLine extends Model
{
    use HasFactory;

    protected $fillable = [
        'id'
    ];

    public function invoice(): BelongsTo
    {
        return $this->belongsTo(Invoice::class);
    }

    public function rfc(): BelongsTo
    {
        return $this->belongsTo(Rfc::class);
    }

    public function invoiceType(): BelongsTo
    {
        return $this->belongsTo(InvoiceType::class);
    }

    public function paymentType(): BelongsTo
    {
        return $this->belongsTo(PaymentType::class);
    }

    public function issuerRfc(): BelongsTo
    {
        return $this->belongsTo(Rfc::class);
    }

    public function receiverRfc(): BelongsTo
    {
        return $this->belongsTo(Rfc::class);
    }

    public function getIssuerRfcAttribute()
    {
        return $this->issuerRfc()->first()->rfc;
    }

    public function getReceiverRfcAttribute()
    {
        return $this->receiverRfc()->first()->rfc;
    }

    protected $keyType = 'string';

    protected $hidden = ['issuer_rfc_id', 'receiver_rfc_id'];

    protected $appends = ['issuer_rfc', 'receiver_rfc'];
}