osb/app/Models/Invoice.php

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class Invoice extends Model
{
	protected $table = 'ab_invoice';
	protected $dates = ['due_date'];
	protected $with = ['items.taxes','account.country.currency','paymentitems'];

	protected $appends = [
		'date_due',
		'due',
		'invoice_id_url',
		'total',
	];

	protected $visible = [
		'date_due',
		'due',
		'id',
		'invoice_id_url',
		'total',
	];

	private $_total = 0;

	public function account()
	{
		return $this->belongsTo(\App\User::class);
	}

	public function items()
	{
		return $this->hasMany(InvoiceItem::class);
	}

	public function paymentitems()
	{
		return $this->hasMany(PaymentItem::class);
	}

	public function getDueAttribute()
	{
		return sprintf('%3.'.$this->currency()->rounding.'f',$this->total - $this->paid);
	}

	public function getDateDueAttribute()
	{
		return $this->due_date->format('Y-m-d');
	}

	public function getInvoiceIdAttribute()
	{
		return sprintf('%02s-%04s-%04s',$this->site_id,$this->account_id,$this->id);
	}

	public function getInvoiceIdUrlAttribute()
	{
		return sprintf('<a href="/u/invoice/view/%s">%s</a>',$this->id,$this->invoice_id);
	}

	public function getPaidAttribute()
	{
		return $this->currency()->round($this->paymentitems->sum('alloc_amt'));
	}

	public function getTotalAttribute()
	{
		if (! $this->_total)
		{
			foreach ($this->items as $o)
			{
				if ($o->active)
					$this->_total += $this->currency()->round($o->total);
			}
		}

		return sprintf('%3.'.$this->currency()->rounding.'f',$this->_total);
	}

	public function currency()
	{
		return $this->account->country->currency;
	}
}