Initial refactoring work

app/Models/InvoiceItem.php

@@ -0,0 +1,46 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Model;
+
+class InvoiceItem extends Model
+{
+	protected $table = 'ab_invoice_item';
+	protected $with = ['taxes'];
+
+	private $_tax = 0;
+
+	public function invoice()
+	{
+		return $this->belongsTo(Invoice::class);
+	}
+
+	public function taxes()
+	{
+		return $this->hasMany(InvoiceItemTax::class);
+	}
+
+	public function getSubTotalAttribute()
+	{
+		return $this->quantity * $this->price_base;
+	}
+
+	public function getTaxAttribute()
+	{
+		if (! $this->_tax)
+		{
+			foreach ($this->taxes as $o)
+			{
+				$this->_tax += $o->amount;
+			}
+		}
+
+		return $this->_tax;
+	}
+
+	public function getTotalAttribute()
+	{
+		return $this->tax + $this->sub_total;
+	}
+}