Woring on invoice is_amount_discounts

app/Factory/InvoiceItemFactory.php

@@ -61,7 +61,7 @@ class InvoiceItemFactory
 			$item->quantity = $faker->numberBetween(1,10);
 			$item->cost = $faker->randomFloat(2, 1, 1000);
 			$item->line_total = $item->quantity * $item->cost;
-			$item->is_amount_discount = false;
+			$item->is_amount_discount = true;
 			$item->discount = $faker->numberBetween(1,10);
 			$item->notes = $faker->realText(20);
 			$item->product_key = $faker->word();

app/Helpers/Invoice/Discounter.php

@@ -20,8 +20,9 @@ trait Discounter
 	public function discount($amount)
 	{
 
-		if($this->invoice->is_amount_discount === true)
+		if($this->invoice->is_amount_discount == true){
 			return $this->invoice->discount;
+		}
 
 		
 		return round($amount * ($this->invoice->discount / 100), 2);

app/Helpers/Invoice/InvoiceItemSum.php

@@ -213,4 +213,51 @@ class InvoiceItemSum
 		return $this;
 	}
 
+
+	/**
+	 * Invoice Amount Discount
+	 *
+	 * The problem, when calculating invoice level discounts,
+	 * the tax collected changes.
+	 *
+	 * We need to synthetically reduce the line_total amounts 
+	 * and recalculate the taxes and then pass back
+	 * the updated map
+	 */
+	
+	public function calcTaxesWithAmountDiscount()
+	{
+		$this->setGroupedTaxes(collect([]));
+
+		foreach($this->line_items as $this->item)
+		{
+			$item_tax = 0;
+			
+			$amount = $this->item->line_total - ($this->item->line_total * ($this->invoice->discount/$this->sub_total));
+			$item_tax_rate1_total = $this->calcAmountLineTax($this->item->tax_rate1, $amount);
+
+			$item_tax += $item_tax_rate1_total;
+
+			if($item_tax_rate1_total > 0)
+				$this->groupTax($this->item->tax_name1, $this->item->tax_rate1, $item_tax_rate1_total);
+		
+			$item_tax_rate2_total = $this->calcAmountLineTax($this->item->tax_rate2, $amount);
+
+			$item_tax += $item_tax_rate2_total;
+
+			if($item_tax_rate2_total > 0)
+				$this->groupTax($this->item->tax_name2, $this->item->tax_rate2, $item_tax_rate2_total);
+
+			$item_tax_rate3_total = $this->calcAmountLineTax($this->item->tax_rate3, $amount);
+
+			$item_tax += $item_tax_rate3_total;
+
+			if($item_tax_rate3_total > 0)
+				$this->groupTax($this->item->tax_name3, $this->item->tax_rate3, $item_tax_rate3_total);
+
+		}
+
+		$this->setTotalTaxes($item_tax);
+
+	}
 }

app/Helpers/Invoice/InvoiceSum.php

@@ -233,6 +233,9 @@ class InvoiceSum
 
 	public function setTaxMap()
 	{
+	//	if($this->invoice->is_amount_discount == true)
+	//		$this->invoice_items->calcTaxesWithAmountDiscount();
+
 		$this->tax_map = collect();
 
         $keys = $this->invoice_items->getGroupedTaxes()->pluck('key')->unique();

app/Helpers/Invoice/Taxer.php

@@ -42,6 +42,11 @@ trait Taxer
 
 	}
 
+	public function calcAmountLineTax($tax_rate, $amount)
+	{
+		return $this->formatValue(($amount * $tax_rate/100), $this->currency->precision);
+	}
+
 	public function inclusiveTax($tax_rate, $item)
 	{
 

app/Models/Invoice.php

@@ -267,7 +267,8 @@ class Invoice extends BaseModel
      */
     public function calc()
     {
-
+//todo will need to switch between inclusive and exclusive implementations of InvoiceSum
+        
         $invoice_calc = new InvoiceSum($this, $this->settings);
         
         return $invoice_calc->build();

database/factories/InvoiceFactory.php

@@ -10,7 +10,7 @@ $factory->define(App\Models\Invoice::class, function (Faker $faker) {
 		'status_id' => App\Models\Invoice::STATUS_SENT,
 		'invoice_number' => $faker->ean13(),
 		'discount' => $faker->numberBetween(1,10),
-		'is_amount_discount' => false,
+		'is_amount_discount' => true,
 		'tax_name1' => 'GST',
 		'tax_rate1' => 10,
 		'tax_name2' => 'VAT',