added import and export recurring invoices

app/Exports/Sales/Invoices/Sheets/InvoiceItems.php

@@ -0,0 +1,44 @@
+<?php
+
+namespace App\Exports\Sales\Invoices\Sheets;
+
+use App\Abstracts\Export;
+use App\Models\Document\DocumentItem as Model;
+
+class InvoiceItems extends Export
+{
+    public function collection()
+    {
+        return Model::with('document', 'item')->invoice()->collectForExport($this->ids, null, 'document_id');
+    }
+
+    public function map($model): array
+    {
+        $document = $model->document;
+
+        if (empty($document)) {
+            return [];
+        }
+
+        $model->invoice_number = $document->document_number;
+        $model->item_name = $model->item->name;
+        $model->item_description = $model->item->description;
+        $model->item_type = $model->item->type;
+
+        return parent::map($model);
+    }
+
+    public function fields(): array
+    {
+        return [
+            'invoice_number',
+            'item_name',
+            'item_description',
+            'item_type',
+            'quantity',
+            'price',
+            'total',
+            'tax',
+        ];
+    }
+}