Invoice PAIN & CSV can be uploaded

app/Providers/InvoiceCsvFileProvider.php

@@ -0,0 +1,49 @@
+<?php
+
+namespace App\Providers;
+
+use App\Models\Invoice;
+use App\Resources\InvoiceResource;
+
+class InvoiceCsvFileProvider {
+
+    /* @var Invoice[] */
+    private array $invoices;
+
+    public function __construct(array $invoices) {
+        $this->invoices = $invoices;
+    }
+
+    public function createCsvFileContent() : string
+    {
+        $csvArray[] = implode(
+            ',', [
+            '"Rechnungsnummer"',
+            '"Zahlungsgrund"',
+            '"Name"',
+            '"IBAN"',
+            '"Kontoinhaber*in"',
+            '"Betrag"',
+            '"Spende"',
+            '"Beleg ohne Auszahlung"',
+        ]);
+
+        foreach ($this->invoices as $invoice) {
+            $invoiceReadable = new InvoiceResource($invoice)->toArray();
+            $csvLine = implode(',', [
+                '"' . $invoiceReadable['invoiceNumber'] . '"',
+                '"' . $invoiceReadable['invoiceType'] . '"',
+                '"' . $invoiceReadable['contactName'] . '"',
+                '"' . $invoiceReadable['accountIban'] . '"',
+                '"' . $invoiceReadable['accountOwner'] . '"',
+                '"' . $invoiceReadable['amountPlain'] . '"',
+                '"' . $invoiceReadable['donation'] . '"',
+                '"' . $invoiceReadable['alreadyPaid'] . '"'
+            ]);
+
+            $csvArray[] = $csvLine;
+        }
+
+       return implode(PHP_EOL, $csvArray);
+    }
+}