add invoice pdf

lib/data/provider/invoice_data_provider.dart

@@ -0,0 +1,25 @@
+import 'package:fcs/domain/entities/invoice.dart';
+import 'package:fcs/helpers/api_helper.dart';
+import 'package:fcs/helpers/firebase_helper.dart';
+import 'package:logging/logging.dart';
+
+class InvoiceDataProvider {
+  final log = Logger('InvoiceDataProvider');
+  static final InvoiceDataProvider instance = InvoiceDataProvider._();
+  InvoiceDataProvider._();
+
+  Future<void> createInvoice(Invoice invoice) async {
+    return await requestAPI("/invoices", "POST",
+        payload: invoice.toMap(), token: await getToken());
+  }
+
+  Future<void> updateInvoice(Invoice invoice) async {
+    return await requestAPI("/invoices", "PUT",
+        payload: invoice.toMap(), token: await getToken());
+  }
+
+  Future<void> cancelInvoice(Invoice invoice) async {
+    return await requestAPI("/invoices/cancel", "PUT",
+        payload: {"id": invoice.id}, token: await getToken());
+  }
+}