Invoices can be created

- Transactions can now be tracked

src/models/invoice/invoice.interface.ts

@@ -0,0 +1,42 @@
+import { Document } from 'mongoose';
+import { CryptoUnits, FiatUnits, PaymentStatus } from '../../helper/types';
+
+export interface ICart {
+    price: number;
+    name: string;
+    image: string;
+    quantity: number;
+}
+
+export interface IInvoice extends Document {
+    // Available payment methods
+    // [btc, xmr, eth, doge]
+    paymentMethods: CryptoUnits[];
+
+    // 1Kss3e9iPB9vTgWJJZ1SZNkkFKcFJXPz9t
+    receiveAddress: string;
+
+    paidWith?: CryptoUnits;
+
+    // Is set when invoice got paid
+    // 3b38c3a215d4e7981e1516b2dcbf76fca58911274d5d55b3d615274d6e10f2c1
+    transcationHash?: string;
+
+    cart?: ICart[];
+    totalPrice?: number;
+    currency: FiatUnits;
+    
+    // Time in minutes the user has to pay.
+    // Time left = (createdAt + dueBy) - Date.now() / 1000
+    dueBy: number;
+
+    status?: PaymentStatus;
+
+    // E-Mail address of user, if he want's a confirmation email.
+    email?: string;
+
+    successUrl: string;
+    cancelUrl: string;
+
+    createdAt?: number;
+}