From 45a6bc8ae21862bff9b0e171a14a0052cb322692 Mon Sep 17 00:00:00 2001
From: Dennis Reimann <mail@dennisreimann.de>
Date: Tue, 26 Nov 2024 11:23:39 +0100
Subject: [PATCH] Add QR Code with link to invitation email

This will help onboarding via the app.
---
 BTCPayServer/BTCPayServer.csproj                 |  5 +----
 BTCPayServer/Components/QRCode/QRCode.cs         |  1 -
 BTCPayServer/Extensions/EmailSenderExtensions.cs | 12 +++++++++++-
 3 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/BTCPayServer/BTCPayServer.csproj b/BTCPayServer/BTCPayServer.csproj
index d2779c668..7d4ef66c5 100644
--- a/BTCPayServer/BTCPayServer.csproj
+++ b/BTCPayServer/BTCPayServer.csproj
@@ -49,7 +49,7 @@
     <PackageReference Include="LNURL" Version="0.0.34" />
     <PackageReference Include="MailKit" Version="3.3.0" />
     <PackageReference Include="BTCPayServer.NETCore.Plugins.Mvc" Version="1.4.4" />
-    <PackageReference Include="QRCoder" Version="1.4.3" />
+    <PackageReference Include="QRCoder" Version="1.6.0" />
     <PackageReference Include="System.IO.Pipelines" Version="8.0.0" />
     <PackageReference Include="NBitpayClient" Version="1.0.0.39" />
     <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
@@ -60,9 +60,6 @@
     <PackageReference Include="Serilog.AspNetCore" Version="8.0.0" />
     <PackageReference Include="Serilog.Sinks.File" Version="5.0.1-dev-00968" />
     <PackageReference Include="SSH.NET" Version="2023.0.0" />
-  </ItemGroup>
-
-	<ItemGroup>
     <PackageReference Include="TwentyTwenty.Storage" Version="2.12.1" />
     <PackageReference Include="TwentyTwenty.Storage.Amazon" Version="2.12.1" />
     <PackageReference Include="TwentyTwenty.Storage.Azure" Version="2.12.1" />
diff --git a/BTCPayServer/Components/QRCode/QRCode.cs b/BTCPayServer/Components/QRCode/QRCode.cs
index 13f7d50b0..29ed5ba7c 100644
--- a/BTCPayServer/Components/QRCode/QRCode.cs
+++ b/BTCPayServer/Components/QRCode/QRCode.cs
@@ -1,5 +1,4 @@
 using System;
-using System.Drawing;
 using Microsoft.AspNetCore.Html;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.AspNetCore.Mvc.ViewComponents;
diff --git a/BTCPayServer/Extensions/EmailSenderExtensions.cs b/BTCPayServer/Extensions/EmailSenderExtensions.cs
index f0e2367e0..cd5466a82 100644
--- a/BTCPayServer/Extensions/EmailSenderExtensions.cs
+++ b/BTCPayServer/Extensions/EmailSenderExtensions.cs
@@ -1,6 +1,7 @@
 using System.Text.Encodings.Web;
 using BTCPayServer.Services.Mails;
 using MimeKit;
+using QRCoder;
 
 namespace BTCPayServer.Services
 {
@@ -42,7 +43,7 @@ namespace BTCPayServer.Services
         public static void SendInvitation(this IEmailSender emailSender, MailboxAddress address, string link)
         {
             emailSender.SendEmail(address, "Invitation", CreateEmailBody(
-                $"Please complete your account setup by clicking <a href='{HtmlEncoder.Default.Encode(link)}'>this link</a>."));
+                $"<p>Please complete your account setup by clicking <a href='{HtmlEncoder.Default.Encode(link)}'>this link</a>.</p><p>You can also use the BTCPay Server app and scan this QR code when connecting:</p>{GetQrCodeImg(link)}"));
         }
 
         public static void SendNewUserInfo(this IEmailSender emailSender, MailboxAddress address, string newUserInfo, string link)
@@ -56,5 +57,14 @@ namespace BTCPayServer.Services
             emailSender.SendEmail(address, userInfo, CreateEmailBody(
                 $"{userInfo}. You can view the store users here: <a href='{HtmlEncoder.Default.Encode(link)}'>Store users</a>"));
         }
+
+        private static string GetQrCodeImg(string data)
+        {
+            using var qrGenerator = new QRCodeGenerator();
+            using var qrCodeData = qrGenerator.CreateQrCode(data, QRCodeGenerator.ECCLevel.Q);
+            using var qrCode = new Base64QRCode(qrCodeData);
+            var base64 = qrCode.GetGraphic(20);
+            return $"<img src='data:image/png;base64,{base64}' alt='{data}' width='320' height='320'/>";
+        }
     }
 }