From 804c423b249df4812bd4fb52dd8dc6b0be620bbd Mon Sep 17 00:00:00 2001
From: jvyden <jvyden@jvyden.xyz>
Date: Sat, 25 Nov 2023 18:01:29 -0500
Subject: [PATCH] Switch to MailKit for SMTP

---
 Refresh.GameServer/Refresh.GameServer.csproj |  1 +
 Refresh.GameServer/Services/SmtpService.cs   | 47 +++++++++++---------
 2 files changed, 27 insertions(+), 21 deletions(-)

diff --git a/Refresh.GameServer/Refresh.GameServer.csproj b/Refresh.GameServer/Refresh.GameServer.csproj
index 0e5f51db..ffb5f923 100644
--- a/Refresh.GameServer/Refresh.GameServer.csproj
+++ b/Refresh.GameServer/Refresh.GameServer.csproj
@@ -65,6 +65,7 @@
       <PackageReference Include="BCrypt.Net-Next" Version="4.0.3" />
       <PackageReference Include="CommandLineParser" Version="2.9.1" />
       <PackageReference Include="Discord.Net.Webhook" Version="3.13.0" />
+      <PackageReference Include="MailKit" Version="4.3.0" />
       <PackageReference Include="NPTicket" Version="3.1.0" />
       <PackageReference Include="Pfim" Version="0.11.2" />
       <PackageReference Include="Realm" Version="11.6.1" />
diff --git a/Refresh.GameServer/Services/SmtpService.cs b/Refresh.GameServer/Services/SmtpService.cs
index 75880281..aba74d3d 100644
--- a/Refresh.GameServer/Services/SmtpService.cs
+++ b/Refresh.GameServer/Services/SmtpService.cs
@@ -1,7 +1,8 @@
-using System.Net;
-using System.Net.Mail;
 using Bunkum.Core;
 using Bunkum.Core.Services;
+using MailKit.Net.Smtp;
+using MailKit.Security;
+using MimeKit;
 using NotEnoughLogs;
 using Refresh.GameServer.Configuration;
 using Refresh.GameServer.Types.UserData;
@@ -10,7 +11,6 @@ namespace Refresh.GameServer.Services;
 
 public class SmtpService : EndpointService
 {
-    private readonly SmtpClient? _smtpClient;
     private readonly IntegrationConfig _integrationConfig;
     private readonly GameServerConfig _gameConfig;
 
@@ -20,33 +20,36 @@ internal SmtpService(IntegrationConfig integrationConfig,
     {
         this._integrationConfig = integrationConfig;
         this._gameConfig = gameConfig;
-
-        if (!this._integrationConfig.SmtpEnabled) return;
-        
-        this._smtpClient = new SmtpClient(this._integrationConfig.SmtpHost)
-        {
-            Port = this._integrationConfig.SmtpPort,
-            EnableSsl = this._integrationConfig.SmtpTlsEnabled,
-            Credentials = new NetworkCredential(this._integrationConfig.SmtpUsername, this._integrationConfig.SmtpPassword),
-            DeliveryMethod = SmtpDeliveryMethod.Network,
-        };
     }
 
     private bool SendEmail(string recipient, string subject, string body)
     {
-        if (!this._integrationConfig.SmtpEnabled || this._smtpClient == null) return false;
+        if (!this._integrationConfig.SmtpEnabled) return false;
+
+        using SmtpClient client = new();
+
+        SecureSocketOptions tlsOptions = SecureSocketOptions.None;
+
+        if (this._integrationConfig is { SmtpTlsEnabled: true, SmtpPort: 587 })
+            tlsOptions = SecureSocketOptions.StartTls;
+        else if (this._integrationConfig.SmtpTlsEnabled)
+            tlsOptions = SecureSocketOptions.SslOnConnect;
         
-        MailMessage message = new()
-        {
-            From = new MailAddress(this._integrationConfig.SmtpUsername),
-            To = { new MailAddress(recipient) },
-            Subject = subject,
-            Body = body,
+        client.Connect(this._integrationConfig.SmtpHost, this._integrationConfig.SmtpPort, tlsOptions);
+        client.Authenticate(this._integrationConfig.SmtpUsername, this._integrationConfig.SmtpPassword);
+
+        MimeMessage message = new();
+        message.From.Add(new MailboxAddress(this._gameConfig.InstanceName, this._integrationConfig.SmtpUsername));
+        message.To.Add(new MailboxAddress(recipient, recipient));
+
+        message.Subject = subject;
+        message.Body = new TextPart("plain") {
+            Text = body,
         };
 
         try
         {
-            this._smtpClient.Send(message);
+            client.Send(message);
         }
         catch (Exception e)
         {
@@ -55,6 +58,8 @@ private bool SendEmail(string recipient, string subject, string body)
         }
         
         this.Logger.LogDebug(BunkumCategory.Service, $"Successfully sent '{subject}' to '{recipient}'");
+        
+        client.Disconnect(true);
         return true;
     }