Sending mails works

Massmailer.Shared/Events/MailSentEvent.cs

@@ -0,0 +1,17 @@
+using System;
+
+namespace Massmailer.Shared.Events
+{
+    public class MailSentEvent
+    {
+        public MailSentEvent(string recipient, DateTime timestamp)
+        {
+            this.Recipient = recipient;
+            this.Timestamp = timestamp;
+        }
+
+        public string Recipient { get; private set; }
+
+        public DateTime Timestamp { get; private set; }
+    }
+}

Massmailer.Shared/IMailer.cs

@@ -1,8 +1,4 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
+using System.Threading.Tasks;
 
 namespace Massmailer.Shared
 {

Massmailer.Shared/Logic/Mailer.cs

@@ -1,7 +1,11 @@
 using MailKit.Net.Smtp;
+using Massmailer.Shared.Events;
 using Massmailer.Shared.Model;
 using MimeKit;
+using PubSub;
 using System;
+using System.Collections.Generic;
+using System.Threading;
 using System.Threading.Tasks;
 
 namespace Massmailer.Shared.Logic
@@ -9,36 +13,99 @@ namespace Massmailer.Shared.Logic
     public class Mailer : IMailer
     {
         private readonly SmtpSettings smtpSettings;
+        private readonly SmtpClient smtpClient;
+        private readonly Hub hub;
+        private readonly int minWaitTime = 0;
+        private DateTime lastMailSent = DateTime.MinValue;
 
-        public Mailer(SmtpSettings smtpSettings)
+        public Mailer(SmtpSettings smtpSettings, Hub hub)
         {
             this.smtpSettings = smtpSettings;
+            this.smtpClient = new SmtpClient();
+            this.smtpClient.ServerCertificateValidationCallback = (s, c, h, e) => true;
+            this.hub = hub;
+
+            // Calculate wait time in seconds
+            this.minWaitTime = (int)Math.Ceiling(60d / this.smtpSettings.MaxSendRate);
         }
 
-        public async Task SendMailAsync(string email, string subject, string body)
+        public MimeMessage CreateMessage(string recipient, string subject, string body)
+        {
+            var message = new MimeMessage();
+            message.From.Add(new MailboxAddress(this.smtpSettings.SenderName, this.smtpSettings.SenderEmail));
+            message.To.Add(new MailboxAddress(recipient, recipient));
+            message.Subject = subject;
+            message.Body = new TextPart("html") { Text = body };
+            return message;
+        }
+
+        public List<MimeMessage> CreateMessages(List<string> recipients, string subject, string body)
+        {
+            var result = new List<MimeMessage>();
+            foreach (var recipient in recipients)
+            {
+                result.Add(this.CreateMessage(recipient, subject, body));
+            }
+
+            return result;
+        }
+
+        public async Task SendMailsAsync(List<string> recipients, string subject, string body)
+        {
+            var messages = this.CreateMessages(recipients, subject, body);
+            await this.SendMailsAsync(messages);
+        }
+
+        public async Task SendMailsAsync(List<MimeMessage> messages)
         {
             try
             {
-                var message = new MimeMessage();
-                message.From.Add(new MailboxAddress(this.smtpSettings.SenderName, this.smtpSettings.SenderEmail));
-                message.To.Add(new MailboxAddress(email, email));
-                message.Subject = subject;
-                message.Body = new TextPart("html") { Text = body };
+                await this.smtpClient.ConnectAsync(this.smtpSettings.Server, this.smtpSettings.Port, this.smtpSettings.UseSsl);
+                await this.smtpClient.AuthenticateAsync(this.smtpSettings.Username, this.smtpSettings.Password);
 
-                using (var client = new SmtpClient())
+                foreach (var message in messages)
                 {
-                    client.ServerCertificateValidationCallback = (s, c, h, e) => true;
-
-                    await client.ConnectAsync(this.smtpSettings.Server, this.smtpSettings.Port, this.smtpSettings.UseSsl);
-                    await client.AuthenticateAsync(this.smtpSettings.Username, this.smtpSettings.Password);
-                    await client.SendAsync(message);
-                    await client.DisconnectAsync(true);
+                    await this.CheckForWaitTime();
+                    await this.smtpClient.SendAsync(message);
+                    this.lastMailSent = DateTime.Now;
+                    this.hub.Publish<MailSentEvent>(new MailSentEvent(message.To[0].ToString(), this.lastMailSent));
                 }
+
+                await this.smtpClient.DisconnectAsync(true);
             }
             catch (Exception ex)
             {
-                throw new InvalidOperationException(ex.Message);
+                throw new InvalidOperationException("Something went wrong while sending many mails", ex);
             }
         }
+
+        public async Task SendMailAsync(string recipient, string subject, string body)
+        {
+            try
+            {
+                var message = this.CreateMessage(recipient, subject, body);
+                await this.SendMailsAsync(new List<MimeMessage> { message });
+            }
+            catch (Exception ex)
+            {
+                throw new InvalidOperationException("Something went wrong while sending a mail", ex);
+            }
+        }
+
+        private async Task CheckForWaitTime()
+        {
+            await Task.Run(() =>
+            {
+                while (true)
+                {
+                    if (this.lastMailSent.AddSeconds(this.minWaitTime) < DateTime.Now)
+                    {
+                        break;
+                    }
+
+                    Thread.Sleep(100);
+                }
+            });
+        }
     }
 }

Massmailer.Shared/Massmailer.Shared.csproj

@@ -6,6 +6,7 @@
 
   <ItemGroup>
     <PackageReference Include="MailKit" Version="2.10.1" />
+    <PackageReference Include="PubSub" Version="4.0.1" />
   </ItemGroup>
 
 </Project>

Massmailer.Shared/Model/MassmailProject.cs

@@ -0,0 +1,13 @@
+using System.Collections.Generic;
+
+namespace Massmailer.Shared.Model
+{
+    public class MassmailProject
+    {
+        public List<MassmailRecipient> Recipient { get; set; }
+
+        public string Subject { get; set; }
+
+        public string Body { get; set; }
+    }
+}

Massmailer.Shared/Model/MassmailRecipient.cs

@@ -0,0 +1,13 @@
+using System;
+
+namespace Massmailer.Shared.Model
+{
+    public class MassmailRecipient
+    {
+        public string Recipient { get; set; }
+
+        public bool IsSent { get; set; }
+
+        public DateTime SentDate { get; set; }
+    }
+}

Massmailer.Shared/Model/SmtpSettings.cs

@@ -21,5 +21,7 @@ namespace Massmailer.Shared.Model
         public string Password { get; set; }
 
         public bool UseSsl { get; set; }
+
+        public int MaxSendRate { get; set; }
     }
 }