Moonlight/Moonlight/App/Services/MailService.cs

using System.Net;
using System.Net.Mail;
using Logging.Net;
using MimeKit;
using Moonlight.App.Database.Entities;
using Moonlight.App.Exceptions;
using Moonlight.App.Helpers;
using SmtpClient = MailKit.Net.Smtp.SmtpClient;

namespace Moonlight.App.Services;

public class MailService
{
    private readonly string Server;
    private readonly string Password;
    private readonly string Email;
    private readonly int Port;
    private readonly bool Ssl;

    public MailService(ConfigService configService)
    {
        var mailConfig = configService
            .GetSection("Moonlight")
            .GetSection("Mail");

        Server = mailConfig.GetValue<string>("Server");
        Password = mailConfig.GetValue<string>("Password");
        Email = mailConfig.GetValue<string>("Email");
        Port = mailConfig.GetValue<int>("Port");
        Ssl = mailConfig.GetValue<bool>("Ssl");
    }
    
    public async Task SendMail(
        User user,
        string name,
        Action<Dictionary<string, string>> values
    )
    {
        if (!File.Exists(PathBuilder.File("storage", "resources", "mail", $"{name}.html")))
        {
            Logger.Warn($"Mail template '{name}' not found. Make sure to place one in the resources folder");
            throw new DisplayException("Mail template not found");
        }

        var rawHtml = await File.ReadAllTextAsync(PathBuilder.File("storage", "resources", "mail", $"{name}.html"));

        var val = new Dictionary<string, string>();
        values.Invoke(val);
        
        val.Add("FirstName", user.FirstName);
        val.Add("LastName", user.LastName);

        var parsed = ParseMail(rawHtml, val);

        Task.Run(async () =>
        {
            try
            {
                using var client = new SmtpClient();

                var mailMessage = new MimeMessage();
                mailMessage.From.Add(new MailboxAddress(Email, Email));
                mailMessage.To.Add(new MailboxAddress(user.Email, user.Email));
                mailMessage.Subject = $"Hey {user.FirstName}, there are news from moonlight";
                
                var body = new BodyBuilder
                {
                    HtmlBody = parsed
                };
                mailMessage.Body = body.ToMessageBody();

                using (var smtpClient = new SmtpClient())
                {
                    await smtpClient.ConnectAsync(Server, Port, Ssl);
                    await smtpClient.AuthenticateAsync(Email, Password);
                    await smtpClient.SendAsync(mailMessage);
                    await smtpClient.DisconnectAsync(true);
                }
            }
            catch (Exception e)
            {
                Logger.Warn("Error sending mail");
                Logger.Warn(e);
            }
        });
    }

    private string ParseMail(string html, Dictionary<string, string> values)
    {
        foreach (var kvp in values)
        {
            html = html.Replace("{{" + kvp.Key + "}}", kvp.Value);
        }

        return html;
    }
}