EmailService.cs

using MailKit;
using MailKit.Net.Smtp;
using MailKit.Security;
using Microsoft.Extensions.Options;
using MimeKit;
using System;
using System.Collections.Generic;
using System.Text;
using System.Threading.Tasks;
using Tsi1.BusinessLayer.Dtos;
using Tsi1.BusinessLayer.Helpers;
using Tsi1.BusinessLayer.Interfaces;
using Tsi1.DataLayer.Entities;

namespace Tsi1.BusinessLayer.Services
{
    public class EmailService : IEmailService
    {
        private readonly MailSettings _mailSettings;

        public EmailService(IOptions<MailSettings> mailSettings)
        {
            _mailSettings = mailSettings.Value;
        }

        public async Task<ServiceResult<bool>> SendEmailAsync(MimeMessage message)
        {
            ServiceResult<bool> result = new ServiceResult<bool>();

            message.Sender = MailboxAddress.Parse(_mailSettings.Mail);

            var client = new SmtpClient();
            client.CheckCertificateRevocation = false;

            try
            {
                await client.ConnectAsync(_mailSettings.Host, _mailSettings.Port, SecureSocketOptions.StartTls);
            }
            catch (Exception e)
            {
                result.HasError = true;
                result.Message = ErrorMessages.CannotConnectToSmtpServer;
                return result;
            }

            try
            {
                await client.AuthenticateAsync(_mailSettings.Mail, _mailSettings.Password);
            }
            catch (Exception)
            {
                result.HasError = true;
                result.Message = ErrorMessages.CannotAuthenticateToSmtpServer;
                return result;
            }

            try
            {
                await client.SendAsync(message);
            }
            catch (Exception)
            {
                result.HasError = true;
                result.Message = string.Format(ErrorMessages.CannotSendEmail, message.Subject);
                return result;
            }

            await client.DisconnectAsync(true);

            return result;
        }

        public async Task<ServiceResult<bool>> NotifyNewPostOrMessage(PostCreateDto postCreateDto,  List<string> mails)
        {
            var message = new MimeMessage();

            foreach (var mail in mails)
            {
                message.To.Add(MailboxAddress.Parse(mail));
            }

            message.Subject = $"Nuevo Post: {postCreateDto.Title}";
            message.Body = new TextPart("html")
            {
                Text = $"<p> Hay un nuevo post perteneciente al foro suscripto."
            };

            var result = await SendEmailAsync(message);

            return result;
        }

    }
}