BotSharp/src/Plugins/BotSharp.Plugin.EmailHandler/Functions/HandleEmailRequestFn.cs

using BotSharp.Abstraction.Email.Settings;
using BotSharp.Plugin.EmailHandler.LlmContexts;
using MailKit;
using MailKit.Net.Smtp;
using MailKit.Security;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;
using MimeKit;
using System.Net.Http;

namespace BotSharp.Plugin.EmailHandler.Functions;

public class HandleEmailRequestFn : IFunctionCallback
{
    public string Name => "handle_email_request";
    public string Indication => "Handling email request";

    private readonly IServiceProvider _services;
    private readonly ILogger<HandleEmailRequestFn> _logger;
    private readonly IHttpClientFactory _httpClientFactory;
    private readonly IHttpContextAccessor _context;
    private readonly BotSharpOptions _options;
    private readonly EmailHandlerSettings _emailSettings;

    public HandleEmailRequestFn(IServiceProvider services,
                ILogger<HandleEmailRequestFn> logger,
                IHttpClientFactory httpClientFactory,
                IHttpContextAccessor context,
                BotSharpOptions options,
                EmailHandlerSettings emailPluginSettings)
    {
        _services = services;
        _logger = logger;
        _httpClientFactory = httpClientFactory;
        _context = context;
        _options = options;
        _emailSettings = emailPluginSettings;
    }
    public async Task<bool> Execute(RoleDialogModel message)
    {
        var args = JsonSerializer.Deserialize<LlmContextIn>(message.FunctionArgs, _options.JsonSerializerOptions);
        var recipient = args?.ToAddress;
        var body = args?.Content;
        var subject = args?.Subject;

        try
        {
            var mailMessage = new MimeMessage();
            mailMessage.From.Add(new MailboxAddress(_emailSettings.Name, _emailSettings.EmailAddress));
            mailMessage.To.Add(new MailboxAddress("", recipient));
            mailMessage.Subject = subject;
            mailMessage.Body = new TextPart("plain")
            {
                Text = body
            };
            var response = await HandleSendEmailBySMTP(mailMessage);
            _logger.LogWarning($"Email successfully send over to {recipient}. Email Subject: {subject} [{response}]");
            message.Content = response;
            return true;
        }
        catch (Exception ex)
        {
            var msg = $"Failed to send the email. {ex.Message}";
            _logger.LogError($"{msg}\n(Error: {ex.Message})");
            message.Content = msg;
            return false;
        }
    }

    public async Task<string> HandleSendEmailBySMTP(MimeMessage mailMessage)
    {
        using var smtpClient = new SmtpClient();
        await smtpClient.ConnectAsync(_emailSettings.SMTPServer, _emailSettings.SMTPPort, SecureSocketOptions.StartTls);
        await smtpClient.AuthenticateAsync(_emailSettings.EmailAddress, _emailSettings.Password);
        var response = await smtpClient.SendAsync(mailMessage);
        return response;
    }
}