using LiteCharms.Features.Email.Commands;
using LiteCharms.Models.Configuraton.Email;

namespace LiteCharms.Features.Email.Commands.Handlers;

public class SendEmailCommandHandler(IOptions<SmtpSettings> smtpOptions) : IRequestHandler<SendEmailCommand, Result>
{
    public async ValueTask<Result> Handle(SendEmailCommand request, CancellationToken cancellationToken)
    {
        try
        {
            var settings = smtpOptions.Value;

            if(settings == null)
                return Result.Fail(new Error("SMTP settings are not configured."));

            if(settings.Credentials == null)
                return Result.Fail(new Error("SMTP credentials are not configured."));

            if(string.IsNullOrWhiteSpace(settings?.Credentials.Username) || string.IsNullOrWhiteSpace(settings.Credentials.Password))
                return Result.Fail(new Error("SMTP credentials are incomplete."));

            if(string.IsNullOrWhiteSpace(settings.Host) || settings.Port == 0)
                return Result.Fail(new Error("SMTP host and port must be configured."));

            var message = new MimeMessage();
            message.From.Add(new MailboxAddress(request.SenderName, request.From!));
            message.To.Add(new MailboxAddress(request.RecipientName, request.To!));
            message.Subject = request.Subject!;

            var bodyBuilder = new BodyBuilder();

            if(request.Attachment?.Length > 0 && !string.IsNullOrEmpty(request.AttachmentFileName))
                bodyBuilder.Attachments.Add(request.AttachmentFileName!, request.Attachment!, cancellationToken);

            if (!request.IsHtml) bodyBuilder.TextBody = request.Message;
            if (request.IsHtml) bodyBuilder.HtmlBody = request.Message;

            message.Body = bodyBuilder.ToMessageBody();

            using var client = new SmtpClient();

            await client.ConnectAsync(settings.Host!, settings.Port, settings.UseSsl, cancellationToken);
            await client.AuthenticateAsync(settings.Credentials!.Username!, settings.Credentials.Password!, cancellationToken);

            var response = await client.SendAsync(message, cancellationToken);

            bool emailSent = response.Contains("OK", StringComparison.InvariantCultureIgnoreCase);

            await client.DisconnectAsync(true, cancellationToken);

            return emailSent
                ? Result.Ok()
                : Result.Fail(new Error("Failed to send email. SMTP response: " + response));
        }
        catch (Exception ex)
        {
            return Result.Fail(new Error(ex.Message).CausedBy(ex));
        }
    }
}