namespace GerbilManagerWebAPI.Inbox
{
    /// <summary>A reply to send, with RFC threading headers already computed.</summary>
    public sealed record OutgoingMail(
        string To,
        string Subject,
        string Body,
        string? InReplyTo,
        string? References);

    /// <summary>Outcome of a send attempt. Error is null on success; otherwise a stable code
    /// ("MailNotConfigured", "MailAuthFailed") the UI maps to a German hint.</summary>
    public sealed record SendOutcome(bool Sent, string? Error)
    {
        public static readonly SendOutcome Ok = new(true, null);
        public static SendOutcome Fail(string code) => new(false, code);
    }

    /// <summary>Sends mail. Abstracted so tests can assert the message/capture it without a live
    /// SMTP server (the live MailKit/Gmail path is gated on Julian's App Password).</summary>
    public interface IGmailMailSender
    {
        /// <summary>Sends the reply. Throws <see cref="MailKit.Security.AuthenticationException"/>
        /// on bad/revoked credentials (surfaced as "MailAuthFailed").</summary>
        Task SendAsync(MailConnection connection, OutgoingMail mail, CancellationToken ct = default);
    }
}