dsn

type Action string

type Message struct {
	SMTPUTF8 bool // Whether the original was received with smtputf8.

	// DSN message From header. E.g. postmaster@ourdomain.example. NOTE:
	// DSNs should be sent with a null reverse path to prevent mail loops.
	// ../rfc/3464:421
	From smtp.Path

	// "To" header, and also SMTP RCP TO to deliver DSN to. Should be taken
	// from original SMTP transaction MAIL FROM.
	// ../rfc/3464:415
	To smtp.Path

	// Message subject header, e.g. describing mail delivery failure.
	Subject string

	MessageID string

	// References header, with Message-ID of original message this DSN is about. So
	// mail user-agents will thread the DSN with the original message.
	References string

	// For message submitted with FUTURERELEASE SMTP extension. Value is either "for;"
	// plus original interval in seconds or "until;" plus original UTC RFC3339
	// date-time.
	FutureReleaseRequest string

	// Human-readable text explaining the failure. Line endings should be
	// bare newlines, not \r\n. They are converted to \r\n when composing.
	TextBody string

	// Per-message fields.
	OriginalEnvelopeID string
	ReportingMTA       string // Required.
	DSNGateway         string
	ReceivedFromMTA    smtp.Ehlo // Host from which message was received.
	ArrivalDate        time.Time

	// All per-message fields, including extensions. Only used for parsing,
	// not composing.
	MessageHeader textproto.MIMEHeader

	// One or more per-recipient fields.
	// ../rfc/3464:436
	Recipients []Recipient

	// Original message or headers to include in DSN as third MIME part.
	// Optional. Only used for generating DSNs, not set for parsed DNSs.
	Original []byte
}

type NameIP struct {
	Name string
	IP   net.IP
}

type Recipient struct {
	// Required fields.
	FinalRecipient smtp.Path // Final recipient of message.
	Action         Action

	// Enhanced status code. First digit indicates permanent or temporary
	// error.
	Status string
	// For additional details, included in comment.
	StatusComment string

	// Optional fields.
	// Original intended recipient of message. Used with the DSN extensions ORCPT
	// parameter.
	// ../rfc/3464:1197
	OriginalRecipient smtp.Path

	// Remote host that returned an error code. Can also be empty for
	// deliveries.
	RemoteMTA NameIP

	// DiagnosticCodeSMTP are the full SMTP response lines, space separated. The marshaled
	// form starts with "smtp; ", this value does not.
	DiagnosticCodeSMTP string

	LastAttemptDate time.Time
	FinalLogID      string

	// For delayed deliveries, deliveries may be retried until this time.
	WillRetryUntil *time.Time

	// All fields, including extensions. Only used for parsing, not
	// composing.
	Header textproto.MIMEHeader
}