queue

type Msg struct {
	ID int64

	// A message for multiple recipients will get a BaseID that is identical to the
	// first Msg.ID queued. The message contents will be identical for each recipient,
	// including MsgPrefix. If other properties are identical too, including recipient
	// domain, multiple Msgs may be delivered in a single SMTP transaction. For
	// messages with a single recipient, this field will be 0.
	BaseID int64 `bstore:"index"`

	Queued             time.Time      `bstore:"default now"`
	SenderAccount      string         // Failures are delivered back to this local account. Also used for routing.
	SenderLocalpart    smtp.Localpart // Should be a local user and domain.
	SenderDomain       dns.IPDomain
	RecipientLocalpart smtp.Localpart // Typically a remote user and domain.
	RecipientDomain    dns.IPDomain
	RecipientDomainStr string              // For filtering.
	Attempts           int                 // Next attempt is based on last attempt and exponential back off based on attempts.
	MaxAttempts        int                 // Max number of attempts before giving up. If 0, then the default of 8 attempts is used instead.
	DialedIPs          map[string][]net.IP // For each host, the IPs that were dialed. Used for IP selection for later attempts.
	NextAttempt        time.Time           // For scheduling.
	LastAttempt        *time.Time
	LastError          string

	Has8bit       bool   // Whether message contains bytes with high bit set, determines whether 8BITMIME SMTP extension is needed.
	SMTPUTF8      bool   // Whether message requires use of SMTPUTF8.
	IsDMARCReport bool   // Delivery failures for DMARC reports are handled differently.
	IsTLSReport   bool   // Delivery failures for TLS reports are handled differently.
	Size          int64  // Full size of message, combined MsgPrefix with contents of message file.
	MessageID     string // Used when composing a DSN, in its References header.
	MsgPrefix     []byte

	// If set, this message is a DSN and this is a version using utf-8, for the case
	// the remote MTA supports smtputf8. In this case, Size and MsgPrefix are not
	// relevant.
	DSNUTF8 []byte

	// If non-empty, the transport to use for this message. Can be set through cli or
	// admin interface. If empty (the default for a submitted message), regular routing
	// rules apply.
	Transport string

	// RequireTLS influences TLS verification during delivery.
	//
	// If nil, the recipient domain policy is followed (MTA-STS and/or DANE), falling
	// back to optional opportunistic non-verified STARTTLS.
	//
	// If RequireTLS is true (through SMTP REQUIRETLS extension or webmail submit),
	// MTA-STS or DANE is required, as well as REQUIRETLS support by the next hop
	// server.
	//
	// If RequireTLS is false (through messag header "TLS-Required: No"), the recipient
	// domain's policy is ignored if it does not lead to a successful TLS connection,
	// i.e. falling back to SMTP delivery with unverified STARTTLS or plain text.
	RequireTLS *bool

	// For DSNs, where the original FUTURERELEASE value must be included as per-message
	// field. This field should be of the form "for;" plus interval, or "until;" plus
	// utc date-time.
	FutureReleaseRequest string
}

type ReadReaderAtCloser interface {
	io.ReadCloser
	io.ReaderAt
}