sip2

type Client struct {
	Address string // host:port of the SIP2 server (the ACS)

	// Login (93) is sent only when User is non-empty: CN=User, CO=Password, and
	// CP=Location when set. Both algorithm bytes are the plain "0".
	User     string
	Password string
	Location string // login location code (CP); optional

	// InstitutionID (AO) and TerminalPass (AC) ride on each Item Information
	// request; both optional, sent as empty fields when unset.
	InstitutionID string
	TerminalPass  string

	// ErrorDetection appends the AY sequence and AZ checksum to each outbound
	// message. Inbound AY/AZ are always tolerated and skipped regardless.
	ErrorDetection bool

	// Dial is the connection seam, overridable in tests. When nil a plain TCP
	// dialer bound to the request context is used.
	Dial func(ctx context.Context, addr string) (net.Conn, error)
}

type Conn struct {
	// contains filtered or unexported fields
}

type ItemInfo struct {
	CirculationStatus string // 2-digit code, 01-13 (see CirculationStatusLabel)
	StatusLabel       string // human meaning of CirculationStatus
	SecurityMarker    string // 2-digit security marker
	FeeType           string // 2-digit fee type
	TransactionDate   string // 18-char SIP2 date

	ItemID            string // AB
	Title             string // AJ
	DueDate           string // AH
	CurrentLocation   string // AP
	PermanentLocation string // AQ
	CallNumber        string // CS (3M extension)
	HoldQueueLength   string // CF

	Fields map[string]string // all variable fields by 2-char code
}