package formatter

import (
	"errors"

	syslog "gopkg.in/mcuadros/go-syslog.v2"
	"gopkg.in/mcuadros/go-syslog.v2/format"
)

// SyslogRFC is the formatter that the server should use
type SyslogRFC struct{ format.Format }

func (rfc *SyslogRFC) Set(v string) error {
	newval, err := parseRFCValue(v)
	if err != nil {
		return err
	}
	rfc.Format = newval
	return nil
}

func (rfc *SyslogRFC) String() string {
	switch {
	case rfc.Format == syslog.Automatic:
		return "auto"
	case rfc.Format == syslog.RFC3164:
		return "rfc3164"
	case rfc.Format == syslog.RFC5424:
		return "rfc5424"
	}
	return ""
}

func parseRFCValue(v string) (format.Format, error) {
	switch {
	case v == "rfc3164":
		return syslog.RFC3164, nil
	case v == "rfc5424":
		return syslog.RFC5424, nil
	case v == "auto":
		return syslog.Automatic, nil
	default:
		return nil, ErrRFCNotSupported
	}
}

// ErrRFCNotSupported is raised if the supplied rfc string is
// not recognized.
var ErrRFCNotSupported = errors.New("RFC not known")