package formatter

import (
	"errors"
	"log"

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

type SyslogRFC string

// SetSyslogFormat does the job of setting the server parser to the provided RFC log format.
func SetSyslogFormat(server *syslog.Server, format SyslogRFC) {
	switch {
	case format == Auto:
		server.SetFormat(syslog.Automatic)
	case format == RFC3164:
		server.SetFormat(syslog.RFC3164)
	case format == RFC5424:
		server.SetFormat(syslog.RFC5424)
	}
	log.Printf("Syslog format set to: %s\n", format)
}

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

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

func parseRFCValue(v string) (SyslogRFC, error) {
	switch {
	case v == "rfc3164":
		return RFC3164, nil
	case v == "rfc5424":
		return RFC5424, nil
	case v == "auto":
		return Auto, nil
	default:
		return "", ErrRFCNotSupported
	}
}

const (
	RFC3164 = "rfc3164"
	RFC5424 = "rfc5424"
	Auto    = "auto"
)

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