package logging

import (
	"fmt"
	"log"
	"log/syslog"

	"r00t2.io/goutils/multierr"
)

// Setup sets up/configures a SyslogLogger and prepares it for use.
func (l *SyslogLogger) Setup() (err error) {

	var errs *multierr.MultiError = multierr.NewMultiError(nil)

	if l.alert, err = syslog.New(syslog.LOG_ALERT|syslogFacility, l.Prefix); err != nil {
		errs.AddError(err)
		err = nil
	}
	if l.crit, err = syslog.New(syslog.LOG_CRIT|syslogFacility, l.Prefix); err != nil {
		errs.AddError(err)
		err = nil
	}
	if l.debug, err = syslog.New(syslog.LOG_DEBUG|syslogFacility, l.Prefix); err != nil {
		errs.AddError(err)
		err = nil
	}
	if l.emerg, err = syslog.New(syslog.LOG_EMERG|syslogFacility, l.Prefix); err != nil {
		errs.AddError(err)
		err = nil
	}
	if l.err, err = syslog.New(syslog.LOG_ERR|syslogFacility, l.Prefix); err != nil {
		errs.AddError(err)
		err = nil
	}
	if l.info, err = syslog.New(syslog.LOG_INFO|syslogFacility, l.Prefix); err != nil {
		errs.AddError(err)
		err = nil
	}
	if l.notice, err = syslog.New(syslog.LOG_NOTICE|syslogFacility, l.Prefix); err != nil {
		errs.AddError(err)
		err = nil
	}
	if l.warning, err = syslog.New(syslog.LOG_WARNING|syslogFacility, l.Prefix); err != nil {
		errs.AddError(err)
		err = nil
	}

	if errs.Count() > 0 {
		err = errs
	}

	return
}

// Shutdown cleanly shuts down a SyslogLogger.
func (l *SyslogLogger) Shutdown() (err error) {

	var errs *multierr.MultiError = multierr.NewMultiError(nil)

	for _, i := range []*syslog.Writer{l.alert, l.crit, l.debug, l.emerg, l.err, l.info, l.notice, l.warning} {
		if err = i.Close(); err != nil {
			errs.AddError(err)
			err = nil
		}
	}

	if errs.Count() > 0 {
		err = errs
	}

	return
}

/*
GetPrefix returns the prefix used by this SyslogLogger.
err will always be nil; it's there for interface-compat.
*/
func (l *SyslogLogger) GetPrefix() (prefix string, err error) {

	prefix = l.Prefix

	return
}

/*
DoDebug sets the debug state of this SyslogLogger.
Note that this merely acts as a *safety filter* for debug messages to avoid sensitive information being written to the log.
err will always be nil; it's there for interface-compat.
*/
func (l *SyslogLogger) DoDebug(d bool) (err error) {

	l.EnableDebug = d

	return
}

// GetDebug returns the debug status of this SyslogLogger.
func (l *SyslogLogger) GetDebug() (d bool) {

	d = l.EnableDebug

	return
}

// SetPrefix sets the prefix for this SyslogLogger.
func (l *SyslogLogger) SetPrefix(prefix string) (err error) {

	l.Prefix = prefix

	// We need to close the current loggers first.
	if err = l.Shutdown(); err != nil {
		return
	}

	if err = l.Setup(); err != nil {
		return
	}

	return
}

// Alert writes an ALERT-level message to this SyslogLogger.
func (l *SyslogLogger) Alert(s string, v ...interface{}) (err error) {

	var msg string

	if v != nil {
		msg = fmt.Sprintf(s, v...)
	} else {
		msg = s
	}

	if _, err = l.alert.Write([]byte(msg)); err != nil {
		log.Panicf("could not write %v to syslog USER:ALERT facility/level", msg)
	}

	return
}

// Crit writes an CRITICAL-level message to this SyslogLogger.
func (l *SyslogLogger) Crit(s string, v ...interface{}) (err error) {

	var msg string

	if v != nil {
		msg = fmt.Sprintf(s, v...)
	} else {
		msg = s
	}

	if _, err = l.crit.Write([]byte(msg)); err != nil {
		log.Panicf("could not write %v to syslog USER:CRIT facility/level", msg)
	}

	return
}

// Debug writes a DEBUG-level message to this SyslogLogger.
func (l *SyslogLogger) Debug(s string, v ...interface{}) (err error) {

	if !l.EnableDebug {
		return
	}

	var msg string

	if v != nil {
		msg = fmt.Sprintf(s, v...)
	} else {
		msg = s
	}

	if _, err = l.debug.Write([]byte(msg)); err != nil {
		log.Panicf("could not write %v to syslog USER:DEBUG facility/level", msg)
	}

	return
}

// Emerg writes an EMERGENCY-level message to this SyslogLogger.
func (l *SyslogLogger) Emerg(s string, v ...interface{}) (err error) {

	var msg string

	if v != nil {
		msg = fmt.Sprintf(s, v...)
	} else {
		msg = s
	}

	if _, err = l.emerg.Write([]byte(msg)); err != nil {
		log.Panicf("could not write %v to syslog USER:EMERG facility/level", msg)
	}

	return
}

// Err writes an ERROR-level message to this SyslogLogger.
func (l *SyslogLogger) Err(s string, v ...interface{}) (err error) {

	var msg string

	if v != nil {
		msg = fmt.Sprintf(s, v...)
	} else {
		msg = s
	}

	if _, err = l.err.Write([]byte(msg)); err != nil {
		log.Panicf("could not write %v to syslog USER:ERR facility/level", msg)
	}

	return
}

// Info writes an INFO-level message to this SyslogLogger.
func (l *SyslogLogger) Info(s string, v ...interface{}) (err error) {

	var msg string

	if v != nil {
		msg = fmt.Sprintf(s, v...)
	} else {
		msg = s
	}

	if _, err = l.info.Write([]byte(msg)); err != nil {
		log.Panicf("could not write %v to syslog USER:INFO facility/level", msg)
	}

	return
}

// Notice writes a NOTICE-level message to this SyslogLogger.
func (l *SyslogLogger) Notice(s string, v ...interface{}) (err error) {

	var msg string

	if v != nil {
		msg = fmt.Sprintf(s, v...)
	} else {
		msg = s
	}

	if _, err = l.notice.Write([]byte(msg)); err != nil {
		log.Panicf("could not write %v to syslog USER:NOTICE facility/level", msg)
	}

	return
}

// Warning writes a WARNING/WARN-level message to this SyslogLogger.
func (l *SyslogLogger) Warning(s string, v ...interface{}) (err error) {
	var msg string

	if v != nil {
		msg = fmt.Sprintf(s, v...)
	} else {
		msg = s
	}

	if _, err = l.warning.Write([]byte(msg)); err != nil {
		log.Panicf("could not write %v to syslog USER:WARNING facility/level", msg)
	}

	return
}

// ToLogger returns a stdlib log.Logger.
func (l *SyslogLogger) ToLogger(prio logPrio) (stdLibLog *log.Logger) {

	stdLibLog = log.New(&logWriter{backend: l, prio: prio}, "", 0)

	return
}