package logging

import (
	`errors`
	`fmt`

	`golang.org/x/sys/windows/svc/eventlog`
)

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

	var err error

	/*
		First a sanity check on the EventIDs.
		Since we use eventcreate, all Event IDs must be 1 <= eid <= 1000.
	*/
	for _, eid := range []uint32{
		l.eids.Alert,
		l.eids.Crit,
		l.eids.Debug,
		l.eids.Emerg,
		l.eids.Err,
		l.eids.Info,
		l.eids.Notice,
		l.eids.Warning,
	} {
		if !((eid <= 1000) && (1 <= eid)) {
			err = errors.New("event IDs must be between 1 and 1000 inclusive")
			panic(err)
		}
	}

	if err = eventlog.InstallAsEventCreate(l.Prefix, eventlog.Error|eventlog.Warning|eventlog.Info); err != nil {
		if idx := ptrnSourceExists.FindStringIndex(err.Error()); idx == nil {
			// It's an error we want to panic on.
			panic(err)
		} else {
			// It already exists, so ignore the error.
			err = nil
		}
	}

	if l.elog, err = eventlog.Open(l.Prefix); err != nil {
		panic(err)
	}

}

// Shutdown cleanly shuts down a WinLogger.
func (l *WinLogger) Shutdown() {

	var err error

	if err = l.elog.Close(); err != nil {
		panic(err)
	}

	if err = eventlog.Remove(l.Prefix); err != nil {
		panic(err)
	}

}

// GetPrefix returns the prefix used by this WinLogger.
func (l *WinLogger) GetPrefix() (prefix string) {

	prefix = l.Prefix

	return
}

/*
	DoDebug sets the debug state of this WinLogger.
	Note that this merely acts as a *safety filter* for debug messages to avoid sensitive information being written to the log.
*/
func (l *WinLogger) DoDebug(d bool) {

	l.EnableDebug = d

}

// SetPrefix sets the prefix for this WinLogger.
func (l *WinLogger) SetPrefix(prefix string) {

	var err error

	l.Prefix = prefix

	// To properly change the prefix, we need to tear down the old event log and create a new one.
	if err = l.elog.Close(); err != nil {
		panic(err)
	}

	if err = eventlog.Remove(l.Prefix); err != nil {
		panic(err)
	}

	if err = eventlog.InstallAsEventCreate(l.Prefix, eventlog.Error|eventlog.Warning|eventlog.Info); err != nil {
		if idx := ptrnSourceExists.FindStringIndex(err.Error()); idx == nil {
			// It's an error we want to panic on.
			panic(err)
		} else {
			// It already exists, so ignore the error.
			err = nil
		}
	}

	if l.elog, err = eventlog.Open(l.Prefix); err != nil {
		panic(err)
	}

}

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

	var msg string

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

	// Treat ALERT as Warning
	err = l.elog.Warning(l.eids.Alert, msg)

	return
}

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

	var msg string

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

	// Treat CRIT as Error
	err = l.elog.Error(l.eids.Crit, msg)

	return
}

// Debug writes a DEBUG-level message to this WinLogger.
func (l *WinLogger) 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
	}

	// Treat DEBUG as Info
	err = l.elog.Info(l.eids.Debug, msg)

	return

}

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

	var msg string

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

	// Treat EMERG as Error
	err = l.elog.Error(l.eids.Emerg, msg)

	return

}

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

	var msg string

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

	err = l.elog.Error(l.eids.Err, msg)

	return

}

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

	var msg string

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

	err = l.elog.Info(l.eids.Info, msg)

	return

}

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

	var msg string

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

	// Treat NOTICE as Info
	err = l.elog.Info(l.eids.Notice, msg)

	return

}

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

	var msg string

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

	err = l.elog.Warning(l.eids.Warning, msg)

	return

}