package telegraf

// LogLevel denotes the level for logging
type LogLevel int

func (e LogLevel) String() string {
	switch e {
	case Error:
		return "ERROR"
	case Warn:
		return "WARN"
	case Info:
		return "INFO"
	case Debug:
		return "DEBUG"
	}
	return "NONE"
}

const (
	// None means nothing is logged
	None LogLevel = iota
	// Error will log error messages
	Error
	// Warn will log error messages and warnings
	Warn
	// Info will log error messages, warnings and information messages
	Info
	// Debug will log all of the above and debugging messages issued by plugins
	Debug
)

// Logger defines an plugin-related interface for logging.
type Logger interface {
	// Level returns the configured log-level of the logger
	Level() LogLevel

	// RegisterErrorCallback registers a callback triggered when logging errors
	RegisterErrorCallback(func())

	// Errorf logs an error message, patterned after log.Printf.
	Errorf(format string, args ...interface{})
	// Error logs an error message, patterned after log.Print.
	Error(args ...interface{})
	// Debugf logs a debug message, patterned after log.Printf.
	Debugf(format string, args ...interface{})
	// Debug logs a debug message, patterned after log.Print.
	Debug(args ...interface{})
	// Warnf logs a warning message, patterned after log.Printf.
	Warnf(format string, args ...interface{})
	// Warn logs a warning message, patterned after log.Print.
	Warn(args ...interface{})
	// Infof logs an information message, patterned after log.Printf.
	Infof(format string, args ...interface{})
	// Info logs an information message, patterned after log.Print.
	Info(args ...interface{})
}