package log

import (
	"os"
	"strings"
)

// Level of log
type Level uint8

const (
	// DebugLevel defines debug log level.
	DebugLevel Level = iota + 1
	// InfoLevel defines info log level.
	InfoLevel
	// WarnLevel defines warn log level.
	WarnLevel
	// ErrorLevel defines error log level.
	ErrorLevel
	// NoLevel defines an absent log level.
	NoLevel Level = 254
	// Disabled disables the logger.
	Disabled Level = 255
)

// Logger is the interface for logger.
type Logger interface {
	// SetLevel sets the logger level
	SetLevel(Level)
	// SetEncoding sets the logger's encoding
	SetEncoding(encoding string)
	// Printf logs a message without level
	Printf(template string, args ...interface{})
	// Debugf logs a message at DebugLevel
	Debugf(template string, args ...interface{})
	// Infof logs a message at InfoLevel
	Infof(template string, args ...interface{})
	// Warnf logs a message at WarnLevel
	Warnf(template string, args ...interface{})
	// Errorf logs a message at ErrorLevel
	Errorf(template string, args ...interface{})
	// Output file path to write log message
	Output(file string)
	// ErrorOutput file path to write error message
	ErrorOutput(file string)
}

// String the logger level
func (l Level) String() string {
	switch l {
	case DebugLevel:
		return "DEBUG"
	case ErrorLevel:
		return "ERROR"
	case WarnLevel:
		return "WARN"
	case InfoLevel:
		return "INFO"
	default:
		return ""
	}
}

// 实例
var logger Logger

func init() {
	logger = Default(isEnableDebug())
}

// SetLogger allows developers to customize the logger instance.
func SetLogger(l Logger) {
	logger = l
}

// EnableDebug enables the development model for logging.
// Deprecated
func EnableDebug() {
	logger = Default(true)
}

// Printf prints a formatted message without a specified level.
func Printf(format string, v ...interface{}) {
	logger.Printf(format, v...)
}

// Debugf logs a message at DebugLevel.
func Debugf(template string, args ...interface{}) {
	logger.Debugf(template, args...)
}

// Infof logs a message at InfoLevel.
func Infof(template string, args ...interface{}) {
	logger.Infof(template, args...)
}

// Warnf logs a message at WarnLevel.
func Warnf(template string, args ...interface{}) {
	logger.Warnf(template, args...)
}

// Errorf logs a message at ErrorLevel.
func Errorf(template string, args ...interface{}) {
	logger.Errorf(template, args...)
}

// isEnableDebug indicates whether the debug is enabled.
func isEnableDebug() bool {
	return os.Getenv("HPDS_ENABLE_DEBUG") == "true"
}

// isJSONFormat indicates whether the log is in JSON format.
func isJSONFormat() bool {
	return os.Getenv("HPDS_LOG_FORMAT") == "json"
}

func logFormat() string {
	return os.Getenv("HPDS_LOG_FORMAT")
}

func logLevel() Level {
	envLevel := strings.ToLower(os.Getenv("HPDS_LOG_LEVEL"))
	level := ErrorLevel
	switch envLevel {
	case "debug":
		return DebugLevel
	case "info":
		return InfoLevel
	case "warn":
		return WarnLevel
	case "error":
		return ErrorLevel
	}
	return level
}

func output() string {
	return strings.ToLower(os.Getenv("HPDS_LOG_OUTPUT"))
}

func errorOutput() string {
	return strings.ToLower(os.Getenv("HPDS_LOG_ERROR_OUTPUT"))
}