// Package log is a global internal logger
package log

import (
	"fmt"
	"os"
	"time"

	"github.com/micro/go-micro/debug/log"
)

// level is a log level
type Level int

const (
	LevelFatal Level = iota
	LevelError
	LevelInfo
	LevelWarn
	LevelDebug
	LevelTrace
)

var (
	// the local logger
	logger log.Log = log.DefaultLog

	// default log level is info
	level = LevelInfo

	// prefix for all messages
	prefix string
)

func init() {
	switch os.Getenv("MICRO_LOG_LEVEL") {
	case "trace":
		level = LevelTrace
	case "debug":
		level = LevelDebug
	case "warn":
		level = LevelWarn
	case "info":
		level = LevelInfo
	case "error":
		level = LevelError
	case "fatal":
		level = LevelFatal
	}
}

func (l Level) String() string {
	switch l {
	case LevelTrace:
		return "trace"
	case LevelDebug:
		return "debug"
	case LevelWarn:
		return "warn"
	case LevelInfo:
		return "info"
	case LevelError:
		return "error"
	case LevelFatal:
		return "fatal"
	default:
		return "unknown"
	}
}

// Log makes use of github.com/micro/debug/log
func Log(v ...interface{}) {
	if len(prefix) > 0 {
		v = append([]interface{}{prefix, " "}, v...)
	}
	logger.Write(log.Record{
		Timestamp: time.Now(),
		Message:   fmt.Sprint(v...),
		Metadata: map[string]string{
			"level": level.String(),
		},
	})
}

// Logf makes use of github.com/micro/debug/log
func Logf(format string, v ...interface{}) {
	if len(prefix) > 0 {
		format = prefix + " " + format
	}
	logger.Write(log.Record{
		Timestamp: time.Now(),
		Message:   fmt.Sprintf(format, v...),
		Metadata: map[string]string{
			"level": level.String(),
		},
	})
}

// WithLevel logs with the level specified
func WithLevel(l Level, v ...interface{}) {
	if l > level {
		return
	}
	Log(v...)
}

// WithLevel logs with the level specified
func WithLevelf(l Level, format string, v ...interface{}) {
	if l > level {
		return
	}
	Logf(format, v...)
}

// Trace provides trace level logging
func Trace(v ...interface{}) {
	WithLevel(LevelTrace, v...)
}

// Tracef provides trace level logging
func Tracef(format string, v ...interface{}) {
	WithLevelf(LevelTrace, format, v...)
}

// Debug provides debug level logging
func Debug(v ...interface{}) {
	WithLevel(LevelDebug, v...)
}

// Debugf provides debug level logging
func Debugf(format string, v ...interface{}) {
	WithLevelf(LevelDebug, format, v...)
}

// Warn provides warn level logging
func Warn(v ...interface{}) {
	WithLevel(LevelWarn, v...)
}

// Warnf provides warn level logging
func Warnf(format string, v ...interface{}) {
	WithLevelf(LevelWarn, format, v...)
}

// Info provides info level logging
func Info(v ...interface{}) {
	WithLevel(LevelInfo, v...)
}

// Infof provides info level logging
func Infof(format string, v ...interface{}) {
	WithLevelf(LevelInfo, format, v...)
}

// Error provides warn level logging
func Error(v ...interface{}) {
	WithLevel(LevelError, v...)
}

// Errorf provides warn level logging
func Errorf(format string, v ...interface{}) {
	WithLevelf(LevelError, format, v...)
}

// Fatal logs with Log and then exits with os.Exit(1)
func Fatal(v ...interface{}) {
	WithLevel(LevelFatal, v...)
	os.Exit(1)
}

// Fatalf logs with Logf and then exits with os.Exit(1)
func Fatalf(format string, v ...interface{}) {
	WithLevelf(LevelFatal, format, v...)
	os.Exit(1)
}

// SetLogger sets the local logger
func SetLogger(l log.Log) {
	logger = l
}

// GetLogger returns the local logger
func GetLogger() log.Log {
	return logger
}

// SetLevel sets the log level
func SetLevel(l Level) {
	level = l
}

// GetLevel returns the current level
func GetLevel() Level {
	return level
}

// Set a prefix for the logger
func SetPrefix(p string) {
	prefix = p
}

// Set service name
func Name(name string) {
	prefix = fmt.Sprintf("[%s]", name)
}