package logrus

import (
	"fmt"
	"log"
)

// Fields type, used to pass to `WithFields`.
type Fields map[string]interface{}

// Level type
type Level uint8

// Convert the Level to a string. E.g. PanicLevel becomes "panic".
func (level Level) String() string {
	switch level {
	case DebugLevel:
		return "debug"
	case InfoLevel:
		return "info"
	case WarnLevel:
		return "warning"
	case ErrorLevel:
		return "error"
	case FatalLevel:
		return "fatal"
	case PanicLevel:
		return "panic"
	}

	return "unknown"
}

// UnmarshalText decodes text to the level.
func (level *Level) UnmarshalText(text []byte) error {
	if len(text) == 0 {
		return nil
	}
	parsed, err := ParseLevel(string(text))
	if err != nil {
		return err
	}
	*level = parsed
	return nil
}

// MarshalText encodes the level into UTF-8-encoded text and returns the result.
func (level Level) MarshalText() (text []byte, err error) {
	return []byte(level.String()), nil
}

// ParseLevel takes a string level and returns the Logrus log level constant.
func ParseLevel(lvl string) (Level, error) {
	switch lvl {
	case "panic":
		return PanicLevel, nil
	case "fatal":
		return FatalLevel, nil
	case "error":
		return ErrorLevel, nil
	case "warn", "warning":
		return WarnLevel, nil
	case "info":
		return InfoLevel, nil
	case "debug":
		return DebugLevel, nil
	}

	var l Level
	return l, fmt.Errorf("not a valid logrus Level: %q", lvl)
}

// These are the different logging levels. You can set the logging level to log
// on your instance of logger, obtained with `logrus.New()`.
const (
	// PanicLevel level, highest level of severity. Logs and then calls panic with the
	// message passed to Debug, Info, ...
	PanicLevel Level = iota
	// FatalLevel level. Logs and then calls `os.Exit(1)`. It will exit even if the
	// logging level is set to Panic.
	FatalLevel
	// ErrorLevel level. Logs. Used for errors that should definitely be noted.
	// Commonly used for hooks to send errors to an error tracking service.
	ErrorLevel
	// WarnLevel level. Non-critical entries that deserve eyes.
	WarnLevel
	// InfoLevel level. General operational entries about what's going on inside the
	// application.
	InfoLevel
	// DebugLevel level. Usually only enabled when debugging. Very verbose logging.
	DebugLevel
)

// Won't compile if StdLogger can't be realized by a log.Logger
var (
	_ StdLogger = &log.Logger{}
	_ StdLogger = &Entry{}
	_ StdLogger = &Logger{}
)

// StdLogger is what your logrus-enabled library should take, that way
// it'll accept a stdlib logger and a logrus logger. There's no standard
// interface, this is the closest we get, unfortunately.
type StdLogger interface {
	Print(...interface{})
	Printf(string, ...interface{})
	Println(...interface{})

	Fatal(...interface{})
	Fatalf(string, ...interface{})
	Fatalln(...interface{})

	Panic(...interface{})
	Panicf(string, ...interface{})
	Panicln(...interface{})
}