level.go

package log

import (
	"errors"
	"fmt"
	"log/slog"
	"strconv"
	"strings"
)

// Level represents the logging level.
// -4: Debug
// 0: Info
// 4: Warn
// 8: Error
// 12: Critical
type Level int

const (
	LevelDebug = Level(slog.LevelDebug)
	LevelInfo  = Level(slog.LevelInfo)
	LevelWarn  = Level(slog.LevelWarn)
	LevelError = Level(slog.LevelError)
	LevelCrit  = Level(slog.Level(12))
)

func LevelFromSlog(l slog.Level) Level {
	switch l {
	case slog.LevelDebug:
		return LevelDebug
	case slog.LevelInfo:
		return LevelInfo
	case slog.LevelWarn:
		return LevelWarn
	case slog.LevelError:
		return LevelError
	default:
		return Level(l)
	}
}

func (l Level) String() string {
	switch l {
	case LevelDebug:
		return "DEBUG"
	case LevelInfo:
		return "INFO"
	case LevelWarn:
		return "WARN"
	case LevelError:
		return "ERROR"
	case LevelCrit:
		return "CRIT"
	default:
		if l < LevelInfo {
			return "DEBUG+" + strconv.Itoa(int(l-LevelDebug))
		}
		if l < LevelWarn {
			return "INFO+" + strconv.Itoa(int(l-LevelInfo))
		}
		if l < LevelError {
			return "WARN+" + strconv.Itoa(int(l-LevelWarn))
		}
		return "ERROR+" + strconv.Itoa(int(l-LevelError))
	}
}

func (l Level) TerminalString() string {
	switch l {
	case LevelDebug:
		return "DEBUG "
	case LevelInfo:
		return "INFO  "
	case LevelWarn:
		return "WARN  "
	case LevelError:
		return "ERROR "
	case LevelCrit:
		return "CRIT  "
	default:
		return "LOG   "
	}
}

func (l Level) MarshalJSON() ([]byte, error) {
	return strconv.AppendQuote(nil, l.String()), nil
}

func (l *Level) UnmarshalJSON(data []byte) error {
	s, err := strconv.Unquote(string(data))
	if err != nil {
		return err
	}
	return l.parse(s)
}

func (l Level) MarshalText() ([]byte, error) {
	return []byte(l.String()), nil
}

func (l *Level) UnmarshalText(data []byte) error {
	return l.parse(string(data))
}

func (l *Level) parse(s string) (err error) {
	defer func() {
		if err != nil {
			err = fmt.Errorf("slog: level string %q: %w", s, err)
		}
	}()

	name := s
	if i := strings.IndexAny(s, "+-"); i >= 0 {
		name = s[:i]
	}
	switch strings.ToUpper(strings.TrimSpace(name)) {
	case "DEBUG":
		*l = LevelDebug
	case "INFO":
		*l = LevelInfo
	case "WARN":
		*l = LevelWarn
	case "ERROR":
		*l = LevelError
	case "CRIT", "CRITICAL":
		*l = LevelCrit
	default:
		return errors.New("unknown name")
	}
	return nil
}

func (l Level) Level() slog.Level { return slog.Level(l) }