package logger

import (
	"log/slog"
	"os"
	"strings"
	"time"
)

// New builds a slog.Logger based on level and format configuration.
func New(level, format string) *slog.Logger {
	slogLevel := parseLevel(level)

	var handler slog.Handler
	opts := &slog.HandlerOptions{
		Level:     slogLevel,
		AddSource: true,
		ReplaceAttr: func(groups []string, a slog.Attr) slog.Attr {
			if a.Key == slog.TimeKey {
				a.Value = slog.StringValue(time.Now().UTC().Format(time.RFC3339Nano))
			}
			return a
		},
	}

	switch strings.ToLower(format) {
	case "json":
		handler = slog.NewJSONHandler(os.Stdout, opts)
	default:
		handler = slog.NewTextHandler(os.Stdout, opts)
	}

	return slog.New(handler)
}

func parseLevel(level string) slog.Level {
	switch strings.ToLower(level) {
	case "debug":
		return slog.LevelDebug
	case "warn", "warning":
		return slog.LevelWarn
	case "error":
		return slog.LevelError
	case "info", "":
		return slog.LevelInfo
	default:
		return slog.LevelInfo
	}
}