package zapr // TODO: put this into logr

import (
	"github.com/go-logr/logr"
	"golang.org/x/exp/slog"
)

type SlogImplementor interface {
	GetSlogHandler() slog.Handler
}

type LogrImplementor interface {
	GetLogrLogSink() logr.LogSink
}

// logr.ToSlog
func ToSlog(logger logr.Logger) *slog.Logger {
	if slogImplementor, ok := logger.GetSink().(SlogImplementor); ok {
		handler := slogImplementor.GetSlogHandler()
		return slog.New(handler)
	}

	// TODO: implement Handler which can write to an arbitrary LogSink.
	//
	// Problem: LogSinks do their own stack unwinding and need to
	// know how many levels to skip to get across the slog.Logger
	// frontend into the user code. Probably doesn't have a good
	// solution.
	return nil
}

// logr.FromSlog
func FromSlog(logger *slog.Logger) logr.Logger {
	if logrImplementor, ok := logger.Handler().(LogrImplementor); ok {
		logSink := logrImplementor.GetLogrLogSink()
		return logr.New(logSink)
	}

	// TODO: implement LogSink which can write to an arbitrary Handler.
	//
	// TBD: the stored WithName prefix has to be added to the Record.Message
	// or added as a new Attr (but with which key?).
	return logr.Discard()
}