package main

import (
	"context"
	"fmt"
	"go.opentelemetry.io/otel"
	sdktrace "go.opentelemetry.io/otel/sdk/trace"
	"go.opentelemetry.io/otel/trace"
	"io"
	"log/slog"
	"os"
)

type Handler struct {
	slog.Handler
}

func NewHandler(w io.Writer, opts *slog.HandlerOptions) *Handler {
	return &Handler{Handler: slog.NewTextHandler(w, opts)}
}

func (h *Handler) Handle(ctx context.Context, r slog.Record) error {
	var attrs []slog.Attr
	spanCtx := trace.SpanContextFromContext(ctx)
	if spanCtx.HasTraceID() {
		attrs = append(attrs, slog.String("trace", spanCtx.TraceID().String()))
	}
	if spanCtx.HasSpanID() {
		attrs = append(attrs, slog.String("span", spanCtx.SpanID().String()))
	}
	if len(attrs) > 0 {
		r.AddAttrs(attrs...)
	}
	return h.Handler.Handle(ctx, r)
}

func init() {
	otel.SetTracerProvider(sdktrace.NewTracerProvider())
}

func main() {
	tracer := otel.Tracer("service")
	ctx, span := tracer.Start(context.Background(), "action")
	defer span.End()
	
	log := slog.New(NewHandler(os.Stdout, &slog.HandlerOptions{}))
	fmt.Printf("%#v\n", log)
	son := log.With(slog.String("son", "yes"))
	fmt.Printf("%#v\n", son)
	son.InfoContext(ctx, "hello")
	log.InfoContext(ctx, "hello")
}