package main

import (
	"context"
	"fmt"
	"log"
	"log/slog"
	"os"
	"os/signal"
	"syscall"

	"github.com/nats-io/nats.go"
	server "github.com/wrpc/wit-bindgen-wrpc/examples/go/hello-server/bindings"
	wrpcnats "github.com/wrpc/wrpc/go/nats"
)

type Handler struct{}

func (Handler) Hello(ctx context.Context) (string, error) {
	slog.InfoContext(ctx, "handling `wrpc-examples:hello/handler.hello`")
	return "hello from Go", nil
}

func run() (err error) {
	nc, err := nats.Connect(nats.DefaultURL)
	if err != nil {
		return fmt.Errorf("failed to connect to NATS.io: %w", err)
	}
	defer nc.Close()
	defer func() {
		if dErr := nc.Drain(); dErr != nil {
			if err == nil {
				err = fmt.Errorf("failed to drain NATS.io connection: %w", dErr)
			} else {
				slog.Error("failed to drain NATS.io connection", "err", dErr)
			}
		}
	}()

	wrpc := wrpcnats.NewClient(nc, "go")
	stop, err := server.Serve(wrpc, Handler{})
	if err != nil {
		return fmt.Errorf("failed to serve `server` world: %w", err)
	}

	signalCh := make(chan os.Signal, 1)
	signal.Notify(signalCh, syscall.SIGINT)
	<-signalCh

	if err = stop(); err != nil {
		return fmt.Errorf("failed to stop `server` world: %w", err)
	}
	return nil
}

func init() {
	slog.SetDefault(slog.New(slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{
		Level: slog.LevelInfo, ReplaceAttr: func(groups []string, a slog.Attr) slog.Attr {
			if a.Key == slog.TimeKey {
				return slog.Attr{}
			}
			return a
		},
	})))
}

func main() {
	if err := run(); err != nil {
		log.Fatal(err)
	}
}