package nats

import (
	"context"

	gnats "github.com/nats-io/nats.go"
)

type Subscriber struct {
	conn  *gnats.Conn
	sub   *gnats.Subscription
	topic string
}

func NewSubscriber(url, topic string) (*Subscriber, error) {
	conn, err := gnats.Connect(url)
	if err != nil {
		return nil, err
	}
	return &Subscriber{conn: conn, topic: topic}, nil
}

func (s *Subscriber) Close() {
	if s.sub != nil {
		_ = s.sub.Unsubscribe()
	}
	s.conn.Close()
}

func (s *Subscriber) Subscribe(ctx context.Context, handler func(msg []byte) error) error {
	sub, err := s.conn.Subscribe(s.topic, func(m *gnats.Msg) {
		_ = handler(m.Data)
	})
	if err != nil {
		return err
	}
	s.sub = sub

	<-ctx.Done()
	return ctx.Err()
}