broker

type Broker interface {
	// Publish sends a message to topic.
	Publish(ctx context.Context, topic string, m *Message, opts ...PublishOption) error
	// Subscribe registers a handler for topic.
	Subscribe(ctx context.Context, topic string, h Handler, opts ...SubscribeOption) (Subscriber, error)
	// Connect establishes the underlying connection.
	Connect() error
	// Disconnect closes the underlying connection.
	Disconnect() error
	// String names the broker implementation.
	String() string
}

type Event interface {
	// Topic returns the topic this event was published to.
	Topic() string
	// Message returns the underlying message.
	Message() *Message
	// Ack acknowledges the message. For at-least-once brokers this commits the
	// message; for at-most-once brokers it is a no-op.
	Ack() error
	// Error returns a delivery error, if any.
	Error() error
}

type Factory func(opts any) (Broker, error)

type Handler func(Event) error

type Message struct {
	Header metadata.Metadata `json:"header,omitempty"`
	Body   []byte            `json:"body,omitempty"`
}

type PublishOption func(*PublishOptions)

type PublishOptions struct{}

type SubscribeOption func(*SubscribeOptions)

type SubscribeOptions struct {
	// Queue is a consumer-group name. Subscribers sharing a queue (and topic)
	// load-balance messages; otherwise each subscriber gets every message.
	Queue string
	// AutoAck acknowledges a message automatically when the handler returns nil.
	// When false, the handler must call Event.Ack explicitly.
	AutoAck bool
	// Concurrency is the number of goroutines consuming the subscription.
	Concurrency int
}

type Subscriber interface {
	// Topic returns the subscribed topic.
	Topic() string
	// Unsubscribe cancels the subscription and releases its resources.
	Unsubscribe() error
}