package event

const (
	namedPrefixer = ":"
)

// Emitter able to emit events
type Emitter interface {
	Emit(Event)
}

// Receiver able to listen to events
type Receiver interface {
	On(name string, handler HandlerFunc)
}

// HandlerFunc func
type HandlerFunc func(Event)

// Event specific interface
type Event interface {
	Name() string
	Data() interface{}
}

// private data
type event struct {
	name string
	data interface{}
}

// New Event
func New(name string, data interface{}) Event {
	return &event{name, data}
}

func (e *event) Name() string {
	return e.name
}

func (e *event) Data() interface{} {
	return e.data
}

// Prefixer

// NamedEmitter data for event prefixer
type NamedEmitter struct {
	name string
	bus  Bus
}

// NewNamedEmitter creates a new emitter pointing to bus
func NewNamedEmitter(name string, bus Bus) Emitter {
	return &NamedEmitter{name, bus}
}

// Emit will prefix with namedemitter name and push to bus
func (ne *NamedEmitter) Emit(evt Event) {
	newEvt := &event{name: ne.name + namedPrefixer + evt.Name(), data: evt.Data()}
	ne.bus.Emit(newEvt)
}