package ws

import (
	"encoding/json"
	"log"
)

type EventType string

const (
	DeliveryCreated       EventType = "delivery.created"
	DeliveryUpdated       EventType = "delivery.updated"
	DeliveryStatusChanged EventType = "delivery.status_changed"
	DeliveryDeleted       EventType = "delivery.deleted"
)

type Event struct {
	Type    EventType `json:"type"`
	Payload any       `json:"payload"`
}

type StatusPayload struct {
	ID     string `json:"id"`
	Status string `json:"status"`
}

type DeletePayload struct {
	ID string `json:"id"`
}

// NewEvent serializes an event to JSON. Returns nil on marshal failure;
// callers should treat nil as "skip broadcast".
func NewEvent(eventType EventType, payload any) []byte {
	data, err := json.Marshal(Event{Type: eventType, Payload: payload})
	if err != nil {
		log.Printf("ws: failed to marshal event %s: %v", eventType, err)
		return nil
	}
	return data
}