pub struct CloudEvent {
    pub spec_version: String,    // Always "1.0"
    pub id: String,              // Event ID
    pub source: String,          // Event source
    pub event_type: String,      // Event type
    pub subject: Option<String>, // Event subject
    pub time: Option<String>,    // RFC 3339 timestamp
    pub data: Option<serde_json::Value>,  // Event payload
}

use a3s_event::{Event, CloudEvent};

let event = Event::typed(
    "events.orders.created", "orders",
    "order.created", 1,
    "New order", "order-service",
    serde_json::json!({"order_id": "ORD-001"}),
);

let cloud_event = CloudEvent::from_event(&event);

println!("spec: {}", cloud_event.spec_version);  // "1.0"
println!("type: {}", cloud_event.event_type);     // "order.created"
println!("source: {}", cloud_event.source);       // "order-service"

let event = cloud_event.to_event("orders")?;

println!("subject: {}", event.subject);
println!("category: {}", event.category);  // "orders"

let json = serde_json::to_string_pretty(&cloud_event)?;

{
  "specversion": "1.0",
  "id": "evt-550e8400-e29b-41d4-a716-446655440000",
  "source": "order-service",
  "type": "order.created",
  "subject": "events.orders.created",
  "time": "2026-02-18T12:00:00Z",
  "data": {
    "order_id": "ORD-001"
  }
}