// Package eventbus is enkly's thin wrapper around RabbitMQ (via
// github.com/rabbitmq/amqp091-go) for every *asynchronous*,
// fire-and-forget cross-context notification — the counterpart to the
// synchronous, request/response calls services make over gRPC (see
// api/proto). Per-service request/response traffic (e.g. the agent
// service asking billing "is this user over quota?") always uses gRPC;
// RabbitMQ is reserved for events a publisher doesn't need an answer to,
// mirroring the rule stated in the task: "gRPC for synchronous
// communication, RabbitMQ for asynchronous communication."
//
// Topology: one durable topic exchange, "enkly.events". Each event is
// published with a routing key of the form "<context>.<aggregate>.
// <event>" (e.g. "iam.user.registered"); a consumer binds a durable
// queue to the routing keys it cares about. Using a topic exchange
// rather than one queue per consumer lets a new consumer be added later
// (e.g. an analytics service) without touching the publisher.
package eventbus

// ExchangeName is the single durable topic exchange every service
// publishes domain events to.
const ExchangeName = "enkly.events"

// Routing keys. Each constant is "<owning context>.<aggregate>.<event,
// past tense>" — only the owning bounded context ever publishes to its
// own keys (see each service's internal/infrastructure/eventing
// package), but any service may subscribe.
const (
	// Published by iam (services/iam) — see internal/handlers/auth.go's
	// sendVerificationEmail/sendResetEmail, now decoupled from the
	// synchronous request path.
	RoutingKeyVerificationCodeIssued = "iam.user.verification_code_issued"
	RoutingKeyPasswordResetRequested = "iam.user.password_reset_requested"
	RoutingKeyUserRegistered         = "iam.user.registered"
	RoutingKeyUserEmailVerified      = "iam.user.email_verified"

	// Published by billing (services/billing).
	RoutingKeySubscriptionChanged = "billing.subscription.changed"

	// Published by conversation (services/conversation) — not consumed
	// by anything in this port of the monolith, but kept so a future
	// consumer (search indexing, analytics, audit) has something to
	// bind to without a producer-side change.
	RoutingKeyMessageCreated = "conversation.message.created"
)

// QueueBinding names the durable queue a consumer should declare and
// the routing key(s) it should bind, so every consumer's topology is
// declared in one place next to the keys it reads.
type QueueBinding struct {
	Queue       string
	RoutingKeys []string
}

// NotificationQueueBindings is the notification service's subscription
// (services/notification/internal/infrastructure/eventing) — every
// event that results in an outbound email.
var NotificationQueueBindings = QueueBinding{
	Queue: "enkly.notification.verification_and_reset",
	RoutingKeys: []string{
		RoutingKeyVerificationCodeIssued,
		RoutingKeyPasswordResetRequested,
	},
}