errors

var (
	// Queue errors
	ErrQueueNotFound = errors.New("queue not found")
	ErrQueueExists   = errors.New("queue already exists")
	ErrQueueFull     = errors.New("queue at capacity")
	ErrQueueEmpty    = errors.New("queue is empty")

	// Client errors
	ErrClientNotFound  = errors.New("client not registered")
	ErrClientExists    = errors.New("client already exists")
	ErrClientNotActive = errors.New("client not active")

	// Message errors
	ErrMessageNotFound = errors.New("message not found")
	ErrMessageExpired  = errors.New("message TTL exceeded")
	ErrMessageTooLarge = errors.New("message exceeds size limit")
	ErrInvalidMessage  = errors.New("invalid message format")

	// Subscription errors
	ErrNotSubscribed     = errors.New("client not subscribed to topic")
	ErrAlreadySubscribed = errors.New("client already subscribed")

	// System errors
	ErrBackpressure = errors.New("system under load")
	ErrCircuitOpen  = errors.New("circuit breaker open")
	ErrShuttingDown = errors.New("system shutting down")
	ErrTimeout      = errors.New("operation timed out")

	// Storage errors
	ErrStorageFailure    = errors.New("storage operation failed")
	ErrTransactionFailed = errors.New("transaction failed")
)