export kInternalAttributes = Symbol('@node-ts/bus-messages/internal-attributes')

export type InternalAttributes<T> =  T

export interface MessageAttributes<
  AttributesType extends MessageAttributeMap = MessageAttributeMap,
  StickyAttributesType extends MessageAttributeMap = MessageAttributeMap,
  InternalAttributesType = InternalAttributes<unknown>
> 
    correlationId?: Uuid;
    attributes: AttributesType;
    stickyAttributes: StickyAttributesType;
    [kInternalAttributes]: InternalAttributesType
}

export const kRabbitMQHeaders = Symbol('@node-ts/bus-rabbitmq/rabbitmq-headers')

export interface RabbitMQInternalAttributes = {
  headers: MessageAttributeMap
}

private async publishMessage(
    message: Message,
    messageOptions: MessageAttributes<..., ..., RabbitMQInternalAttributes> = { attributes: {}, stickyAttributes: {}, internalAttributes: {} }
  ): Promise<void> {
    await this.assertExchange(message.$name)
    const payload = this.coreDependencies.messageSerializer.serialize(message)
    const internalAttributes = messageOptions[kInternalAttributes]
    this.channel.publish(message.$name, '', Buffer.from(payload), {
      correlationId: messageOptions.correlationId,
      messageId: uuid.v4(),
      headers: {
        attributes: messageOptions.attributes
          ? JSON.stringify(messageOptions.attributes)
          : undefined,
        stickyAttributes: messageOptions.stickyAttributes
          ? JSON.stringify(messageOptions.stickyAttributes)
          : undefined
        ...internalAttributes.headers
      }
    })
  }

import { kInternalAttributes } from '@node-ts/bus-messages'

bus.publish(new Message(), {
  [kInternalAttributes]: { // typed
    headers: {
      'x-delay': 5000
    }
  }
})