import { NumberAllocator } from 'number-allocator'
import { IMessageIdProvider } from './default-message-id-provider'

/**
 * UniqueMessageAllocator constructor
 * @constructor
 */
export default class UniqueMessageIdProvider implements IMessageIdProvider {
	private numberAllocator: NumberAllocator

	private lastId: number

	constructor() {
		this.numberAllocator = new NumberAllocator(1, 65535)
	}

	/**
	 * allocate
	 *
	 * Get the next messageId.
	 * @return if messageId is fully allocated then return null,
	 *         otherwise return the smallest usable unsigned int messageId.
	 */
	allocate() {
		this.lastId = this.numberAllocator.alloc()
		return this.lastId
	}

	/**
	 * getLastAllocated
	 * Get the last allocated messageId.
	 * @return unsigned int
	 */
	getLastAllocated() {
		return this.lastId
	}

	/**
	 * register
	 * Register messageId. If success return true, otherwise return false.
	 * @param { unsigned int } - messageId to register,
	 * @return boolean
	 */
	register(messageId: number) {
		return this.numberAllocator.use(messageId) as boolean
	}

	/**
	 * deallocate
	 * Deallocate messageId.
	 * @param { unsigned int } - messageId to deallocate,
	 */
	deallocate(messageId: number) {
		this.numberAllocator.free(messageId)
	}

	/**
	 * clear
	 * Deallocate all messageIds.
	 */
	clear() {
		this.numberAllocator.clear()
	}
}