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import { QueueType, DataType, QueueApi } from "./helper.d.ts"import { QueueNode } from "./queueNode.ts"import {	searchGenerator,	updateGenerator,	iteratorGenerator} from "./generators.ts"

export class Queue implements QueueApi {	public frontNode: QueueType	private backNode: QueueType	public size: number
	constructor() {		this.frontNode = null		this.backNode = null		this.size = 0	}
	getFront() {		if (this.frontNode === null) return null		return this.frontNode!.data	}
	getBack() {		if (this.frontNode === null) return null		return this.backNode!.data	}
	enqueue(data: DataType<any>) {		const newNode = new QueueNode(data)		if (this.frontNode === null) {			// adding same pointer for frontNode & backNode			this.frontNode = newNode			this.backNode = newNode			return true;		}
		// pointer and it's greatness		this.backNode!.next = newNode		this.backNode = newNode		this.size++
		return true;	}
	dequeue() {		if (this.frontNode === null) {			return false;		} else if (this.frontNode!.next === null) {			this.backNode = null		}				const node = this.frontNode		this.frontNode = node!.next		this.size--		if (this.frontNode === null) this.size = 0
		return node!.data;	}
	search(key: string|number) {		if (this.frontNode === null) {			return false		}
		if (key === this.frontNode!.data.key) {			return this.frontNode!.data		}		if (key === this.backNode!.data.key) {			return this.backNode!.data		}
		// generator function that returns an iterator		const iterator = searchGenerator(key, this.frontNode)		const iteratorNext = iterator.next()		if (iteratorNext.value) {			return iteratorNext.value		}
		return false	}
	update(key: string|number, newValue: any) {		if (this.frontNode === null) {			return false		}
		if (key === this.frontNode!.data.key) {			this.frontNode!.data.value = newValue			return this.frontNode!.data		}		if (key === this.backNode!.data.key) {			this.backNode!.data.value = newValue			return this.backNode!.data		}
		// generator function that returns an iterator		const iterator = updateGenerator(key, this.frontNode, newValue)		const iteratorNext = iterator.next()		if (iteratorNext.value) {			return iteratorNext.value		}
		return false	}
	log() {		const iterator = this.iterator()		let iteratorNext = iterator.next()				while (iteratorNext.done === false) {			console.log(iteratorNext.value);			iteratorNext = iterator.next()		}	}
	iterator() {		// generator function that returns an iterator		const iterator = iteratorGenerator(this.frontNode)		return iterator	}}