/**
 * 循环队列
 */
export class LoopQueue<E> {
    private data: E[];
    private front: number;
    private readonly tail: number;
    private readonly size: number;
    private capacity: number;

    constructor(capacity?: number) {
        this.data = [];
        this.front = 0;
        this.tail = 0;
        this.size = 0;
        this.capacity = capacity ? capacity + 1 : -1;
    }

    public getCapacity() {
        return this.capacity - 1;
    }

    public isEmpty() {
        return (this.front = this.tail);
    }

    public getSize() {
        return this.size;
    }

    public enqueue(e: E) {
        if ((this.tail + 1) % this.data.length === this.front) {
            this._resize(this.getCapacity() * 2);
        }
    }

    private _resize(newCapacity: number) {
        this.capacity = newCapacity;
    }
}