//================================================================
/**
 * @packageDocumentation
 * @module std
 */
//================================================================
import { AdaptorContainer } from "../internal/container/linear/AdaptorContainer";
import { List } from "./List";

/**
 * Queue; FIFO (First In First Out).
 *
 * @author Jeongho Nam - https://github.com/samchon
 */
export class Queue<T> extends AdaptorContainer<T, List<T>, Queue<T>> {
    /* ---------------------------------------------------------
        CONSTRUCTORS
    --------------------------------------------------------- */
    /**
     * Default Constructor.
     */
    public constructor();

    /**
     * Copy Constructor.
     *
     * @param obj Object to copy.
     */
    public constructor(obj: Queue<T>);

    public constructor(obj?: Queue<T>) {
        super(new List());

        if (obj !== undefined)
            this.source_.assign(obj.source_.begin(), obj.source_.end());
    }

    /* ---------------------------------------------------------
        ACCESSORS
    --------------------------------------------------------- */
    /**
     * Get the first element.
     *
     * @return The first element.
     */
    public front(): T {
        return this.source_.front();
    }

    /**
     * Get the last element.
     *
     * @return The last element.
     */
    public back(): T {
        return this.source_.back();
    }

    /**
     * @inheritDoc
     */
    public pop(): void {
        this.source_.pop_front();
    }
}