//================================================================
/**
 * @packageDocumentation
 * @module std.internal
 */
//================================================================
import { IForwardIterator } from "../../../iterator/IForwardIterator";

/**
 * Adaptor for `for ... of` iteration.
 *
 * @author Jeongho Nam - https://github.com/samchon
 */
export class ForOfAdaptor<
    T,
    InputIterator extends Readonly<IForwardIterator<T, InputIterator>>,
> implements IterableIterator<T>
{
    private it_: InputIterator;
    private last_: InputIterator;

    /**
     * Initializer Constructor.
     *
     * @param first Input iteartor of the first position.
     * @param last Input iterator of the last position.
     */
    public constructor(first: InputIterator, last: InputIterator) {
        this.it_ = first;
        this.last_ = last;
    }

    /**
     * @inheritDoc
     */
    public next(): IteratorResult<T> {
        if (this.it_.equals(this.last_))
            return {
                done: true,
                value: undefined!,
            };
        else {
            const it: InputIterator = this.it_;
            this.it_ = this.it_.next();

            return {
                done: false,
                value: it.value,
            };
        }
    }

    /**
     * @inheritDoc
     */
    public [Symbol.iterator](): IterableIterator<T> {
        return this;
    }
}