import { OpenPromise } from "./OpenPromise.js";

export class Stream<T> implements AsyncIterable<T> {

    public pending: OpenPromise<T> = new OpenPromise<T>();

    [Symbol.asyncIterator](): AsyncIterator<T> {
        return new StreamIterator<T>(this);
    }

    append(value: T) {
        //console.warn("STREAMING WITH", value);
        this.pending.resolve(value);
        this.pending = new OpenPromise<T>();
    }
}

export class StreamIterator<T> implements AsyncIterator<T> {

    constructor(public source: Stream<T>) {
    }

    next(): Promise<IteratorResult<T, any>> {
        let prom: Promise<IteratorResult<T>>;
        prom = new Promise(async (resolve, reject) => {
            this.source.pending.then((value: T) => {
                resolve({ done: false, value: value as T });
            });
            this.source.pending.catch((reason: any) => {
                resolve({ done: true, value: undefined });
            })
        });
        return prom;
    }
}