import {
    SeriesNextCallback,
    SeriesFunction
} from "../interfaces";

import {
    once
} from "../common";

/**
 * This method executes a series of functions one by one in order, or break
 * if an error occured. Finally, the final callback will be call, with the
 * ending reason if exists.
 */
export function series<E>(
    fns: SeriesFunction<E>[],
    final?: SeriesNextCallback<E>
): void {

    fns = fns.slice();

    let loop = function(i: number, ...args: any[]): void {

        if (i < fns.length) {

            fns[i](once(function(err?: E, ...args: any[]): void {

                if (err !== null && err !== undefined) {

                    final && final(err);
                }
                else {

                    loop(i + 1, ...args);
                }
            }), ...args);
        }
        else {

            final && final();
        }
    };

    loop(0);
}