"use strict";

const through2 = require("through2");

const sortDependencies = require("../sort-dependencies");
const stream = require("../stream");

module.exports = function createKahnSortingStream() {
	let sortables = [];

	function handleItem(item) {
		sortables.push(item);
	}

	function flush() {
		let sorted = sortDependencies(sortables);

		// TODO: Verify that the 'null' push here is necessary
		return sorted.concat([ null ]);
	}

	return stream(handleItem, flush);
};