"use strict";

const propagateAbort = require("@promistream/propagate-abort");

const createSequentialQueue = require("./sequential-queue");

module.exports = function sequentialize() {
	let withQueue = createSequentialQueue();

	return {
		_promistreamVersion: 0,
		description: `sequentialize`,
		// FIXME: We don't queue up aborts because once a downstream has encountered an error, it may have stopped trying to read, and we would deadlock. While the Aborted marker reads *do* get queued, the abort itself should probably be immediate. Need to make sure that this doesn't clash with any other part of the spec.
		abort: propagateAbort,
		peek: function peek(source) {
			return withQueue(() => {
				return source.peek();
			});
		},
		read: function read(source) {
			return withQueue(() => {
				return source.read();
			});
		}
	};
};