/*
 * Fetches and parses RSS feeds.
 *
 * This handles the fetching, XML parsing and formatting of
 * RSS feed data so that the frontent clients do not have to.
 *
 * This is operating on a "by-feed" basis such that each
 * run only processes one feed, and the clients are expected
 * to make multiple requests if they have a list of feeds to
 * follow.
 */

import axios from "axios";
import { parseFeed } from "htmlparser2";

function processFeedXML(feed) {
	return {
		title: feed.title,
		lastPull: String(Date.now()),
		items: feed.items.reduce((items, feedItem) => {
			items.push({
				title: feedItem.title,
				url: feedItem.link,
				published: new Date(feedItem.pubDate),
			});

			return items;
		}, []),
	};
}

const handler = async (event) => {
	try {
		const url = event.queryStringParameters.url;
		const responseData = await axios.get(url);
		const newFeedData = parseFeed(responseData.data);
		const newFeed = processFeedXML(newFeedData);
		const mergedFeeds = newFeed;

		return {
			statusCode: 200,
			body: JSON.stringify(mergedFeeds),
		};
	} catch (error) {
		return { statusCode: 500, body: error.toString() };
	}
};

module.exports = { handler };