/*
  There's a little inconsistency with how feeds report certain things like
  title, links and timestamps. These helpers try to normalize that bit and
  provide an order-of-operations list of properties to look for.

  Note: these are tightly-coupled to the template and a personal preference.
*/

import { Response } from "node-fetch";
import { readFile } from "fs/promises";
import { FeedItem, JSONValue } from "./@types/bubo";

export const getLink = (obj: FeedItem): string => {
  const link_values: string[] = ["link", "url", "guid", "home_page_url"];
  const keys: string[] = Object.keys(obj);
  const link_property: string | undefined = link_values.find(link_value =>
    keys.includes(link_value)
  );
  return link_property ? (obj[link_property] as string) : "";
};

// fallback to URL for the title if not present
// (title -> url -> link)
export const getTitle = (obj: FeedItem): string => {
  const title_values: string[] = ["title", "url", "link"];
  const keys: string[] = Object.keys(obj);

  // if title is empty for some reason, fall back on url or link
  const title_property: string | undefined = title_values.find(
    title_value => keys.includes(title_value) && obj[title_value]
  );
  return title_property ? (obj[title_property] as string) : "";
};

// More dependable way to get timestamps
export const getTimestamp = (obj: FeedItem): string => {
  const dateString: string = (
    obj.pubDate ||
    obj.isoDate ||
    obj.date ||
    obj.date_published
  ).toString();
  const timestamp: number = new Date(dateString).getTime();
  return isNaN(timestamp) ? dateString : timestamp.toString();
};

// parse RSS/XML or JSON feeds
export async function parseFeed(response: Response): Promise<JSONValue> {
  const contentType = response.headers.get("content-type")?.split(";")[0];

  if (!contentType) return {};

  const rssFeed = [contentType]
    .map(item =>
      [
        "application/atom+xml",
        "application/rss+xml",
        "application/xml",
        "text/xml",
        "text/html" // this is kind of a gamble
      ].includes(item)
        ? response.text()
        : false
    )
    .filter(_ => _)[0];

  const jsonFeed = [contentType]
    .map(item =>
      ["application/json", "application/feed+json"].includes(item)
        ? (response.json() as Promise<JSONValue>)
        : false
    )
    .filter(_ => _)[0];

  return (rssFeed && rssFeed) || (jsonFeed && jsonFeed) || {};
}

export const getFeedList = async (): Promise<JSONValue> => {
  return JSON.parse(
    (
      await readFile(new URL("../config/feeds.json", import.meta.url))
    ).toString()
  );
};

export const getBuboInfo = async (): Promise<JSONValue> => {
  return JSON.parse(
    (await readFile(new URL("../package.json", import.meta.url))).toString()
  );
};