#!/usr/bin/env -S npx nodejsscript
/* jshint esversion: 11,-W097, -W040, module: true, node: true, expr: true, undef: true *//* global echo, $, pipe, s, fetch, cyclicLoop */
import { JSDOM } from "jsdom";
const url_drops= "https://pagenotfound.cz/drop/";
const { name, version, description }= s.cat("package.json").xargs(JSON.parse);
/**
 * @typedef {Object} Article
 * @property {string} title
 * @property {string} perex
 * @property {string} author
 * @property {string} loc
 * @property {string} drop
 * */
/**
 * @typedef {Object} Drop
 * @property {string} drop
 * @property {string} date
 * */
/**
 * @typedef {Object} Sitemap
 * @property {Article[]} articles
 * @property {Drop[]} drops
 * */

$.api()
.version(version)
.describe(description)
.command("pull", "Update article list")
.action(async function pull(){
	const json= await sitemap();
	toRSS(json);
	$.exit(0);
})
.parse();

/** @param {Sitemap} json */
async function toRSS(json){
	const path= "rss.xml";
	const host= "https://pagenotfound.cz";
	const articles= json.articles.map(function({ title, perex, author, loc, drop }){
		return [
			"<item>",
			...[
				`<title>${title}</title>`,
				`<link>${host+loc}</link>`,
				`<description>${perex}</description>`,
				`<author>${author}</author>`,
				`<pubDate>${json.drops.find(d=> d.drop === drop).date}</pubDate>`,
				`<category>${drop}</category>`,
			].map(l=> "\t"+l),
			"</item>"
		].map(l=> "\t"+l).join("\n");
	});

	s.echo([
		`<?xml version="1.0" encoding="UTF-8" ?>`,
		`<rss version="2.0">`,
		"<channel>",
		`	<title>Pagenotfound.cz</title>`,
		`	<link>${host}</link>`,
		...articles,
		"</channel>",
		"</rss>"
	].join("\n")).to(path);
}
async function sitemap(){
	const path= "sitemap.json";
	
	/** @type {Sitemap} */
	const json= s.test("-f", path) ? s.cat(path).xargs(JSON.parse) : { drops: [], articles: [] };
	const [ article_last= { drop: "" } ]= json.articles;
	await syncDrops(json);
	const [ { drop: drop_last } ]= json.drops;
	if(drop_last === article_last.drop) return json;
	
	const res= await fetch(url_drops+drop_last);
	if(res.status !== 200) return;
	const dom= new JSDOM(await res.text());
	const diff= [];
	for(const article of dom.window.document.querySelectorAll("article")){
		diff.push({
			title: article.querySelector("h2").textContent.trim(),
			perex: article.querySelector("[class^=ArticleTile_perex]").textContent.trim(),
			author: article.querySelector("[class^=ArticleTile_author]").textContent.trim(),
			loc: article.querySelector("a").href,
			drop: drop_last,
		});
	}

	json.articles.unshift(...diff);
	s.echo(JSON.stringify(json, null, "\t")).to(path);
	return json;
}
/** @param {Sitemap} json */
async function syncDrops(json){
	const [ { drop: drop_last } ]= json.drops;
	const i_index= drop_last.search(/\d/);
	const pre= drop_last.slice(0, i_index);
	const index= pipe(
		Number,
		i=> i+1,
		i=> i.toString().padStart(drop_last.length - i_index, "0"),
	)(drop_last.slice(i_index));

	const drop= pre+index;
	const res= await fetch(url_drops+drop, { method: "HEAD" });
	if(res.status !== 200) return json;

	const date= pipe(
		d=> new Date(d),
		d=> d.toISOString(),
	)(res.headers.get("date"));
	json.drops.unshift({ drop, date });
	return json;
}