#!/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 */
const store= "./mastodonCzStats.json";
const instances_cz_pre= new Set(s.cat(store).xargs(JSON.parse).instances_cz.map(i=> i.instance));
const { version, description }= s.cat("package.json").xargs(JSON.parse);
const timeOut= (l= 500)=> AbortSignal.timeout(l);

$.api("", true)
.version(version)
.describe(description)
.option("--git", "Commit changes to git")
.action(async function main({ git: is_git }){
	let stats= [];
	for(const instance of instances_cz_pre){
		echo.use("-R", "Shromažďuji instance: " + instance);
		const peers= await fetch("https://"+instance+"/api/v1/instance/peers", { signal: timeOut() })
			.then(res=> res.json()).catch(()=> []);
		if(peers && Array.isArray(peers))
			peers.filter(i=> i.endsWith(".cz")).forEach(i=> instances_cz_pre.add(i));
	}
	const instances_cz= Array.from(instances_cz_pre);
	const { length }= instances_cz;
	for await(const data of collectStats(instances_cz, 4)){
		echo.use("-R", "Shromažďuji data za instance: " + instances_cz.indexOf(data.instance)+"/"+length+": "+data.instance);
		stats.push(data);
	}
	const out= {
		instances_cz: stats.sort((a, b)=> b.registrations-a.registrations),
		sum: stats.reduce((acc, stats) => sumStats([acc, stats]), { statuses: 0, logins: 0, registrations: 0, mau: 0, user_count: 0 })
	};
	echo(JSON.stringify(out, null, "	")).to(store);
	if(is_git) gitCommit([ store ], "cron");
	$.exit(0);
})
.parse();

function gitCommit(files, des= "not specified"){
	if(!files.length || !s.run`git diff --numstat`.trim())
		return echo("Nothig todo");
	
	echo("Diff to save");
	s.run`git config user.name "Bot"`;
	s.run`git config user.email "${"zc.murtnec@naj.elrdna".split("").reverse().join("")}"`;
	s.run`git add ${files}`;
	s.run`git commit -m "Updated by bot – ${des}"`;
	s.run`git push`;
	s.run`git config --remove-section user`;
}
async function* collectStats(instances, weeks = 1) {
	for(const instance of instances){
		const { stats, mau, user_count }= await fetchInstanceStats(instance).catch(e=> ({}));
		if(!stats || !Array.isArray(stats)) continue;
		yield { instance, mau, user_count, ...sumStats(stats.slice(0, weeks + 1)) };
	}
}
function sumStats(arr) {
	const out= Object.keys(arr[0]).reduce((acc, curr)=> (acc[curr]= 0, acc), {});
	for (const key of Object.keys(out))
		for (const s of arr) out[key]+= Number(s[key]);
	return out;
}
async function fetchInstanceStats(instance) {
	const url_main= "https://" + instance + "/api/";
	const stats= await fetch(url_main+"v1/instance/activity", { signal: timeOut() }).then(res=> res.json());
	const { usage: { users } }= await fetch(url_main+"v2/instance", { signal: timeOut() }).then(res=> res.json());
	const { stats: { user_count } }= await fetch(url_main+"v1/instance", { signal: timeOut() }).then(res=> res.json());
	return { instance, stats, mau: users.active_month, user_count };
}