const querystring = require('querystring');
const prettyBytes = require('pretty-bytes');
const moment = require('moment');

function humanTimeAgo(utcDate) {
	const diff = moment.utc().diff(moment.utc(utcDate));
	const uptime = {};

	uptime.s = Math.round(diff / 1000);
	uptime.m = Math.floor(uptime.s / 60);
	uptime.h = Math.floor(uptime.m / 60);
	uptime.d = Math.floor(uptime.h / 24);

	uptime.s %= 60;
	uptime.m %= 60;
	uptime.h %= 24;

	let readableUptime = '';
	readableUptime += uptime.d ? ` ${uptime.d}d` : '';
	readableUptime += uptime.h ? ` ${uptime.h}h` : '';
	if ((!uptime.d || !uptime.h) && uptime.m) {
		readableUptime += ` ${uptime.m}m`;
	}

	return readableUptime.trim();
}

const filters = {
	bandwidth: node => `${prettyBytes(node.advertised_bandwidth)}/s`,
	uptime: node => {
		// Check node is up
		if (!node.running) {
			return 'Down';
		}

		// Check uptime
		return humanTimeAgo(node.last_restarted);
	},
	pagination: (req, direction) => {
		// Clone query string
		const query = Object.assign({}, req.query);

		// Set page as 1 by default
		query.p = query.p ? query.p : 1;

		// Update page
		if (direction === 'next') {
			query.p++;
		} else if (direction === 'prev') {
			query.p--;
		}

		// Don't add p var if it's page 1
		if (query.p === 1) {
			delete query.p;
		}

		// Encode query string
		const queryString = querystring.encode(query);
		return queryString ? `/?${queryString}` : '/';
	},
	name: node => {
		let name = '';
		if (node.nickname) {
			name = node.nickname;
		} else if (node.fingerprint || node.hashed_fingerprint) {
			name = (node.fingerprint || node.hashed_fingerprint).slice(0, 8);
		}
		return name;
	},
	status: node => node.running ?
		`Up for ${humanTimeAgo(node.last_restarted)}` :
		`Down for ${humanTimeAgo(node.last_seen)}`
};

module.exports = app => Object.keys(filters).forEach(filter => {
	app.settings.nunjucksEnv.addFilter(filter, filters[filter]);
});