'use strict';

var dns = require('dns');
var request = require('@root/request');
request = require('util').promisify(request);

module.exports.create = function(config) {
	// config = { baseUrl, token, dnsWait }
	var authtoken = config.token;
	var dnsWait = config.dnsWait || 5000;
	var baseUrl = config.baseUrl || 'https://www.duckdns.org/update';
	baseUrl = baseUrl.replace(/\/$/, '');

	// return object containing get/set/remove functions
	return {
		init: function(opts) {
			// ignore
			return null;
		},
		zones: function(opts) {
			// DuckDNS does not support listing zones
			return [];
		},
		set: function(data) {
			var domain_name = data.challenge.identifier.value;
			var txt = data.challenge.dnsAuthorization;
			var url =
				baseUrl +
				'?domains=' +
				domain_name +
				'&token=' +
				authtoken +
				'&txt=' +
				txt;

			// console.log("adding txt", data);
			return request({
				method: 'GET',
				url: url
			}).then(function(resp) {
				if (resp.body === 'OK') {
					return true;
				}
				console.error(resp.toJSON());
				throw new Error(
					'record did not set. check subdomain, api key, etc'
				);
			});
		},
		remove: function(data) {
			var domain_name = data.challenge.identifier.value;
			var txt = data.challenge.dnsAuthorization;
			var url =
				baseUrl +
				'?domains=' +
				domain_name +
				'&token=' +
				authtoken +
				'&txt=' +
				txt +
				'&clear=true';

			// console.log("removing txt");
			return request({
				method: 'GET',
				url: url
			}).then(function(resp) {
				if (resp.body === 'OK') {
					return true;
				}
				console.error(resp.toJSON());
				throw new Error(
					"Couldn't remove record. Check subdomain, api key, etc"
				);
			});
		},
		get: function(data) {
			// the duckdns doesnt provide an API to fetch DNS records so we are using Node DNS library to get TXT record.
			// We need to add manual delay as the DNS records do not get updated instantly.
			var domain_name = data.challenge.identifier.value;
			return delay(dnsWait).then(function() {
				// console.log('fetching txt', data);
				return new Promise(function(resolve, reject) {
					dns.resolveTxt(domain_name, function(err, txt) {
						if (err) {
							console.error(err);
							reject(null);
						}
						// console.log(txt);
						if (txt && txt[0] && txt[0][0]) {
							resolve({ dnsAuthorization: txt[0][0] });
						} else {
							resolve(null);
						}
					});
				});
			});
		}
	};
};

function delay(ms) {
	return new Promise(function(resolve) {
		setTimeout(resolve, ms);
	});
}