'use strict';

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

var dns = require('dns');

module.exports.create = function(config) {
	// config = { baseUrl, token, apiTimeout }
	var baseUrl = config.baseUrl || 'https://www.duckdns.org';
	var authtoken = config.token;
	var apiTimeout = config.apiTimeout || 5000;
	// return object containing get/set/remove functions
	return {
		set: function(data) {
			var domain_name = data.challenge.identifier.value;
			var txt = data.challenge.dnsAuthorization;
			var url =
				baseUrl +
				'/update?domains=' +
				domain_name +
				'&token=' +
				authtoken +
				'&txt=' +
				txt;

			// console.log("adding txt", data);
			return request({
				method: 'GET',
				url: url
			}).then(function(resp) {
				if (resp === 'OK') {
					return true;
				}
				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 +
				'/update?domains=' +
				domain_name +
				'&token=' +
				authtoken +
				'&txt=' +
				txt +
				'&clear=true';

			// console.log("removing txt");
			return request({
				method: 'GET',
				url: url
			}).then(function(resp) {
				if (resp === 'OK') {
					return true;
				}
				throw new Error('Couldnt 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(apiTimeout).then(function() {
				console.log('fetching txt', data);
				return new Promise(function(resolve, reject) {
					dns.resolveTxt(domain_name, (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(resolve => setTimeout(resolve, ms));
}