<?php

use GeoIp2\Database\Reader;

require_once realpath(dirname(__FILE__)) . '/../vendor/autoload.php';
require_once realpath(dirname(__FILE__)) . '/newsletter-api.php';
require_once realpath(dirname(__FILE__)) . '/../config.php';

const USER_AGENT_CLIENT_ANDROID = '/^Mozilla\/5\.0 \(Android\) (ownCloud|Nextcloud)\-android.*$/';
const USER_AGENT_TALK_ANDROID = '/^Mozilla\/5\.0 \(Android\) Nextcloud\-Talk v.*$/';
const USER_AGENT_CLIENT_DESKTOP = '/^Mozilla\/5\.0 \([A-Za-z ]+\) (mirall|csyncoC)\/.*$/';
const USER_AGENT_CLIENT_IOS = '/^Mozilla\/5\.0 \(iOS\) (ownCloud|Nextcloud)\-iOS.*$/';
const USER_AGENT_TALK_IOS = '/^Mozilla\/5\.0 \(iOS\) Nextcloud\-Talk v.*$/';

add_action('rest_api_init', 'registration_register_routes');

$redis = new Predis\Client(REDIS);
$readerCity = new Reader(realpath(dirname(__FILE__)) . '/../assets/GeoLite2/GeoLite2-City.mmdb');
$readerCountry = new Reader(realpath(dirname(__FILE__)) . '/../assets/GeoLite2/GeoLite2-Country.mmdb');

// Get proper ip in case of reverse proxy
function whatismyip() {
	return $_SERVER['REMOTE_ADDR'];
}

function get_device() {
	$userAgents = [
		'Android' => USER_AGENT_CLIENT_ANDROID,
		'Android Talk' => USER_AGENT_TALK_ANDROID,
		'Desktop' => USER_AGENT_CLIENT_DESKTOP,
		'iOS' => USER_AGENT_CLIENT_IOS,
		'iOS Talk' => USER_AGENT_TALK_IOS
	];

	if (isset($_SERVER['HTTP_USER_AGENT'])) {
		$userAgent = $_SERVER['HTTP_USER_AGENT'];
		foreach ($userAgents as $name => $regex) {
			if (preg_match($regex, $userAgent)) {
				return $name;
			}
		}
		return 'Website';
	}
	return 'unknown';
}

function registration_register_routes() {
	// signup post method
	register_rest_route('signup', '/account', array(
		'methods'  => WP_REST_Server::CREATABLE,
		'callback' => 'request_account',
		'args'     => array(
			'id'    => array(
				'validate_callback' => function ($param) {
					return is_numeric($param);
				}
			),
			'email' => array(
				'validate_callback' => function ($param) {
					return filter_var($param, FILTER_VALIDATE_EMAIL);
				}
			)
		)
	));

	// providers json
	register_rest_route('signup', '/providers', array(
		'methods'  => WP_REST_Server::READABLE,
		'callback' => 'get_providers_list'
	));

	// get statistics
	register_rest_route('signup', '/stats', array(
		'methods'  => WP_REST_Server::READABLE,
		'callback' => 'get_statistics',
		'args'     => array(
			'key'  => array(
				'required'          => true,
				'validate_callback' => function ($key) {
					return strlen($key) === 32;
				}
			),
			'time' => array(
				'validate_callback' => function ($time) {
					return is_numeric($time);
				}
			)
		)
	));
}

function request_account($request) {

	// redis rate limit
	global $redis;
	global $readerCountry;

	$limit = [
		'interval'     => 300, // seconds
		'num_requests' => 10, // number of requests allowed per interval
		'user_ip'      => whatismyip() // getting the user IP.
	];

	$rateId    = "requests_count_{$limit['user_ip']}";
	$rateLimit = (int) $redis->get($rateId);
	if ($rateLimit + 1 > $limit['num_requests']) {
		$remainingTTL = $redis->ttl($rateId);
		if ($remainingTTL < 1) {
			$remainingTTL = $limit['interval'];
		}
		$minutes = max((int)round($remainingTTL / 60), 1);
		$text = "Please retry in $minutes minutes";
		if ($minutes === 1) {
			$text = "Please retry in 1 minute";
		}
		return new WP_Error('rate_limit_exceeded', 'Too many requests - ' . $text, array('status' => 429));
	}

	$request = json_decode($request->get_body(), true);

	// verify data
	if (!array_key_exists('email', $request) || !array_key_exists('id', $request)) {
		return new WP_Error('rest_invalid_param', 'Invalid parameter(s)', array('status' => 400));
	}

	// init vars
	$email      = $request['email'];
	$providerId = intval($request['id']);
	$locationId = intval($request['location']);
	$newsletter = array_key_exists('newsletter', $request) ? true : false;
	$subscribe  = boolval($request['subscribe']);

	// get providers list && check provider id
	$json = json_decode(file_get_contents(PROVIDERS_FILE));
	if (!array_key_exists($providerId, $json)) {
		return new WP_Error('rest_invalid_param', 'Invalid parameter(s)', array('status' => 400));
	}

	// init post request
	$provider = $json[$providerId];
	$url      = $provider->locations[$locationId]->url . '/ocs/v2.php/account/request/' . $provider->locations[$locationId]->key;
	$data     = array(
		'headers' => array(
			'Content-Type' => 'application/x-www-form-urlencoded;charset=UTF-8'
		),
		'body'    => 'email=' . $email,
		'timeout' => 60
	);

	// request account && consume one rate token
	$post = wp_remote_post($url, $data);
	$ttl  = $redis->ttl($rateId);
	$redis->set($rateId, $rateLimit + 1);
	$redis->expire($rateId, $ttl > 0 ? $ttl : $limit['interval']);


	if (!array_key_exists('response', $post)) {
		error_log('Provider did not returned 201: ' . json_encode($post));
		return new WP_Error('unknown_error', 'Something happened', array('status' => 400));
	} else if ($post['response']['code'] !== 201) {
		if ($post['response']['code'] === 400 && $post['response']['message'] === 'invalid mail address') {
			return new WP_Error('invalid_mail_address', 'invalid mail address', array('status' => 400));
		}
		if ($post['response']['code'] === 400 && $post['response']['message'] === 'Bad Request') {
			$decodedBody = json_decode($post['body'], true);
			if ($decodedBody !== null &&
				isset($decodedBody['data']['message']) &&
				$decodedBody['data']['message'] === 'user already exists') {

				return new WP_Error('username_already_used', 'User already exists', array('status' => 400));
			}
		}
		error_log('Provider did not returned 201: ' . json_encode($post));
		return new WP_Error('unknown_error', 'Something happened', array('status' => 400));
	}

	$response = json_decode($post['body'])->data;

	if (!is_string($response->setPassword)) {
		return new WP_Error('rest_invalid_param', 'An unknown error occured', array('status' => 400));
	}

	// SUCCESS let's continue
	if ($subscribe) {
		// don't do anything else even if it fails.
		// let's focus on the ux flow
		subscribe($email);
	}

    // store stats
    try {
        $country = $readerCountry->country(whatismyip())->country->isoCode;
    } catch (Exception $e) {
        $country = 'unknown';
    }
    try {
	    $redis->set(time(), json_encode([
	        'device' => get_device(),
	        'country' => $country,
	        'provider' => $provider->name
	    ]));
	} catch (Exception $e) {
		error_log($e->getMessage());
	}

	// return nc://url
	if (array_key_exists('ocsapi', $request) && $request['ocsapi'] === true) {
		return $response->setPassword . '/ocs';
	}

	return $response->setPassword;
}

function get_providers_list() {
	// get providers list
	$json = json_decode(file_get_contents(PROVIDERS_FILE));

	if (!is_array($json)) {
		return new WP_Error('unknown_error', 'Invalid provider file', array('status' => 400, 'json' => PROVIDERS_FILE));
	}

	// obfuscate keys
	foreach ($json as $provider) {
		// safety fallback
		unset($provider->key);
		unset($provider->url);
		foreach ($provider->locations as $location) {
			unset($location->key);
			unset($location->url);
		}
	}

	return $json;
}

function get_statistics($params) {
	if ($_GET['key'] && $_GET['key'] === PPP_KEY) {
		global $redis;

		// select every proper timestamp ()
		// TODO: change the timestamp for May 18, 2033 @ 5:33:20 am 😂
		$keys = $redis->keys('1*');

		// filter out
		if ($_GET['time']) {
			$keys = array_filter($keys, function($time) {
				return $time > $_GET['time'];
			});
		}

		// no results
		if (count($keys) === 0) {
			return [];
		}

		set_time_limit(0);
		$data = array_reduce($keys, function ($array, $key) {
			global $redis;
			$array[$key] = json_decode($redis->get($key));

			return $array;
		});

		return $data;
	}

	return new WP_Error('forbidden', 'Forbidden', array('status' => 403));
}