<?php
/**
 * Get telegram user data
 * 
 * Gets telegram user data from cookie and save it to array
 * 
 * @return void
 *
 * @author Telegram
 *
 *
 * @since 0.1
 */
function getTelegramUserData() {
	if (isset($_COOKIE['tg_user'])) {
		$auth_data_json = urldecode($_COOKIE['tg_user']);
		 $auth_data = json_decode($auth_data_json, true);
		return $auth_data;
	}
	return false;
}
/** 
 * Check if data is from telegram
 * 
 * This checks if the data provides is from telegram. It includes a Fix for firefox
 * 
 * @param mixed $auth_data The Authentication Data
 * 
 * @return $auth_data
 * 
*/
function checkTelegramAuthorization($auth_data) {
	$check_hash = $auth_data['hash'];
	unset($auth_data['hash']);
	$data_check_arr = [];
	foreach ($auth_data as $key => $value) {
	 // $data_check_arr[] = $key . '=' . $value;
	  $data_check_arr[] = $key . '=' . str_replace('https:/t', 'https://t', $value);
	}
	sort($data_check_arr);
	$data_check_string = implode("\n", $data_check_arr);
	$secret_key = hash('sha256', TG_BOT_API_TOKEN, true);
	$hash = hash_hmac('sha256', $data_check_string, $secret_key);
	if (strcmp($hash, $check_hash) !== 0) {
	  throw new Exception('Data is NOT from Telegram');
	}
	if ((time() - $auth_data['auth_date']) > 86400) {
	  throw new Exception('Data is outdated');
	}
	return $auth_data;
  }


/**
 * Save telegram userdata
 * 
 * Save the telegram user data in a cookie
 *  @return void
 */  
function saveTelegramUserData($auth_data) {
	$auth_data_json = json_encode($auth_data);
	setcookie('tg_user', $auth_data_json);
  }