function supports_html5_storage() {
      try {
        return 'localStorage' in window && window['localStorage'] !== null;
    } catch (e) {
        return false;
      }
}

function submitArgs(){
    //args._users = _users;//{}
    //args._rights = _rights;//[]
    //args._groups = _groups;//[{id:0, groupname: "guest", access: []}];
    //
    //args._sessions = _sessions;//{};
    //args._currentUser = _currentUser;
    //args._realUser = _realUser;
    //args._listeners = _listeners;//[];

    localStorage['myUsefulVar'] = JSON.stringify(args);
}

if(!supports_html5_storage())
    alert('No localStorage here! I am out!');

var args = typeof localStorage['myUsefulVar'] === 'undefined' ? initArgs() : JSON.parse(localStorage['myUsefulVar']);
console.log(args);  //<--------------------------------------------------------------------------------------------------------------debug

var _users = args._users;//{}
var _rights = args._rights;//[]
var _groups = args._groups//[{id:0, groupname: "guest", access: []}];

var _sessions = args._sessions;//{};
var _currentUser = args._currentUser;
var _realUser = args._realUser;
var _listeners = args._listeners;//[];

function initArgs(){
    var args = {
         "_users": {},
         "_rights": [],
         "_groups": [],
         "_sessions": {},
         "_currentUser": null,
         "_realUser": null,
         "_listeners": []
    }

    return args;
}

/*
var _users = {
    "admin": {username:"admin", password: "1234", groups: [0, 1, 2]},
    "sobakajozhec": {username:"s1", password: "ekh228", groups: [1, 2]},
    "patriot007": {username:"s2", password: "russiaFTW", groups: [1]}
};

var _rights = [0,1,2,3,4,5,6,7,8,9];

var _groups = [
    { id:0, groupname: "guest", access: []},
    { id:1, groupname: "admin", access: [,,_rights[2]]},
    { id:2, groupname: "manager", access: [_rights[0]]},
    { id:3, groupname: "basic", access: [,_rights[1],,_rights[3]]}
];

var _sessions = {};
var _currentUser;
var _realUser;
var _listeners = [];
*/

function clearGaps(array){
  var arr = [];
  for(var i in array){
    if(array[i] != undefined)
      arr.push(array[i]);
  }
  return arr;
}

//function users(): Array<Any> Возвращает массив всех пользователей.
function users(){
    return Object.values(_users);
}
//function createUser(username: String, password: String): Any Создает нового пользователя с указанным логином username и паролем password, возвращает созданного пользователя.
function createUser(username, password)
{
    if (!(username in _users)){
    _users[username] = { username: username, password: password, groups: [] };
    }

    return _users[username];
}
//function deleteUser(user: Any): undefined Удаляет пользователя user
function deleteUser(user){
  if(typeof user == 'object' && user.username in _users){
    delete _users[user.username];
  }
  else
    throw new Error('Wrong user for deleteUser');
}
//function userGroups(user: Any): Array<Any> Возвращает массив групп, к которым принадлежит пользователь user
function userGroups(user){
  var user_groups=[]
  for(var groupid in user.groups){
    user_groups.push(_groups[user.groups[groupid]]);
  }
  return clearGaps(user_groups);
}

//function addUserToGroup(user: Any, group: Any): undefined Добавляет пользователя user в группу group
function addUserToGroup(user, group){
  if(typeof user === 'object' && user.username in _users && typeof group === 'object' && _groups[group.id] === group){
    _users[user.username].groups[group.id] = group.id;
  }
  else
    throw new Error('Wrong user or group');
}

//function removeUserFromGroup(user: Any, group: Any): undefined Удаляет пользователя user из группы group
function removeUserFromGroup(user, group) {
  if(typeof user === 'object' && user.username in _users && typeof group == 'object' && _groups[group.id] === group){
    if(user.groups[group.id] !== group.id)
      throw new Error('User is not in this group');

    delete _users[user.username].groups[group.id];
  }
  else
    throw new Error('Error from removeUserFromGroup');
}

//function rights(): Array<Any> Возвращает массив прав
function rights(){
  return clearGaps(_rights);
}
//function createRight(): Any Создает новое право и возвращает его
function createRight(){
       var num = _rights.length;
       _rights[num] = num;
      return num;
}
//function deleteRight(right: Any): undefined Удаляет право right
function deleteRight(right) {
  if(typeof right === 'number' && _rights[right] === right){
    for (var groupId in _groups)
      if (_groups[groupId].access[right] === right)
        delete _groups[groupId].access[right];
  delete _rights[right];
  }
  else
    throw new Error('Error from deleteRight');
}

//function addRightToGroup(right: Any, group: Any) : undefined Добавляет право right к группе group
function addRightToGroup(right, group)
{
  if(group != undefined && right != undefined && _rights[right] === right && _groups[group.id] === group)
      _groups[group.id].access[right] = right;
     else
      throw new Error('Error from addRightToGroup');
}

//function removeRightFromGroup(right: Any, group: Any) : undefined Удаляет право right из группы group
function removeRightFromGroup(right, group) {
  if(group != undefined && right != undefined && group.access[right] === right && _groups[group.id] === group )
    delete _groups[group.id].access[right];
  else
    throw new Error('Error from removeRightFromGroup');
}
//function groups(): Array<Any> Возвращает массив групп
function groups()
{
    return clearGaps(_groups);
}
//function createGroup(): Any Создает новую группу и возвращает её.
function createGroup(){
  var num = _groups.length;
       _groups[num] = { id: num, groupname: '', access: [rights[0]] };
      return _groups[num];
}
//function deleteGroup(group: Any): undefined Удаляет группу group
function deleteGroup(group){
  if(typeof group === 'object' && _groups[group.id] === group)
  {
    for(var userKey in _users)
      delete _users[userKey].groups[group.id];

    delete _groups[group.id];
  }
  else
    throw new Error('Wrong group in deleteGroup');
}

//function groupRights(group: Any): Array<Any> Возвращает массив прав, которые принадлежат группе group
function groupRights(group){
  return clearGaps(_groups[group.id].access);
}

function login(username, password){
  if (username === 'guest'){
    var guestUniqName = 'guest' + Math.random();
    _sessions[guestUniqName]
    _currentUser = guestUniqName;
    return true;
  }
  else
    if(username in _users && _users[username].password === password && !(username in _sessions)){
      _sessions[username] = 'logged';
      _currentUser = username;
      return true;
    }
    return false;
  }


function logout(){
  if(typeof _realUser !== 'string'){
    delete _sessions[_currentUser];
    _currentUser = undefined;
  }
  else{
    _currentUser = _realUser;
    _realUser = undefined;
  }
}

function currentUser(){
  return _users[_currentUser];
}

function isAuthorized(user, right){
  if(user != undefined && right != undefined && user.username in _users && _rights.includes(right)) {
    for( var groupId in _users[user.username].groups)
    {
      if(_groups[groupId].access[right] === right ){
        return true;
      }
    }
    return false;
  }
  else
  throw new Error('Error from isAuthorized');
}


//Пусть right[0] дает право на это
function loginAs(username){
  if(isAuthorized(_users[_currentUser], _rights[0])){
    _realUser = _currentUser;
    _currentUser = username;
  }
  else
    throw new Error('У вас нет прав');
}


function securityWrapper(action, right){
  if(isAuthorized(_users[_currentUser], right))
    return function(){
      for(var i in _listeners)
        _listeners[i](_users[_currentUser], action);

      return action(...arguments);
    }
  else
    throw new Error('You have no access');
}

function addActionListener(listenerFunction){
  _listeners.push(listenerFunction);
}

function logger(user, action){
  console.log("Пользователь " + user.username + " только что сделал " + action.name);
}
addActionListener(logger);




//var _counter = 0;
//function actionOne(arg = 1){
//  _counter += arg;
//}
//login('admin','1234');
//var wrapped = securityWrapper(actionOne, _rights[0]);