public bool AddMultiCoins(int number)
        {
            using (SmartTreeEntities db = new SmartTreeEntities())
            {
                var user = User.GetUserFromDb(db);
                user.MultiCoins += number;
                try
                {
                    db.SaveChanges();
                }
                catch (DbUpdateConcurrencyException e)
                {
                    return AddMultiCoins(number);
                }
                MarketController.re_sell(user);
            }

            return true;
        }
        public ActionResult Deposit()
        {
            using (SmartTreeEntities db = new SmartTreeEntities())
            {
                var user = User.GetUserFromDb(db);
                user.Balance += Constants.MULTI_COIN_PRICE;
                try { db.SaveChanges(); }
                catch (DbUpdateConcurrencyException e){ Deposit(); }

            }
            return RedirectToAction("Index", "Profile");
        }
        /// <summary>
        /// Buy to an other user
        /// </summary>
        /// <param name="_other"> The other User we want to buy to</param>
        /// <param name="amounth"> The amounth of multicoins we want to buy</param>
        /// <returns></returns>
        private static Boolean buy(User _me, User _other, int amounth = 1)
        {
            // First check if _other is the father of the user or
            // if user has no father, an elligible seller
            if (_me.Balance >= Constants.MULTI_COIN_PRICE * amounth
                && _other.MultiCoins >= amounth
                && (_me.Father == _other
                || (_me.Father == null && _other.isElligibleSeller())))
            {
                // Proceed the sell
                using (SmartTreeEntities db = new SmartTreeEntities())
                {
                    var other = db.Users.Find(_other.UserId);
                    var me = db.Users.Find(_me.UserId);

                    //Update seller infos
                    other.MultiCoins -= amounth;
                    sell(other, amounth);

                    //Update user infos
                    me.Balance -= Constants.MULTI_COIN_PRICE * amounth;
                    me.MultiCoins += amounth * 5;
                    me.untaxed += amounth;

                    // update infos about calls
                    var nbCallToCancel = Math.Min(_me.EmitedCalls, amounth);
                    me.EmitedCalls -= nbCallToCancel;
                    me.ReservedPartOfBalance -= Constants.MULTI_COIN_PRICE * nbCallToCancel;
                    other.ReceivedCalls -= nbCallToCancel;

                    // bind seller & buyer if it is not the case yet
                    if (me.Father == null)
                    {
                        me.Father = other;
                        other.Childs.Add(me);
                        me.Rank = other.Rank + 1;
                    }
                    try { db.SaveChanges(); }
                    catch (DbUpdateConcurrencyException e) { return buy(_me, _other, amounth); }
                }
                re_sell(_me);
                return true;
            }
            return false;
        }
        /// <summary>
        /// Call the father
        /// </summary>
        /// <param name="amounth"></param>
        /// <returns></returns>
        private static Boolean call(User _me, int amounth = 1)
        {
            //Check if the user has enough money to call
            if (_me.Balance - _me.ReservedPartOfBalance >= Constants.MULTI_COIN_PRICE * amounth)
            {
                // if the amounth is 0 or less, do nothing and return true
                if (amounth > 0)
                {
                    //check if the father has some Multicoins to sell before calling him
                    if (_me.Father.MultiCoins != 0)
                    {
                        // buy the available multicoins.
                        var amounthBuy = Math.Min(_me.Father.MultiCoins, amounth);
                        if (buy(_me, _me.Father, amounthBuy))
                        {
                            // Call for the difference
                            return call(_me, amounth - amounthBuy);
                        }
                        // If buy failed recall call function
                        return call(_me, amounth);
                    }

                    // If there is no available multicoins, proceed call
                    using (SmartTreeEntities db = new SmartTreeEntities())
                    {
                        var user = db.Users.Find(_me.UserId);
                        var father = db.Users.Find(_me.FatherId);

                        user.EmitedCalls += amounth;
                        user.ReservedPartOfBalance += Constants.MULTI_COIN_PRICE * amounth;
                        father.ReceivedCalls += amounth;
                        try{ db.SaveChanges(); }
                        catch (DbUpdateConcurrencyException e) { return call(_me, amounth); }
                    }
                }
                return true;
            }
            return false;
        }
        public ActionResult ExternalLoginConfirmation(RegisterExternalLoginModel model, string returnUrl)
        {
            string provider = null;
            string providerUserId = null;

            if (User.Identity.IsAuthenticated || !OAuthWebSecurity.TryDeserializeProviderUserId(model.ExternalLoginData, out provider, out providerUserId))
            {
                return RedirectToAction("Manage");
            }

            if (ModelState.IsValid)
            {
                // Insert a new user into the database
                using (SmartTreeEntities db = new SmartTreeEntities())
                {
                    User user = db.Users.FirstOrDefault(u => u.Email.ToLower() == model.Email.ToLower());
                    // Check if user already exists
                    if (user == null)
                    {
                        // Insert name into the profile table
                        db.Users.Add(new User { Email = model.Email });
                        db.SaveChanges();

                        OAuthWebSecurity.CreateOrUpdateAccount(provider, providerUserId, model.Email);
                        OAuthWebSecurity.Login(provider, providerUserId, createPersistentCookie: false);

                        return RedirectToLocal(returnUrl);
                    }
                    else
                    {
                        ModelState.AddModelError("UserName", "User name already exists. Please enter a different user name.");
                    }
                }
            }

            ViewBag.ProviderDisplayName = OAuthWebSecurity.GetOAuthClientData(provider).DisplayName;
            ViewBag.ReturnUrl = returnUrl;
            return View(model);
        }