pset7 finance sell route

@login_required
def sell():
    """Sell shares of stock."""
    if request.method == "POST":
        # ensure that entered stock symbol is valid
        stock = lookup(request.form.get("symbol"))
        if not stock:
            return apology("invalid symbol!")

        # check if user has shares of that stock
        stock_query = db.execute("SELECT * FROM user_stocks WHERE user_id=:uid AND stock_symbol=:ssymbol", uid=session["user_id"], ssymbol=stock["symbol"])
        for i in range(len(stock_query)):
            if stock_query[i]["stock_symbol"] != request.form.get("symbol"):
                return apology("You don't have any shares of that stock!")

        # ensure that user has enough shares of the stock
        total_shares = 0;
        for i in range(len(stock_query)):
            total_shares += stock_query[i]["no_of_shares"]

        # check if subtracting that number of shares will leave the user with no shares of that stock left
        # or if it leaves him/her with the amount he/she wants
        shares_to_sell = int(request.form.get("shares"))
        for i in range(len(stock_query)):
            if shares_to_sell > 0:
                if total_shares < shares_to_sell:
                    return apology("You don't have enough shares of that stock for this!")
                elif total_shares >= shares_to_sell or stock_query[i]["no_of_shares"] >= shares_to_sell:
                    db.execute("INSERT INTO user_stocks (stock_name, stock_price, stock_symbol, no_of_shares, user_id) VALUES(:sname, :sprice, :ssymbol, :shares, :uid)",
                    sname=stock_query[i]["stock_name"], sprice=stock_query[i]["stock_price"], ssymbol=request.form.get("symbol"), shares=(-1 * shares_to_sell), uid=session["user_id"])
            else:
                return apology("The shares you have to sell has to be a positive number greater than 0!")

        user_cash = db.execute("SELECT cash FROM users WHERE id=:uid", uid=session["user_id"])
        db.execute("UPDATE users SET cash=:cash WHERE id=:uid", cash=user_cash[0]["cash"] + (stock["price"] * int(request.form.get("shares"))), uid=session["user_id"])

        return redirect(url_for("index"))

    elif request.method == "GET":
        return render_template("sell.html")