public function index(Request $request)
    {
        // проверки
        if ($request->input("type") == "bet" ||
            $request->input("type") == "withdraw" ||
            $request->input("type") !== "create") 
        {
            if (!Auth::check()) {
                return json_encode(["errors" => "Вы должны быть авторизованы"]);
            }
        }
        if ($request->input("type") == "bet" ||
            $request->input("type") == "create") 
            {
                if (User::getUser()->balance < intval($request->input("bet"))) 
                {
                    return json_encode(["errors" => "Недостаточно средств"]);
                }
            }
        //
        $game = $request->input("game");
        switch ($game) {
            case "dice":
                $validator = Validator::make($request->all(), [
                    "bet" => "required|numeric|min:1|max:10000",
                    "coef" => "required|numeric|min:1.05|max:100",
                ]);
                if ($validator->fails()) 
                {
                    return json_encode(["errors" => $validator->errors()->first()]);
                }
                $this->bet = intval($request->input("bet"));
                $this->coef = floatval($request->input("coef"));
                return $this->dice();
                break;
            case "coin":
                if ($request->input("type") !== "bet" && $request->input("type") !== "withdraw") 
                    {
                        $validator = Validator::make($request->all(), [
                            "bet" => "required|numeric|min:1|max:15000",
                        ]);
                        if ($validator->fails() && $request->input("type") !== "is_active") 
                        {
                            return json_encode(["errors" => $validator->errors()->first()]);
                        }
                    } 
                $this->bet = intval($request->input("bet"));
                $this->side = $request->input("side");
                $this->type = $request->input("type");
                return $this->coin();
                break;
            case "mines":
                if (
                    $request->input("type") !== "bet" &&
                    $request->input("type") !== "get_coefs"
                ) {
                    $validator = Validator::make($request->all(), [
                        "bet" => "required|numeric|min:1|max:5000",
                        "mines" => "required|numeric|min:3|max:24",
                    ]);
                    if  ($validator->fails() &&
                        $request->input("type") !== "is_active" &&
                        $request->input("type") !== "withdraw") 
                        {
                            return json_encode(["errors" => $validator->errors()->first(),]);
                        }
                }
                $this->bet = intval($request->input("bet"));
                $this->mines = $request->input("mines");
                $this->mine = $request->input("mine");
                $this->type = $request->input("type");
                return $this->mines();
                break;
            case "wheel":
                $validator = Validator::make($request->all(), [
                    "bet" => "required|numeric|min:1"
                ]);
                if ($validator->fails() && $request->input("type") == "create")
                {
                    return json_encode(["errors" => $validator->errors()->first(),]);
                }
                $this->type = $request->input("type");
                $this->color = $request->input("color");
                $this->bet = $request->input("bet");
                $this->game_id = $request->input("game_id");
                return $this->wheel();
                break;
            case "bonus_wheel":
                $this->type = $request->input("type");
                return $this->wheel_bonus();
                break;
            default:
                return "unknown game";
        }
    }if ($request->input("type") заменяй на switch case, тем более далее по тексту у тебя оно используется, пиши код хотя бы в одном стиле.