/**
     * @dev  Performs a swap using the provided route and swap parameters.
     * @param   route  The route parameters for the swap.
     * @param   swap_parameters  The parameters for the swaps to perform.
     * @return  The amount of the output token received.
     */
    function swap(RouteParam calldata route, SwapParams[] calldata swap_parameters)
        external
        payable
        returns (uint256)

struct RouteParam {
    address token_in;
    address token_out;
    uint256 amount_in;
    uint256 min_received;
    address destination;
    SwapType swap_type;
}

enum SwapType {
    ethToToken,
    tokenToEth,
    tokenToToken
}

struct SwapParams {
    address token_in;
    address token_out;
    uint32 rate;
    uint256 protocol_id;
    address pool_address;
    SwapType swap_type;
    uint256[] extra_data;
}

event Swap(
    address sender,
    uint256 amount_in,
    uint256 amount_out,
    address token_in,
    address token_out,
    address destination
  )