tokencustodiante.sol

/*
SPDX-License-Identifier: CC-BY-4.0
(c) Desenvolvido por Jeff Prestes
This work is licensed under a Creative Commons Attribution 4.0 International License.
*/

pragma solidity 0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

    function name() external view returns(string memory);
    
    function symbol() external view returns(string memory);
    
}

contract Custodiante {
    
    IERC20 public token; 
    address public administrador;
    
    constructor(address _enderecoToken) {
        token = IERC20(_enderecoToken);
        administrador = msg.sender;
    }
    
    function mudarToken(address _enderecoToken) public returns (bool) {
        require(msg.sender == administrador, "Somente administrador pode mudar o token");
        token = IERC20(_enderecoToken);
        return true;
    }
    
    function saldoCustodiante() public view returns (uint) {
        return token.balanceOf(address(this));
    }
    
    function qualMeuToken() public view returns (string memory, string memory) {
        return (token.name(), token.symbol());
    }
}