pragma solidity ^0.6.12;

/**
 * @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);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {      
        if (a == 0) {
            return 0;
        }
        uint256 c = a * b;
        require(c / a == b);

        return c;
    }

   
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b > 0);
        uint256 c = a / b;
        return c;
    }

    
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a);
        uint256 c = a - b;
        return c;
    }

   
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a);
        return c;
    }

    
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b != 0);
        return a % b;
    }
}

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
        // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
        // for accounts without code, i.e. `keccak256('')`
        bytes32 codehash;
        bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
        // solhint-disable-next-line no-inline-assembly
        assembly { codehash := extcodehash(account) }
        return (codehash != accountHash && codehash != 0x0);
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (bool success, ) = recipient.call{ value: amount }("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain`call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
      return functionCall(target, data, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        return _functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        return _functionCallWithValue(target, data, value, errorMessage);
    }

    function _functionCallWithValue(address target, bytes memory data, uint256 weiValue, string memory errorMessage) private returns (bytes memory) {
        require(isContract(target), "Address: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.call{ value: weiValue }(data);
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                // solhint-disable-next-line no-inline-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address payable) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}

contract Ownable {
    address public _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    constructor () public {
        _owner = msg.sender;
        emit OwnershipTransferred(address(0), msg.sender);
    }

    function owner() public view returns (address) {
        return _owner;
    }

    modifier onlyOwner() {
        require(_owner == msg.sender, "Ownable: caller is not the owner");
        _;
    }

    function renounceOwnership() public onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    function transferOwnership(address newOwner) public onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

contract GoBrrrToken is Context, IERC20, Ownable {
    using SafeMath for uint256;
    using Address for address;
    
    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed owner, address indexed spender, uint256 value);
    
    mapping(address => uint256) private _balanceOf;
    mapping (address => mapping (address => uint256)) private _allowance;
    
    modifier validRecipient(address to) {
        require(to != address(0x0));
        require(to != address(this));
        _;
    }

    string private constant _name = "Go BRRR";
    string private constant _symbol = "BRRR";
    uint256 private constant _decimals = 18;

    uint256 private _totalSupply = 111 * (uint256(10) ** _decimals);
    
    uint256 public transBurnrate = 3;//0.03%

    constructor() public {
        _owner = msg.sender;
        
        // Initially assign all tokens to the contract's creator.
        _balanceOf[msg.sender] = _totalSupply;
        emit Transfer(address(0x0), msg.sender, _totalSupply);       
    }
    
    function name() public pure returns (string memory) {
        return _name;
    }
    
    function symbol() public pure returns (string memory) {
        return _symbol;
    }
    
    function decimals() public pure returns (uint256) {
        return _decimals;
    }
    
    function totalSupply() public view override returns (uint256) {
        return _totalSupply;
    }
    
    function balanceOf(address account) public view override returns (uint256)
    {
        return _balanceOf[account];
    }
    
    function transfer(address to, uint256 value) public validRecipient(to) virtual override returns (bool)
    {
        require(_balanceOf[msg.sender] >= value);
        
        uint256 remainrate = 10000; 
        remainrate = remainrate.sub(transBurnrate); //99.97%->99.97/10000
        uint256 leftvalue = value.mul(remainrate);
        leftvalue = leftvalue.sub(leftvalue.mod(10000));
        leftvalue = leftvalue.div(10000);

        _balanceOf[msg.sender] -= value;  // deduct from sender's balance
        _balanceOf[to] += leftvalue;          // add to recipient's balance
        
        uint256 decayvalue = value.sub(leftvalue); //3%->3/100->value-leftvalue
        _totalSupply = _totalSupply.sub(decayvalue);
        
        emit Transfer(msg.sender, address(0x0), decayvalue);
        emit Transfer(msg.sender, to, leftvalue);
        
        return true;
    }

    function transferFrom(address from, address to, uint256 value) public validRecipient(to) virtual override returns (bool)
    {
        require(value <= _balanceOf[from]);
        require(value <= _allowance[from][msg.sender]);
        
        uint256 remainrate = 10000; 
        remainrate = remainrate.sub(transBurnrate); //99.97%->99.97/10000
        uint256 leftvalue = value.mul(remainrate);
        leftvalue = leftvalue.sub(leftvalue.mod(10000));
        leftvalue = leftvalue.div(10000);

        _balanceOf[from] -= value;
        _balanceOf[to] += leftvalue;
        _allowance[from][msg.sender] -= value;
        
        uint256 decayvalue = value.sub(leftvalue); //0.03%->3/10000->value-leftvalue
        _totalSupply = _totalSupply.sub(decayvalue);
        
        emit Transfer(from, address(0x0), decayvalue);
        emit Transfer(from, to, leftvalue);
        return true;
    }

    function approve(address spender, uint256 value) public virtual override returns (bool)
    {
        _allowance[msg.sender][spender] = value;
        emit Approval(msg.sender, spender, value);
        return true;
    }
    
    function allowance(address owner, address spender) public view virtual override returns (uint256)
    {
        return _allowance[owner][spender];
    }      
    
    function increaseAllowance(address spender, uint256 addedValue) public returns (bool)
    {
        _allowance[msg.sender][spender] = _allowance[msg.sender][spender].add(addedValue);
        emit Approval(msg.sender, spender, _allowance[msg.sender][spender]);
        return true;
    }

    function decreaseAllowance(address spender, uint256 subtractedValue) public returns (bool)
    {
        uint256 oldValue = _allowance[msg.sender][spender];
        if (subtractedValue >= oldValue) {
            _allowance[msg.sender][spender] = 0;
        } else {
            _allowance[msg.sender][spender] = oldValue.sub(subtractedValue);
        }
        emit Approval(msg.sender, spender, _allowance[msg.sender][spender]);
        return true;
    }        
    
    function changetransBurnrate(uint256 _transBurnrate) external onlyOwner returns (bool) {
        transBurnrate = _transBurnrate;
        return true;
    }

    function mint(address account, uint256 amount) public onlyOwner {
        require(account != address(0));
        
        _beforeTokenTransfer(address(0), account, amount);

        _totalSupply = _totalSupply.add(amount);
        _balanceOf[account] = _balanceOf[account].add(amount);
        emit Transfer(address(0), account, amount);
    }
    
    function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual { }
}

{
  "compilationTarget": {
    "browser/GoBrrr.sol": "GoBrrrToken"
  },
  "evmVersion": "istanbul",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "ipfs"
  },
  "optimizer": {
    "enabled": false,
    "runs": 200
  },
  "remappings": []
}