TimeLock.sol

// SPDX-License-Identifier: MIT
pragma solidity  ^0.8.6;

interface IERC20 {
  function totalSupply() external view returns (uint256);
  function balanceOf(address account) external view returns (uint256);
  function transfer(address recipient, uint256 amount) external returns (bool);
  function allowance(address owner, address spender) external view returns (uint256);
  function approve(address spender, uint256 amount) external returns (bool);
  function transferFrom(
      address sender,
      address recipient,
      uint256 amount
  ) external returns (bool);
  event Transfer(address indexed from, address indexed to, uint256 value);
  event Approval(address indexed owner, address indexed spender, uint256 value);
}

library Address {
  function isContract(address account) internal view returns (bool) {
    uint256 size;
    assembly {
        size := extcodesize(account)
    }
    return size > 0;
  }

  function sendValue(address payable recipient, uint256 amount) internal {
    require(address(this).balance >= amount, "Address: insufficient balance");

    (bool success, ) = recipient.call{value: amount}("");
    require(success, "Address: unable to send value, recipient may have reverted");
  }

  function functionCall(address target, bytes memory data) internal returns (bytes memory) {
    return functionCall(target, data, "Address: low-level call failed");
  }

  function functionCall(
    address target,
    bytes memory data,
    string memory errorMessage
  ) internal returns (bytes memory) {
    return functionCallWithValue(target, data, 0, errorMessage);
  }

  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");
  }

  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");
    require(isContract(target), "Address: call to non-contract");

    (bool success, bytes memory returndata) = target.call{value: value}(data);
    return verifyCallResult(success, returndata, errorMessage);
  }

  function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
    return functionStaticCall(target, data, "Address: low-level static call failed");
  }

  function functionStaticCall(
    address target,
    bytes memory data,
    string memory errorMessage
  ) internal view returns (bytes memory) {
    require(isContract(target), "Address: static call to non-contract");
    (bool success, bytes memory returndata) = target.staticcall(data);
    return verifyCallResult(success, returndata, errorMessage);
  }

  function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
    return functionDelegateCall(target, data, "Address: low-level delegate call failed");
  }

  function functionDelegateCall(
    address target,
    bytes memory data,
    string memory errorMessage
  ) internal returns (bytes memory) {
    require(isContract(target), "Address: delegate call to non-contract");

    (bool success, bytes memory returndata) = target.delegatecall(data);
    return verifyCallResult(success, returndata, errorMessage);
  }

  function verifyCallResult(
    bool success,
    bytes memory returndata,
    string memory errorMessage
  ) internal pure returns (bytes memory) {
    if (success) {
      return returndata;
    } else {
      if (returndata.length > 0) {
        assembly {
          let returndata_size := mload(returndata)
          revert(add(32, returndata), returndata_size)
        }
      } else {
        revert(errorMessage);
      }
    }
}
}

library SafeERC20 {
  using Address for address;
  function safeTransfer(
    IERC20 token,
    address to,
    uint256 value
  ) internal {
    _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
  }

  function safeTransferFrom(
    IERC20 token,
    address from,
    address to,
    uint256 value
  ) internal {
    _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
  }

  function safeApprove(
      IERC20 token,
      address spender,
      uint256 value
  ) internal {
    require(
      (value == 0) || (token.allowance(address(this), spender) == 0),
      "SafeERC20: approve from non-zero to non-zero allowance"
    );
    _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
  }

  function safeIncreaseAllowance(
    IERC20 token,
    address spender,
    uint256 value
  ) internal {
    uint256 newAllowance = token.allowance(address(this), spender) + value;
    _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
  }

  function safeDecreaseAllowance(
    IERC20 token,
    address spender,
    uint256 value
  ) internal {
    unchecked {
      uint256 oldAllowance = token.allowance(address(this), spender);
      require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
      uint256 newAllowance = oldAllowance - value;
      _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }
  }

  function _callOptionalReturn(IERC20 token, bytes memory data) private {
    bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
    if (returndata.length > 0) {
      require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
    }
  }
}



contract DecentralizedTokenLockBank {
  address public admin;
  using SafeERC20 for IERC20;

  struct Lock {
    uint amount;
    uint expiration;
  } 

  // sender -> token -> Lock
  mapping(address => mapping(address => Lock)) locks;

  function deposit(address _token, uint _amount, uint _duration) external {
    address _sender = msg.sender;
    require(_amount > 0, "No amount specified");
    uint _expiration = block.timestamp + _duration;
    require(_expiration > 0, "Lock Period In The Past");
    IERC20(_token).safeTransferFrom(_sender, address(this), _amount);
    locks[_sender][_token] = Lock(_amount, _expiration);
  }

  function withdraw(address _token) external {
    address _sender = msg.sender;
    Lock memory _lock = locks[_sender][_token];
    require(block.timestamp >= _lock.expiration, "Too early");
    IERC20 token = IERC20(_token);
    locks[_sender][_token] = Lock(0, block.timestamp);
    IERC20(token).safeTransfer(_sender, _lock.amount);
  }
  
  function showLock(address _account, address _token) public view returns(Lock memory) {
    return locks[_account][_token];
  }
}