Solidity Lab

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.6;

contract Bank {

    mapping(address=>uint256) public balances;
    mapping(address=>uint256) public last_refill_times;

    uint constant SECONDS_PER_DAY = 24 * 60 * 60;
    uint constant SECONDS_PER_HOUR = 60 * 60;
    uint constant SECONDS_PER_MINUTE = 60;
    int constant OFFSET19700101 = 2440588;
    uint constant INTEREST_TIME = 60;

    function Deposit() public payable {
        balances[msg.sender] += msg.value;
        last_refill_times[msg.sender] = block.timestamp;
    }

    function Withdrawal(uint256 _to_withdraw) external {
        require(balances[msg.sender] >= _to_withdraw, "not enough money");
        require(_to_withdraw <= 10 ether, "withdrawal more than 10 ETH");
        balances[msg.sender] -= _to_withdraw;
        (bool success, ) = msg.sender.call{value: _to_withdraw}("");
        require(success, "failed to complete");
    }

    function BalanceOf() public view returns(uint256) {
        return(balances[msg.sender]);
    }

    function TransferTo(address _to_transfer, uint256 _value) external {
        require(balances[msg.sender] >= _value, "not enough money");
        require(_value <= 10 ether, "transfer more than 10 ETH");
        balances[msg.sender] -= _value;
        balances[_to_transfer] += _value;
        last_refill_times[_to_transfer] = block.timestamp;
        (bool success, ) = msg.sender.call{value: _value}("");
        require(success, "failed to complete");
    }

    function Interest() public payable {
        uint256 diff = block.timestamp - last_refill_times[msg.sender];
        require(diff >= INTEREST_TIME, "time for interest hasn't passed");
        balances[msg.sender] += (diff / INTEREST_TIME) * (balances[msg.sender] * 7 / 100);
        last_refill_times[msg.sender] = block.timestamp;
    }
}