test.sol

pragma solidity ^0.8.0;

interface IERC20 {

    function totalSupply() external view returns (uint256);
    function balanceOf(address account) external view returns (uint256);
    function allowance(address owner, address spender) external view returns (uint256);

    function transfer(address recipient, uint256 amount) external returns (bool);
    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);
}


contract gutTest is IERC20 {

    string public constant name = "@italexey";
    string public constant symbol = "test";
    uint8 public constant decimals = 18;

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

    mapping(address => mapping (address => uint256)) allowed;

    uint256 totalSupply_ = 0;
    uint256 public periodSecond = 86400 * 200;
    uint256 public price;


   constructor() {
       price = 0.1 ether;
    }

    function totalSupply() public override view returns (uint256) {
        return totalSupply_;
    }

    function balanceOf(address tokenOwner) public override view returns (uint256) {
        return balances[tokenOwner];
    }


    function delayedBuy() payable public returns (uint256 perSecond, uint32 lockedAt, uint32 lockedUntil, uint32 left, uint32 avail, uint256 leftAmount, uint256 availAmount) {
        require(msg.value > 0, "ERR_NOT_ENOUGH");
        claim();
        uint256 leftValue = 0;
        (uint256 perSecond, uint32 lockedAt, uint32 lockedUntil, uint32 left, uint32 avail, uint256 leftAmount, uint256 availAmount) = claimable(msg.sender);
        if (perSecond > 0) {
            leftValue = leftAmount * price / 1 ether;
        }
        uint256 totalAmount = (msg.value + leftValue) * 1 ether / price;
        perSecond = totalAmount / periodSecond;
        lockedPacked[msg.sender] = 
            (perSecond << 64) + (block.timestamp << 32) + (block.timestamp + periodSecond)
        ;
        return claimable(msg.sender);
    }

    function claimable(address sender) public view returns (uint256 perSecond, uint32 lockedAt, uint32 lockedUntil, uint32 left, uint32 avail, uint256 leftAmount, uint256 availAmount) {
        perSecond = uint128(lockedPacked[sender] >> 64);
        lockedAt = uint32(uint64(lockedPacked[sender] - (perSecond << 64)) >> 32);
        lockedUntil = uint32(uint64(lockedPacked[sender] - (perSecond << 64)) - (uint64(lockedAt) << 32));
        if(lockedUntil < block.timestamp) {
            avail = lockedUntil - lockedAt;
        } else {
            avail = uint32(block.timestamp - lockedAt);
        }
        left = lockedUntil - lockedAt;
        leftAmount = perSecond * left;
        availAmount = perSecond * avail;
    }

    function claim() public {
        (uint256 perSecond, uint32 lockedAt, uint32 lockedUntil, , , , uint256 availAmount) = claimable(msg.sender);
        if(availAmount == 0) return;
        if(lockedUntil < block.timestamp) {
            lockedPacked[msg.sender] = 0;
        } else {
            lockedAt = uint32(block.timestamp);
            lockedPacked[msg.sender] = 
                (perSecond << 64) + (uint256(lockedAt) << 32) + uint256(lockedUntil)
            ;
        }
        balances[msg.sender] += availAmount;
        totalSupply_ += availAmount;
        emit Transfer(address(0x0), msg.sender, availAmount);
    }

    function transfer(address receiver, uint256 numTokens) public override returns (bool) {
        require(numTokens <= balances[msg.sender]);
        balances[msg.sender] = balances[msg.sender]-numTokens;
        balances[receiver] = balances[receiver]+numTokens;
        emit Transfer(msg.sender, receiver, numTokens);
        return true;
    }

    function approve(address delegate, uint256 numTokens) public override returns (bool) {
        allowed[msg.sender][delegate] = numTokens;
        emit Approval(msg.sender, delegate, numTokens);
        return true;
    }

    function allowance(address owner, address delegate) public override view returns (uint) {
        return allowed[owner][delegate];
    }

    function transferFrom(address owner, address buyer, uint256 numTokens) public override returns (bool) {
        require(numTokens <= balances[owner]);
        require(numTokens <= allowed[owner][msg.sender]);

        balances[owner] = balances[owner]-numTokens;
        allowed[owner][msg.sender] = allowed[owner][msg.sender]-numTokens;
        balances[buyer] = balances[buyer]+numTokens;
        emit Transfer(owner, buyer, numTokens);
        return true;
    }
}