Coin Flip Contract

CoinFlip.sol

// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.18;

contract CoinFlip {
    enum CoinSide {HEADS, TAILS, UNKNOWN}

    CoinSide public winSide = CoinSide.UNKNOWN;

    struct Bet {
        uint256 amount;
        address payable bettor;
    }

    mapping(CoinSide => Bet) public bets;
    mapping(CoinSide => uint256) public wins;
    uint256 private constant BET_AMOUNT = 0.01 ether;
    uint256 private constant SIDES = 2;

    event BetPlaced(CoinSide winSide, address winAddress);
    event WinSideDeclared(CoinSide winSide, address winAddress, address loseAddress);

    function bet(CoinSide side) external payable { 
        require(msg.value == BET_AMOUNT, "Bet amount must be 0.01 Ether");
        require(bets[side].amount == 0, "A bet for this side has already been placed");
        bets[side] = Bet(msg.value, payable(msg.sender));
        emit BetPlaced(side, msg.sender);

        if (bets[CoinSide.HEADS].amount == BET_AMOUNT && bets[CoinSide.TAILS].amount == BET_AMOUNT) {
            flip();
        }
    }

    function flip() internal {
        require(bets[CoinSide.HEADS].amount == BET_AMOUNT, "Heads bet not set");
        require(bets[CoinSide.TAILS].amount == BET_AMOUNT, "Tails bet required");
        require(address(this).balance >= BET_AMOUNT * SIDES, "Insufficient contract balance");

        winSide = getWinSide();
        CoinSide loseSide = (winSide == CoinSide.HEADS ? CoinSide.TAILS : CoinSide.HEADS);
        address loseAddress = bets[loseSide].bettor;
        address payable winAddress = bets[winSide].bettor;
        wins[winSide]++;
        winAddress.transfer(BET_AMOUNT * SIDES);

        emit WinSideDeclared(winSide, winAddress, loseAddress);
        reset();
    }

    function getWinSide() internal view returns (CoinSide) {
        uint256 random = uint256(keccak256(abi.encodePacked(block.timestamp)));
        return CoinSide(random % SIDES);
    }

    function reset() internal {
        delete bets[CoinSide.HEADS];
        delete bets[CoinSide.TAILS];
        winSide = CoinSide.UNKNOWN;
    }
    
    function getBet(CoinSide side) public view returns (uint256, address) {
        return (bets[side].amount, bets[side].bettor);
    }

    function getWins(CoinSide side) public view returns (uint256) {
        return wins[side];
    }
}