LunaBet.sol

// SPDX-License-Identifier: MIT
// @fbsloXBT

pragma solidity 0.8.12;

interface IChainLink {
    function latestAnswer() external returns (uint256);
}

interface IUSDC {
    function transfer(address to, uint256 amount) external;
    function transferFrom(address from, address to, uint256 amount) external;
    function balanceOf(address user) external returns (uint256);
}

contract LunaBet {
   uint256 public start;
   uint256 public startPrice;
   
   address public lower;
   address public higher;

    function enter(bool side) external {
        //Transfer 1,000,000 USDC from sender
        IUSDC(0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48).transferFrom(msg.sender, address(this), 1000000000000);
        //if side = false, user is betting that luna price will be lower
        if (side == false){
            require(lower == address(0), "Side already occupied");
            lower = msg.sender;
        } else {
            require(higher == address(0), "Side already occupied");
            higher = msg.sender;
        }

        if (lower != address(0) && higher != address(0)){
            start = block.timestamp;
            startPrice = getLunaPrice();
        } 
    }

    function redeem() external {
        require(block.timestamp - start > 31556926, "1 year has not yet passed");

        uint256 balance = IUSDC(0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48).balanceOf(address(this));

        if (getLunaPrice() > startPrice){
            IUSDC(0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48).transfer(higher, balance);
        } else if (getLunaPrice() < startPrice) {
            IUSDC(0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48).transfer(lower, balance);
        } else {
            IUSDC(0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48).transfer(higher, balance / 2);
            IUSDC(0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48).transfer(lower, balance / 2);
        }
    }  

    //Returns USD value using ChainLink on Ethereum
    function getLunaPrice() public returns (uint256) {
        //get LUNA-ETH price
        uint256 ethLuna = IChainLink(0x91E9331556ED76C9393055719986409e11b56f73).latestAnswer(); //18 decimals
        //get ETH-USD
        uint256 usdEth = IChainLink(0x5f4eC3Df9cbd43714FE2740f5E3616155c5b8419).latestAnswer(); //8 decimals
        //LUNA-USD value 
        return ethLuna * usdEth; //26 decimal places
    }
}