contract SushiToken is ERC20("SushiToken", "SUSHI"), Ownable {
	/// @notice Creates `_amount` token to `_to`. Must only be called by the owner (MasterChef).
	function mint(address _to, uint256 _amount) public onlyOwner {
		_mint(_to, _amount);
		_moveDelegates(address(0), _delegates[_to], _amount);
	}

	// Copied and modified from YAM code:
	// https://github.com/yam-finance/yam-protocol/blob/master/contracts/token/YAMGovernanceStorage.sol
	// https://github.com/yam-finance/yam-protocol/blob/master/contracts/token/YAMGovernance.sol
	// Which is copied and modified from COMPOUND:
	// https://github.com/compound-finance/compound-protocol/blob/master/contracts/Governance/Comp.sol

	/// @notice A record of each accounts delegate
	mapping(address => address) internal _delegates;

	/// @notice A checkpoint for marking number of votes from a given block
	struct Checkpoint {
		uint32 fromBlock;
		uint256 votes;
	}

	/// @notice A record of votes checkpoints for each account, by index
	mapping(address => mapping(uint32 => Checkpoint)) public checkpoints;

	/// @notice The number of checkpoints for each account
	mapping(address => uint32) public numCheckpoints;

	/// @notice The EIP-712 typehash for the contract's domain
	bytes32 public constant DOMAIN_TYPEHASH =
		keccak256("EIP712Domain(string name,uint256 chainId,address verifyingContract)");

	/// @notice The EIP-712 typehash for the delegation struct used by the contract
	bytes32 public constant DELEGATION_TYPEHASH = keccak256("Delegation(address delegatee,uint256 nonce,uint256 expiry)");

	/// @notice A record of states for signing / validating signatures
	mapping(address => uint256) public nonces;

	/// @notice An event thats emitted when an account changes its delegate
	event DelegateChanged(address indexed delegator, address indexed fromDelegate, address indexed toDelegate);

	/// @notice An event thats emitted when a delegate account's vote balance changes
	event DelegateVotesChanged(address indexed delegate, uint256 previousBalance, uint256 newBalance);

	/**
	 * @notice Delegate votes from `msg.sender` to `delegatee`
	 * @param delegator The address to get delegatee for
	 */
	function delegates(address delegator) external view returns (address) {
		return _delegates[delegator];
	}

	/**
	 * @notice Delegate votes from `msg.sender` to `delegatee`
	 * @param delegatee The address to delegate votes to
	 */
	function delegate(address delegatee) external {
		return _delegate(msg.sender, delegatee);
	}

	/**
	 * @notice Delegates votes from signatory to `delegatee`
	 * @param delegatee The address to delegate votes to
	 * @param nonce The contract state required to match the signature
	 * @param expiry The time at which to expire the signature
	 * @param v The recovery byte of the signature
	 * @param r Half of the ECDSA signature pair
	 * @param s Half of the ECDSA signature pair
	 */
	function delegateBySig(
		address delegatee,
		uint256 nonce,
		uint256 expiry,
		uint8 v,
		bytes32 r,
		bytes32 s
	) external {
		bytes32 domainSeparator =
			keccak256(abi.encode(DOMAIN_TYPEHASH, keccak256(bytes(name())), getChainId(), address(this)));

		bytes32 structHash = keccak256(abi.encode(DELEGATION_TYPEHASH, delegatee, nonce, expiry));

		bytes32 digest = keccak256(abi.encodePacked("\x19\x01", domainSeparator, structHash));

		address signatory = ecrecover(digest, v, r, s);
		require(signatory != address(0), "SUSHI::delegateBySig: invalid signature");
		require(nonce == nonces[signatory]++, "SUSHI::delegateBySig: invalid nonce");
		require(now <= expiry, "SUSHI::delegateBySig: signature expired");
		return _delegate(signatory, delegatee);
	}

	/**
	 * @notice Gets the current votes balance for `account`
	 * @param account The address to get votes balance
	 * @return The number of current votes for `account`
	 */
	function getCurrentVotes(address account) external view returns (uint256) {
		uint32 nCheckpoints = numCheckpoints[account];
		return nCheckpoints > 0 ? checkpoints[account][nCheckpoints - 1].votes : 0;
	}

	/**
	 * @notice Determine the prior number of votes for an account as of a block number
	 * @dev Block number must be a finalized block or else this function will revert to prevent misinformation.
	 * @param account The address of the account to check
	 * @param blockNumber The block number to get the vote balance at
	 * @return The number of votes the account had as of the given block
	 */
	function getPriorVotes(address account, uint256 blockNumber) external view returns (uint256) {
		require(blockNumber < block.number, "SUSHI::getPriorVotes: not yet determined");

		uint32 nCheckpoints = numCheckpoints[account];
		if (nCheckpoints == 0) {
			return 0;
		}

		// First check most recent balance
		if (checkpoints[account][nCheckpoints - 1].fromBlock <= blockNumber) {
			return checkpoints[account][nCheckpoints - 1].votes;
		}

		// Next check implicit zero balance
		if (checkpoints[account][0].fromBlock > blockNumber) {
			return 0;
		}

		uint32 lower = 0;
		uint32 upper = nCheckpoints - 1;
		while (upper > lower) {
			uint32 center = upper - (upper - lower) / 2; // ceil, avoiding overflow
			Checkpoint memory cp = checkpoints[account][center];
			if (cp.fromBlock == blockNumber) {
				return cp.votes;
			} else if (cp.fromBlock < blockNumber) {
				lower = center;
			} else {
				upper = center - 1;
			}
		}
		return checkpoints[account][lower].votes;
	}

	function _delegate(address delegator, address delegatee) internal {
		address currentDelegate = _delegates[delegator];
		uint256 delegatorBalance = balanceOf(delegator); // balance of underlying SUSHIs (not scaled);
		_delegates[delegator] = delegatee;

		emit DelegateChanged(delegator, currentDelegate, delegatee);

		_moveDelegates(currentDelegate, delegatee, delegatorBalance);
	}

	function _moveDelegates(
		address srcRep,
		address dstRep,
		uint256 amount
	) internal {
		if (srcRep != dstRep && amount > 0) {
			if (srcRep != address(0)) {
				// decrease old representative
				uint32 srcRepNum = numCheckpoints[srcRep];
				uint256 srcRepOld = srcRepNum > 0 ? checkpoints[srcRep][srcRepNum - 1].votes : 0;
				uint256 srcRepNew = srcRepOld.sub(amount);
				_writeCheckpoint(srcRep, srcRepNum, srcRepOld, srcRepNew);
			}

			if (dstRep != address(0)) {
				// increase new representative
				uint32 dstRepNum = numCheckpoints[dstRep];
				uint256 dstRepOld = dstRepNum > 0 ? checkpoints[dstRep][dstRepNum - 1].votes : 0;
				uint256 dstRepNew = dstRepOld.add(amount);
				_writeCheckpoint(dstRep, dstRepNum, dstRepOld, dstRepNew);
			}
		}
	}

	function _writeCheckpoint(
		address delegatee,
		uint32 nCheckpoints,
		uint256 oldVotes,
		uint256 newVotes
	) internal {
		uint32 blockNumber = safe32(block.number, "SUSHI::_writeCheckpoint: block number exceeds 32 bits");

		if (nCheckpoints > 0 && checkpoints[delegatee][nCheckpoints - 1].fromBlock == blockNumber) {
			checkpoints[delegatee][nCheckpoints - 1].votes = newVotes;
		} else {
			checkpoints[delegatee][nCheckpoints] = Checkpoint(blockNumber, newVotes);
			numCheckpoints[delegatee] = nCheckpoints + 1;
		}

		emit DelegateVotesChanged(delegatee, oldVotes, newVotes);
	}

	function safe32(uint256 n, string memory errorMessage) internal pure returns (uint32) {
		require(n < 2**32, errorMessage);
		return uint32(n);
	}

	function getChainId() internal pure returns (uint256) {
		uint256 chainId;
		assembly {
			chainId := chainid()
		}
		return chainId;
	}
}
// SushiToken with Governance.
function delegates(address delegator) external view returns (address) {
	return _delegates[delegator];
}

/**
 	 * @notice Delegate votes from `msg.sender` to `delegatee`
 	 * @param delegator The address to get delegatee for
 	 */