PoolUSDC.sol

/**
 *Submitted for verification at Optimistic.Etherscan.io on 2022-08-14
*/

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns token decimals.
     */
    function decimals() external view returns (uint8);

    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        assembly {
            size := extcodesize(account)
        }
        return size > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCall(target, data, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");

        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");

        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}
/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using Address for address;

    function safeTransfer(
        IERC20 token,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(
        IERC20 token,
        address from,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        require(
            (value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        uint256 newAllowance = token.allowance(address(this), spender) + value;
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        unchecked {
            uint256 oldAllowance = token.allowance(address(this), spender);
            require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
            uint256 newAllowance = oldAllowance - value;
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
        }
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        if (returndata.length > 0) {
            // Return data is optional
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}
interface IRouter {
    function trading() external view returns (address);

    function capPool() external view returns (address);

    function oracle() external view returns (address);

    function treasury() external view returns (address);

    function darkOracle() external view returns (address);

    function isSupportedCurrency(address currency) external view returns (bool);

    function currencies(uint256 index) external view returns (address);

    function currenciesLength() external view returns (uint256);

    function getDecimals(address currency) external view returns(uint8);

    function getPool(address currency) external view returns (address);

    function getPoolShare(address currency) external view returns(uint256);

    function getCapShare(address currency) external view returns(uint256);

    function getPoolRewards(address currency) external view returns (address);

    function getCapRewards(address currency) external view returns (address);
}
interface IRewards {
    function updateRewards(address account) external;

    function notifyRewardReceived(uint256 amount) external;
}
contract Pool {

	using SafeERC20 for IERC20; 
    using Address for address payable;

    // Contracts
	address public owner;
	address public router;
	address public trading;

	uint256 public withdrawFee = 30; // 0.3%

    address public currency;
    address public rewards; // contract

    uint256 public utilizationMultiplier = 100; // in bps

    uint256 public maxCap = 1000000 ether;

    mapping(address => uint256) private balances; // account => amount staked
    uint256 public totalSupply;

    mapping(address => uint256) lastDeposited;
    uint256 public minDepositTime = 1 hours;

    uint256 public openInterest;

	uint256 public constant UNIT = 10**18;

    // Events
    event Deposit(
    	address indexed user, 
    	address indexed currency,
    	uint256 amount, 
    	uint256 clpAmount
    );
    event Withdraw(
    	address indexed user, 
    	address indexed currency,
    	uint256 amount, 
    	uint256 clpAmount
    );

	constructor(address _currency) {
		owner = msg.sender;
		currency = _currency;
	}

	// Governance methods

	function setOwner(address newOwner) external onlyOwner {
		owner = newOwner;
	}

	function setRouter(address _router) external onlyOwner {
		router = _router;
		trading = IRouter(router).trading();
		rewards = IRouter(router).getPoolRewards(currency);
	}

	function setParams(
		uint256 _minDepositTime,
		uint256 _utilizationMultiplier,
		uint256 _maxCap,
		uint256 _withdrawFee
	) external onlyOwner {
		minDepositTime = _minDepositTime;
		utilizationMultiplier = _utilizationMultiplier;
		maxCap = _maxCap;
		withdrawFee = _withdrawFee;
	}

	// Open interest
	function updateOpenInterest(uint256 amount, bool isDecrease) external onlyTrading {
		if (isDecrease) {
			if (openInterest <= amount) {
				openInterest = 0;
			} else {
				openInterest -= amount;
			}
		} else {
			openInterest += amount;
		}
	}

	// Methods

	function deposit(uint256 amount) external payable {

		uint256 lastBalance = _getCurrentBalance();

		if (currency == address(0)) {
			amount = msg.value;
			lastBalance -= amount;
		} else {
			_transferIn(amount);
		}

		require(amount > 0, "!amount");
		require(amount + lastBalance <= maxCap, "!max-cap");

        uint256 clpAmountToMint = lastBalance == 0 || totalSupply == 0 ? amount : amount * totalSupply / lastBalance;

        lastDeposited[msg.sender] = block.timestamp;

        IRewards(rewards).updateRewards(msg.sender);

        totalSupply += clpAmountToMint;
        balances[msg.sender] += clpAmountToMint;

        emit Deposit(
        	msg.sender,
        	currency,
        	amount,
        	clpAmountToMint
        );

	}

	function withdraw(uint256 currencyAmount) external {

		require(currencyAmount > 0, "!amount");
		require(block.timestamp > lastDeposited[msg.sender] + minDepositTime, "!cooldown");

		IRewards(rewards).updateRewards(msg.sender);

		// Determine corresponding CLP amount

		uint256 currentBalance = _getCurrentBalance();
		require(currentBalance > 0 && totalSupply > 0, "!empty");

		uint256 utilization = getUtilization();
		require(utilization < 10**4, "!utilization");
		
		// CLP amount
		uint256 amount = currencyAmount * totalSupply / currentBalance;

		// Set to max if above max
		if (amount >= balances[msg.sender]) {
			amount = balances[msg.sender];
			currencyAmount = amount * currentBalance / totalSupply;
		}

		uint256 availableBalance = currentBalance * (10**4 - utilization) / 10**4;
		uint256 currencyAmountAfterFee = currencyAmount * (10**4 - withdrawFee) / 10**4;
		require(currencyAmountAfterFee <= availableBalance, "!available-balance");

		totalSupply -= amount;
		balances[msg.sender] -= amount;

		_transferOut(msg.sender, currencyAmountAfterFee);

		// Send fee to this pool's rewards contract
		uint256 feeAmount = currencyAmount - currencyAmountAfterFee;
		_transferOut(rewards, feeAmount);
		IRewards(rewards).notifyRewardReceived(feeAmount);

		emit Withdraw(
			msg.sender,
			currency,
			currencyAmountAfterFee,
			amount
		);
		
	}

	function creditUserProfit(address destination, uint256 amount) external onlyTrading {
		if (amount == 0) return;
		uint256 currentBalance = _getCurrentBalance();
		require(amount < currentBalance, "!balance");
		_transferOut(destination, amount);
	}

	// To receive ETH
	fallback() external payable {}
	receive() external payable {}

	// Utils

	function _transferIn(uint256 amount) internal {
		// adjust decimals
		uint256 decimals = IRouter(router).getDecimals(currency);
		amount = amount * (10**decimals) / UNIT;
		IERC20(currency).safeTransferFrom(msg.sender, address(this), amount);
	}

	function _transferOut(address to, uint256 amount) internal {
		if (amount == 0 || to == address(0)) return;
		// adjust decimals
		uint256 decimals = IRouter(router).getDecimals(currency);
		amount = amount * (10**decimals) / UNIT;
		if (currency == address(0)) {
			payable(to).sendValue(amount);
		} else {
			IERC20(currency).safeTransfer(to, amount);
		}
	}

	function _getCurrentBalance() internal view returns(uint256) {
		uint256 currentBalance;
		if (currency == address(0)) {
			currentBalance = address(this).balance;
		} else {
			currentBalance = IERC20(currency).balanceOf(address(this));
		}
		uint256 decimals = IRouter(router).getDecimals(currency);
		return currentBalance * UNIT / (10**decimals);
	}

	// Getters

	function getUtilization() public view returns(uint256) {
		uint256 currentBalance = _getCurrentBalance();
		if (currentBalance == 0) return 0;
		return openInterest * utilizationMultiplier / currentBalance; // in bps
	}

	function getCurrencyBalance(address account) external view returns(uint256) {
		if (totalSupply == 0) return 0;
		uint256 currentBalance = _getCurrentBalance();
		return balances[account] * currentBalance / totalSupply;
	}

	// In Clp
	function getBalance(address account) external view returns(uint256) {
		return balances[account];
	}

	// Modifier

	modifier onlyOwner() {
		require(msg.sender == owner, "!owner");
		_;
	}

	modifier onlyTrading() {
		require(msg.sender == trading, "!trading");
		_;
	}

}