Cryo Explorer Ethereum Mainnet

// SPDX-License-Identifier: MIT
pragma solidity 0.8.9;

import "GenericDistributor.sol";
import "IERC4626.sol";

contract sCrvUsdDistributor is GenericDistributor {
    using SafeERC20 for IERC20;

    uint256 private constant DECIMALS = 1e9;
    uint256 public platformFee = 2e7;
    address public platform = 0x9Bc7c6ad7E7Cf3A6fCB58fb21e27752AC1e53f99;

    event PlatformFeeUpdated(uint256 _fee);
    event PlatformUpdated(address indexed _platform);

    /// @notice Updates the part of incentives redirected to the platform
    /// @param _fee - the amount of the new platform fee (in BIPS)
    function setPlatformFee(uint256 _fee) external onlyAdmin {
        assert(_fee < 1e8);
        platformFee = _fee;
        emit PlatformFeeUpdated(_fee);
    }

    /// @notice Updates the address to which platform fees are paid out
    /// @param _platform - the new platform wallet address
    function setPlatform(
        address _platform
    ) external onlyAdmin notToZeroAddress(_platform) {
        platform = _platform;
        emit PlatformUpdated(_platform);
    }

    constructor(
        address _vault,
        address _depositor,
        address _token
    ) GenericDistributor(_vault, _depositor, _token) {}

    /// @notice Stakes the contract's entire crvUSD balance in the scrvUSD Vault
    function stake() external override onlyAdminOrDistributor {
        uint256 _crvUsdBalance = IERC20(token).balanceOf(address(this));
        uint256 _scrvUsdBalancce = IERC4626(vault).deposit(_crvUsdBalance, address(this));
        uint256 _feeAmount = (_scrvUsdBalancce * platformFee) / DECIMALS;
        IERC4626(vault).transfer(platform, _feeAmount);
    }
}

// SPDX-License-Identifier: MIT
// https://etherscan.io/address/0xcbe6b83e77cdc011cc18f6f0df8444e5783ed982#code
pragma solidity 0.8.9;

import "SafeERC20.sol";
import "MerkleProof.sol";
import "IGenericVault.sol";

// Allows anyone to claim a token if they exist in a merkle root.
contract GenericDistributor {
    using SafeERC20 for IERC20;

    address public vault;
    address public token;
    bytes32 public merkleRoot;
    uint32 public week;
    bool public frozen;

    address public admin;
    address public depositor;

    // This is a packed array of booleans.
    mapping(uint256 => mapping(uint256 => uint256)) private claimedBitMap;

    // This event is triggered whenever a call to #claim succeeds.
    event Claimed(
        uint256 index,
        uint256 indexed amount,
        address indexed account,
        uint256 week
    );
    // This event is triggered whenever the merkle root gets updated.
    event MerkleRootUpdated(bytes32 indexed merkleRoot, uint32 indexed week);
    // This event is triggered whenever the admin is updated.
    event AdminUpdated(address indexed oldAdmin, address indexed newAdmin);
    // This event is triggered whenever the depositor contract is updated.
    event DepositorUpdated(
        address indexed oldDepositor,
        address indexed newDepositor
    );
    // This event is triggered whenever the vault contract is updated.
    event VaultUpdated(address indexed oldVault, address indexed newVault);
    // When recovering stuck ERC20s
    event Recovered(address token, uint256 amount);

    constructor(address _vault, address _depositor, address _token) {
        require(_vault != address(0));
        vault = _vault;
        admin = msg.sender;
        depositor = _depositor;
        token = _token;
        week = 0;
        frozen = true;
    }

    /// @notice Set approvals for the tokens used when swapping
    function setApprovals() external virtual onlyAdmin {
        IERC20(token).safeApprove(vault, 0);
        IERC20(token).safeApprove(vault, type(uint256).max);
    }

    /// @notice Check if the index has been marked as claimed.
    /// @param index - the index to check
    /// @return true if index has been marked as claimed.
    function isClaimed(uint256 index) public view returns (bool) {
        uint256 claimedWordIndex = index / 256;
        uint256 claimedBitIndex = index % 256;
        uint256 claimedWord = claimedBitMap[week][claimedWordIndex];
        uint256 mask = (1 << claimedBitIndex);
        return claimedWord & mask == mask;
    }

    function _setClaimed(uint256 index) private {
        uint256 claimedWordIndex = index / 256;
        uint256 claimedBitIndex = index % 256;
        claimedBitMap[week][claimedWordIndex] =
            claimedBitMap[week][claimedWordIndex] |
            (1 << claimedBitIndex);
    }

    /// @notice Transfers ownership of the contract
    /// @param newAdmin - address of the new admin of the contract
    function updateAdmin(
        address newAdmin
    ) external onlyAdmin notToZeroAddress(newAdmin) {
        address oldAdmin = admin;
        admin = newAdmin;
        emit AdminUpdated(oldAdmin, newAdmin);
    }

    /// @notice Changes the contract allowed to freeze before depositing
    /// @param newDepositor - address of the new depositor contract
    function updateDepositor(
        address newDepositor
    ) external onlyAdmin notToZeroAddress(newDepositor) {
        address oldDepositor = depositor;
        depositor = newDepositor;
        emit DepositorUpdated(oldDepositor, newDepositor);
    }

    /// @notice Changes the Vault where funds are staked
    /// @param newVault - address of the new vault contract
    function updateVault(
        address newVault
    ) external onlyAdmin notToZeroAddress(newVault) {
        address oldVault = vault;
        vault = newVault;
        emit VaultUpdated(oldVault, newVault);
    }

    /// @notice Internal function to handle users' claims
    /// @param index - claimer index
    /// @param account - claimer account
    /// @param amount - claim amount
    /// @param merkleProof - merkle proof for the claim
    function _claim(
        uint256 index,
        address account,
        uint256 amount,
        bytes32[] calldata merkleProof
    ) internal {
        require(!frozen, "Claiming is frozen.");
        require(!isClaimed(index), "Drop already claimed.");

        // Verify the merkle proof.
        bytes32 node = keccak256(abi.encodePacked(index, account, amount));
        require(
            MerkleProof.verify(merkleProof, merkleRoot, node),
            "Invalid proof."
        );

        // Mark it claimed and send the token.
        _setClaimed(index);
    }

    /// @notice Claim the given amount of uCRV to the given address.
    /// @param index - claimer index
    /// @param account - claimer account
    /// @param amount - claim amount
    /// @param merkleProof - merkle proof for the claim
    function claim(
        uint256 index,
        address account,
        uint256 amount,
        bytes32[] calldata merkleProof
    ) external {
        // Claim
        _claim(index, account, amount, merkleProof);

        // Send shares to account
        IERC20(vault).safeTransfer(account, amount);

        emit Claimed(index, amount, account, week);
    }

    /// @notice Stakes the contract's entire balance in the Vault
    function stake() external virtual onlyAdminOrDistributor {
        IGenericVault(vault).depositAll(address(this));
    }

    /// @notice Freezes the claim function to allow the merkleRoot to be changed
    /// @dev Can be called by the owner or the depositor zap contract
    function freeze() external onlyAdminOrDistributor {
        frozen = true;
    }

    /// @notice Unfreezes the claim function.
    function unfreeze() public onlyAdmin {
        frozen = false;
    }

    /// @notice Update the merkle root and increment the week.
    /// @param _merkleRoot - the new root to push
    /// @param _unfreeze - whether to unfreeze the contract after unlock
    function updateMerkleRoot(
        bytes32 _merkleRoot,
        bool _unfreeze
    ) external onlyAdmin {
        require(frozen, "Contract not frozen.");

        // Increment the week (simulates the clearing of the claimedBitMap)
        week = week + 1;
        // Set the new merkle root
        merkleRoot = _merkleRoot;

        emit MerkleRootUpdated(merkleRoot, week);

        if (_unfreeze) {
            unfreeze();
        }
    }

    /// @notice Recover ERC20s mistakenly sent to the contract
    /// @param tokenAddress - address of the token to retrieve
    /// @param tokenAmount - amount to retrieve
    /// @dev Will revert if token is same as token being distributed
    function recoverERC20(
        address tokenAddress,
        uint256 tokenAmount
    ) external onlyAdmin {
        require(
            tokenAddress != address(token),
            "Cannot withdraw the distributed token"
        );
        IERC20(tokenAddress).safeTransfer(msg.sender, tokenAmount);
        emit Recovered(tokenAddress, tokenAmount);
    }

    receive() external payable {}

    modifier onlyAdmin() {
        require(msg.sender == admin, "Admin only");
        _;
    }

    modifier onlyAdminOrDistributor() {
        require(
            (msg.sender == admin) || (msg.sender == depositor),
            "Admin or depositor only"
        );
        _;
    }

    modifier notToZeroAddress(address _to) {
        require(_to != address(0), "Invalid address!");
        _;
    }
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "IERC20.sol";
import "Address.sol";

/**
 * @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'
        // solhint-disable-next-line max-line-length
        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
            // solhint-disable-next-line max-line-length
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @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);
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @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;
        // solhint-disable-next-line no-inline-assembly
        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");

        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (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");

        // solhint-disable-next-line avoid-low-level-calls
        (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");

        // solhint-disable-next-line avoid-low-level-calls
        (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");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private 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

                // solhint-disable-next-line no-inline-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev These functions deal with verification of Merkle Trees proofs.
 *
 * The proofs can be generated using the JavaScript library
 * https://github.com/miguelmota/merkletreejs[merkletreejs].
 * Note: the hashing algorithm should be keccak256 and pair sorting should be enabled.
 *
 * See `test/utils/cryptography/MerkleProof.test.js` for some examples.
 */
library MerkleProof {
    /**
     * @dev Returns true if a `leaf` can be proved to be a part of a Merkle tree
     * defined by `root`. For this, a `proof` must be provided, containing
     * sibling hashes on the branch from the leaf to the root of the tree. Each
     * pair of leaves and each pair of pre-images are assumed to be sorted.
     */
    function verify(bytes32[] memory proof, bytes32 root, bytes32 leaf) internal pure returns (bool) {
        bytes32 computedHash = leaf;

        for (uint256 i = 0; i < proof.length; i++) {
            bytes32 proofElement = proof[i];

            if (computedHash <= proofElement) {
                // Hash(current computed hash + current element of the proof)
                computedHash = keccak256(abi.encodePacked(computedHash, proofElement));
            } else {
                // Hash(current element of the proof + current computed hash)
                computedHash = keccak256(abi.encodePacked(proofElement, computedHash));
            }
        }

        // Check if the computed hash (root) is equal to the provided root
        return computedHash == root;
    }
}

// SPDX-License-Identifier: MIT
pragma solidity 0.8.9;

interface IGenericVault {
    function withdraw(address _to, uint256 _shares)
        external
        returns (uint256 withdrawn);

    function withdrawAll(address _to) external returns (uint256 withdrawn);

    function depositAll(address _to) external returns (uint256 _shares);

    function deposit(address _to, uint256 _amount)
        external
        returns (uint256 _shares);

    function harvest() external;

    function balanceOfUnderlying(address user)
        external
        view
        returns (uint256 amount);

    function totalUnderlying() external view returns (uint256 total);

    function totalSupply() external view returns (uint256 total);

    function underlying() external view returns (address);

    function strategy() external view returns (address);

    function platform() external view returns (address);

    function setPlatform(address _platform) external;

    function setPlatformFee(uint256 _fee) external;

    function setCallIncentive(uint256 _incentive) external;

    function setWithdrawalPenalty(uint256 _penalty) external;

    function setApprovals() external;

    function callIncentive() external view returns (uint256);

    function withdrawalPenalty() external view returns (uint256);

    function platformFee() external view returns (uint256);

    function balanceOf(address owner) external view returns (uint256);

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

    function approve(address spender, uint256 value) external returns (bool);

    function transfer(address to, uint256 value) external returns (bool);

    function transferFrom(
        address from,
        address to,
        uint256 value
    ) external returns (bool);
}

// SPDX-License-Identifier: MIT
pragma solidity 0.8.9;

/**
 * @title EIP 4626 specification
 * @notice Interface of EIP 4626 Interface
 * as defined in https://eips.ethereum.org/EIPS/eip-4626
 */
interface IERC4626 {
    /**
     * @notice Event indicating that `caller` exchanged `assets` for `shares`, and transferred those `shares` to `owner`
     * @dev Emitted when tokens are deposited into the vault via {mint} and {deposit} methods
     */
    event Deposit(
        address indexed caller,
        address indexed owner,
        uint256 assets,
        uint256 shares
    );

    /**
     * @notice Event indicating that `caller` exchanged `shares`, owned by `owner`, for `assets`, and transferred those
     * `assets` to `receiver`
     * @dev Emitted when shares are withdrawn from the vault via {redeem} or {withdraw} methods
     */
    event Withdraw(
        address indexed caller,
        address indexed receiver,
        address indexed owner,
        uint256 assets,
        uint256 shares
    );

    /**
     * @notice Returns the address of the underlying token used by the Vault
     * @return assetTokenAddress The address of the underlying ERC20 Token
     * @dev MUST be an ERC-20 token contract
     *
     * MUST not revert
     */
    function asset() external view returns (address assetTokenAddress);

    /**
     * @notice Returns the total amount of the underlying asset managed by the Vault
     * @return totalManagedAssets Amount of the underlying asset
     * @dev Should include any compounding that occurs from yield.
     *
     * Should be inclusive of any fees that are charged against assets in the vault.
     *
     * Must not revert
     *
     */
    function totalAssets() external view returns (uint256 totalManagedAssets);

    /**
     *
     * @notice Returns the amount of shares that, in an ideal scenario, the vault would exchange for the amount of assets
     * provided
     *
     * @param assets Amount of assets to convert
     * @return shares Amount of shares that would be exchanged for the provided amount of assets
     *
     * @dev MUST NOT be inclusive of any fees that are charged against assets in the Vault.
     *
     * MUST NOT show any variations depending on the caller.
     *
     * MUST NOT reflect slippage or other on-chain conditions, when performing the actual exchange.
     *
     * MUST NOT revert unless due to integer overflow caused by an unreasonably large input.
     *
     * MUST round down towards 0.
     *
     * This calculation MAY NOT reflect the “per-user” price-per-share, and instead should reflect the
     * “average-user’s” price-per-share, meaning what the average user should expect to see when exchanging to and from.
     */
    function convertToShares(uint256 assets)
        external
        view
        returns (uint256 shares);

    /**
     *
     * @notice Returns the amount of assets that the vault would exchange for the amount of shares provided
     *
     * @param shares Amount of vault shares to convert
     * @return assets Amount of assets that would be exchanged for the provided amount of shares
     *
     * @dev MUST NOT be inclusive of any fees that are charged against assets in the Vault.
     *
     * MUST NOT show any variations depending on the caller.
     *
     * MUST NOT reflect slippage or other on-chain conditions, when performing the actual exchange.
     *
     * MUST NOT revert unless due to integer overflow caused by an unreasonably large input.
     *
     * MUST round down towards 0.
     *
     * This calculation MAY NOT reflect the “per-user” price-per-share, and instead should reflect the
     * “average-user’s” price-per-share, meaning what the average user should expect to see when exchanging to and from.
     */
    function convertToAssets(uint256 shares)
        external
        view
        returns (uint256 assets);

    /**
     *
     * @notice Returns the maximum amount of the underlying asset that can be deposited into the vault for the `receiver`
     * through a {deposit} call
     *
     * @param receiver Address whose maximum deposit is being queries
     * @return maxAssets
     *
     * @dev MUST return the maximum amount of assets {deposit} would allow to be deposited for receiver and not cause a
     * revert, which MUST NOT be higher than the actual maximum that would be accepted (it should underestimate if
     *necessary). This assumes that the user has infinite assets, i.e. MUST NOT rely on {balanceOf} of asset.
     *
     * MUST factor in both global and user-specific limits, like if deposits are entirely disabled (even temporarily)
     * it MUST return 0.
     *
     * MUST return 2 ** 256 - 1 if there is no limit on the maximum amount of assets that may be deposited.
     *
     * MUST NOT revert.
     */
    function maxDeposit(address receiver)
        external
        view
        returns (uint256 maxAssets);

    /**
     * @notice Simulate the effects of a user's deposit at the current block, given current on-chain conditions
     * @param assets Amount of assets
     * @return shares Amount of shares
     * @dev MUST return as close to and no more than the exact amount of Vault shares that would be minted in a {deposit}
     * call in the same transaction. I.e. deposit should return the same or more shares as {previewDeposit} if called in
     * the same transaction. (I.e. {previewDeposit} should underestimate or round-down)
     *
     * MUST NOT account for deposit limits like those returned from maxDeposit and should always act as though the
     * deposit would be accepted, regardless if the user has enough tokens approved, etc.
     *
     * MUST be inclusive of deposit fees. Integrators should be aware of the existence of deposit fees.
     *
     * MUST NOT revert due to vault specific user/global limits. MAY revert due to other conditions that would also
     * cause deposit to revert.
     *
     * Note that any unfavorable discrepancy between convertToShares and previewDeposit SHOULD be considered slippage
     * in share price or some other type of condition, meaning the depositor will lose assets by depositing.
     */
    function previewDeposit(uint256 assets)
        external
        view
        returns (uint256 shares);

    /**
     * @notice Mints `shares` Vault shares to `receiver` by depositing exactly `amount` of underlying tokens
     * @param assets Amount of assets
     * @param receiver Address to deposit underlying tokens into
     * @dev Must emit the {Deposit} event
     *
     * MUST support ERC-20 {approve} / {transferFrom} on asset as a deposit flow. MAY support an additional flow in
     * which the underlying tokens are owned by the Vault contract before the {deposit} execution, and are accounted for
     * during {deposit}.
     *
     * MUST revert if all of `assets` cannot be deposited (due to deposit limit being reached, slippage, the user not
     * approving enough underlying tokens to the Vault contract, etc).
     *
     * Note that most implementations will require pre-approval of the Vault with the Vault’s underlying asset token.
     */
    function deposit(uint256 assets, address receiver)
        external
        returns (uint256 shares);

    /**
     * @notice Returns the maximum amount of shares that can be minted from the vault for the `receiver``, via a `mint`
     * call
     * @param receiver Address to deposit minted shares into
     * @return maxShares The maximum amount of shares
     * @dev MUST return the maximum amount of shares mint would allow to be deposited to receiver and not cause a revert,
     * which MUST NOT be higher than the actual maximum that would be accepted (it should underestimate if necessary).
     * This assumes that the user has infinite assets, i.e. MUST NOT rely on balanceOf of asset.
     *
     * MUST factor in both global and user-specific limits, like if mints are entirely disabled (even temporarily) it
     *
     * MUST return 0.
     *
     * MUST return 2 ** 256 - 1 if there is no limit on the maximum amount of shares that may be minted.
     *
     * MUST NOT revert.
     */
    function maxMint(address receiver)
        external
        view
        returns (uint256 maxShares);

    /**
     * @notice Simulate the effects of a user's mint at the current block, given current on-chain conditions
     * @param shares Amount of shares to mint
     * @return assets Amount of assets required to mint `mint` amount of shares
     * @dev MUST return as close to and no fewer than the exact amount of assets that would be deposited in a mint call
     * in the same transaction. I.e. mint should return the same or fewer assets as previewMint if called in the same
     * transaction. (I.e. {previewMint} should overestimate or round-up)
     *
     * MUST NOT account for mint limits like those returned from maxMint and should always act as though the mint
     * would be accepted, regardless if the user has enough tokens approved, etc.
     *
     * MUST be inclusive of deposit fees. Integrators should be aware of the existence of deposit fees.
     *
     * MUST NOT revert due to vault specific user/global limits. MAY revert due to other conditions that would also
     * cause mint to revert.
     *
     * Note that any unfavorable discrepancy between convertToAssets and previewMint SHOULD be considered slippage in
     * share price or some other type of condition, meaning the depositor will lose assets by minting.
     */
    function previewMint(uint256 shares) external view returns (uint256 assets);

    /**
     * @notice Mints exactly `shares` vault shares to `receiver` by depositing `amount` of underlying tokens
     * @param shares Amount of shares to mint
     * @param receiver Address to deposit minted shares into
     * @return assets Amount of assets transferred to vault
     * @dev Must emit the {Deposit} event
     *
     * MUST support ERC-20 {approve} / {transferFrom} on asset as a mint flow. MAY support an additional flow in
     *  which the underlying tokens are owned by the Vault contract before the mint execution, and are accounted for
     * during mint.
     *
     * MUST revert if all of `shares` cannot be minted (due to deposit limit being reached, slippage, the user not
     * approving enough underlying tokens to the Vault contract, etc).
     *
     * Note that most implementations will require pre-approval of the Vault with the Vault’s underlying asset token.
     */
    function mint(uint256 shares, address receiver)
        external
        returns (uint256 assets);

    /**
     * @notice Returns the maximum amount of the underlying asset that can be withdrawn from the `owner` balance in the
     * vault, through a `withdraw` call.
     * @param owner Address of the owner whose max withdrawal amount is being queries
     * @return maxAssets Maximum amount of underlying asset that can be withdrawn
     * @dev MUST return the maximum amount of assets that could be transferred from `owner` through {withdraw} and not
     * cause a revert, which MUST NOT be higher than the actual maximum that would be accepted (it should underestimate if
     * necessary).
     *
     * MUST factor in both global and user-specific limits, like if withdrawals are entirely disabled
     * (even temporarily)  it MUST return 0.
     *
     * MUST NOT revert.
     */
    function maxWithdraw(address owner)
        external
        view
        returns (uint256 maxAssets);

    /**
     * @notice Simulate the effects of a user's withdrawal at the current block, given current on-chain conditions.
     * @param assets Amount of assets
     * @return shares Amount of shares
     * @dev MUST return as close to and no fewer than the exact amount of Vault shares that would be burned in a
     * {withdraw} call in the same transaction. I.e. {withdraw} should return the same or fewer shares as
     * {previewWithdraw} if called in the same transaction. (I.e. {previewWithdraw should overestimate or round-up})
     *
     * MUST NOT account for withdrawal limits like those returned from {maxWithdraw} and should always act as though
     * the withdrawal would be accepted, regardless if the user has enough shares, etc.
     *
     * MUST be inclusive of withdrawal fees. Integrators should be aware of the existence of withdrawal fees.
     *
     * MUST NOT revert due to vault specific user/global limits. MAY revert due to other conditions that would also
     * cause {withdraw} to revert.
     *
     * Note that any unfavorable discrepancy between convertToShares and previewWithdraw SHOULD be considered slippage in
     * share price or some other type of condition, meaning the depositor will lose assets by depositing.
     */
    function previewWithdraw(uint256 assets)
        external
        view
        returns (uint256 shares);

    /**
     * @notice Burns `shares` from `owner` and sends exactly `assets` of underlying tokens to `receiver`
     * @param assets Amount of underling assets to withdraw
     * @return shares Amount of shares that will be burned
     * @dev Must emit the {Withdraw} event
     *
     * MUST support a withdraw flow where the shares are burned from `owner` directly where `owner` is `msg.sender`
     * or `msg.sender` has ERC-20 approval over the shares of `owner`. MAY support an additional flow in which the shares
     * are transferred to the Vault contract before the withdraw execution, and are accounted for during withdraw.
     *
     * MUST revert if all of assets cannot be withdrawn (due to withdrawal limit being reached, slippage, the owner
     * not having enough shares, etc).
     *
     * Note that some implementations will require pre-requesting to the Vault before a withdrawal may be performed.
     *  Those methods should be performed separately.
     */
    function withdraw(
        uint256 assets,
        address receiver,
        address owner
    ) external returns (uint256 shares);

    /**
     * @notice Returns the maximum amount of vault shares that can be redeemed from the `owner` balance in the vault, via
     * a `redeem` call.
     * @param owner Address of the owner whose shares are being queries
     * @return maxShares Maximum amount of shares that can be redeemed
     * @dev MUST return the maximum amount of shares that could be transferred from `owner` through `redeem` and not cause
     * a revert, which MUST NOT be higher than the actual maximum that would be accepted (it should underestimate if
     * necessary).
     *
     * MUST factor in both global and user-specific limits, like if redemption is entirely disabled
     * (even temporarily) it MUST return 0.
     *
     * MUST NOT revert
     */
    function maxRedeem(address owner) external view returns (uint256 maxShares);

    /**
     * @notice Simulate the effects of a user's redemption at the current block, given current on-chain conditions
     * @param shares Amount of shares that are being simulated to be redeemed
     * @return assets Amount of underlying assets that can be redeemed
     * @dev MUST return as close to and no more than the exact amount of `assets `that would be withdrawn in a {redeem}
     * call in the same transaction. I.e. {redeem} should return the same or more assets as {previewRedeem} if called in
     * the same transaction. I.e. {previewRedeem} should underestimate/round-down
     *
     * MUST NOT account for redemption limits like those returned from {maxRedeem} and should always act as though
     * the redemption would be accepted, regardless if the user has enough shares, etc.
     *
     * MUST be inclusive of withdrawal fees. Integrators should be aware of the existence of withdrawal fees.
     *
     * MUST NOT revert due to vault specific user/global limits. MAY revert due to other conditions that would also
     * cause {redeem} to revert.
     *
     * Note that any unfavorable discrepancy between {convertToAssets} and {previewRedeem} SHOULD be considered
     * slippage in share price or some other type of condition, meaning the depositor will lose assets by redeeming.
     */
    function previewRedeem(uint256 shares)
        external
        view
        returns (uint256 assets);

    /**
     * @notice Burns exactly `shares` from `owner` and sends `assets` of underlying tokens to `receiver`
     * @param shares Amount of shares to burn
     * @param receiver Address to deposit redeemed underlying tokens to
     * @return assets Amount of underlying tokens redeemed
     * @dev Must emit the {Withdraw} event
     * MUST support a {redeem} flow where the shares are burned from owner directly where `owner` is `msg.sender` or
     *
     * `msg.sender` has ERC-20 approval over the shares of `owner`. MAY support an additional flow in which the shares
     * are transferred to the Vault contract before the {redeem} execution, and are accounted for during {redeem}.
     *
     * MUST revert if all of {shares} cannot be redeemed (due to withdrawal limit being reached, slippage, the owner
     * not having enough shares, etc).
     *
     * Note that some implementations will require pre-requesting to the Vault before a withdrawal may be performed.
     * Those methods should be performed separately.
     */
    function redeem(
        uint256 shares,
        address receiver,
        address owner
    ) external returns (uint256 assets);

    event Approval(
        address indexed owner,
        address indexed spender,
        uint256 value
    );
    event Transfer(address indexed from, address indexed to, uint256 value);

    function name() external view returns (string memory);

    function symbol() external view returns (string memory);

    function decimals() external view returns (uint8);

    function totalSupply() external view returns (uint256);

    function balanceOf(address owner) external view returns (uint256);

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

    function approve(address spender, uint256 value) external returns (bool);

    function transfer(address to, uint256 value) external returns (bool);

    function transferFrom(
        address from,
        address to,
        uint256 value
    ) external returns (bool);
}