// File: src/WETHGateway.sol



// SPDX-License-Identifier: Unlicense
pragma solidity ^0.8.13;

import { Ownable } from "../lib/openzeppelin-contracts/contracts/access/Ownable.sol";
import "./base/ErrorMessages.sol";
import "./interfaces/IZeroLiquid.sol";
import "./interfaces/external/IWETH9.sol";
import "./interfaces/IWETHGateway.sol";

/// @title  WETHGateway
/// @author ZeroLiquid
contract WETHGateway is IWETHGateway, Ownable {
    /// @notice The version.
    string public constant version = "1.0.0";

    /// @notice The wrapped ethereum contract.
    IWETH9 public immutable WETH;

    constructor(address weth) {
        WETH = IWETH9(weth);
    }

    /// @dev Allows for payments from the WETH contract.
    receive() external payable {
        if (IWETH9(msg.sender) != WETH) {
            revert Unauthorized("msg.sender is not WETH contract");
        }
    }

    /// @inheritdoc IWETHGateway
    function refreshAllowance(address zeroliquid) external onlyOwner {
        WETH.approve(zeroliquid, type(uint256).max);
    }

    /// @inheritdoc IWETHGateway
    function depositUnderlying(
        address zeroliquid,
        address yieldToken,
        uint256 amount,
        address recipient,
        uint256 minimumAmountOut
    )
        external
        payable
    {
        if (amount != msg.value) {
            revert IllegalArgument("Invalid deposit amount");
        }
        WETH.deposit{ value: msg.value }();
        IZeroLiquid(zeroliquid).depositUnderlying(yieldToken, amount, recipient, minimumAmountOut);
    }

    /// @inheritdoc IWETHGateway
    function withdrawUnderlying(
        address zeroliquid,
        address yieldToken,
        uint256 shares,
        address recipient,
        uint256 minimumAmountOut
    )
        external
    {
        // Ensure that the underlying of the target yield token is in fact WETH
        IZeroLiquid.YieldTokenParams memory params = IZeroLiquid(zeroliquid).getYieldTokenParameters(yieldToken);
        if (params.underlyingToken != address(WETH)) {
            revert IllegalArgument("Token is not WETH contract");
        }

        IZeroLiquid(zeroliquid).withdrawUnderlyingFrom(msg.sender, yieldToken, shares, address(this), minimumAmountOut);

        uint256 amount = WETH.balanceOf(address(this));
        WETH.withdraw(amount);

        (bool success,) = recipient.call{ value: amount }(new bytes(0));
        if (!success) {
            revert IllegalState("Unsuccessful withdrawal");
        }
    }
}

// File: lib/openzeppelin-contracts/contracts/access/Ownable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (access/Ownable.sol)

pragma solidity ^0.8.0;

import "../utils/Context.sol";

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_msgSender());
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby disabling any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

// File: src/base/ErrorMessages.sol



// SPDX-License-Identifier: UNLICENSED
pragma solidity >=0.8.4;

/// @notice An error used to indicate that an argument passed to a function is illegal or
///         inappropriate.
///
/// @param message The error message.
error IllegalArgument(string message);

/// @notice An error used to indicate that a function has encountered an unrecoverable state.
///
/// @param message The error message.
error IllegalState(string message);

/// @notice An error used to indicate that an operation is unsupported.
///
/// @param message The error message.
error UnsupportedOperation(string message);

/// @notice An error used to indicate that a message sender tried to execute a privileged function.
///
/// @param message The error message.
error Unauthorized(string message);

// File: src/interfaces/IZeroLiquid.sol



pragma solidity >=0.5.0;

import "./zeroliquid/IZeroLiquidActions.sol";
import "./zeroliquid/IZeroLiquidAdminActions.sol";
import "./zeroliquid/IZeroLiquidErrors.sol";
import "./zeroliquid/IZeroLiquidImmutables.sol";
import "./zeroliquid/IZeroLiquidEvents.sol";
import "./zeroliquid/IZeroLiquidState.sol";

/// @title  IZeroLiquid
/// @author ZeroLiquid
interface IZeroLiquid is
    IZeroLiquidActions,
    IZeroLiquidAdminActions,
    IZeroLiquidErrors,
    IZeroLiquidImmutables,
    IZeroLiquidEvents,
    IZeroLiquidState
{ }

// File: src/interfaces/external/IWETH9.sol



pragma solidity >=0.5.0;

import "../../../lib/openzeppelin-contracts/contracts/token/ERC20/IERC20.sol";

import "../IERC20Metadata.sol";

/// @title IWETH9
interface IWETH9 is IERC20, IERC20Metadata {
    /// @notice Deposits `msg.value` ethereum into the contract and mints `msg.value` tokens.
    function deposit() external payable;

    /// @notice Burns `amount` tokens to retrieve `amount` ethereum from the contract.
    ///
    /// @dev This version of WETH utilizes the `transfer` function which hard codes the amount of gas
    ///      that is allowed to be utilized to be exactly 2300 when receiving ethereum.
    ///
    /// @param amount The amount of tokens to burn.
    function withdraw(uint256 amount) external;
}

// File: src/interfaces/IWETHGateway.sol



pragma solidity >=0.5.0;

/// @title  IWETHGateway
/// @author ZeroLiquid
interface IWETHGateway {
    /// @notice Refreshes the wrapped ethereum ERC20 approval for an zeroliquid contract.
    ///
    /// @param zeroliquid The address of the zeroliquid to refresh the allowance for.
    function refreshAllowance(address zeroliquid) external;

    /// @notice Takes ethereum, converts it to wrapped ethereum, and then deposits it into an zeroliquid.
    ///
    /// See [IZeroLiquidActions.depositUnderlying](./zeroliquid/IZeroLiquidActions.md#depositunderlying) for more
    /// details.
    ///
    /// @param zeroliquid        The address of the zeroliquid to deposit wrapped ethereum into.
    /// @param yieldToken       The yield token to deposit the wrapped ethereum as.
    /// @param amount           The amount of ethereum to deposit.
    /// @param recipient        The address which will receive the deposited yield tokens.
    /// @param minimumAmountOut The minimum amount of yield tokens that are expected to be deposited to `recipient`.
    function depositUnderlying(
        address zeroliquid,
        address yieldToken,
        uint256 amount,
        address recipient,
        uint256 minimumAmountOut
    )
        external
        payable;

    /// @notice Withdraws a wrapped ethereum based yield token from an zeroliquid, converts it to ethereum, and then
    ///         transfers it to the recipient.
    ///
    /// A withdraw approval on the zeroliquid is required for this call to succeed.
    ///
    /// See [IZeroLiquidActions.withdrawUnderlying](./zeroliquid/IZeroLiquidActions.md#withdrawunderlying) for more
    /// details.
    ///
    /// @param zeroliquid        The address of the zeroliquid to withdraw wrapped ethereum from.
    /// @param yieldToken       The address of the yield token to withdraw.
    /// @param shares           The amount of shares to withdraw.
    /// @param recipient        The address which will receive the ethereum.
    /// @param minimumAmountOut The minimum amount of underlying tokens that are expected to be withdrawn to
    /// `recipient`.
    function withdrawUnderlying(
        address zeroliquid,
        address yieldToken,
        uint256 shares,
        address recipient,
        uint256 minimumAmountOut
    )
        external;
}

// File: lib/openzeppelin-contracts/contracts/utils/Context.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

// File: src/interfaces/zeroliquid/IZeroLiquidActions.sol



pragma solidity >=0.5.0;

/// @title  IZeroLiquidActions
/// @author ZeroLiquid
///
/// @notice Specifies user actions.
interface IZeroLiquidActions {
    /// @notice Approve `spender` to mint `amount` debt tokens.
    ///
    ///
    /// @param spender The address that will be approved to mint.
    /// @param amount  The amount of tokens that `spender` will be allowed to mint.
    function approveMint(address spender, uint256 amount) external;

    /// @notice Approve `spender` to withdraw `amount` shares of `yieldToken`.
    ///
    ///
    /// @param spender    The address that will be approved to withdraw.
    /// @param yieldToken The address of the yield token that `spender` will be allowed to withdraw.
    /// @param shares     The amount of shares that `spender` will be allowed to withdraw.
    function approveWithdraw(address spender, address yieldToken, uint256 shares) external;

    /// @notice Synchronizes the state of the account owned by `owner`.
    ///
    /// @param owner The owner of the account to synchronize.
    function poke(address owner) external;

    /// @notice Deposit a yield token into a user's account.
    ///
    /// @notice An approval must be set for `yieldToken` which is greater than `amount`.
    ///
    /// @notice `yieldToken` must be registered or this call will revert with a {UnsupportedToken} error.
    /// @notice `yieldToken` must be enabled or this call will revert with a {TokenDisabled} error.
    /// @notice `yieldToken` underlying token must be enabled or this call will revert with a {TokenDisabled} error.
    /// @notice `recipient` must be non-zero or this call will revert with an {IllegalArgument} error.
    /// @notice `amount` must be greater than zero or the call will revert with an {IllegalArgument} error.
    ///
    /// @notice Emits a {Deposit} event.
    ///
    ///
    /// @notice **_NOTE:_** When depositing, the `ZeroLiquid` contract must have **allowance()** to spend funds on
    /// behalf of **msg.sender** for at least **amount** of the **yieldToken** being deposited.  This can be done via
    /// the standard `ERC20.approve()` method.
    ///
    /// @notice **Example:**
    /// @notice ```
    /// @notice address wstETH = 0x7f39c581f595b53c5cb19bd0b3f8da6c935e2ca0;
    /// @notice uint256 amount = 50000;
    /// @notice IERC20(wstETH).approve(ZeroLiquidAddress, amount);
    /// @notice ZeroLiquid(ZeroLiquidAddress).deposit(wstETH, amount, msg.sender);
    /// @notice ```
    ///
    /// @param yieldToken The yield-token to deposit.
    /// @param amount     The amount of yield tokens to deposit.
    /// @param recipient  The owner of the account that will receive the resulting shares.
    ///
    /// @return sharesIssued The number of shares issued to `recipient`.
    function deposit(address yieldToken, uint256 amount, address recipient) external returns (uint256 sharesIssued);

    /// @notice Deposit an underlying token into the account of `recipient` as `yieldToken`.
    ///
    /// @notice An approval must be set for the underlying token of `yieldToken` which is greater than `amount`.
    ///
    /// @notice `yieldToken` must be registered or this call will revert with a {UnsupportedToken} error.
    /// @notice `recipient` must be non-zero or this call will revert with an {IllegalArgument} error.
    /// @notice `amount` must be greater than zero or the call will revert with an {IllegalArgument} error.
    ///
    /// @notice Emits a {Deposit} event.
    ///
    /// @notice **_NOTE:_** When depositing, the `ZeroLiquid` contract must have **allowance()** to spend funds on
    /// behalf of **msg.sender** for at least **amount** of the **underlyingToken** being deposited.  This can be done
    /// via the standard `ERC20.approve()` method.
    ///
    /// @notice **Example:**
    /// @notice ```
    /// @notice address wstETH = 0x7f39c581f595b53c5cb19bd0b3f8da6c935e2ca0;
    /// @notice uint256 amount = 50000;
    /// @notice ZeroLiquid(ZeroLiquidAddress).depositUnderlying(wstETH, amount, msg.sender, 1);
    /// @notice ```
    ///
    /// @param yieldToken       The address of the yield token to wrap the underlying tokens into.
    /// @param amount           The amount of the underlying token to deposit.
    /// @param recipient        The address of the recipient.
    /// @param minimumAmountOut The minimum amount of yield tokens that are expected to be deposited to `recipient`.
    ///
    /// @return sharesIssued The number of shares issued to `recipient`.
    function depositUnderlying(
        address yieldToken,
        uint256 amount,
        address recipient,
        uint256 minimumAmountOut
    )
        external
        returns (uint256 sharesIssued);

    /// @notice Withdraw yield tokens to `recipient` by burning `share` shares. The number of yield tokens withdrawn to
    /// `recipient` will depend on the value of shares for that yield token at the time of the call.
    ///
    /// @notice `yieldToken` must be registered or this call will revert with a {UnsupportedToken} error.
    /// @notice `recipient` must be non-zero or this call will revert with an {IllegalArgument} error.
    ///
    /// @notice Emits a {Withdraw} event.
    ///
    ///
    /// @notice **Example:**
    /// @notice ```
    /// @notice address wstETH = 0x7f39c581f595b53c5cb19bd0b3f8da6c935e2ca0;
    /// @notice uint256 pps = ZeroLiquid(ZeroLiquidAddress).getYieldTokensPerShare(wstETH);
    /// @notice uint256 amtYieldTokens = 5000;
    /// @notice ZeroLiquid(ZeroLiquidAddress).withdraw(wstETH, amtYieldTokens / pps, msg.sender);
    /// @notice ```
    ///
    /// @param yieldToken The address of the yield token to withdraw.
    /// @param shares     The number of shares to burn.
    /// @param recipient  The address of the recipient.
    ///
    /// @return amountWithdrawn The number of yield tokens that were withdrawn to `recipient`.
    function withdraw(
        address yieldToken,
        uint256 shares,
        address recipient
    )
        external
        returns (uint256 amountWithdrawn);

    /// @notice Withdraw yield tokens to `recipient` by burning `share` shares from the account of `owner`
    ///
    /// @notice `owner` must have an withdrawal allowance which is greater than `amount` for this call to succeed.
    ///
    /// @notice `yieldToken` must be registered or this call will revert with a {UnsupportedToken} error.
    /// @notice `recipient` must be non-zero or this call will revert with an {IllegalArgument} error.
    ///
    /// @notice Emits a {Withdraw} event.
    ///
    ///
    /// @notice **Example:**
    /// @notice ```
    /// @notice address wstETH = 0x7f39c581f595b53c5cb19bd0b3f8da6c935e2ca0;
    /// @notice uint256 pps = ZeroLiquid(ZeroLiquidAddress).getYieldTokensPerShare(wstETH);
    /// @notice uint256 amtYieldTokens = 5000;
    /// @notice ZeroLiquid(ZeroLiquidAddress).withdrawFrom(msg.sender, wstETH, amtYieldTokens / pps, msg.sender);
    /// @notice ```
    ///
    /// @param owner      The address of the account owner to withdraw from.
    /// @param yieldToken The address of the yield token to withdraw.
    /// @param shares     The number of shares to burn.
    /// @param recipient  The address of the recipient.
    ///
    /// @return amountWithdrawn The number of yield tokens that were withdrawn to `recipient`.
    function withdrawFrom(
        address owner,
        address yieldToken,
        uint256 shares,
        address recipient
    )
        external
        returns (uint256 amountWithdrawn);

    /// @notice Withdraw underlying tokens to `recipient` by burning `share` shares and unwrapping the yield tokens that
    /// the shares were redeemed for.
    ///
    /// @notice `yieldToken` must be registered or this call will revert with a {UnsupportedToken} error.
    /// @notice `recipient` must be non-zero or this call will revert with an {IllegalArgument} error.
    /// @notice The loss in expected value of `yieldToken` must be less than the maximum permitted by the system or this
    /// call will revert with a {LossExceeded} error.
    ///
    /// @notice Emits a {Withdraw} event.
    ///
    /// @notice **_NOTE:_** The caller of `withdrawFrom()` must have **withdrawAllowance()** to withdraw funds on behalf
    /// of **owner** for at least the amount of `yieldTokens` that **shares** will be converted to.  This can be done
    /// via the `approveWithdraw()` or `permitWithdraw()` methods.
    ///
    /// @notice **Example:**
    /// @notice ```
    /// @notice address wstETH = 0x7f39c581f595b53c5cb19bd0b3f8da6c935e2ca0;
    /// @notice uint256 pps = ZeroLiquid(ZeroLiquidAddress).getUnderlyingTokensPerShare(wstETH);
    /// @notice uint256 amountUnderlyingTokens = 5000;
    /// @notice ZeroLiquid(ZeroLiquidAddress).withdrawUnderlying(wstETH, amountUnderlyingTokens / pps, msg.sender, 1);
    /// @notice ```
    ///
    /// @param yieldToken       The address of the yield token to withdraw.
    /// @param shares           The number of shares to burn.
    /// @param recipient        The address of the recipient.
    /// @param minimumAmountOut The minimum amount of underlying tokens that are expected to be withdrawn to
    /// `recipient`.
    ///
    /// @return amountWithdrawn The number of underlying tokens that were withdrawn to `recipient`.
    function withdrawUnderlying(
        address yieldToken,
        uint256 shares,
        address recipient,
        uint256 minimumAmountOut
    )
        external
        returns (uint256 amountWithdrawn);

    /// @notice Withdraw underlying tokens to `recipient` by burning `share` shares from the account of `owner` and
    /// unwrapping the yield tokens that the shares were redeemed for.
    ///
    /// @notice `yieldToken` must be registered or this call will revert with a {UnsupportedToken} error.
    /// @notice `recipient` must be non-zero or this call will revert with an {IllegalArgument} error.
    /// @notice The loss in expected value of `yieldToken` must be less than the maximum permitted by the system or this
    /// call will revert with a {LossExceeded} error.
    ///
    /// @notice Emits a {Withdraw} event.
    ///
    /// @notice **_NOTE:_** The caller of `withdrawFrom()` must have **withdrawAllowance()** to withdraw funds on behalf
    /// of **owner** for at least the amount of `yieldTokens` that **shares** will be converted to.  This can be done
    /// via the `approveWithdraw()` or `permitWithdraw()` methods.
    ///
    /// @notice **Example:**
    /// @notice ```
    /// @notice address wstETH = 0x7f39c581f595b53c5cb19bd0b3f8da6c935e2ca0;
    /// @notice uint256 pps = ZeroLiquid(ZeroLiquidAddress).getUnderlyingTokensPerShare(wstETH);
    /// @notice uint256 amtUnderlyingTokens = 5000 * 10**wstETH.decimals();
    /// @notice ZeroLiquid(ZeroLiquidAddress).withdrawUnderlying(msg.sender, wstETH, amtUnderlyingTokens / pps,
    /// msg.sender, 1);
    /// @notice ```
    ///
    /// @param owner            The address of the account owner to withdraw from.
    /// @param yieldToken       The address of the yield token to withdraw.
    /// @param shares           The number of shares to burn.
    /// @param recipient        The address of the recipient.
    /// @param minimumAmountOut The minimum amount of underlying tokens that are expected to be withdrawn to
    /// `recipient`.
    ///
    /// @return amountWithdrawn The number of underlying tokens that were withdrawn to `recipient`.
    function withdrawUnderlyingFrom(
        address owner,
        address yieldToken,
        uint256 shares,
        address recipient,
        uint256 minimumAmountOut
    )
        external
        returns (uint256 amountWithdrawn);

    /// @notice Mint `amount` debt tokens.
    ///
    /// @notice `recipient` must be non-zero or this call will revert with an {IllegalArgument} error.
    /// @notice `amount` must be greater than zero or this call will revert with a {IllegalArgument} error.
    ///
    /// @notice Emits a {Mint} event.
    ///
    ///
    /// @notice **Example:**
    /// @notice ```
    /// @notice uint256 amtDebt = 5000;
    /// @notice ZeroLiquid(ZeroLiquidAddress).mint(amtDebt, msg.sender);
    /// @notice ```
    ///
    /// @param amount     The amount of tokens to mint.
    /// @param recipient  The address of the recipient.
    function mint(uint256 amount, address recipient) external;

    /// @notice Mint `amount` debt tokens from the account owned by `owner` to `recipient`.
    ///
    /// @notice `recipient` must be non-zero or this call will revert with an {IllegalArgument} error.
    /// @notice `amount` must be greater than zero or this call will revert with a {IllegalArgument} error.
    ///
    /// @notice Emits a {Mint} event.
    ///
    /// @notice **_NOTE:_** The caller of `mintFrom()` must have **mintAllowance()** to mint debt from the `Account`
    /// controlled by **owner** for at least the amount of **yieldTokens** that **shares** will be converted to.  This
    /// can be done via the `approveMint()` or `permitMint()` methods.
    ///
    /// @notice **Example:**
    /// @notice ```
    /// @notice uint256 amtDebt = 5000;
    /// @notice ZeroLiquid(ZeroLiquidAddress).mintFrom(msg.sender, amtDebt, msg.sender);
    /// @notice ```
    ///
    /// @param owner      The address of the owner of the account to mint from.
    /// @param amount     The amount of tokens to mint.
    /// @param recipient  The address of the recipient.
    function mintFrom(address owner, uint256 amount, address recipient) external;

    /// @notice Burn `amount` debt tokens to credit the account owned by `recipient`.
    ///
    /// @notice `amount` will be limited up to the amount of debt that `recipient` currently holds.
    ///
    /// @notice `recipient` must be non-zero or this call will revert with an {IllegalArgument} error.
    /// @notice `amount` must be greater than zero or this call will revert with a {IllegalArgument} error.
    /// @notice `recipient` must have non-zero debt or this call will revert with an {IllegalState} error.
    ///
    /// @notice Emits a {Burn} event.
    ///
    ///
    /// @notice **Example:**
    /// @notice ```
    /// @notice uint256 amtBurn = 5000;
    /// @notice ZeroLiquid(ZeroLiquidAddress).burn(amtBurn, msg.sender);
    /// @notice ```
    ///
    /// @param amount     The amount of tokens to burn.
    /// @param recipient  The address of the recipient.
    ///
    /// @return amountBurned The amount of tokens that were burned.
    function burn(uint256 amount, address recipient) external returns (uint256 amountBurned);

    /// @notice Repay `amount` debt using `underlyingToken` to credit the account owned by `recipient`.
    ///
    /// @notice `amount` will be limited up to the amount of debt that `recipient` currently holds.
    ///
    /// @notice `amount` must be greater than zero or this call will revert with a {IllegalArgument} error.
    /// @notice `recipient` must be non-zero or this call will revert with an {IllegalArgument} error.
    /// @notice `underlyingToken` must be enabled or this call will revert with a {TokenDisabled} error.
    /// @notice `amount` must be less than or equal to the current available repay limit or this call will revert with a
    /// {ReplayLimitExceeded} error.
    ///
    /// @notice Emits a {Repay} event.
    ///
    /// @notice **Example:**
    /// @notice ```
    /// @notice address weth = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;
    /// @notice uint256 amtRepay = 5000;
    /// @notice ZeroLiquid(ZeroLiquidAddress).repay(weth, amtRepay, msg.sender);
    /// @notice ```
    ///
    /// @param underlyingToken The address of the underlying token to repay.
    /// @param amount          The amount of the underlying token to repay.
    /// @param recipient       The address of the recipient which will receive credit.
    ///
    /// @return amountRepaid The amount of tokens that were repaid.
    function repay(
        address underlyingToken,
        uint256 amount,
        address recipient
    )
        external
        returns (uint256 amountRepaid);

    /// @notice
    ///
    /// @notice `shares` will be limited up to an equal amount of debt that `recipient` currently holds.
    ///
    /// @notice `shares` must be greater than zero or this call will revert with a {IllegalArgument} error.
    /// @notice `yieldToken` must be registered or this call will revert with a {UnsupportedToken} error.
    /// @notice `yieldToken` must be enabled or this call will revert with a {TokenDisabled} error.
    /// @notice `yieldToken` underlying token must be enabled or this call will revert with a {TokenDisabled} error.
    /// @notice The loss in expected value of `yieldToken` must be less than the maximum permitted by the system or this
    /// call will revert with a {LossExceeded} error.
    /// @notice `amount` must be less than or equal to the current available liquidation limit or this call will revert
    /// with a {LiquidationLimitExceeded} error.
    ///
    /// @notice Emits a {Liquidate} event.
    ///
    ///
    /// @notice **Example:**
    /// @notice ```
    /// @notice address wstETH = 0x7f39c581f595b53c5cb19bd0b3f8da6c935e2ca0;
    /// @notice uint256 amtSharesLiquidate = 5000 * 10**wstETH.decimals();
    /// @notice ZeroLiquid(ZeroLiquidAddress).liquidate(wstETH, amtSharesLiquidate, 1);
    /// @notice ```
    ///
    /// @param yieldToken       The address of the yield token to liquidate.
    /// @param shares           The number of shares to burn for credit.
    /// @param minimumAmountOut The minimum amount of underlying tokens that are expected to be liquidated.
    ///
    /// @return sharesLiquidated The amount of shares that were liquidated.
    function liquidate(
        address yieldToken,
        uint256 shares,
        uint256 minimumAmountOut
    )
        external
        returns (uint256 sharesLiquidated);

    /// @notice Burns `amount` debt tokens to credit accounts which have deposited `yieldToken`.
    ///
    /// @notice `amount` must be greater than zero or this call will revert with a {IllegalArgument} error.
    /// @notice `yieldToken` must be registered or this call will revert with a {UnsupportedToken} error.
    ///
    /// @notice Emits a {Donate} event.
    ///
    ///
    /// @notice **Example:**
    /// @notice ```
    /// @notice address wstETH = 0x7f39c581f595b53c5cb19bd0b3f8da6c935e2ca0;
    /// @notice uint256 amtSharesLiquidate = 5000;
    /// @notice ZeroLiquid(ZeroLiquidAddress).liquidate(wstETH, amtSharesLiquidate, 1);
    /// @notice ```
    ///
    /// @param yieldToken The address of the yield token to credit accounts for.
    /// @param amount     The amount of debt tokens to burn.
    function donate(address yieldToken, uint256 amount) external;

    /// @notice Harvests outstanding yield that a yield token has accumulated and distributes it as credit to holders.
    ///
    /// @notice `msg.sender` must be a keeper or this call will revert with an {Unauthorized} error.
    /// @notice `yieldToken` must be registered or this call will revert with a {UnsupportedToken} error.
    /// @notice The amount being harvested must be greater than zero or else this call will revert with an
    /// {IllegalState} error.
    ///
    /// @notice Emits a {Harvest} event.
    ///
    /// @param yieldToken       The address of the yield token to harvest.
    /// @param minimumAmountOut The minimum amount of underlying tokens that are expected to be withdrawn to
    /// `recipient`.
    function harvest(address yieldToken, uint256 minimumAmountOut) external;
}

// File: src/interfaces/zeroliquid/IZeroLiquidAdminActions.sol



// SPDX-License-Identifier: UNLICENSED
pragma solidity >=0.5.0;

/// @title  IZeroLiquidAdminActions
/// @author ZeroLiquid
///
/// @notice Specifies admin and or sentinel actions.
interface IZeroLiquidAdminActions {
    /// @notice Contract initialization parameters.
    struct InitializationParams {
        // The initial admin account.
        address admin;
        // The ERC20 token used to represent debt.
        address debtToken;
        // The initial steamer or steamer buffer.
        address steamer;
        // The minimum collateralization ratio that an account must maintain.
        uint256 minimumCollateralization;
        // The percentage fee taken from each harvest measured in units of basis points.
        uint256 protocolFee;
        // The address that receives protocol fees.
        address protocolFeeReceiver;
        // A limit used to prevent administrators from making minting functionality inoperable.
        uint256 mintingLimitMinimum;
        // The maximum number of tokens that can be minted per period of time.
        uint256 mintingLimitMaximum;
        // The number of blocks that it takes for the minting limit to be refreshed.
        uint256 mintingLimitBlocks;
    }

    /// @notice Configuration parameters for an underlying token.
    struct UnderlyingTokenConfig {
        // A limit used to prevent administrators from making repayment functionality inoperable.
        uint256 repayLimitMinimum;
        // The maximum number of underlying tokens that can be repaid per period of time.
        uint256 repayLimitMaximum;
        // The number of blocks that it takes for the repayment limit to be refreshed.
        uint256 repayLimitBlocks;
        // A limit used to prevent administrators from making liquidation functionality inoperable.
        uint256 liquidationLimitMinimum;
        // The maximum number of underlying tokens that can be liquidated per period of time.
        uint256 liquidationLimitMaximum;
        // The number of blocks that it takes for the liquidation limit to be refreshed.
        uint256 liquidationLimitBlocks;
    }

    /// @notice Configuration parameters of a yield token.
    struct YieldTokenConfig {
        // The adapter used by the system to interop with the token.
        address adapter;
        // The maximum percent loss in expected value that can occur before certain actions are disabled measured in
        // units of basis points.
        uint256 maximumLoss;
        // The maximum value that can be held by the system before certain actions are disabled measured in the
        // underlying token.
        uint256 maximumExpectedValue;
        // The number of blocks that credit will be distributed over to depositors.
        uint256 creditUnlockBlocks;
    }

    /// @notice Initialize the contract.
    ///
    /// @notice `params.protocolFee` must be in range or this call will with an {IllegalArgument} error.
    /// @notice The minting growth limiter parameters must be valid or this will revert with an {IllegalArgument} error.
    /// For more information, see the {Limiters} library.
    ///
    /// @notice Emits an {AdminUpdated} event.
    /// @notice Emits a {SteamerUpdated} event.
    /// @notice Emits a {MinimumCollateralizationUpdated} event.
    /// @notice Emits a {ProtocolFeeUpdated} event.
    /// @notice Emits a {ProtocolFeeReceiverUpdated} event.
    /// @notice Emits a {MintingLimitUpdated} event.
    ///
    /// @param params The contract initialization parameters.
    function initialize(InitializationParams memory params) external;

    /// @notice Sets the pending administrator.
    ///
    /// @notice `msg.sender` must be the admin or this call will will revert with an {Unauthorized} error.
    ///
    /// @notice Emits a {PendingAdminUpdated} event.
    ///
    /// @dev This is the first step in the two-step process of setting a new administrator. After this function is
    /// called, the pending administrator will then need to call {acceptAdmin} to complete the process.
    ///
    /// @param value the address to set the pending admin to.
    function setPendingAdmin(address value) external;

    /// @notice Allows for `msg.sender` to accepts the role of administrator.
    ///
    /// @notice `msg.sender` must be the admin or this call will revert with an {Unauthorized} error.
    /// @notice The current pending administrator must be non-zero or this call will revert with an {IllegalState}
    /// error.
    ///
    /// @dev This is the second step in the two-step process of setting a new administrator. After this function is
    /// successfully called, this pending administrator will be reset and the new administrator will be set.
    ///
    /// @notice Emits a {AdminUpdated} event.
    /// @notice Emits a {PendingAdminUpdated} event.
    function acceptAdmin() external;

    /// @notice Sets an address as a sentinel.
    ///
    /// @notice `msg.sender` must be the admin or this call will revert with an {Unauthorized} error.
    ///
    /// @param sentinel The address to set or unset as a sentinel.
    /// @param flag     A flag indicating of the address should be set or unset as a sentinel.
    function setSentinel(address sentinel, bool flag) external;

    /// @notice Sets an address as a keeper.
    ///
    /// @notice `msg.sender` must be the admin or this call will revert with an {Unauthorized} error.
    ///
    /// @param keeper The address to set or unset as a keeper.
    /// @param flag   A flag indicating of the address should be set or unset as a keeper.
    function setKeeper(address keeper, bool flag) external;

    /// @notice Adds an underlying token to the system.
    ///
    /// @notice `msg.sender` must be the admin or this call will revert with an {Unauthorized} error.
    ///
    /// @param underlyingToken The address of the underlying token to add.
    /// @param config          The initial underlying token configuration.
    function addUnderlyingToken(address underlyingToken, UnderlyingTokenConfig calldata config) external;

    /// @notice Adds a yield token to the system.
    ///
    /// @notice `msg.sender` must be the admin or this call will revert with an {Unauthorized} error.
    ///
    /// @notice Emits a {AddYieldToken} event.
    /// @notice Emits a {TokenAdapterUpdated} event.
    /// @notice Emits a {MaximumLossUpdated} event.
    ///
    /// @param yieldToken The address of the yield token to add.
    /// @param config     The initial yield token configuration.
    function addYieldToken(address yieldToken, YieldTokenConfig calldata config) external;

    /// @notice Sets an underlying token as either enabled or disabled.
    ///
    /// @notice `msg.sender` must be either the admin or a sentinel or this call will revert with an {Unauthorized}
    /// error.
    /// @notice `underlyingToken` must be registered or this call will revert with a {UnsupportedToken} error.
    ///
    /// @notice Emits an {UnderlyingTokenEnabled} event.
    ///
    /// @param underlyingToken The address of the underlying token to enable or disable.
    /// @param enabled         If the underlying token should be enabled or disabled.
    function setUnderlyingTokenEnabled(address underlyingToken, bool enabled) external;

    /// @notice Sets a yield token as either enabled or disabled.
    ///
    /// @notice `msg.sender` must be either the admin or a sentinel or this call will revert with an {Unauthorized}
    /// error.
    /// @notice `yieldToken` must be registered or this call will revert with a {UnsupportedToken} error.
    ///
    /// @notice Emits a {YieldTokenEnabled} event.
    ///
    /// @param yieldToken The address of the yield token to enable or disable.
    /// @param enabled    If the underlying token should be enabled or disabled.
    function setYieldTokenEnabled(address yieldToken, bool enabled) external;

    /// @notice Configures the the repay limit of `underlyingToken`.
    ///
    /// @notice `msg.sender` must be the admin or this call will revert with an {Unauthorized} error.
    /// @notice `underlyingToken` must be registered or this call will revert with a {UnsupportedToken} error.
    ///
    /// @notice Emits a {ReplayLimitUpdated} event.
    ///
    /// @param underlyingToken The address of the underlying token to configure the repay limit of.
    /// @param maximum         The maximum repay limit.
    /// @param blocks          The number of blocks it will take for the maximum repayment limit to be replenished when
    /// it is completely exhausted.
    function configureRepayLimit(address underlyingToken, uint256 maximum, uint256 blocks) external;

    /// @notice Configure the liquidation limiter of `underlyingToken`.
    ///
    /// @notice `msg.sender` must be the admin or this call will revert with an {Unauthorized} error.
    /// @notice `underlyingToken` must be registered or this call will revert with a {UnsupportedToken} error.
    ///
    /// @notice Emits a {LiquidationLimitUpdated} event.
    ///
    /// @param underlyingToken The address of the underlying token to configure the liquidation limit of.
    /// @param maximum         The maximum liquidation limit.
    /// @param blocks          The number of blocks it will take for the maximum liquidation limit to be replenished
    /// when it is completely exhausted.
    function configureLiquidationLimit(address underlyingToken, uint256 maximum, uint256 blocks) external;

    /// @notice Set the address of the steamer.
    ///
    /// @notice `msg.sender` must be the admin or this call will revert with an {Unauthorized} error.
    /// @notice `value` must be non-zero or this call will revert with an {IllegalArgument} error.
    ///
    /// @notice Emits a {SteamerUpdated} event.
    ///
    /// @param value The address of the steamer.
    function setSteamer(address value) external;

    /// @notice Set the minimum collateralization ratio.
    ///
    /// @notice `msg.sender` must be the admin or this call will revert with an {Unauthorized} error.
    ///
    /// @notice Emits a {MinimumCollateralizationUpdated} event.
    ///
    /// @param value The new minimum collateralization ratio.
    function setMinimumCollateralization(uint256 value) external;

    /// @notice Sets the fee that the protocol will take from harvests.
    ///
    /// @notice `msg.sender` must be the admin or this call will revert with an {Unauthorized} error.
    /// @notice `value` must be in range or this call will with an {IllegalArgument} error.
    ///
    /// @notice Emits a {ProtocolFeeUpdated} event.
    ///
    /// @param value The value to set the protocol fee to measured in basis points.
    function setProtocolFee(uint256 value) external;

    /// @notice Sets the address which will receive protocol fees.
    ///
    /// @notice `msg.sender` must be the admin or this call will revert with an {Unauthorized} error.
    /// @notice `value` must be non-zero or this call will revert with an {IllegalArgument} error.
    ///
    /// @notice Emits a {ProtocolFeeReceiverUpdated} event.
    ///
    /// @param value The address to set the protocol fee receiver to.
    function setProtocolFeeReceiver(address value) external;

    /// @notice Configures the minting limiter.
    ///
    /// @notice `msg.sender` must be the admin or this call will revert with an {Unauthorized} error.
    ///
    /// @notice Emits a {MintingLimitUpdated} event.
    ///
    /// @param maximum The maximum minting limit.
    /// @param blocks  The number of blocks it will take for the maximum minting limit to be replenished when it is
    /// completely exhausted.
    function configureMintingLimit(uint256 maximum, uint256 blocks) external;

    /// @notice Sets the rate at which credit will be completely available to depositors after it is harvested.
    ///
    /// @notice Emits a {CreditUnlockRateUpdated} event.
    ///
    /// @param yieldToken The address of the yield token to set the credit unlock rate for.
    /// @param blocks     The number of blocks that it will take before the credit will be unlocked.
    function configureCreditUnlockRate(address yieldToken, uint256 blocks) external;

    /// @notice Sets the token adapter of a yield token.
    ///
    /// @notice `msg.sender` must be the admin or this call will revert with an {Unauthorized} error.
    /// @notice `yieldToken` must be registered or this call will revert with a {UnsupportedToken} error.
    /// @notice The token that `adapter` supports must be `yieldToken` or this call will revert with a {IllegalState}
    /// error.
    ///
    /// @notice Emits a {TokenAdapterUpdated} event.
    ///
    /// @param yieldToken The address of the yield token to set the adapter for.
    /// @param adapter    The address to set the token adapter to.
    function setTokenAdapter(address yieldToken, address adapter) external;

    /// @notice Sets the maximum expected value of a yield token that the system can hold.
    ///
    /// @notice `msg.sender` must be the admin or this call will revert with an {Unauthorized} error.
    /// @notice `yieldToken` must be registered or this call will revert with a {UnsupportedToken} error.
    ///
    /// @param yieldToken The address of the yield token to set the maximum expected value for.
    /// @param value      The maximum expected value of the yield token denoted measured in its underlying token.
    function setMaximumExpectedValue(address yieldToken, uint256 value) external;

    /// @notice Sets the maximum loss that a yield bearing token will permit before restricting certain actions.
    ///
    /// @notice `msg.sender` must be the admin or this call will revert with an {Unauthorized} error.
    /// @notice `yieldToken` must be registered or this call will revert with a {UnsupportedToken} error.
    ///
    /// @dev There are two types of loss of value for yield bearing assets: temporary or permanent. The system will
    /// automatically restrict actions which are sensitive to both forms of loss when detected. For example, deposits
    /// must be restricted when an excessive loss is encountered to prevent users from having their collateral harvested
    /// from them. While the user would receive credit, which then could be exchanged for value equal to the collateral
    /// that was harvested from them, it is seen as a negative user experience because the value of their collateral
    /// should have been higher than what was originally recorded when they made their deposit.
    ///
    /// @param yieldToken The address of the yield bearing token to set the maximum loss for.
    /// @param value      The value to set the maximum loss to. This is in units of basis points.
    function setMaximumLoss(address yieldToken, uint256 value) external;

    /// @notice Snap the expected value `yieldToken` to the current value.
    ///
    /// @notice `msg.sender` must be the admin or this call will revert with an {Unauthorized} error.
    /// @notice `yieldToken` must be registered or this call will revert with a {UnsupportedToken} error.
    ///
    /// @dev This function should only be used in the event of a loss in the target yield-token. For example, say a
    /// third-party protocol experiences a fifty percent loss. The expected value (amount of underlying tokens) of the
    /// yield tokens being held by the system would be two times the real value that those yield tokens could be
    /// redeemed for. This function gives governance a way to realize those losses so that users can continue using the
    /// token as normal.
    ///
    /// @param yieldToken The address of the yield token to snap.
    function snap(address yieldToken) external;
}

// File: src/interfaces/zeroliquid/IZeroLiquidErrors.sol



// SPDX-License-Identifier: UNLICENSED
pragma solidity >=0.5.0;

/// @title  IZeroLiquidErrors
/// @author ZeroLiquid
///
/// @notice Specifies errors.
interface IZeroLiquidErrors {
    /// @notice An error which is used to indicate that an operation failed because it tried to operate on a token that
    /// the system did not recognize.
    ///
    /// @param token The address of the token.
    error UnsupportedToken(address token);

    /// @notice An error which is used to indicate that an operation failed because it tried to operate on a token that
    /// has been disabled.
    ///
    /// @param token The address of the token.
    error TokenDisabled(address token);

    /// @notice An error which is used to indicate that an operation failed because an account became
    /// undercollateralized.
    error Undercollateralized();

    /// @notice An error which is used to indicate that an operation failed because the expected value of a yield token
    /// in the system exceeds the maximum value permitted.
    ///
    /// @param yieldToken           The address of the yield token.
    /// @param expectedValue        The expected value measured in units of the underlying token.
    /// @param maximumExpectedValue The maximum expected value permitted measured in units of the underlying token.
    error ExpectedValueExceeded(address yieldToken, uint256 expectedValue, uint256 maximumExpectedValue);

    /// @notice An error which is used to indicate that an operation failed because the loss that a yield token in the
    /// system exceeds the maximum value permitted.
    ///
    /// @param yieldToken  The address of the yield token.
    /// @param loss        The amount of loss measured in basis points.
    /// @param maximumLoss The maximum amount of loss permitted measured in basis points.
    error LossExceeded(address yieldToken, uint256 loss, uint256 maximumLoss);

    /// @notice An error which is used to indicate that a minting operation failed because the minting limit has been
    /// exceeded.
    ///
    /// @param amount    The amount of debt tokens that were requested to be minted.
    /// @param available The amount of debt tokens which are available to mint.
    error MintingLimitExceeded(uint256 amount, uint256 available);

    /// @notice An error which is used to indicate that an repay operation failed because the repay limit for an
    /// underlying token has been exceeded.
    ///
    /// @param underlyingToken The address of the underlying token.
    /// @param amount          The amount of underlying tokens that were requested to be repaid.
    /// @param available       The amount of underlying tokens that are available to be repaid.
    error RepayLimitExceeded(address underlyingToken, uint256 amount, uint256 available);

    /// @notice An error which is used to indicate that an repay operation failed because the liquidation limit for an
    /// underlying token has been exceeded.
    ///
    /// @param underlyingToken The address of the underlying token.
    /// @param amount          The amount of underlying tokens that were requested to be liquidated.
    /// @param available       The amount of underlying tokens that are available to be liquidated.
    error LiquidationLimitExceeded(address underlyingToken, uint256 amount, uint256 available);

    /// @notice An error which is used to indicate that the slippage of a wrap or unwrap operation was exceeded.
    ///
    /// @param amount           The amount of underlying or yield tokens returned by the operation.
    /// @param minimumAmountOut The minimum amount of the underlying or yield token that was expected when performing
    ///                         the operation.
    error SlippageExceeded(uint256 amount, uint256 minimumAmountOut);
}

// File: src/interfaces/zeroliquid/IZeroLiquidImmutables.sol



// SPDX-License-Identifier: UNLICENSED
pragma solidity >=0.5.0;

/// @title  IZeroLiquidImmutables
/// @author ZeroLiquid
interface IZeroLiquidImmutables {
    /// @notice Returns the version of the zeroliquid.
    ///
    /// @return The version.
    function version() external view returns (string memory);

    /// @notice Returns the address of the debt token used by the system.
    ///
    /// @return The address of the debt token.
    function debtToken() external view returns (address);
}

// File: src/interfaces/zeroliquid/IZeroLiquidEvents.sol



pragma solidity >=0.5.0;

/// @title  IZeroLiquidEvents
/// @author ZeroLiquid
interface IZeroLiquidEvents {
    /// @notice Emitted when the pending admin is updated.
    ///
    /// @param pendingAdmin The address of the pending admin.
    event PendingAdminUpdated(address pendingAdmin);

    /// @notice Emitted when the administrator is updated.
    ///
    /// @param admin The address of the administrator.
    event AdminUpdated(address admin);

    /// @notice Emitted when an address is set or unset as a sentinel.
    ///
    /// @param sentinel The address of the sentinel.
    /// @param flag     A flag indicating if `sentinel` was set or unset as a sentinel.
    event SentinelSet(address sentinel, bool flag);

    /// @notice Emitted when an address is set or unset as a keeper.
    ///
    /// @param sentinel The address of the keeper.
    /// @param flag     A flag indicating if `keeper` was set or unset as a sentinel.
    event KeeperSet(address sentinel, bool flag);

    /// @notice Emitted when an underlying token is added.
    ///
    /// @param underlyingToken The address of the underlying token that was added.
    event AddUnderlyingToken(address indexed underlyingToken);

    /// @notice Emitted when a yield token is added.
    ///
    /// @param yieldToken The address of the yield token that was added.
    event AddYieldToken(address indexed yieldToken);

    /// @notice Emitted when an underlying token is enabled or disabled.
    ///
    /// @param underlyingToken The address of the underlying token that was enabled or disabled.
    /// @param enabled         A flag indicating if the underlying token was enabled or disabled.
    event UnderlyingTokenEnabled(address indexed underlyingToken, bool enabled);

    /// @notice Emitted when an yield token is enabled or disabled.
    ///
    /// @param yieldToken The address of the yield token that was enabled or disabled.
    /// @param enabled    A flag indicating if the yield token was enabled or disabled.
    event YieldTokenEnabled(address indexed yieldToken, bool enabled);

    /// @notice Emitted when the repay limit of an underlying token is updated.
    ///
    /// @param underlyingToken The address of the underlying token.
    /// @param maximum         The updated maximum repay limit.
    /// @param blocks          The updated number of blocks it will take for the maximum repayment limit to be
    /// replenished when it is completely exhausted.
    event RepayLimitUpdated(address indexed underlyingToken, uint256 maximum, uint256 blocks);

    /// @notice Emitted when the liquidation limit of an underlying token is updated.
    ///
    /// @param underlyingToken The address of the underlying token.
    /// @param maximum         The updated maximum liquidation limit.
    /// @param blocks          The updated number of blocks it will take for the maximum liquidation limit to be
    /// replenished when it is completely exhausted.
    event LiquidationLimitUpdated(address indexed underlyingToken, uint256 maximum, uint256 blocks);

    /// @notice Emitted when the steamer is updated.
    ///
    /// @param steamer The updated address of the steamer.
    event SteamerUpdated(address steamer);

    /// @notice Emitted when the minimum collateralization is updated.
    ///
    /// @param minimumCollateralization The updated minimum collateralization.
    event MinimumCollateralizationUpdated(uint256 minimumCollateralization);

    /// @notice Emitted when the protocol fee is updated.
    ///
    /// @param protocolFee The updated protocol fee.
    event ProtocolFeeUpdated(uint256 protocolFee);

    /// @notice Emitted when the protocol fee receiver is updated.
    ///
    /// @param protocolFeeReceiver The updated address of the protocol fee receiver.
    event ProtocolFeeReceiverUpdated(address protocolFeeReceiver);

    /// @notice Emitted when the minting limit is updated.
    ///
    /// @param maximum The updated maximum minting limit.
    /// @param blocks  The updated number of blocks it will take for the maximum minting limit to be replenished when it
    /// is completely exhausted.
    event MintingLimitUpdated(uint256 maximum, uint256 blocks);

    /// @notice Emitted when the credit unlock rate is updated.
    ///
    /// @param yieldToken The address of the yield token.
    /// @param blocks     The number of blocks that distributed credit will unlock over.
    event CreditUnlockRateUpdated(address yieldToken, uint256 blocks);

    /// @notice Emitted when the adapter of a yield token is updated.
    ///
    /// @param yieldToken   The address of the yield token.
    /// @param tokenAdapter The updated address of the token adapter.
    event TokenAdapterUpdated(address yieldToken, address tokenAdapter);

    /// @notice Emitted when the maximum expected value of a yield token is updated.
    ///
    /// @param yieldToken           The address of the yield token.
    /// @param maximumExpectedValue The updated maximum expected value.
    event MaximumExpectedValueUpdated(address indexed yieldToken, uint256 maximumExpectedValue);

    /// @notice Emitted when the maximum loss of a yield token is updated.
    ///
    /// @param yieldToken  The address of the yield token.
    /// @param maximumLoss The updated maximum loss.
    event MaximumLossUpdated(address indexed yieldToken, uint256 maximumLoss);

    /// @notice Emitted when the expected value of a yield token is snapped to its current value.
    ///
    /// @param yieldToken    The address of the yield token.
    /// @param expectedValue The updated expected value measured in the yield token's underlying token.
    event Snap(address indexed yieldToken, uint256 expectedValue);

    /// @notice Emitted when `owner` grants `spender` the ability to mint debt tokens on its behalf.
    ///
    /// @param owner   The address of the account owner.
    /// @param spender The address which is being permitted to mint tokens on the behalf of `owner`.
    /// @param amount  The amount of debt tokens that `spender` is allowed to mint.
    event ApproveMint(address indexed owner, address indexed spender, uint256 amount);

    /// @notice Emitted when `owner` grants `spender` the ability to withdraw `yieldToken` from its account.
    ///
    /// @param owner      The address of the account owner.
    /// @param spender    The address which is being permitted to mint tokens on the behalf of `owner`.
    /// @param yieldToken The address of the yield token that `spender` is allowed to withdraw.
    /// @param amount     The amount of shares of `yieldToken` that `spender` is allowed to withdraw.
    event ApproveWithdraw(address indexed owner, address indexed spender, address indexed yieldToken, uint256 amount);

    /// @notice Emitted when a user deposits `amount of `yieldToken` to `recipient`.
    ///
    /// @notice This event does not imply that `sender` directly deposited yield tokens. It is possible that the
    ///         underlying tokens were wrapped.
    ///
    /// @param sender       The address of the user which deposited funds.
    /// @param yieldToken   The address of the yield token that was deposited.
    /// @param amount       The amount of yield tokens that were deposited.
    /// @param recipient    The address that received the deposited funds.
    event Deposit(address indexed sender, address indexed yieldToken, uint256 amount, address recipient);

    /// @notice Emitted when `shares` shares of `yieldToken` are burned to withdraw `yieldToken` from the account owned
    ///         by `owner` to `recipient`.
    ///
    /// @notice This event does not imply that `recipient` received yield tokens. It is possible that the yield tokens
    ///         were unwrapped.
    ///
    /// @param owner      The address of the account owner.
    /// @param yieldToken The address of the yield token that was withdrawn.
    /// @param shares     The amount of shares that were burned.
    /// @param recipient  The address that received the withdrawn funds.
    event Withdraw(address indexed owner, address indexed yieldToken, uint256 shares, address recipient);

    /// @notice Emitted when `amount` debt tokens are minted to `recipient` using the account owned by `owner`.
    ///
    /// @param owner     The address of the account owner.
    /// @param amount    The amount of tokens that were minted.
    /// @param recipient The recipient of the minted tokens.
    event Mint(address indexed owner, uint256 amount, address recipient);

    /// @notice Emitted when `sender` burns `amount` debt tokens to grant credit to `recipient`.
    ///
    /// @param sender    The address which is burning tokens.
    /// @param amount    The amount of tokens that were burned.
    /// @param recipient The address that received credit for the burned tokens.
    event Burn(address indexed sender, uint256 amount, address recipient);

    /// @notice Emitted when `amount` of `underlyingToken` are repaid to grant credit to `recipient`.
    ///
    /// @param sender          The address which is repaying tokens.
    /// @param underlyingToken The address of the underlying token that was used to repay debt.
    /// @param amount          The amount of the underlying token that was used to repay debt.
    /// @param recipient       The address that received credit for the repaid tokens.
    /// @param credit          The amount of debt that was paid-off to the account owned by owner.
    event Repay(
        address indexed sender, address indexed underlyingToken, uint256 amount, address recipient, uint256 credit
    );

    /// @notice Emitted when `sender` liquidates `share` shares of `yieldToken`.
    ///
    /// @param owner           The address of the account owner liquidating shares.
    /// @param yieldToken      The address of the yield token.
    /// @param underlyingToken The address of the underlying token.
    /// @param shares          The amount of the shares of `yieldToken` that were liquidated.
    /// @param credit          The amount of debt that was paid-off to the account owned by owner.
    event Liquidate(
        address indexed owner,
        address indexed yieldToken,
        address indexed underlyingToken,
        uint256 shares,
        uint256 credit
    );

    /// @notice Emitted when `sender` burns `amount` debt tokens to grant credit to users who have deposited
    /// `yieldToken`.
    ///
    /// @param sender     The address which burned debt tokens.
    /// @param yieldToken The address of the yield token.
    /// @param amount     The amount of debt tokens which were burned.
    event Donate(address indexed sender, address indexed yieldToken, uint256 amount);

    /// @notice Emitted when `yieldToken` is harvested.
    ///
    /// @param yieldToken       The address of the yield token that was harvested.
    /// @param minimumAmountOut The maximum amount of loss that is acceptable when unwrapping the underlying tokens into
    /// yield tokens, measured in basis points.
    /// @param totalHarvested   The total amount of underlying tokens harvested.
    /// @param credit           The total amount of debt repaid to depositors of `yieldToken`.
    event Harvest(address indexed yieldToken, uint256 minimumAmountOut, uint256 totalHarvested, uint256 credit);
}

// File: src/interfaces/zeroliquid/IZeroLiquidState.sol



// SPDX-License-Identifier: UNLICENSED
pragma solidity >=0.5.0;

/// @title  IZeroLiquidState
/// @author ZeroLiquid
interface IZeroLiquidState {
    /// @notice Defines underlying token parameters.
    struct UnderlyingTokenParams {
        // The number of decimals the token has. This value is cached once upon registering the token so it is important
        // that the decimals of the token are immutable or the system will begin to have computation errors.
        uint8 decimals;
        // A coefficient used to normalize the token to a value comparable to the debt token. For example, if the
        // underlying token is 8 decimals and the debt token is 18 decimals then the conversion factor will be
        // 10^10. One unit of the underlying token will be comparably equal to one unit of the debt token.
        uint256 conversionFactor;
        // A flag to indicate if the token is enabled.
        bool enabled;
    }

    /// @notice Defines yield token parameters.
    struct YieldTokenParams {
        // The number of decimals the token has. This value is cached once upon registering the token so it is important
        // that the decimals of the token are immutable or the system will begin to have computation errors.
        uint8 decimals;
        // The associated underlying token that can be redeemed for the yield-token.
        address underlyingToken;
        // The adapter used by the system to wrap, unwrap, and lookup the conversion rate of this token into its
        // underlying token.
        address adapter;
        // The maximum percentage loss that is acceptable before disabling certain actions.
        uint256 maximumLoss;
        // The maximum value of yield tokens that the system can hold, measured in units of the underlying token.
        uint256 maximumExpectedValue;
        // The percent of credit that will be unlocked per block. The representation of this value is a 18  decimal
        // fixed point integer.
        uint256 creditUnlockRate;
        // The current balance of yield tokens which are held by users.
        uint256 activeBalance;
        // The current balance of yield tokens which are earmarked to be harvested by the system at a later time.
        uint256 harvestableBalance;
        // The total number of shares that have been minted for this token.
        uint256 totalShares;
        // The expected value of the tokens measured in underlying tokens. This value controls how much of the token
        // can be harvested. When users deposit yield tokens, it increases the expected value by how much the tokens
        // are exchangeable for in the underlying token. When users withdraw yield tokens, it decreases the expected
        // value by how much the tokens are exchangeable for in the underlying token.
        uint256 expectedValue;
        // The current amount of credit which is will be distributed over time to depositors.
        uint256 pendingCredit;
        // The amount of the pending credit that has been distributed.
        uint256 distributedCredit;
        // The block number which the last credit distribution occurred.
        uint256 lastDistributionBlock;
        // The total accrued weight. This is used to calculate how much credit a user has been granted over time. The
        // representation of this value is a 18 decimal fixed point integer.
        uint256 accruedWeight;
        // A flag to indicate if the token is enabled.
        bool enabled;
    }

    /// @notice Gets the address of the admin.
    ///
    /// @return admin The admin address.
    function admin() external view returns (address admin);

    /// @notice Gets the address of the pending administrator.
    ///
    /// @return pendingAdmin The pending administrator address.
    function pendingAdmin() external view returns (address pendingAdmin);

    /// @notice Gets if an address is a sentinel.
    ///
    /// @param sentinel The address to check.
    ///
    /// @return isSentinel If the address is a sentinel.
    function sentinels(address sentinel) external view returns (bool isSentinel);

    /// @notice Gets if an address is a keeper.
    ///
    /// @param keeper The address to check.
    ///
    /// @return isKeeper If the address is a keeper
    function keepers(address keeper) external view returns (bool isKeeper);

    /// @notice Gets the address of the steamer.
    ///
    /// @return steamer The steamer address.
    function steamer() external view returns (address steamer);

    /// @notice Gets the minimum collateralization.
    ///
    /// @notice Collateralization is determined by taking the total value of collateral that a user has deposited into
    /// their account and dividing it their debt.
    ///
    /// @dev The value returned is a 18 decimal fixed point integer.
    ///
    /// @return minimumCollateralization The minimum collateralization.
    function minimumCollateralization() external view returns (uint256 minimumCollateralization);

    /// @notice Gets the protocol fee.
    ///
    /// @return protocolFee The protocol fee.
    function protocolFee() external view returns (uint256 protocolFee);

    /// @notice Gets the protocol fee receiver.
    ///
    /// @return protocolFeeReceiver The protocol fee receiver.
    function protocolFeeReceiver() external view returns (address protocolFeeReceiver);

    /// @notice Gets the conversion rate of underlying tokens per share.
    ///
    /// @param yieldToken The address of the yield token to get the conversion rate for.
    ///
    /// @return rate The rate of underlying tokens per share.
    function getUnderlyingTokensPerShare(address yieldToken) external view returns (uint256 rate);

    /// @notice Gets the conversion rate of yield tokens per share.
    ///
    /// @param yieldToken The address of the yield token to get the conversion rate for.
    ///
    /// @return rate The rate of yield tokens per share.
    function getYieldTokensPerShare(address yieldToken) external view returns (uint256 rate);

    /// @notice Gets the supported underlying tokens.
    ///
    /// @dev The order of the entries returned by this function is not guaranteed to be consistent between calls.
    ///
    /// @return tokens The supported underlying tokens.
    function getSupportedUnderlyingTokens() external view returns (address[] memory tokens);

    /// @notice Gets the supported yield tokens.
    ///
    /// @dev The order of the entries returned by this function is not guaranteed to be consistent between calls.
    ///
    /// @return tokens The supported yield tokens.
    function getSupportedYieldTokens() external view returns (address[] memory tokens);

    /// @notice Gets if an underlying token is supported.
    ///
    /// @param underlyingToken The address of the underlying token to check.
    ///
    /// @return isSupported If the underlying token is supported.
    function isSupportedUnderlyingToken(address underlyingToken) external view returns (bool isSupported);

    /// @notice Gets if a yield token is supported.
    ///
    /// @param yieldToken The address of the yield token to check.
    ///
    /// @return isSupported If the yield token is supported.
    function isSupportedYieldToken(address yieldToken) external view returns (bool isSupported);

    /// @notice Gets information about the account owned by `owner`.
    ///
    /// @param owner The address that owns the account.
    ///
    /// @return debt            The unrealized amount of debt that the account had incurred.
    /// @return depositedTokens The yield tokens that the owner has deposited.
    function accounts(address owner) external view returns (int256 debt, address[] memory depositedTokens);

    /// @notice Gets information about a yield token position for the account owned by `owner`.
    ///
    /// @param owner      The address that owns the account.
    /// @param yieldToken The address of the yield token to get the position of.
    ///
    /// @return shares            The amount of shares of that `owner` owns of the yield token.
    /// @return lastAccruedWeight The last recorded accrued weight of the yield token.
    function positions(
        address owner,
        address yieldToken
    )
        external
        view
        returns (uint256 shares, uint256 lastAccruedWeight);

    /// @notice Gets the amount of debt tokens `spender` is allowed to mint on behalf of `owner`.
    ///
    /// @param owner   The owner of the account.
    /// @param spender The address which is allowed to mint on behalf of `owner`.
    ///
    /// @return allowance The amount of debt tokens that `spender` can mint on behalf of `owner`.
    function mintAllowance(address owner, address spender) external view returns (uint256 allowance);

    /// @notice Gets the amount of shares of `yieldToken` that `spender` is allowed to withdraw on behalf of `owner`.
    ///
    /// @param owner      The owner of the account.
    /// @param spender    The address which is allowed to withdraw on behalf of `owner`.
    /// @param yieldToken The address of the yield token.
    ///
    /// @return allowance The amount of shares that `spender` can withdraw on behalf of `owner`.
    function withdrawAllowance(
        address owner,
        address spender,
        address yieldToken
    )
        external
        view
        returns (uint256 allowance);

    /// @notice Gets the parameters of an underlying token.
    ///
    /// @param underlyingToken The address of the underlying token.
    ///
    /// @return params The underlying token parameters.
    function getUnderlyingTokenParameters(address underlyingToken)
        external
        view
        returns (UnderlyingTokenParams memory params);

    /// @notice Get the parameters and state of a yield-token.
    ///
    /// @param yieldToken The address of the yield token.
    ///
    /// @return params The yield token parameters.
    function getYieldTokenParameters(address yieldToken) external view returns (YieldTokenParams memory params);

    /// @notice Gets current limit, maximum, and rate of the minting limiter.
    ///
    /// @return currentLimit The current amount of debt tokens that can be minted.
    /// @return rate         The maximum possible amount of tokens that can be liquidated at a time.
    /// @return maximum      The highest possible maximum amount of debt tokens that can be minted at a time.
    function getMintLimitInfo() external view returns (uint256 currentLimit, uint256 rate, uint256 maximum);

    /// @notice Gets current limit, maximum, and rate of a repay limiter for `underlyingToken`.
    ///
    /// @param underlyingToken The address of the underlying token.
    ///
    /// @return currentLimit The current amount of underlying tokens that can be repaid.
    /// @return rate         The rate at which the the current limit increases back to its maximum in tokens per block.
    /// @return maximum      The maximum possible amount of tokens that can be repaid at a time.
    function getRepayLimitInfo(address underlyingToken)
        external
        view
        returns (uint256 currentLimit, uint256 rate, uint256 maximum);

    /// @notice Gets current limit, maximum, and rate of the liquidation limiter for `underlyingToken`.
    ///
    /// @param underlyingToken The address of the underlying token.
    ///
    /// @return currentLimit The current amount of underlying tokens that can be liquidated.
    /// @return rate         The rate at which the function increases back to its maximum limit (tokens / block).
    /// @return maximum      The highest possible maximum amount of debt tokens that can be liquidated at a time.
    function getLiquidationLimitInfo(address underlyingToken)
        external
        view
        returns (uint256 currentLimit, uint256 rate, uint256 maximum);
}

// File: lib/openzeppelin-contracts/contracts/token/ERC20/IERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @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 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 `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, 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 `from` to `to` 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 from, address to, uint256 amount) external returns (bool);
}

// File: src/interfaces/IERC20Metadata.sol



pragma solidity >=0.5.0;

/// @title  IERC20Metadata
/// @author ZeroLiquid
interface IERC20Metadata {
    /// @notice Gets the name of the token.
    ///
    /// @return The name.
    function name() external view returns (string memory);

    /// @notice Gets the symbol of the token.
    ///
    /// @return The symbol.
    function symbol() external view returns (string memory);

    /// @notice Gets the number of decimals that the token has.
    ///
    /// @return The number of decimals.
    function decimals() external view returns (uint8);
}