Cryo Explorer Ethereum Mainnet

// 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);
    }
}

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

pragma solidity ^0.8.0;

/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 *
 * TIP: If you would like to learn more about reentrancy and alternative ways
 * to protect against it, check out our blog post
 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
 */
abstract contract ReentrancyGuard {
    // Booleans are more expensive than uint256 or any type that takes up a full
    // word because each write operation emits an extra SLOAD to first read the
    // slot's contents, replace the bits taken up by the boolean, and then write
    // back. This is the compiler's defense against contract upgrades and
    // pointer aliasing, and it cannot be disabled.

    // The values being non-zero value makes deployment a bit more expensive,
    // but in exchange the refund on every call to nonReentrant will be lower in
    // amount. Since refunds are capped to a percentage of the total
    // transaction's gas, it is best to keep them low in cases like this one, to
    // increase the likelihood of the full refund coming into effect.
    uint256 private constant _NOT_ENTERED = 1;
    uint256 private constant _ENTERED = 2;

    uint256 private _status;

    constructor() {
        _status = _NOT_ENTERED;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and making it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        _nonReentrantBefore();
        _;
        _nonReentrantAfter();
    }

    function _nonReentrantBefore() private {
        // On the first call to nonReentrant, _status will be _NOT_ENTERED
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;
    }

    function _nonReentrantAfter() private {
        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }

    /**
     * @dev Returns true if the reentrancy guard is currently set to "entered", which indicates there is a
     * `nonReentrant` function in the call stack.
     */
    function _reentrancyGuardEntered() internal view returns (bool) {
        return _status == _ENTERED;
    }
}

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

pragma solidity ^0.8.0;

import "./IERC20.sol";
import "./extensions/IERC20Metadata.sol";
import "../../utils/Context.sol";

/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {ERC20PresetMinterPauser}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.openzeppelin.com/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * The default value of {decimals} is 18. To change this, you should override
 * this function so it returns a different value.
 *
 * We have followed general OpenZeppelin Contracts guidelines: functions revert
 * instead returning `false` on failure. This behavior is nonetheless
 * conventional and does not conflict with the expectations of ERC20
 * applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
contract ERC20 is Context, IERC20, IERC20Metadata {
    mapping(address => uint256) private _balances;

    mapping(address => mapping(address => uint256)) private _allowances;

    uint256 private _totalSupply;

    string private _name;
    string private _symbol;

    /**
     * @dev Sets the values for {name} and {symbol}.
     *
     * All two of these values are immutable: they can only be set once during
     * construction.
     */
    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }

    /**
     * @dev Returns the name of the token.
     */
    function name() public view virtual override returns (string memory) {
        return _name;
    }

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5.05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei. This is the default value returned by this function, unless
     * it's overridden.
     *
     * NOTE: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() public view virtual override returns (uint8) {
        return 18;
    }

    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() public view virtual override returns (uint256) {
        return _totalSupply;
    }

    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public view virtual override returns (uint256) {
        return _balances[account];
    }

    /**
     * @dev See {IERC20-transfer}.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(address to, uint256 amount) public virtual override returns (bool) {
        address owner = _msgSender();
        _transfer(owner, to, amount);
        return true;
    }

    /**
     * @dev See {IERC20-allowance}.
     */
    function allowance(address owner, address spender) public view virtual override returns (uint256) {
        return _allowances[owner][spender];
    }

    /**
     * @dev See {IERC20-approve}.
     *
     * NOTE: If `amount` is the maximum `uint256`, the allowance is not updated on
     * `transferFrom`. This is semantically equivalent to an infinite approval.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 amount) public virtual override returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, amount);
        return true;
    }

    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Emits an {Approval} event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of {ERC20}.
     *
     * NOTE: Does not update the allowance if the current allowance
     * is the maximum `uint256`.
     *
     * Requirements:
     *
     * - `from` and `to` cannot be the zero address.
     * - `from` must have a balance of at least `amount`.
     * - the caller must have allowance for ``from``'s tokens of at least
     * `amount`.
     */
    function transferFrom(address from, address to, uint256 amount) public virtual override returns (bool) {
        address spender = _msgSender();
        _spendAllowance(from, spender, amount);
        _transfer(from, to, amount);
        return true;
    }

    /**
     * @dev Atomically increases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, allowance(owner, spender) + addedValue);
        return true;
    }

    /**
     * @dev Atomically decreases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `spender` must have allowance for the caller of at least
     * `subtractedValue`.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        address owner = _msgSender();
        uint256 currentAllowance = allowance(owner, spender);
        require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
        unchecked {
            _approve(owner, spender, currentAllowance - subtractedValue);
        }

        return true;
    }

    /**
     * @dev Moves `amount` of tokens from `from` to `to`.
     *
     * This internal function is equivalent to {transfer}, and can be used to
     * e.g. implement automatic token fees, slashing mechanisms, etc.
     *
     * Emits a {Transfer} event.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `from` must have a balance of at least `amount`.
     */
    function _transfer(address from, address to, uint256 amount) internal virtual {
        require(from != address(0), "ERC20: transfer from the zero address");
        require(to != address(0), "ERC20: transfer to the zero address");

        _beforeTokenTransfer(from, to, amount);

        uint256 fromBalance = _balances[from];
        require(fromBalance >= amount, "ERC20: transfer amount exceeds balance");
        unchecked {
            _balances[from] = fromBalance - amount;
            // Overflow not possible: the sum of all balances is capped by totalSupply, and the sum is preserved by
            // decrementing then incrementing.
            _balances[to] += amount;
        }

        emit Transfer(from, to, amount);

        _afterTokenTransfer(from, to, amount);
    }

    /** @dev Creates `amount` tokens and assigns them to `account`, increasing
     * the total supply.
     *
     * Emits a {Transfer} event with `from` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     */
    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");

        _beforeTokenTransfer(address(0), account, amount);

        _totalSupply += amount;
        unchecked {
            // Overflow not possible: balance + amount is at most totalSupply + amount, which is checked above.
            _balances[account] += amount;
        }
        emit Transfer(address(0), account, amount);

        _afterTokenTransfer(address(0), account, amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`, reducing the
     * total supply.
     *
     * Emits a {Transfer} event with `to` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     */
    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");

        _beforeTokenTransfer(account, address(0), amount);

        uint256 accountBalance = _balances[account];
        require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
        unchecked {
            _balances[account] = accountBalance - amount;
            // Overflow not possible: amount <= accountBalance <= totalSupply.
            _totalSupply -= amount;
        }

        emit Transfer(account, address(0), amount);

        _afterTokenTransfer(account, address(0), amount);
    }

    /**
     * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
     *
     * This internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     */
    function _approve(address owner, address spender, uint256 amount) internal virtual {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");

        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    /**
     * @dev Updates `owner` s allowance for `spender` based on spent `amount`.
     *
     * Does not update the allowance amount in case of infinite allowance.
     * Revert if not enough allowance is available.
     *
     * Might emit an {Approval} event.
     */
    function _spendAllowance(address owner, address spender, uint256 amount) internal virtual {
        uint256 currentAllowance = allowance(owner, spender);
        if (currentAllowance != type(uint256).max) {
            require(currentAllowance >= amount, "ERC20: insufficient allowance");
            unchecked {
                _approve(owner, spender, currentAllowance - amount);
            }
        }
    }

    /**
     * @dev Hook that is called before any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * will be transferred to `to`.
     * - when `from` is zero, `amount` tokens will be minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual {}

    /**
     * @dev Hook that is called after any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * has been transferred to `to`.
     * - when `from` is zero, `amount` tokens have been minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens have been burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _afterTokenTransfer(address from, address to, uint256 amount) internal virtual {}
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)

pragma solidity ^0.8.0;

import "../IERC20.sol";

/**
 * @dev Interface for the optional metadata functions from the ERC20 standard.
 *
 * _Available since v4.1._
 */
interface IERC20Metadata is IERC20 {
    /**
     * @dev Returns the name of the token.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the symbol of the token.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the decimals places of the token.
     */
    function decimals() external view returns (uint8);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.4) (token/ERC20/extensions/IERC20Permit.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
 * https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
 *
 * Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
 * presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't
 * need to send a transaction, and thus is not required to hold Ether at all.
 *
 * ==== Security Considerations
 *
 * There are two important considerations concerning the use of `permit`. The first is that a valid permit signature
 * expresses an allowance, and it should not be assumed to convey additional meaning. In particular, it should not be
 * considered as an intention to spend the allowance in any specific way. The second is that because permits have
 * built-in replay protection and can be submitted by anyone, they can be frontrun. A protocol that uses permits should
 * take this into consideration and allow a `permit` call to fail. Combining these two aspects, a pattern that may be
 * generally recommended is:
 *
 * ```solidity
 * function doThingWithPermit(..., uint256 value, uint256 deadline, uint8 v, bytes32 r, bytes32 s) public {
 *     try token.permit(msg.sender, address(this), value, deadline, v, r, s) {} catch {}
 *     doThing(..., value);
 * }
 *
 * function doThing(..., uint256 value) public {
 *     token.safeTransferFrom(msg.sender, address(this), value);
 *     ...
 * }
 * ```
 *
 * Observe that: 1) `msg.sender` is used as the owner, leaving no ambiguity as to the signer intent, and 2) the use of
 * `try/catch` allows the permit to fail and makes the code tolerant to frontrunning. (See also
 * {SafeERC20-safeTransferFrom}).
 *
 * Additionally, note that smart contract wallets (such as Argent or Safe) are not able to produce permit signatures, so
 * contracts should have entry points that don't rely on permit.
 */
interface IERC20Permit {
    /**
     * @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
     * given ``owner``'s signed approval.
     *
     * IMPORTANT: The same issues {IERC20-approve} has related to transaction
     * ordering also apply here.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `deadline` must be a timestamp in the future.
     * - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
     * over the EIP712-formatted function arguments.
     * - the signature must use ``owner``'s current nonce (see {nonces}).
     *
     * For more information on the signature format, see the
     * https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
     * section].
     *
     * CAUTION: See Security Considerations above.
     */
    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;

    /**
     * @dev Returns the current nonce for `owner`. This value must be
     * included whenever a signature is generated for {permit}.
     *
     * Every successful call to {permit} increases ``owner``'s nonce by one. This
     * prevents a signature from being used multiple times.
     */
    function nonces(address owner) external view returns (uint256);

    /**
     * @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
     */
    // solhint-disable-next-line func-name-mixedcase
    function DOMAIN_SEPARATOR() external view returns (bytes32);
}

// 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);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.3) (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.0;

import "../IERC20.sol";
import "../extensions/IERC20Permit.sol";
import "../../../utils/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;

    /**
     * @dev Transfer `value` amount of `token` from the calling contract to `to`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    /**
     * @dev Transfer `value` amount of `token` from `from` to `to`, spending the approval given by `from` to the
     * calling contract. If `token` returns no value, non-reverting calls are assumed to be successful.
     */
    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

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

    /**
     * @dev Increase the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 oldAllowance = token.allowance(address(this), spender);
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, oldAllowance + value));
    }

    /**
     * @dev Decrease the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    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");
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, oldAllowance - value));
        }
    }

    /**
     * @dev Set the calling contract's allowance toward `spender` to `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful. Meant to be used with tokens that require the approval
     * to be set to zero before setting it to a non-zero value, such as USDT.
     */
    function forceApprove(IERC20 token, address spender, uint256 value) internal {
        bytes memory approvalCall = abi.encodeWithSelector(token.approve.selector, spender, value);

        if (!_callOptionalReturnBool(token, approvalCall)) {
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, 0));
            _callOptionalReturn(token, approvalCall);
        }
    }

    /**
     * @dev Use a ERC-2612 signature to set the `owner` approval toward `spender` on `token`.
     * Revert on invalid signature.
     */
    function safePermit(
        IERC20Permit token,
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal {
        uint256 nonceBefore = token.nonces(owner);
        token.permit(owner, spender, value, deadline, v, r, s);
        uint256 nonceAfter = token.nonces(owner);
        require(nonceAfter == nonceBefore + 1, "SafeERC20: permit did not succeed");
    }

    /**
     * @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");
        require(returndata.length == 0 || abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
    }

    /**
     * @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).
     *
     * This is a variant of {_callOptionalReturn} that silents catches all reverts and returns a bool instead.
     */
    function _callOptionalReturnBool(IERC20 token, bytes memory data) private returns (bool) {
        // 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 cannot use {Address-functionCall} here since this should return false
        // and not revert is the subcall reverts.

        (bool success, bytes memory returndata) = address(token).call(data);
        return
            success && (returndata.length == 0 || abi.decode(returndata, (bool))) && Address.isContract(address(token));
    }
}

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

pragma solidity ^0.8.1;

/**
 * @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
     *
     * Furthermore, `isContract` will also return true if the target contract within
     * the same transaction is already scheduled for destruction by `SELFDESTRUCT`,
     * which only has an effect at the end of a transaction.
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 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://consensys.net/diligence/blog/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/v0.8.0/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

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

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, "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");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResultFromTarget(target, 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) {
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResultFromTarget(target, 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) {
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
     * the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
     *
     * _Available since v4.8._
     */
    function verifyCallResultFromTarget(
        address target,
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        if (success) {
            if (returndata.length == 0) {
                // only check isContract if the call was successful and the return data is empty
                // otherwise we already know that it was a contract
                require(isContract(target), "Address: call to non-contract");
            }
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    /**
     * @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason or using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    function _revert(bytes memory returndata, string memory errorMessage) private pure {
        // 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
            /// @solidity memory-safe-assembly
            assembly {
                let returndata_size := mload(returndata)
                revert(add(32, returndata), returndata_size)
            }
        } else {
            revert(errorMessage);
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.4) (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;
    }

    function _contextSuffixLength() internal view virtual returns (uint256) {
        return 0;
    }
}

// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity >=0.5.0;

/// @title Callback for IUniswapV3PoolActions#swap
/// @notice Any contract that calls IUniswapV3PoolActions#swap must implement this interface
interface IUniswapV3SwapCallback {
    /// @notice Called to `msg.sender` after executing a swap via IUniswapV3Pool#swap.
    /// @dev In the implementation you must pay the pool tokens owed for the swap.
    /// The caller of this method must be checked to be a UniswapV3Pool deployed by the canonical UniswapV3Factory.
    /// amount0Delta and amount1Delta can both be 0 if no tokens were swapped.
    /// @param amount0Delta The amount of token0 that was sent (negative) or must be received (positive) by the pool by
    /// the end of the swap. If positive, the callback must send that amount of token0 to the pool.
    /// @param amount1Delta The amount of token1 that was sent (negative) or must be received (positive) by the pool by
    /// the end of the swap. If positive, the callback must send that amount of token1 to the pool.
    /// @param data Any data passed through by the caller via the IUniswapV3PoolActions#swap call
    function uniswapV3SwapCallback(
        int256 amount0Delta,
        int256 amount1Delta,
        bytes calldata data
    ) external;
}

// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity >=0.7.5;
pragma abicoder v2;

import '@uniswap/v3-core/contracts/interfaces/callback/IUniswapV3SwapCallback.sol';

/// @title Router token swapping functionality
/// @notice Functions for swapping tokens via Uniswap V3
interface ISwapRouter is IUniswapV3SwapCallback {
    struct ExactInputSingleParams {
        address tokenIn;
        address tokenOut;
        uint24 fee;
        address recipient;
        uint256 deadline;
        uint256 amountIn;
        uint256 amountOutMinimum;
        uint160 sqrtPriceLimitX96;
    }

    /// @notice Swaps `amountIn` of one token for as much as possible of another token
    /// @param params The parameters necessary for the swap, encoded as `ExactInputSingleParams` in calldata
    /// @return amountOut The amount of the received token
    function exactInputSingle(ExactInputSingleParams calldata params) external payable returns (uint256 amountOut);

    struct ExactInputParams {
        bytes path;
        address recipient;
        uint256 deadline;
        uint256 amountIn;
        uint256 amountOutMinimum;
    }

    /// @notice Swaps `amountIn` of one token for as much as possible of another along the specified path
    /// @param params The parameters necessary for the multi-hop swap, encoded as `ExactInputParams` in calldata
    /// @return amountOut The amount of the received token
    function exactInput(ExactInputParams calldata params) external payable returns (uint256 amountOut);

    struct ExactOutputSingleParams {
        address tokenIn;
        address tokenOut;
        uint24 fee;
        address recipient;
        uint256 deadline;
        uint256 amountOut;
        uint256 amountInMaximum;
        uint160 sqrtPriceLimitX96;
    }

    /// @notice Swaps as little as possible of one token for `amountOut` of another token
    /// @param params The parameters necessary for the swap, encoded as `ExactOutputSingleParams` in calldata
    /// @return amountIn The amount of the input token
    function exactOutputSingle(ExactOutputSingleParams calldata params) external payable returns (uint256 amountIn);

    struct ExactOutputParams {
        bytes path;
        address recipient;
        uint256 deadline;
        uint256 amountOut;
        uint256 amountInMaximum;
    }

    /// @notice Swaps as little as possible of one token for `amountOut` of another along the specified path (reversed)
    /// @param params The parameters necessary for the multi-hop swap, encoded as `ExactOutputParams` in calldata
    /// @return amountIn The amount of the input token
    function exactOutput(ExactOutputParams calldata params) external payable returns (uint256 amountIn);
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/security/ReentrancyGuard.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";

import "@uniswap/v3-periphery/contracts/interfaces/ISwapRouter.sol";

import "./interfaces/IUniswapV3Pool.sol";

interface ISMSFund {
    function getWBGLPrice() external view returns (uint256);
    function getCurrentAPY() external view returns (uint256);
    function getCollateralRatio() external view returns (uint256);
    function buckets(uint256 index) external view returns (uint256);
    function accumulatedDebt() external view returns (uint256);
    function mintSMSFromBond(address user, uint256 USDamount) external;
}

contract BondToken is ERC20, Ownable, ReentrancyGuard {
    using SafeERC20 for IERC20;

    ISMSFund public immutable smsFund;
    
    // Token addresses from SMSFund
    address public constant WBGL = 0x2bA64EFB7A4Ec8983E22A49c81fa216AC33f383A;
    address public constant WETH = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;
    address public constant LUSD = 0x5f98805A4E8be255a32880FDeC7F6728C6568bA0;
    address public constant USDT = 0xdAC17F958D2ee523a2206206994597C13D831ec7;
    address public constant USDC = 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48;
    address public constant DAI = 0x6B175474E89094C44Da98b954EedeAC495271d0F;
    
    ISwapRouter public constant router = ISwapRouter(0xE592427A0AEce92De3Edee1F18E0157C05861564);
    
    struct UserInfo {
        uint256 amount;
        uint256 rewardDebt;
        uint256 lastUpdateTime;
    }
    
    struct DepositAuction {
        address depositor;
        address stablecoin;
        uint256 stablecoinAmount;
        uint256 auctionDuration;
        uint256 startTime;
        uint256 endTime;
        address bestBidder;
        uint256 bestBidAmount; // WBGL amount
        bool finished;
        bool executed;
        mapping(address => uint256) bids;
        address[] bidders;
    }
    
    struct RedeemAuction {
        address redeemer;
        address stablecoin;
        uint256 bondAmount;
        uint256 wbglAmount;
        uint256 auctionDuration;
        uint256 startTime;
        uint256 endTime;
        address bestBidder;
        uint256 bestBidAmount; // Stablecoin amount
        bool finished;
        bool executed;
        mapping(address => uint256) bids;
        address[] bidders;
    }
    
    mapping(address => UserInfo) public userInfo;
    mapping(uint256 => DepositAuction) public depositAuctions;
    mapping(uint256 => RedeemAuction) public redeemAuctions;
    
    uint256 public nextDepositAuctionId;
    uint256 public nextRedeemAuctionId;
    
    uint256 public accRewardPerShare;
    uint256 public lastRewardTime;
    
    uint256 private constant PRECISION = 1e18;
    uint256 private constant YEAR_SECONDS = 365 days;
    uint256 private constant MAX_AUCTION_DURATION = 24 hours;
    uint256 private constant USDC_PRECISION = 1e6;
    
    event Deposit(address indexed user, uint256 wbglAmount, uint256 bondAmount);
    event Withdraw(address indexed user, uint256 bondAmount, uint256 wbglAmount);
    event RewardClaimed(address indexed user, uint256 amount);
    event DepositAuctionCreated(uint256 indexed auctionId, address indexed depositor, address stablecoin, uint256 amount, uint256 duration);
    event DepositAuctionBid(uint256 indexed auctionId, address indexed bidder, uint256 wbglAmount);
    event DepositAuctionFinished(uint256 indexed auctionId, address indexed winner, uint256 wbglAmount);
    event RedeemAuctionCreated(uint256 indexed auctionId, address indexed redeemer, address stablecoin, uint256 bondAmount, uint256 duration);
    event RedeemAuctionBid(uint256 indexed auctionId, address indexed bidder, uint256 stablecoinAmount);
    event RedeemAuctionFinished(uint256 indexed auctionId, address indexed winner, uint256 stablecoinAmount);
    event BidRetracted(uint256 indexed auctionId, address indexed bidder, uint256 amount, bool isDeposit);
    
    constructor(address _smsFund) ERC20("Bond Token", "BOND") {
        smsFund = ISMSFund(_smsFund);
        lastRewardTime = block.timestamp;
    }
    
    modifier onlySMSFund() {
        require(msg.sender == address(smsFund), "Only SMS Fund can call");
        _;
    }
    
    modifier validStablecoin(address stablecoin) {
        require(
            stablecoin == USDT || 
            stablecoin == USDC || 
            stablecoin == DAI || 
            stablecoin == LUSD, 
            "Invalid stablecoin"
        );
        _;
    }
    
    function updatePool() public {
        if (block.timestamp <= lastRewardTime) {
            return;
        }
        
        uint256 bondSupply = totalSupply();
        if (bondSupply == 0) {
            lastRewardTime = block.timestamp;
            return;
        }
        
        uint256 timeElapsed = block.timestamp - lastRewardTime;
        uint256 apy = smsFund.getCurrentAPY();
        uint256 reward = (bondSupply * apy * timeElapsed) / (100 * YEAR_SECONDS);
        
        uint256 increment = (reward * PRECISION);
        increment = increment / bondSupply;
        accRewardPerShare += increment;
        lastRewardTime = block.timestamp;
    }
    
    function pendingReward(address _user) public view returns (uint256) {
        UserInfo storage user = userInfo[_user];
        uint256 _accRewardPerShare = accRewardPerShare;
        
        uint256 bondSupply = totalSupply();
        if (block.timestamp > lastRewardTime && bondSupply != 0) {
            uint256 timeElapsed = block.timestamp - lastRewardTime;
            uint256 apy = smsFund.getCurrentAPY();
            uint256 reward = (bondSupply * apy * timeElapsed) / (100 * YEAR_SECONDS);
            _accRewardPerShare += (reward * PRECISION) / bondSupply;
        }
        
        return (user.amount * _accRewardPerShare) / PRECISION - user.rewardDebt;
    }
    
    function pendingTotalRewards() external view returns (uint256) {
        uint256 _accRewardPerShare = accRewardPerShare;
        
        if (block.timestamp > lastRewardTime && totalSupply() != 0) {
            uint256 timeElapsed = block.timestamp - lastRewardTime;
            uint256 apy = smsFund.getCurrentAPY();
            uint256 reward = (totalSupply() * apy * timeElapsed) / (100 * YEAR_SECONDS);
            _accRewardPerShare += (reward * PRECISION);
        }
        
        return (_accRewardPerShare) / PRECISION;
    }

    function burnBondForSMS(uint256 bondAmount) external nonReentrant {
        require(bondAmount > 0, "Bond amount must be greater than 0");
        require(balanceOf(msg.sender) >= bondAmount, "Insufficient BOND balance");
        
        updatePool();
        
        UserInfo storage user = userInfo[msg.sender];
        require(user.amount >= bondAmount, "Insufficient user bond amount");
        
        // Calculate pending rewards for the amount being burned
        uint256 pendingRewardsForBurn = pendingReward(msg.sender);

        // Update user info before burning
        user.amount -= bondAmount;
        user.rewardDebt = (user.amount * accRewardPerShare) / PRECISION;
        
        // Burn the BOND tokens
        _burn(msg.sender, bondAmount);
        
        uint256 valueInUSD = (bondAmount + pendingRewardsForBurn);

        // Call SMS Fund to mint SMS tokens
        smsFund.mintSMSFromBond(msg.sender, valueInUSD);
    }
    
    function depositWBGL(uint256 amount) external nonReentrant {
        require(amount > 0, "Amount must be greater than 0");
        
        require(IERC20(WBGL).transferFrom(msg.sender, address(smsFund), amount), "Transfer failed");
        
        updatePool();
        
        UserInfo storage user = userInfo[msg.sender];
        
        if (user.amount > 0) {
            uint256 pending = (user.amount * accRewardPerShare) / PRECISION - user.rewardDebt;
            if (pending > 0) {
                user.rewardDebt += pending;
            }
        }
        
        uint256 wbglPrice = smsFund.getWBGLPrice();
        uint256 bondAmount = (amount * wbglPrice) / PRECISION;
        
        user.amount += bondAmount;
        user.rewardDebt = (user.amount * accRewardPerShare) / PRECISION;
        user.lastUpdateTime = block.timestamp;
        
        _mint(msg.sender, bondAmount);
        
        emit Deposit(msg.sender, amount, bondAmount);
    }
    
    function depositStablecoin(address stablecoin, uint256 amount) external validStablecoin(stablecoin) nonReentrant {
        depositStablecoinWithAuction(stablecoin, amount, 0);
    }
    
    function depositStablecoinWithAuction(address stablecoin, uint256 amount, uint256 auctionDuration) public validStablecoin(stablecoin) nonReentrant {
        require(amount > 0, "Amount must be greater than 0");
        require(auctionDuration <= MAX_AUCTION_DURATION, "Auction duration too long");
        
        require(IERC20(stablecoin).transferFrom(msg.sender, address(this), amount), "Transfer failed");
        
        uint256 auctionId = nextDepositAuctionId++;
        DepositAuction storage auction = depositAuctions[auctionId];
        
        auction.depositor = msg.sender;
        auction.stablecoin = stablecoin;
        auction.stablecoinAmount = amount;
        auction.auctionDuration = auctionDuration;
        auction.startTime = block.timestamp;
        auction.endTime = block.timestamp + auctionDuration;
        
        emit DepositAuctionCreated(auctionId, msg.sender, stablecoin, amount, auctionDuration);
        
        // If auction duration is 0, finish immediately
        if (auctionDuration == 0) {
            _finishDepositAuction(auctionId);
        }
    }
    
    function bidOnDepositAuction(uint256 auctionId, uint256 wbglAmount) external nonReentrant {
        DepositAuction storage auction = depositAuctions[auctionId];
        require(!auction.finished, "Auction already finished");
        require(block.timestamp < auction.endTime, "Auction ended");
        require(wbglAmount > auction.bestBidAmount, "Bid too low");
        
        require(IERC20(WBGL).transferFrom(msg.sender, address(this), wbglAmount), "Transfer failed");
        
        // Return previous bid if exists
        if (auction.bids[msg.sender] > 0) {
            require(IERC20(WBGL).transfer(msg.sender, auction.bids[msg.sender]), "Return failed");
        } else {
            auction.bidders.push(msg.sender);
        }
        
        // Return previous best bid
        if (auction.bestBidder != address(0)) {
            require(IERC20(WBGL).transfer(auction.bestBidder, auction.bestBidAmount), "Return failed");
        }
        
        auction.bids[msg.sender] = wbglAmount;
        auction.bestBidder = msg.sender;
        auction.bestBidAmount = wbglAmount;
        
        emit DepositAuctionBid(auctionId, msg.sender, wbglAmount);
    }
    
    function finishDepositAuction(uint256 auctionId) external nonReentrant {
        _finishDepositAuction(auctionId);
    }
    
    function _finishDepositAuction(uint256 auctionId) internal {
        DepositAuction storage auction = depositAuctions[auctionId];
        require(!auction.finished, "Auction already finished");
        require(block.timestamp >= auction.endTime, "Auction not ended");
        
        auction.finished = true;
        
        uint256 wbglAmount;
        address winner;
        
        if (auction.bestBidder != address(0)) {
            // Auction had bids
            wbglAmount = auction.bestBidAmount;
            winner = auction.bestBidder;
            
            // Transfer stablecoin to winner
            require(IERC20(auction.stablecoin).transfer(winner, auction.stablecoinAmount), "Transfer failed");
            
            // Transfer WBGL to SMS Fund
            require(IERC20(WBGL).transfer(address(smsFund), wbglAmount), "Transfer failed");
        } else {
            // No bids, execute Uniswap trade
            wbglAmount = _executeStablecoinToWBGLSwap(auction.stablecoin, auction.stablecoinAmount);
            winner = address(this); // Contract executed the trade
        }
        
        // Mint BOND tokens to depositor
        _mintBondTokens(auction.depositor, wbglAmount);
        
        emit DepositAuctionFinished(auctionId, winner, wbglAmount);
    }
    
    function redeemBond(uint256 bondAmount) external nonReentrant {
        redeemBondWithAuction(bondAmount, USDT, 0);
    }
    
    function redeemBondWithAuction(uint256 bondAmount, address stablecoin, uint256 auctionDuration) public validStablecoin(stablecoin) nonReentrant {
        require(balanceOf(msg.sender) >= bondAmount, "Insufficient BOND balance");
        require(auctionDuration <= MAX_AUCTION_DURATION, "Auction duration too long");
        
        uint256 cr = smsFund.getCollateralRatio();
        require(cr >= (11 * PRECISION) / 10, "CR must be >= 1.1 for redemption");
        
        // Calculate WBGL amount to be redeemed
        uint256 wbglPrice = smsFund.getWBGLPrice();
        uint256 wbglAmount = (bondAmount * PRECISION) / wbglPrice;
        
        // Check if first bucket has enough WBGL
        uint256 firstBucketAmount = smsFund.buckets(0);
        require(firstBucketAmount >= wbglAmount, "Not enough WBGL in first bucket");
        
        // Burn BOND tokens
        _burn(msg.sender, bondAmount);
        
        uint256 auctionId = nextRedeemAuctionId++;
        RedeemAuction storage auction = redeemAuctions[auctionId];
        
        auction.redeemer = msg.sender;
        auction.stablecoin = stablecoin;
        auction.bondAmount = bondAmount;
        auction.wbglAmount = wbglAmount;
        auction.auctionDuration = auctionDuration;
        auction.startTime = block.timestamp;
        auction.endTime = block.timestamp + auctionDuration;
        
        emit RedeemAuctionCreated(auctionId, msg.sender, stablecoin, bondAmount, auctionDuration);
        
        // If auction duration is 0, finish immediately
        if (auctionDuration == 0) {
            _finishRedeemAuction(auctionId);
        }
    }
    
    function bidOnRedeemAuction(uint256 auctionId, uint256 stablecoinAmount) external nonReentrant {
        RedeemAuction storage auction = redeemAuctions[auctionId];
        require(!auction.finished, "Auction already finished");
        require(block.timestamp < auction.endTime, "Auction ended");
        require(stablecoinAmount > auction.bestBidAmount, "Bid too low");
        
        require(IERC20(auction.stablecoin).transferFrom(msg.sender, address(this), stablecoinAmount), "Transfer failed");
        
        // Return previous bid if exists
        if (auction.bids[msg.sender] > 0) {
            require(IERC20(auction.stablecoin).transfer(msg.sender, auction.bids[msg.sender]), "Return failed");
        } else {
            auction.bidders.push(msg.sender);
        }
        
        // Return previous best bid
        if (auction.bestBidder != address(0)) {
            require(IERC20(auction.stablecoin).transfer(auction.bestBidder, auction.bestBidAmount), "Return failed");
        }
        
        auction.bids[msg.sender] = stablecoinAmount;
        auction.bestBidder = msg.sender;
        auction.bestBidAmount = stablecoinAmount;
        
        emit RedeemAuctionBid(auctionId, msg.sender, stablecoinAmount);
    }
    
    function finishRedeemAuction(uint256 auctionId) external nonReentrant {
        _finishRedeemAuction(auctionId);
    }
    
    function _finishRedeemAuction(uint256 auctionId) internal {
        RedeemAuction storage auction = redeemAuctions[auctionId];
        require(!auction.finished, "Auction already finished");
        require(block.timestamp >= auction.endTime, "Auction not ended");
        
        auction.finished = true;
        
        uint256 stablecoinAmount;
        address winner;
        
        if (auction.bestBidder != address(0)) {
            // Auction had bids
            stablecoinAmount = auction.bestBidAmount;
            winner = auction.bestBidder;
            
            // Transfer WBGL to winner (from SMS Fund first bucket)
            require(IERC20(WBGL).transferFrom(address(smsFund), winner, auction.wbglAmount), "Transfer failed");
            
            // Transfer stablecoin to redeemer
            require(IERC20(auction.stablecoin).transfer(auction.redeemer, stablecoinAmount), "Transfer failed");
        } else {
            // No bids, execute Uniswap trade
            stablecoinAmount = _executeWBGLToStablecoinSwap(auction.wbglAmount, auction.stablecoin);
            winner = address(this); // Contract executed the trade
            
            // Transfer stablecoin to redeemer
            require(IERC20(auction.stablecoin).transfer(auction.redeemer, stablecoinAmount), "Transfer failed");
        }
        
        emit RedeemAuctionFinished(auctionId, winner, stablecoinAmount);
    }
    
    function retractDepositBid(uint256 auctionId) external nonReentrant {
        DepositAuction storage auction = depositAuctions[auctionId];
        require(auction.finished, "Auction not finished");
        require(auction.bids[msg.sender] > 0, "No bid to retract");
        require(msg.sender != auction.bestBidder, "Cannot retract winning bid");
        
        uint256 bidAmount = auction.bids[msg.sender];
        auction.bids[msg.sender] = 0;
        
        require(IERC20(WBGL).transfer(msg.sender, bidAmount), "Transfer failed");
        
        emit BidRetracted(auctionId, msg.sender, bidAmount, true);
    }
    
    function retractRedeemBid(uint256 auctionId) external nonReentrant {
        RedeemAuction storage auction = redeemAuctions[auctionId];
        require(auction.finished, "Auction not finished");
        require(auction.bids[msg.sender] > 0, "No bid to retract");
        require(msg.sender != auction.bestBidder, "Cannot retract winning bid");
        
        uint256 bidAmount = auction.bids[msg.sender];
        auction.bids[msg.sender] = 0;
        
        require(IERC20(auction.stablecoin).transfer(msg.sender, bidAmount), "Transfer failed");
        
        emit BidRetracted(auctionId, msg.sender, bidAmount, false);
    }
    
    function _executeStablecoinToWBGLSwap(address stablecoin, uint256 amount) internal returns (uint256 amountOut) {
        // Swap stablecoin to WBGL using the same logic as SMSFund
        uint256 allowance = IERC20(stablecoin).allowance(address(this), address(router));
        if (allowance < amount) {
            uint256 newAllowance = 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff;
            IERC20(stablecoin).safeIncreaseAllowance(address(router), newAllowance - allowance);
        }

        if (stablecoin == USDT || stablecoin == USDC) {
            // First swap stablecoin to WETH
            ISwapRouter.ExactInputParams memory params = ISwapRouter.ExactInputParams({
                path: abi.encodePacked(
                    stablecoin,
                    uint24(100), // 0.01% fee
                    WETH
                ),
                recipient: address(this),
                deadline: block.timestamp,
                amountIn: amount,
                amountOutMinimum: 0
            });

            uint256 wethOut = ISwapRouter(router).exactInput(params);
            
            allowance = IERC20(WETH).allowance(address(this), address(router));
            if (allowance < wethOut) {
                uint256 newAllowance = 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff;
                IERC20(WETH).safeIncreaseAllowance(address(router), newAllowance - allowance);
            }

            // swap WETH to WBGL
            params = ISwapRouter.ExactInputParams({
                path: abi.encodePacked(
                    WETH,
                    uint24(100), // 0.01% fee
                    WBGL
                ),
                recipient: address(smsFund),
                deadline: block.timestamp,
                amountIn: wethOut,
                amountOutMinimum: 0
            });

            amountOut = ISwapRouter(router).exactInput(params);

        } else if (stablecoin == LUSD || stablecoin == DAI) {
            // First swap LUSD/DAI to USDC
            uint24 poolFee = 100;
            if (stablecoin == LUSD) {
                poolFee = 500;
            }
            ISwapRouter.ExactInputParams memory params = ISwapRouter.ExactInputParams({
                path: abi.encodePacked(
                    stablecoin,
                    poolFee,
                    USDC
                ),
                recipient: address(this),
                deadline: block.timestamp,
                amountIn: amount,
                amountOutMinimum: 0
            });

            uint256 usdcOut = ISwapRouter(router).exactInput(params);

            allowance = IERC20(USDC).allowance(address(this), address(router));
            if (allowance < usdcOut) {
                uint256 newAllowance = 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff;
                IERC20(USDC).safeIncreaseAllowance(address(router), newAllowance - allowance);
            }

            // swap USDC to WETH
            params = ISwapRouter.ExactInputParams({
                path: abi.encodePacked(
                    USDC,
                    uint24(100), // 0.01% fee
                    WETH
                ),
                recipient: address(this),
                deadline: block.timestamp,
                amountIn: usdcOut,
                amountOutMinimum: 0
            });

            uint256 wethOut = ISwapRouter(router).exactInput(params);

            allowance = IERC20(WETH).allowance(address(this), address(router));
            if (allowance < wethOut) {
                uint256 newAllowance = 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff;
                IERC20(WETH).safeIncreaseAllowance(address(router), newAllowance - allowance);
            }

            // swap WETH to WBGL
            params = ISwapRouter.ExactInputParams({
                path: abi.encodePacked(
                    WETH,
                    uint24(100), // 0.01% fee
                    WBGL
                ),
                recipient: address(smsFund),
                deadline: block.timestamp,
                amountIn: wethOut,
                amountOutMinimum: 0
            });

            amountOut = ISwapRouter(router).exactInput(params);
        }
    }
    
    function _executeWBGLToStablecoinSwap(uint256 wbglAmount, address stablecoin) internal returns (uint256 amountOut) {
        // Get WBGL from SMS Fund first bucket
        require(IERC20(WBGL).transferFrom(address(smsFund), address(this), wbglAmount), "Transfer failed");
        
        uint256 allowance = IERC20(WBGL).allowance(address(this), address(router));
        if (allowance < wbglAmount) {
            uint256 newAllowance = 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff;
            IERC20(WBGL).safeIncreaseAllowance(address(router), newAllowance - allowance);
        }

        if (stablecoin == USDT || stablecoin == USDC) {
            // First swap WBGL to WETH
            ISwapRouter.ExactInputParams memory params = ISwapRouter.ExactInputParams({
                path: abi.encodePacked(
                    WBGL,
                    uint24(100), // 0.01% fee
                    WETH
                ),
                recipient: address(this),
                deadline: block.timestamp,
                amountIn: wbglAmount,
                amountOutMinimum: 0
            });

            uint256 wethOut = ISwapRouter(router).exactInput(params);
            
            allowance = IERC20(WETH).allowance(address(this), address(router));
            if (allowance < wethOut) {
                uint256 newAllowance = 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff;
                IERC20(WETH).safeIncreaseAllowance(address(router), newAllowance - allowance);
            }

            // swap WETH to stablecoin
            params = ISwapRouter.ExactInputParams({
                path: abi.encodePacked(
                    WETH,
                    uint24(100), // 0.01% fee
                    stablecoin
                ),
                recipient: address(this),
                deadline: block.timestamp,
                amountIn: wethOut,
                amountOutMinimum: 0
            });

            amountOut = ISwapRouter(router).exactInput(params);

        } else if (stablecoin == LUSD || stablecoin == DAI) {
            // First swap WBGL to WETH
            ISwapRouter.ExactInputParams memory params = ISwapRouter.ExactInputParams({
                path: abi.encodePacked(
                    WBGL,
                    uint24(100), // 0.01% fee
                    WETH
                ),
                recipient: address(this),
                deadline: block.timestamp,
                amountIn: wbglAmount,
                amountOutMinimum: 0
            });

            uint256 wethOut = ISwapRouter(router).exactInput(params);

            allowance = IERC20(WETH).allowance(address(this), address(router));
            if (allowance < wethOut) {
                uint256 newAllowance = 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff;
                IERC20(WETH).safeIncreaseAllowance(address(router), newAllowance - allowance);
            }

            // swap WETH to USDC
            params = ISwapRouter.ExactInputParams({
                path: abi.encodePacked(
                    WETH,
                    uint24(100), // 0.01% fee
                    USDC
                ),
                recipient: address(this),
                deadline: block.timestamp,
                amountIn: wethOut,
                amountOutMinimum: 0
            });

            uint256 usdcOut = ISwapRouter(router).exactInput(params);

            allowance = IERC20(USDC).allowance(address(this), address(router));
            if (allowance < usdcOut) {
                uint256 newAllowance = 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff;
                IERC20(USDC).safeIncreaseAllowance(address(router), newAllowance - allowance);
            }

            // swap USDC to final stablecoin
            uint24 poolFee = 100;
            if (stablecoin == LUSD) {
                poolFee = 500;
            }
            params = ISwapRouter.ExactInputParams({
                path: abi.encodePacked(
                    USDC,
                    poolFee,
                    stablecoin
                ),
                recipient: address(this),
                deadline: block.timestamp,
                amountIn: usdcOut,
                amountOutMinimum: 0
            });

            amountOut = ISwapRouter(router).exactInput(params);
        }
    }
    
    function _mintBondTokens(address to, uint256 wbglAmount) internal {
        updatePool();
        
        UserInfo storage user = userInfo[to];
        
        if (user.amount > 0) {
            uint256 pending = (user.amount * accRewardPerShare) / PRECISION - user.rewardDebt;
            if (pending > 0) {
                user.rewardDebt += pending;
            }
        }
        
        uint256 bondAmount = wbglAmount * 1e18 / smsFund.getCollateralRatio(); // 1:1 for stablecoins
        
        user.amount += bondAmount;
        user.rewardDebt = (user.amount * accRewardPerShare) / PRECISION;
        user.lastUpdateTime = block.timestamp;
        
        _mint(to, bondAmount);
        
        emit Deposit(to, 0, bondAmount);
    }
    
    function claimRewards() external nonReentrant {
        updatePool();
        
        UserInfo storage user = userInfo[msg.sender];
        uint256 pending = (user.amount * accRewardPerShare) / PRECISION - user.rewardDebt;
        
        require(pending > 0, "No rewards to claim");
        
        user.rewardDebt = (user.amount * accRewardPerShare) / PRECISION;
        
        emit RewardClaimed(msg.sender, pending);
    }
        
    function updateDebt() external onlySMSFund {
        updatePool();
    }

    function getDepositAuctionInfo(uint256 auctionId) external view returns (
        address depositor,
        address stablecoin,
        uint256 stablecoinAmount,
        uint256 startTime,
        uint256 endTime,
        address bestBidder,
        uint256 bestBidAmount,
        bool finished
    ) {
        DepositAuction storage auction = depositAuctions[auctionId];
        return (
            auction.depositor,
            auction.stablecoin,
            auction.stablecoinAmount,
            auction.startTime,
            auction.endTime,
            auction.bestBidder,
            auction.bestBidAmount,
            auction.finished
        );
    }
    
    function getRedeemAuctionInfo(uint256 auctionId) external view returns (
        address redeemer,
        address stablecoin,
        uint256 bondAmount,
        uint256 wbglAmount,
        uint256 startTime,
        uint256 endTime,
        address bestBidder,
        uint256 bestBidAmount,
        bool finished
    ) {
        RedeemAuction storage auction = redeemAuctions[auctionId];
        return (
            auction.redeemer,
            auction.stablecoin,
            auction.bondAmount,
            auction.wbglAmount,
            auction.startTime,
            auction.endTime,
            auction.bestBidder,
            auction.bestBidAmount,
            auction.finished
        );
    }
    
    function getDepositAuctionBid(uint256 auctionId, address bidder) external view returns (uint256) {
        return depositAuctions[auctionId].bids[bidder];
    }
    
    function getRedeemAuctionBid(uint256 auctionId, address bidder) external view returns (uint256) {
        return redeemAuctions[auctionId].bids[bidder];
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

interface IUniswapV3Pool {
    function factory() external view returns (address);
    function token0() external view returns (address);
    function token1() external view returns (address);
    function fee() external view returns (uint24);
    function tickSpacing() external view returns (int24);
    function maxLiquidityPerTick() external view returns (uint128);
    
    function slot0()
        external
        view
        returns (
            uint160 sqrtPriceX96,
            int24 tick,
            uint16 observationIndex,
            uint16 observationCardinality,
            uint16 observationCardinalityNext,
            uint8 feeProtocol,
            bool unlocked
        );
        
    function liquidity() external view returns (uint128);
    
    function observe(uint32[] calldata secondsAgos)
        external
        view
        returns (int56[] memory tickCumulatives, uint160[] memory secondsPerLiquidityCumulativeX128s);
        
    function swap(
        address recipient,
        bool zeroForOne,
        int256 amountSpecified,
        uint160 sqrtPriceLimitX96,
        bytes calldata data
    ) external returns (int256 amount0, int256 amount1);
    
    function mint(
        address recipient,
        int24 tickLower,
        int24 tickUpper,
        uint128 amount,
        bytes calldata data
    ) external returns (uint256 amount0, uint256 amount1);
    
    function burn(
        int24 tickLower,
        int24 tickUpper,
        uint128 amount
    ) external returns (uint256 amount0, uint256 amount1);
}