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// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (access/Ownable.sol)

pragma solidity ^0.8.20;

import {Context} from "../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.
 *
 * The initial owner is set to the address provided by the deployer. 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;

    /**
     * @dev The caller account is not authorized to perform an operation.
     */
    error OwnableUnauthorizedAccount(address account);

    /**
     * @dev The owner is not a valid owner account. (eg. `address(0)`)
     */
    error OwnableInvalidOwner(address owner);

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

    /**
     * @dev Initializes the contract setting the address provided by the deployer as the initial owner.
     */
    constructor(address initialOwner) {
        if (initialOwner == address(0)) {
            revert OwnableInvalidOwner(address(0));
        }
        _transferOwnership(initialOwner);
    }

    /**
     * @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 {
        if (owner() != _msgSender()) {
            revert OwnableUnauthorizedAccount(_msgSender());
        }
    }

    /**
     * @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 {
        if (newOwner == address(0)) {
            revert OwnableInvalidOwner(address(0));
        }
        _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 v5.1.0) (interfaces/IERC1363.sol)

pragma solidity ^0.8.20;

import {IERC20} from "./IERC20.sol";
import {IERC165} from "./IERC165.sol";

/**
 * @title IERC1363
 * @dev Interface of the ERC-1363 standard as defined in the https://eips.ethereum.org/EIPS/eip-1363[ERC-1363].
 *
 * Defines an extension interface for ERC-20 tokens that supports executing code on a recipient contract
 * after `transfer` or `transferFrom`, or code on a spender contract after `approve`, in a single transaction.
 */
interface IERC1363 is IERC20, IERC165 {
    /*
     * Note: the ERC-165 identifier for this interface is 0xb0202a11.
     * 0xb0202a11 ===
     *   bytes4(keccak256('transferAndCall(address,uint256)')) ^
     *   bytes4(keccak256('transferAndCall(address,uint256,bytes)')) ^
     *   bytes4(keccak256('transferFromAndCall(address,address,uint256)')) ^
     *   bytes4(keccak256('transferFromAndCall(address,address,uint256,bytes)')) ^
     *   bytes4(keccak256('approveAndCall(address,uint256)')) ^
     *   bytes4(keccak256('approveAndCall(address,uint256,bytes)'))
     */

    /**
     * @dev Moves a `value` amount of tokens from the caller's account to `to`
     * and then calls {IERC1363Receiver-onTransferReceived} on `to`.
     * @param to The address which you want to transfer to.
     * @param value The amount of tokens to be transferred.
     * @return A boolean value indicating whether the operation succeeded unless throwing.
     */
    function transferAndCall(address to, uint256 value) external returns (bool);

    /**
     * @dev Moves a `value` amount of tokens from the caller's account to `to`
     * and then calls {IERC1363Receiver-onTransferReceived} on `to`.
     * @param to The address which you want to transfer to.
     * @param value The amount of tokens to be transferred.
     * @param data Additional data with no specified format, sent in call to `to`.
     * @return A boolean value indicating whether the operation succeeded unless throwing.
     */
    function transferAndCall(address to, uint256 value, bytes calldata data) external returns (bool);

    /**
     * @dev Moves a `value` amount of tokens from `from` to `to` using the allowance mechanism
     * and then calls {IERC1363Receiver-onTransferReceived} on `to`.
     * @param from The address which you want to send tokens from.
     * @param to The address which you want to transfer to.
     * @param value The amount of tokens to be transferred.
     * @return A boolean value indicating whether the operation succeeded unless throwing.
     */
    function transferFromAndCall(address from, address to, uint256 value) external returns (bool);

    /**
     * @dev Moves a `value` amount of tokens from `from` to `to` using the allowance mechanism
     * and then calls {IERC1363Receiver-onTransferReceived} on `to`.
     * @param from The address which you want to send tokens from.
     * @param to The address which you want to transfer to.
     * @param value The amount of tokens to be transferred.
     * @param data Additional data with no specified format, sent in call to `to`.
     * @return A boolean value indicating whether the operation succeeded unless throwing.
     */
    function transferFromAndCall(address from, address to, uint256 value, bytes calldata data) external returns (bool);

    /**
     * @dev Sets a `value` amount of tokens as the allowance of `spender` over the
     * caller's tokens and then calls {IERC1363Spender-onApprovalReceived} on `spender`.
     * @param spender The address which will spend the funds.
     * @param value The amount of tokens to be spent.
     * @return A boolean value indicating whether the operation succeeded unless throwing.
     */
    function approveAndCall(address spender, uint256 value) external returns (bool);

    /**
     * @dev Sets a `value` amount of tokens as the allowance of `spender` over the
     * caller's tokens and then calls {IERC1363Spender-onApprovalReceived} on `spender`.
     * @param spender The address which will spend the funds.
     * @param value The amount of tokens to be spent.
     * @param data Additional data with no specified format, sent in call to `spender`.
     * @return A boolean value indicating whether the operation succeeded unless throwing.
     */
    function approveAndCall(address spender, uint256 value, bytes calldata data) external returns (bool);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (interfaces/IERC165.sol)

pragma solidity ^0.8.20;

import {IERC165} from "../utils/introspection/IERC165.sol";

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (interfaces/IERC20.sol)

pragma solidity ^0.8.20;

import {IERC20} from "../token/ERC20/IERC20.sol";

// 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 v5.1.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.20;

/**
 * @dev Interface of the ERC-20 standard as defined in the ERC.
 */
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 value of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

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

    /**
     * @dev Moves a `value` amount of 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 value) 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 a `value` amount of tokens 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 value) external returns (bool);

    /**
     * @dev Moves a `value` amount of tokens from `from` to `to` using the
     * allowance mechanism. `value` 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 value) external returns (bool);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.2.0) (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.20;

import {IERC20} from "../IERC20.sol";
import {IERC1363} from "../../../interfaces/IERC1363.sol";

/**
 * @title SafeERC20
 * @dev Wrappers around ERC-20 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 {
    /**
     * @dev An operation with an ERC-20 token failed.
     */
    error SafeERC20FailedOperation(address token);

    /**
     * @dev Indicates a failed `decreaseAllowance` request.
     */
    error SafeERC20FailedDecreaseAllowance(address spender, uint256 currentAllowance, uint256 requestedDecrease);

    /**
     * @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.encodeCall(token.transfer, (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.encodeCall(token.transferFrom, (from, to, 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.
     *
     * IMPORTANT: If the token implements ERC-7674 (ERC-20 with temporary allowance), and if the "client"
     * smart contract uses ERC-7674 to set temporary allowances, then the "client" smart contract should avoid using
     * this function. Performing a {safeIncreaseAllowance} or {safeDecreaseAllowance} operation on a token contract
     * that has a non-zero temporary allowance (for that particular owner-spender) will result in unexpected behavior.
     */
    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 oldAllowance = token.allowance(address(this), spender);
        forceApprove(token, spender, oldAllowance + value);
    }

    /**
     * @dev Decrease the calling contract's allowance toward `spender` by `requestedDecrease`. If `token` returns no
     * value, non-reverting calls are assumed to be successful.
     *
     * IMPORTANT: If the token implements ERC-7674 (ERC-20 with temporary allowance), and if the "client"
     * smart contract uses ERC-7674 to set temporary allowances, then the "client" smart contract should avoid using
     * this function. Performing a {safeIncreaseAllowance} or {safeDecreaseAllowance} operation on a token contract
     * that has a non-zero temporary allowance (for that particular owner-spender) will result in unexpected behavior.
     */
    function safeDecreaseAllowance(IERC20 token, address spender, uint256 requestedDecrease) internal {
        unchecked {
            uint256 currentAllowance = token.allowance(address(this), spender);
            if (currentAllowance < requestedDecrease) {
                revert SafeERC20FailedDecreaseAllowance(spender, currentAllowance, requestedDecrease);
            }
            forceApprove(token, spender, currentAllowance - requestedDecrease);
        }
    }

    /**
     * @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.
     *
     * NOTE: If the token implements ERC-7674, this function will not modify any temporary allowance. This function
     * only sets the "standard" allowance. Any temporary allowance will remain active, in addition to the value being
     * set here.
     */
    function forceApprove(IERC20 token, address spender, uint256 value) internal {
        bytes memory approvalCall = abi.encodeCall(token.approve, (spender, value));

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

    /**
     * @dev Performs an {ERC1363} transferAndCall, with a fallback to the simple {ERC20} transfer if the target has no
     * code. This can be used to implement an {ERC721}-like safe transfer that rely on {ERC1363} checks when
     * targeting contracts.
     *
     * Reverts if the returned value is other than `true`.
     */
    function transferAndCallRelaxed(IERC1363 token, address to, uint256 value, bytes memory data) internal {
        if (to.code.length == 0) {
            safeTransfer(token, to, value);
        } else if (!token.transferAndCall(to, value, data)) {
            revert SafeERC20FailedOperation(address(token));
        }
    }

    /**
     * @dev Performs an {ERC1363} transferFromAndCall, with a fallback to the simple {ERC20} transferFrom if the target
     * has no code. This can be used to implement an {ERC721}-like safe transfer that rely on {ERC1363} checks when
     * targeting contracts.
     *
     * Reverts if the returned value is other than `true`.
     */
    function transferFromAndCallRelaxed(
        IERC1363 token,
        address from,
        address to,
        uint256 value,
        bytes memory data
    ) internal {
        if (to.code.length == 0) {
            safeTransferFrom(token, from, to, value);
        } else if (!token.transferFromAndCall(from, to, value, data)) {
            revert SafeERC20FailedOperation(address(token));
        }
    }

    /**
     * @dev Performs an {ERC1363} approveAndCall, with a fallback to the simple {ERC20} approve if the target has no
     * code. This can be used to implement an {ERC721}-like safe transfer that rely on {ERC1363} checks when
     * targeting contracts.
     *
     * NOTE: When the recipient address (`to`) has no code (i.e. is an EOA), this function behaves as {forceApprove}.
     * Opposedly, when the recipient address (`to`) has code, this function only attempts to call {ERC1363-approveAndCall}
     * once without retrying, and relies on the returned value to be true.
     *
     * Reverts if the returned value is other than `true`.
     */
    function approveAndCallRelaxed(IERC1363 token, address to, uint256 value, bytes memory data) internal {
        if (to.code.length == 0) {
            forceApprove(token, to, value);
        } else if (!token.approveAndCall(to, value, data)) {
            revert SafeERC20FailedOperation(address(token));
        }
    }

    /**
     * @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 {_callOptionalReturnBool} that reverts if call fails to meet the requirements.
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        uint256 returnSize;
        uint256 returnValue;
        assembly ("memory-safe") {
            let success := call(gas(), token, 0, add(data, 0x20), mload(data), 0, 0x20)
            // bubble errors
            if iszero(success) {
                let ptr := mload(0x40)
                returndatacopy(ptr, 0, returndatasize())
                revert(ptr, returndatasize())
            }
            returnSize := returndatasize()
            returnValue := mload(0)
        }

        if (returnSize == 0 ? address(token).code.length == 0 : returnValue != 1) {
            revert SafeERC20FailedOperation(address(token));
        }
    }

    /**
     * @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 silently catches all reverts and returns a bool instead.
     */
    function _callOptionalReturnBool(IERC20 token, bytes memory data) private returns (bool) {
        bool success;
        uint256 returnSize;
        uint256 returnValue;
        assembly ("memory-safe") {
            success := call(gas(), token, 0, add(data, 0x20), mload(data), 0, 0x20)
            returnSize := returndatasize()
            returnValue := mload(0)
        }
        return success && (returnSize == 0 ? address(token).code.length > 0 : returnValue == 1);
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.1) (utils/Context.sol)

pragma solidity ^0.8.20;

/**
 * @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: MIT
// OpenZeppelin Contracts (last updated v5.1.0) (utils/introspection/IERC165.sol)

pragma solidity ^0.8.20;

/**
 * @dev Interface of the ERC-165 standard, as defined in the
 * https://eips.ethereum.org/EIPS/eip-165[ERC].
 *
 * Implementers can declare support of contract interfaces, which can then be
 * queried by others ({ERC165Checker}).
 *
 * For an implementation, see {ERC165}.
 */
interface IERC165 {
    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[ERC section]
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}

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

pragma solidity ^0.8.0;

// CAUTION
// This version of SafeMath should only be used with Solidity 0.8 or later,
// because it relies on the compiler's built in overflow checks.

/**
 * @dev Wrappers over Solidity's arithmetic operations.
 *
 * NOTE: `SafeMath` is generally not needed starting with Solidity 0.8, since the compiler
 * now has built in overflow checking.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            uint256 c = a + b;
            if (c < a) return (false, 0);
            return (true, c);
        }
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b > a) return (false, 0);
            return (true, a - b);
        }
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
            // benefit is lost if 'b' is also tested.
            // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
            if (a == 0) return (true, 0);
            uint256 c = a * b;
            if (c / a != b) return (false, 0);
            return (true, c);
        }
    }

    /**
     * @dev Returns the division of two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a / b);
        }
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a % b);
        }
    }

    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        return a + b;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return a - b;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     *
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        return a * b;
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator.
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return a / b;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return a % b;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {trySub}.
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        unchecked {
            require(b <= a, errorMessage);
            return a - b;
        }
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a / b;
        }
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting with custom message when dividing by zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryMod}.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a % b;
        }
    }
}

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

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

/**
 * @title LotteryFarm
 * @dev A staking contract that implements a lottery system where users can win prizes.
 * Users stake tokens for a specified period and earn lottery tickets (1 ticket per day staked).
 * A drawing is performed every 7 days (configurable) where winners are randomly selected.
 */
contract LotteryFarm is Ownable, ReentrancyGuard {
    using SafeERC20 for IERC20;
    using SafeMath for uint256;

    // Structs
    struct UserInfo {
        uint256 amount;           // How many tokens the user has staked
        uint256 rewardDebt;       // Reward debt
        uint256 ticketCount;      // How many lottery tickets the user has
        uint256 stakeTime;        // When the user staked
        uint256 unlockTime;       // When the user can withdraw
        bool hasUnlockedTokens;   // Whether the user has tokens ready to unlock
        bool hasClaimed;          // Whether the user has claimed their prize
    }

    struct Farm {
        address stakeToken;       // Address of token to stake
        address rewardToken;      // Address of token to reward
        uint256 rewardPerSecond;  // Reward per second
        uint256 startTime;        // Start time of the farm
        uint256 endTime;          // End time of the farm
        uint256 lastRewardTime;   // Last timestamp reward was calculated
        uint256 accRewardPerShare;// Accumulated rewards per share, times 1e18
        uint256 totalStaked;      // Total tokens staked
        uint256 lockDuration;     // Duration in seconds tokens are locked
        uint256 depositFee;       // Deposit fee (if any)
        uint256 withdrawFee;      // Withdraw fee (if any)
        uint256 minStakeAmount;   // Minimum amount to stake
        uint256 maxStakeAmount;   // Maximum amount to stake (0 = no limit)
        bool paused;              // Is the farm paused?
        bool active;              // Is the farm active?
        uint256 drawInterval;     // Interval between lottery draws in seconds (default 7 days)
        uint256 ticketsPerStake;  // Number of tickets per day of staking per token
        uint256 winnerCount;      // Number of winners per draw
        uint256 lastDrawTime;     // Last time a draw was performed
        uint256 prizePool;        // Current prize pool amount
        address[] currentWinners; // Current winners of the draw
    }

    // Events
    event Deposit(address indexed user, uint256 indexed farmId, uint256 amount);
    event Withdraw(address indexed user, uint256 indexed farmId, uint256 amount);
    event EmergencyWithdraw(address indexed user, uint256 indexed farmId, uint256 amount);
    event FarmCreated(uint256 indexed farmId, address stakeToken, address rewardToken);
    event FarmUpdated(uint256 indexed farmId);
    event LotteryDrawPerformed(uint256 indexed farmId, address[] winners, uint256 prizeAmount);
    event PrizeClaimed(address indexed user, uint256 indexed farmId, uint256 amount);

    // State variables
    Farm[] public farms;
    mapping(uint256 => mapping(address => UserInfo)) public userInfo;
    mapping(uint256 => address[]) public participants;
    mapping(uint256 => mapping(address => uint256)) public userTicketsMap;
    mapping(uint256 => uint256) public totalTickets;

    // Fee receiver address
    address public feeReceiver;
    
    // Constants
    uint256 public constant SECONDS_PER_DAY = 86400;
    uint256 public constant DEFAULT_DRAW_INTERVAL = 7 * SECONDS_PER_DAY;
    uint256 public constant PRECISION_FACTOR = 1e18;

    /**
     * @dev Constructor
     * @param _feeReceiver Address to receive fees
     */
    constructor(address _feeReceiver) Ownable(msg.sender) {
        require(_feeReceiver != address(0), "Fee receiver cannot be zero address");
        feeReceiver = _feeReceiver;
    }

    /**
     * @dev Create a new farm
     * @param _stakeToken Stake token address
     * @param _rewardToken Reward token address
     * @param _rewardPerSecond Reward tokens per second
     * @param _startTime Start time of the farm
     * @param _endTime End time of the farm
     * @param _lockDuration Duration in seconds tokens are locked
     * @param _depositFee Deposit fee (percentage with 2 decimals, e.g. 100 = 1%)
     * @param _withdrawFee Withdraw fee (percentage with 2 decimals, e.g. 100 = 1%)
     * @param _minStakeAmount Minimum amount to stake
     * @param _maxStakeAmount Maximum amount to stake (0 = no limit)
     * @param _drawInterval Interval between draws in seconds
     * @param _ticketsPerStake Number of tickets per day of staking per token
     * @param _winnerCount Number of winners per draw
     */
    function createFarm(
        address _stakeToken,
        address _rewardToken,
        uint256 _rewardPerSecond,
        uint256 _startTime,
        uint256 _endTime,
        uint256 _lockDuration,
        uint256 _depositFee,
        uint256 _withdrawFee,
        uint256 _minStakeAmount,
        uint256 _maxStakeAmount,
        uint256 _drawInterval,
        uint256 _ticketsPerStake,
        uint256 _winnerCount
    ) external {
        require(_stakeToken != address(0), "Stake token cannot be zero address");
        require(_rewardToken != address(0), "Reward token cannot be zero address");
        require(_startTime >= block.timestamp, "Start time must be in the future");
        require(_endTime > _startTime, "End time must be after start time");
        require(_depositFee <= 1000, "Deposit fee cannot be more than 10%");
        require(_withdrawFee <= 1000, "Withdraw fee cannot be more than 10%");
        require(_rewardPerSecond > 0, "Reward per second must be positive");
        require(_minStakeAmount > 0, "Min stake amount must be positive");
        require(_drawInterval > 0, "Draw interval must be positive");
        require(_ticketsPerStake > 0, "Tickets per stake must be positive");
        require(_winnerCount > 0, "Winner count must be positive");
        
        // Set default draw interval if not specified
        uint256 drawInterval = _drawInterval > 0 ? _drawInterval : DEFAULT_DRAW_INTERVAL;
        
        // Create new farm
        farms.push(
            Farm({
                stakeToken: _stakeToken,
                rewardToken: _rewardToken,
                rewardPerSecond: _rewardPerSecond,
                startTime: _startTime,
                endTime: _endTime,
                lastRewardTime: _startTime,
                accRewardPerShare: 0,
                totalStaked: 0,
                lockDuration: _lockDuration,
                depositFee: _depositFee,
                withdrawFee: _withdrawFee,
                minStakeAmount: _minStakeAmount,
                maxStakeAmount: _maxStakeAmount,
                paused: false,
                active: true,
                drawInterval: drawInterval,
                ticketsPerStake: _ticketsPerStake,
                winnerCount: _winnerCount,
                lastDrawTime: _startTime,
                prizePool: 0,
                currentWinners: new address[](0)
            })
        );
        
        uint256 farmId = farms.length - 1;
        emit FarmCreated(farmId, _stakeToken, _rewardToken);
    }

    /**
     * @dev Stake tokens in a farm
     * @param _farmId Farm ID
     * @param _amount Amount to stake
     */
    function stake(uint256 _farmId, uint256 _amount) external nonReentrant {
        require(_farmId < farms.length, "Farm does not exist");
        Farm storage farm = farms[_farmId];
        
        require(farm.active, "Farm is not active");
        require(!farm.paused, "Farm is paused");
        require(block.timestamp >= farm.startTime, "Farm has not started yet");
        require(block.timestamp < farm.endTime, "Farm has ended");
        require(_amount >= farm.minStakeAmount, "Amount less than minimum stake");
        
        if (farm.maxStakeAmount > 0) {
            require(_amount <= farm.maxStakeAmount, "Amount more than maximum stake");
        }
        
        // Update the farm
        updateFarm(_farmId);
        
        // Get user info
        UserInfo storage user = userInfo[_farmId][msg.sender];
        
        // Transfer tokens
        IERC20(farm.stakeToken).safeTransferFrom(
            address(msg.sender),
            address(this),
            _amount
        );
        
        // Calculate deposit fee
        uint256 depositFee = _amount.mul(farm.depositFee).div(10000);
        uint256 amountAfterFee = _amount.sub(depositFee);
        
        // Transfer fee to fee receiver if applicable
        if (depositFee > 0) {
            IERC20(farm.stakeToken).safeTransfer(feeReceiver, depositFee);
        }
        
        // Update user info
        if (user.amount == 0) {
            // First time staking
            user.stakeTime = block.timestamp;
            user.unlockTime = block.timestamp.add(farm.lockDuration);
            
            // Add user to participants list
            participants[_farmId].push(msg.sender);
        }
        
        // Calculate new ticket count for user
        uint256 newTickets = calculateTickets(farm.ticketsPerStake, amountAfterFee, farm.lockDuration);
        user.ticketCount = user.ticketCount.add(newTickets);
        userTicketsMap[_farmId][msg.sender] = user.ticketCount;
        totalTickets[_farmId] = totalTickets[_farmId].add(newTickets);
        
        // Update user amount and reward debt
        user.amount = user.amount.add(amountAfterFee);
        user.rewardDebt = user.amount.mul(farm.accRewardPerShare).div(PRECISION_FACTOR);
        
        // Update farm total staked
        farm.totalStaked = farm.totalStaked.add(amountAfterFee);
        
        // Add to prize pool (50% of staking amount goes to prize pool)
        uint256 prizeContribution = amountAfterFee.mul(50).div(100);
        farm.prizePool = farm.prizePool.add(prizeContribution);
        
        emit Deposit(msg.sender, _farmId, amountAfterFee);
    }

    /**
     * @dev Calculate tickets based on amount and duration
     * @param _ticketsPerStake Tickets per token per day
     * @param _amount Amount staked
     * @param _lockDuration Lock duration in seconds
     * @return Number of tickets
     */
    function calculateTickets(
        uint256 _ticketsPerStake,
        uint256 _amount,
        uint256 _lockDuration
    ) internal pure returns (uint256) {
        uint256 daysLocked = _lockDuration.div(SECONDS_PER_DAY);
        if (daysLocked == 0) daysLocked = 1; // Minimum 1 day even for no lock
        
        // Calculate tickets: amount * ticketsPerStake * daysLocked / 1e18
        return _amount.mul(_ticketsPerStake).mul(daysLocked).div(PRECISION_FACTOR);
    }

    /**
     * @dev Withdraw tokens from a farm
     * @param _farmId Farm ID
     * @param _amount Amount to withdraw
     */
    function withdraw(uint256 _farmId, uint256 _amount) external nonReentrant {
        require(_farmId < farms.length, "Farm does not exist");
        Farm storage farm = farms[_farmId];
        
        UserInfo storage user = userInfo[_farmId][msg.sender];
        require(user.amount >= _amount, "Withdraw amount exceeds balance");
        require(block.timestamp >= user.unlockTime, "Tokens are still locked");
        
        // Update the farm
        updateFarm(_farmId);
        
        // Calculate pending reward
        uint256 userPendingReward = user.amount.mul(farm.accRewardPerShare).div(PRECISION_FACTOR).sub(user.rewardDebt);
        
        // Update user info
        user.amount = user.amount.sub(_amount);
        user.rewardDebt = user.amount.mul(farm.accRewardPerShare).div(PRECISION_FACTOR);
        
        // Calculate withdraw fee
        uint256 withdrawFee = _amount.mul(farm.withdrawFee).div(10000);
        uint256 amountAfterFee = _amount.sub(withdrawFee);
        
        // Transfer fee to fee receiver if applicable
        if (withdrawFee > 0) {
            IERC20(farm.stakeToken).safeTransfer(feeReceiver, withdrawFee);
        }
        
        // Transfer tokens back to user
        IERC20(farm.stakeToken).safeTransfer(address(msg.sender), amountAfterFee);
        
        // Transfer pending reward to user
        if (userPendingReward > 0) {
            IERC20(farm.rewardToken).safeTransfer(address(msg.sender), userPendingReward);
        }
        
        // Update farm total staked
        farm.totalStaked = farm.totalStaked.sub(_amount);
        
        emit Withdraw(msg.sender, _farmId, amountAfterFee);
    }

    /**
     * @dev Perform lottery draw for a farm
     * @param _farmId Farm ID
     */
    function performDraw(uint256 _farmId) external nonReentrant {
        require(_farmId < farms.length, "Farm does not exist");
        Farm storage farm = farms[_farmId];
        
        require(farm.active, "Farm is not active");
        require(!farm.paused, "Farm is paused");
        require(
            block.timestamp >= farm.lastDrawTime.add(farm.drawInterval),
            "Not time for draw yet"
        );
        require(totalTickets[_farmId] > 0, "No tickets in the pool");
        
        // Get the prize amount (half the prize pool)
        uint256 prizeAmount = farm.prizePool.div(2);
        
        // Select winners
        address[] memory winners = selectWinners(_farmId, farm.winnerCount);
        farm.currentWinners = winners;
        
        // Update farm state
        farm.lastDrawTime = block.timestamp;
        farm.prizePool = farm.prizePool.sub(prizeAmount);
        
        emit LotteryDrawPerformed(_farmId, winners, prizeAmount);
    }

    /**
     * @dev Select winners randomly for a draw
     * @param _farmId Farm ID
     * @param _winnerCount Number of winners to select
     * @return Array of winner addresses
     */
    function selectWinners(uint256 _farmId, uint256 _winnerCount) internal view returns (address[] memory) {
        // Make sure we don't try to select more winners than participants
        uint256 participantCount = participants[_farmId].length;
        uint256 actualWinnerCount = _winnerCount > participantCount ? participantCount : _winnerCount;
        
        address[] memory winners = new address[](actualWinnerCount);
        uint256[] memory selectedIndices = new uint256[](participantCount);
        
        // Initialize array with sequential indices
        for (uint256 i = 0; i < participantCount; i++) {
            selectedIndices[i] = i;
        }
        
        // Select winners using Fisher-Yates shuffle algorithm
        uint256 ticketTotal = totalTickets[_farmId];
        
        for (uint256 i = 0; i < actualWinnerCount; i++) {
            // Generate random index
            uint256 randomIndex = uint256(keccak256(abi.encodePacked(
                block.timestamp,
                block.prevrandao,
                msg.sender,
                i
            ))) % (participantCount - i);
            
            // Get the participant at the random index
            address selected = participants[_farmId][selectedIndices[randomIndex]];
            
            // Adjust selection probability based on ticket count
            uint256 userTickets = userTicketsMap[_farmId][selected];
            uint256 probability = userTickets.mul(PRECISION_FACTOR).div(ticketTotal);
            
            // Roll for selection
            uint256 roll = uint256(keccak256(abi.encodePacked(
                block.timestamp,
                block.prevrandao,
                selected,
                i
            ))) % PRECISION_FACTOR;
            
            if (roll < probability) {
                // Selected!
                winners[i] = selected;
            } else {
                // Try next highest ticket holder
                uint256 maxTickets = 0;
                address maxTicketHolder = address(0);
                
                for (uint256 j = 0; j < participantCount; j++) {
                    address participant = participants[_farmId][j];
                    uint256 participantTickets = userTicketsMap[_farmId][participant];
                    
                    // Skip already selected winners
                    bool alreadySelected = false;
                    for (uint256 k = 0; k < i; k++) {
                        if (winners[k] == participant) {
                            alreadySelected = true;
                            break;
                        }
                    }
                    
                    if (!alreadySelected && participantTickets > maxTickets) {
                        maxTickets = participantTickets;
                        maxTicketHolder = participant;
                    }
                }
                
                winners[i] = maxTicketHolder;
            }
            
            // Swap the used index to the end to avoid reselection
            selectedIndices[randomIndex] = selectedIndices[participantCount - i - 1];
        }
        
        return winners;
    }

    /**
     * @dev Claim lottery prize
     * @param _farmId Farm ID
     */
    function claimPrize(uint256 _farmId) external nonReentrant {
        require(_farmId < farms.length, "Farm does not exist");
        Farm storage farm = farms[_farmId];
        
        // Check if caller is a winner
        bool isWinner = false;
        for (uint256 i = 0; i < farm.currentWinners.length; i++) {
            if (farm.currentWinners[i] == msg.sender) {
                isWinner = true;
                break;
            }
        }
        
        require(isWinner, "Not a winner");
        
        UserInfo storage user = userInfo[_farmId][msg.sender];
        require(!user.hasClaimed, "Already claimed prize");
        
        // Calculate prize amount (split evenly among winners)
        uint256 prizeAmount = farm.prizePool.div(farm.currentWinners.length);
        
        // Mark as claimed
        user.hasClaimed = true;
        
        // Transfer prize
        IERC20(farm.rewardToken).safeTransfer(msg.sender, prizeAmount);
        
        emit PrizeClaimed(msg.sender, _farmId, prizeAmount);
    }

    /**
     * @dev Emergency withdraw without caring about rewards
     * @param _farmId Farm ID
     */
    function emergencyWithdraw(uint256 _farmId) external nonReentrant {
        require(_farmId < farms.length, "Farm does not exist");
        Farm storage farm = farms[_farmId];
        
        UserInfo storage user = userInfo[_farmId][msg.sender];
        uint256 amount = user.amount;
        
        // Reset user info
        user.amount = 0;
        user.rewardDebt = 0;
        user.ticketCount = 0;
        userTicketsMap[_farmId][msg.sender] = 0;
        
        // Update total tickets
        totalTickets[_farmId] = totalTickets[_farmId] > user.ticketCount ? totalTickets[_farmId].sub(user.ticketCount) : 0;
        
        // Update farm total staked
        farm.totalStaked = farm.totalStaked > amount ? farm.totalStaked.sub(amount) : 0;
        
        // Transfer tokens back to user with emergency fee (higher than normal)
        uint256 emergencyFee = amount.mul(farm.withdrawFee.mul(2)).div(10000);
        uint256 amountAfterFee = amount.sub(emergencyFee);
        
        // Transfer fee to fee receiver if applicable
        if (emergencyFee > 0) {
            IERC20(farm.stakeToken).safeTransfer(feeReceiver, emergencyFee);
        }
        
        // Transfer tokens back to user
        IERC20(farm.stakeToken).safeTransfer(address(msg.sender), amountAfterFee);
        
        emit EmergencyWithdraw(msg.sender, _farmId, amountAfterFee);
    }

    /**
     * @dev Update farm rewards
     * @param _farmId Farm ID
     */
    function updateFarm(uint256 _farmId) public {
        Farm storage farm = farms[_farmId];
        
        if (block.timestamp <= farm.lastRewardTime) {
            return;
        }
        
        if (farm.totalStaked == 0) {
            farm.lastRewardTime = block.timestamp;
            return;
        }
        
        uint256 endTime = farm.endTime < block.timestamp ? farm.endTime : block.timestamp;
        uint256 timeElapsed = endTime.sub(farm.lastRewardTime);
        
        if (timeElapsed == 0) {
            return;
        }
        
        uint256 reward = timeElapsed.mul(farm.rewardPerSecond);
        farm.accRewardPerShare = farm.accRewardPerShare.add(
            reward.mul(PRECISION_FACTOR).div(farm.totalStaked)
        );
        farm.lastRewardTime = block.timestamp;
    }

    /**
     * @dev Update farm parameters
     * @param _farmId Farm ID
     * @param _rewardPerSecond New reward per second
     * @param _lockDuration New lock duration
     * @param _depositFee New deposit fee
     * @param _withdrawFee New withdraw fee
     * @param _minStakeAmount New minimum stake amount
     * @param _maxStakeAmount New maximum stake amount
     * @param _drawInterval New draw interval
     * @param _ticketsPerStake New tickets per stake
     * @param _winnerCount New winner count
     */
    function updateFarmParams(
        uint256 _farmId,
        uint256 _rewardPerSecond,
        uint256 _lockDuration,
        uint256 _depositFee,
        uint256 _withdrawFee,
        uint256 _minStakeAmount,
        uint256 _maxStakeAmount,
        uint256 _drawInterval,
        uint256 _ticketsPerStake,
        uint256 _winnerCount
    ) external onlyOwner {
        require(_farmId < farms.length, "Farm does not exist");
        Farm storage farm = farms[_farmId];
        
        require(_depositFee <= 1000, "Deposit fee cannot be more than 10%");
        require(_withdrawFee <= 1000, "Withdraw fee cannot be more than 10%");
        
        // Update the farm
        updateFarm(_farmId);
        
        // Update farm parameters
        farm.rewardPerSecond = _rewardPerSecond;
        farm.lockDuration = _lockDuration;
        farm.depositFee = _depositFee;
        farm.withdrawFee = _withdrawFee;
        farm.minStakeAmount = _minStakeAmount;
        farm.maxStakeAmount = _maxStakeAmount;
        farm.drawInterval = _drawInterval;
        farm.ticketsPerStake = _ticketsPerStake;
        farm.winnerCount = _winnerCount;
        
        emit FarmUpdated(_farmId);
    }

    /**
     * @dev Pause farm
     * @param _farmId Farm ID
     * @param _paused Pause state
     */
    function pauseFarm(uint256 _farmId, bool _paused) external onlyOwner {
        require(_farmId < farms.length, "Farm does not exist");
        farms[_farmId].paused = _paused;
    }

    /**
     * @dev Set farm active status
     * @param _farmId Farm ID
     * @param _active Active state
     */
    function setFarmActive(uint256 _farmId, bool _active) external onlyOwner {
        require(_farmId < farms.length, "Farm does not exist");
        farms[_farmId].active = _active;
    }

    /**
     * @dev Set fee receiver
     * @param _feeReceiver Fee receiver address
     */
    function setFeeReceiver(address _feeReceiver) external onlyOwner {
        require(_feeReceiver != address(0), "Fee receiver cannot be zero address");
        feeReceiver = _feeReceiver;
    }

    /**
     * @dev Get farm count
     * @return Farm count
     */
    function getFarmCount() external view returns (uint256) {
        return farms.length;
    }

    /**
     * @dev Get active farms
     * @return Array of active farm IDs
     */
    function getActiveFarms() external view returns (uint256[] memory) {
        uint256 count = 0;
        
        // Count active farms
        for (uint256 i = 0; i < farms.length; i++) {
            if (farms[i].active) {
                count++;
            }
        }
        
        // Create array of active farm IDs
        uint256[] memory activeFarms = new uint256[](count);
        uint256 index = 0;
        
        for (uint256 i = 0; i < farms.length; i++) {
            if (farms[i].active) {
                activeFarms[index] = i;
                index++;
            }
        }
        
        return activeFarms;
    }

    /**
     * @dev Get pending reward for a user
     * @param _farmId Farm ID
     * @param _user User address
     * @return Pending reward
     */
    function pendingReward(uint256 _farmId, address _user) external view returns (uint256) {
        require(_farmId < farms.length, "Farm does not exist");
        Farm storage farm = farms[_farmId];
        UserInfo storage user = userInfo[_farmId][_user];
        
        uint256 accRewardPerShare = farm.accRewardPerShare;
        
        if (block.timestamp > farm.lastRewardTime && farm.totalStaked > 0) {
            uint256 endTime = farm.endTime < block.timestamp ? farm.endTime : block.timestamp;
            uint256 timeElapsed = endTime.sub(farm.lastRewardTime);
            uint256 reward = timeElapsed.mul(farm.rewardPerSecond);
            accRewardPerShare = accRewardPerShare.add(
                reward.mul(PRECISION_FACTOR).div(farm.totalStaked)
            );
        }
        
        return user.amount.mul(accRewardPerShare).div(PRECISION_FACTOR).sub(user.rewardDebt);
    }

    /**
     * @dev Get prize pool for a farm
     * @param _farmId Farm ID
     * @return Prize pool amount
     */
    function getPrizePool(uint256 _farmId) external view returns (uint256) {
        require(_farmId < farms.length, "Farm does not exist");
        return farms[_farmId].prizePool;
    }

    /**
     * @dev Get last draw time for a farm
     * @param _farmId Farm ID
     * @return Last draw time
     */
    function getLastDrawTime(uint256 _farmId) external view returns (uint256) {
        require(_farmId < farms.length, "Farm does not exist");
        return farms[_farmId].lastDrawTime;
    }

    /**
     * @dev Get total tickets for a farm
     * @param _farmId Farm ID
     * @return Total tickets
     */
    function getTotalTickets(uint256 _farmId) external view returns (uint256) {
        require(_farmId < farms.length, "Farm does not exist");
        return totalTickets[_farmId];
    }

    /**
     * @dev Get user tickets for a farm
     * @param _farmId Farm ID
     * @param _user User address
     * @return User tickets
     */
    function getUserTickets(uint256 _farmId, address _user) external view returns (uint256) {
        require(_farmId < farms.length, "Farm does not exist");
        return userTicketsMap[_farmId][_user];
    }

    /**
     * @dev Get current winners for a farm
     * @param _farmId Farm ID
     * @return Array of winner addresses
     */
    function getCurrentWinners(uint256 _farmId) external view returns (address[] memory) {
        require(_farmId < farms.length, "Farm does not exist");
        return farms[_farmId].currentWinners;
    }

    /**
     * @dev Get farm by ID
     * @param _farmId Farm ID
     * @return Farm details
     */
    function getFarm(uint256 _farmId) external view returns (Farm memory) {
        require(_farmId < farms.length, "Farm does not exist");
        return farms[_farmId];
    }

    /**
     * @dev Get user info for a farm
     * @param _farmId Farm ID
     * @param _user User address
     * @return User info
     */
    function getUserInfo(uint256 _farmId, address _user) external view returns (UserInfo memory) {
        require(_farmId < farms.length, "Farm does not exist");
        return userInfo[_farmId][_user];
    }

    /**
     * @dev Get participants for a farm
     * @param _farmId Farm ID
     * @return Array of participant addresses
     */
    function getParticipants(uint256 _farmId) external view returns (address[] memory) {
        require(_farmId < farms.length, "Farm does not exist");
        return participants[_farmId];
    }

    /**
     * @dev Recover wrong tokens sent to the contract
     * @param _token Token address
     * @param _amount Amount to recover
     */
    function recoverWrongTokens(address _token, uint256 _amount) external onlyOwner {
        IERC20(_token).safeTransfer(address(msg.sender), _amount);
    }
}