// Sources flattened with hardhat v2.12.7 https://hardhat.org

// File @openzeppelin/contracts/utils/Context.sol@v4.8.1

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}


// File @openzeppelin/contracts/access/Ownable.sol@v4.8.1


// OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)

pragma solidity ^0.8.0;

/**
 * @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 anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}


// File @openzeppelin/contracts/security/Pausable.sol@v4.8.1


// OpenZeppelin Contracts (last updated v4.7.0) (security/Pausable.sol)

pragma solidity ^0.8.0;

/**
 * @dev Contract module which allows children to implement an emergency stop
 * mechanism that can be triggered by an authorized account.
 *
 * This module is used through inheritance. It will make available the
 * modifiers `whenNotPaused` and `whenPaused`, which can be applied to
 * the functions of your contract. Note that they will not be pausable by
 * simply including this module, only once the modifiers are put in place.
 */
abstract contract Pausable is Context {
    /**
     * @dev Emitted when the pause is triggered by `account`.
     */
    event Paused(address account);

    /**
     * @dev Emitted when the pause is lifted by `account`.
     */
    event Unpaused(address account);

    bool private _paused;

    /**
     * @dev Initializes the contract in unpaused state.
     */
    constructor() {
        _paused = false;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is not paused.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    modifier whenNotPaused() {
        _requireNotPaused();
        _;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is paused.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    modifier whenPaused() {
        _requirePaused();
        _;
    }

    /**
     * @dev Returns true if the contract is paused, and false otherwise.
     */
    function paused() public view virtual returns (bool) {
        return _paused;
    }

    /**
     * @dev Throws if the contract is paused.
     */
    function _requireNotPaused() internal view virtual {
        require(!paused(), "Pausable: paused");
    }

    /**
     * @dev Throws if the contract is not paused.
     */
    function _requirePaused() internal view virtual {
        require(paused(), "Pausable: not paused");
    }

    /**
     * @dev Triggers stopped state.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    function _pause() internal virtual whenNotPaused {
        _paused = true;
        emit Paused(_msgSender());
    }

    /**
     * @dev Returns to normal state.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    function _unpause() internal virtual whenPaused {
        _paused = false;
        emit Unpaused(_msgSender());
    }
}


// File @openzeppelin/contracts/utils/introspection/IERC165.sol@v4.8.1


// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC165 standard, as defined in the
 * https://eips.ethereum.org/EIPS/eip-165[EIP].
 *
 * 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[EIP 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);
}


// File @openzeppelin/contracts/token/ERC721/IERC721.sol@v4.8.1


// OpenZeppelin Contracts (last updated v4.8.0) (token/ERC721/IERC721.sol)

pragma solidity ^0.8.0;

/**
 * @dev Required interface of an ERC721 compliant contract.
 */
interface IERC721 is IERC165 {
    /**
     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
     */
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
     */
    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
     */
    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);

    /**
     * @dev Returns the number of tokens in ``owner``'s account.
     */
    function balanceOf(address owner) external view returns (uint256 balance);

    /**
     * @dev Returns the owner of the `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function ownerOf(uint256 tokenId) external view returns (address owner);

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes calldata data
    ) external;

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
     * are aware of the ERC721 protocol to prevent tokens from being forever locked.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must have been allowed to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

    /**
     * @dev Transfers `tokenId` token from `from` to `to`.
     *
     * WARNING: Note that the caller is responsible to confirm that the recipient is capable of receiving ERC721
     * or else they may be permanently lost. Usage of {safeTransferFrom} prevents loss, though the caller must
     * understand this adds an external call which potentially creates a reentrancy vulnerability.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

    /**
     * @dev Gives permission to `to` to transfer `tokenId` token to another account.
     * The approval is cleared when the token is transferred.
     *
     * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
     *
     * Requirements:
     *
     * - The caller must own the token or be an approved operator.
     * - `tokenId` must exist.
     *
     * Emits an {Approval} event.
     */
    function approve(address to, uint256 tokenId) external;

    /**
     * @dev Approve or remove `operator` as an operator for the caller.
     * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
     *
     * Requirements:
     *
     * - The `operator` cannot be the caller.
     *
     * Emits an {ApprovalForAll} event.
     */
    function setApprovalForAll(address operator, bool _approved) external;

    /**
     * @dev Returns the account approved for `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function getApproved(uint256 tokenId) external view returns (address operator);

    /**
     * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
     *
     * See {setApprovalForAll}
     */
    function isApprovedForAll(address owner, address operator) external view returns (bool);
}


// File @openzeppelin/contracts/token/ERC721/extensions/IERC721Enumerable.sol@v4.8.1


// OpenZeppelin Contracts (last updated v4.5.0) (token/ERC721/extensions/IERC721Enumerable.sol)

pragma solidity ^0.8.0;

/**
 * @title ERC-721 Non-Fungible Token Standard, optional enumeration extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721Enumerable is IERC721 {
    /**
     * @dev Returns the total amount of tokens stored by the contract.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns a token ID owned by `owner` at a given `index` of its token list.
     * Use along with {balanceOf} to enumerate all of ``owner``'s tokens.
     */
    function tokenOfOwnerByIndex(address owner, uint256 index) external view returns (uint256);

    /**
     * @dev Returns a token ID at a given `index` of all the tokens stored by the contract.
     * Use along with {totalSupply} to enumerate all tokens.
     */
    function tokenByIndex(uint256 index) external view returns (uint256);
}


// File @openzeppelin/contracts/security/ReentrancyGuard.sol@v4.8.1


// OpenZeppelin Contracts (last updated v4.8.0) (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;
    }
}


// File @openzeppelin/contracts/token/ERC20/IERC20.sol@v4.8.1


// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);

    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `from` to `to` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) external returns (bool);
}


// File @openzeppelin/contracts/utils/Counters.sol@v4.8.1


// OpenZeppelin Contracts v4.4.1 (utils/Counters.sol)

pragma solidity ^0.8.0;

/**
 * @title Counters
 * @author Matt Condon (@shrugs)
 * @dev Provides counters that can only be incremented, decremented or reset. This can be used e.g. to track the number
 * of elements in a mapping, issuing ERC721 ids, or counting request ids.
 *
 * Include with `using Counters for Counters.Counter;`
 */
library Counters {
    struct Counter {
        // This variable should never be directly accessed by users of the library: interactions must be restricted to
        // the library's function. As of Solidity v0.5.2, this cannot be enforced, though there is a proposal to add
        // this feature: see https://github.com/ethereum/solidity/issues/4637
        uint256 _value; // default: 0
    }

    function current(Counter storage counter) internal view returns (uint256) {
        return counter._value;
    }

    function increment(Counter storage counter) internal {
        unchecked {
            counter._value += 1;
        }
    }

    function decrement(Counter storage counter) internal {
        uint256 value = counter._value;
        require(value > 0, "Counter: decrement overflow");
        unchecked {
            counter._value = value - 1;
        }
    }

    function reset(Counter storage counter) internal {
        counter._value = 0;
    }
}


// File contracts/interfaces/IERC721Mintable.sol

pragma solidity ^0.8.0;

interface IERC721Mintable is IERC721Enumerable{

    function mintSeries1(address to) external;
    function mintSeries2(address to) external;
    function series1CurrentSupply() external view returns (uint256);

}


// File contracts/interfaces/ITether.sol

pragma solidity ^0.8.0;


interface ITether {

    function transferFrom(address _from, address _to, uint _value) external;

}


// File contracts/ERC721Minter.sol

pragma solidity ^0.8.0;







contract ERC721Minter is
    Context,
    Ownable,
    Pausable,
    ReentrancyGuard
{
    using Counters for Counters.Counter;

    struct Round {
        uint256 supply;
        uint256 price;
    }

    struct ReferalLevel {
        uint256 noOfPurchases;
        uint256 referalFraction;
    }

    struct ReferalStats {
        uint256 id;
        address parent;
        uint256 noOfPurchases;
    }

    address private _bank;
    IERC721Mintable private _nft;
    ITether private _priceToken;
    mapping(uint256 => Round) private _rounds;
    uint256 private _numOfRounds;
    mapping(uint256 => ReferalLevel) private _referalLevels;
    uint256 private _numOfReferalLevels;
    mapping(address => ReferalStats) private _referals;
    mapping(uint256 => address) private _referalsById;
    Counters.Counter private _referalIdTracker;
    uint256 private _partnerIdTracker = 100_000;
    mapping(uint256 => uint256) private _partnerFee;
    uint256 private _series2Price;


    event ReferalAdded(address indexed referalAddress, uint256 indexed id);
    event ReferalPaid(address indexed referalAddress, uint256 indexed amount);

    constructor(
        uint256[] memory roundSupplies,
        uint256[] memory roundPrices,
        uint256[] memory noOfPurchases,
        uint256[] memory referalFractions,
        uint256 series2Price,
        address nft,
        address priceToken,
        address bank
    ) {
        _nft = IERC721Mintable(nft);
        _priceToken = ITether(priceToken);
        _bank = bank;
        _series2Price = series2Price;
        _setRounds(roundSupplies, roundPrices);
        _setReferalLevels(noOfPurchases, referalFractions);
        _referalIdTracker.increment();
    }

    function mint(uint256 referalId, uint256 tokens, uint256 series) external whenNotPaused nonReentrant {
        address referalAddress = _referalsById[referalId];
        ReferalStats storage referalStats = _referals[referalAddress];
        for(uint256 i = 0; i < tokens; i++) {
            uint256 price = currentPrice(series);
            if (referalAddress != address(0)) {
                uint256 referalFraction;
                if (referalId >= 100_000) {
                    referalFraction = _partnerFee[referalId];
                } else {
                    referalFraction = _referalFractionByNoOfPurchases(referalStats.noOfPurchases);
                }
                uint256 referalFee = _referalFee(price, referalFraction);
                referalStats.noOfPurchases++;
                if (referalStats.parent != address(0)) {
                    ReferalStats memory parentReferalStats = _referals[referalStats.parent];
                    uint256 parentFee = _referalFee(price, 500);
                    _priceToken.transferFrom(_msgSender(), referalStats.parent, parentFee);
                    emit ReferalPaid(referalStats.parent, parentFee);
                    price -= parentFee;
                    if (parentReferalStats.parent != address(0)) {
                        _priceToken.transferFrom(_msgSender(), parentReferalStats.parent, parentFee);
                        emit ReferalPaid(parentReferalStats.parent, parentFee);
                        price -= parentFee;
                    }
                }
                _priceToken.transferFrom(_msgSender(), referalAddress, referalFee);
                _priceToken.transferFrom(_msgSender(), _bank, price - referalFee);
                emit ReferalPaid(referalAddress, referalFee);
            } else {
                _priceToken.transferFrom(_msgSender(), _bank, price);
            }
            if (series == 1) {
                _nft.mintSeries1(_msgSender());
            } else {
                _nft.mintSeries2(_msgSender());
            }
        }
    }

    function addReferal(address referal, uint256 parentId) external whenNotPaused returns (uint256) {
        require(parentId < 100_000, "Wrong parent referal id");
        uint256 referalId = _referalIdTracker.current();
        _referalsById[referalId] = referal;
        _referals[referal] = ReferalStats(referalId, _referalsById[parentId], 0);
        _referalIdTracker.increment();
        emit ReferalAdded(referal, referalId);
        return referalId;
    }

    function addPartnerReferal(address referal, uint256 fee) external onlyOwner returns (uint256) {
        _partnerIdTracker++;
        _referalsById[_partnerIdTracker] = referal;
        _referals[referal] = ReferalStats(_partnerIdTracker, address(0), 0);
        _partnerFee[_partnerIdTracker] = fee;
        emit ReferalAdded(referal, _partnerIdTracker);
        return _partnerIdTracker;
    }

    function mintAdmin(uint256 tokens, uint256 series, address receiver) external onlyOwner {
        for(uint256 i = 0; i < tokens; i++) {
            if (series == 1) {
                _nft.mintSeries1(receiver);
            } else {
                _nft.mintSeries2(receiver);
            }
        }
    }

    function getReferalIdByAddress(address referal) external view returns (uint256) {
        return _referals[referal].id;
    }

    function nextReferalId() external view returns (uint256) {
        return _referalIdTracker.current();
    }

    function setRounds(
        uint256[] memory roundSupplies,
        uint256[] memory roundPrices
    ) external onlyOwner {
        _setRounds(roundSupplies, roundPrices);
    }

    function setBank(address bank) external onlyOwner {
        _bank = bank;
    }

    function setSeries2Price(uint256 price) external onlyOwner {
        _series2Price = price;
    }

    function pause() public onlyOwner {
        _pause();
    }

    function unpause() public onlyOwner {
        _unpause();
    }

    function currentPrice(uint256 series) public view returns (uint256) {
        if (series == 1) {
            return _currentPrice();
        } else {
            return _series2Price;
        }
    }

    function _currentPrice() private view returns (uint256) {
        uint256 currentRoundIndex = _currentRoundIndex();
        return _rounds[currentRoundIndex].price;
    }

    function _setRounds(
        uint256[] memory roundSupplies,
        uint256[] memory roundPrices
    ) private {
        uint256 roundSuppliesLength = roundSupplies.length;
        uint256 roundPricesLength = roundPrices.length;
        require(roundSuppliesLength == roundPricesLength, "ERC721Minter: Must have same number of round supplies and round prices");
        _numOfRounds = roundSuppliesLength;
        for(uint256 i = 0; i < _numOfRounds; i++) {
            _rounds[i] = Round(roundSupplies[i], roundPrices[i]);
        }
    }

    function _currentRoundIndex() private view returns (uint256 roundIndex) {
        uint256 nftSupply = _nft.series1CurrentSupply();
        for(uint256 i = 0; i < _numOfRounds; i++) {
            if (nftSupply < _rounds[i].supply) {
                return i;
            }
        }
        require(false, "ERC721Minter: More tokens minted than allowed in rounds");
    }

    function _setReferalLevels(
        uint256[] memory noOfPurchases,
        uint256[] memory referalFraction
    ) private {
        uint256 noOfPurchasesLength = noOfPurchases.length;
        uint256 referalFractionLength = referalFraction.length;
        require(noOfPurchasesLength == referalFractionLength, "ERC721Minter: Must have same number of no of purchases and referal fractions");
        _numOfReferalLevels = noOfPurchasesLength;
        for(uint256 i = 0; i < _numOfReferalLevels; i++) {
            _referalLevels[i] = ReferalLevel(noOfPurchases[i], referalFraction[i]);
        }
    }

    function _referalFractionByNoOfPurchases(uint256 noOfPurchases) private view returns (uint256 referalFraction) {
        for(uint256 i = 0; i < _numOfReferalLevels; i++) {
            if (noOfPurchases < _referalLevels[i].noOfPurchases) {
                return _referalLevels[i].referalFraction;
            }
        }
        return 0;
    }

    function _referalFee(uint256 price, uint256 referalFraction) private pure returns (uint256) {
        return (price * referalFraction) / _feeDenominator();
    }

    function _feeDenominator() private pure returns (uint96) {
        return 10000;
    }

}