// File: docs.chain.link/samples/VRF/EtherLotto.sol



// SPDX-License-Identifier: GPL-2.0-or-later
/* Created by & Property of EtherLotto*/

pragma solidity ^0.8.4;
pragma abicoder v2;

import '@openzeppelin/contracts/access/Ownable.sol';
import '@openzeppelin/contracts/utils/Strings.sol';
import './ERC721SUB.sol';
import "@openzeppelin/contracts/utils/math/SafeMath.sol";
import "@openzeppelin/contracts/security/ReentrancyGuard.sol";
import "@chainlink/contracts/src/v0.8/VRFConsumerBaseV2.sol";
import "@chainlink/contracts/src/v0.8/interfaces/VRFCoordinatorV2Interface.sol";
import "@openzeppelin/contracts/security/ReentrancyGuard.sol";


  contract EtherLotto is ERC721SUB, Ownable, ReentrancyGuard, VRFConsumerBaseV2 {
      
    /* -- Random Number Variables Chainlink VRF -- */
    VRFCoordinatorV2Interface COORDINATOR;
    uint64 s_subscriptionId;
    address vrfCoordinator = 0x271682DEB8C4E0901D1a1550aD2e64D568E69909;
    bytes32 keyHash = 0x8af398995b04c28e9951adb9721ef74c74f93e6a478f39e7e0777be13527e7ef;
    uint32 callbackGasLimit = 100000;
    uint16 requestConfirmations = 3;
    uint32 numWords =  1;
    uint256[] public s_randomWords;
    uint256 public randomNumber;
    uint256 public s_requestId;
    address s_owner;
    /* ---- */

    /* -- Lottery Variables -- */
    mapping (uint256 => uint256[]) public pastWinningNumbers;
    mapping (uint256 => address[]) public historyOfWinningAddresses;
    uint256[] public arrayofWinningTickets;
    uint256 public numberOfWinners = 3;
    uint256 public prizePercentagePerWinner = 20;
    uint256 public prizePercentagePerWinnerBoost = 25;
    uint256 public pricePerTicket = 5000000000000000;
    address public ETLottoWallet = 0x1c7001eEf7d90583B0BE987784034EC3d3d40A41;
    /* ---- */
    
    /* -- NFT Variables -- */
    string public baseURI = "";
    string public ticketBoostURI = "";
    string public ticketExpiredURI = "";
    bool public isTicketSalesActive = false;
    uint256 public ticketPrice = 1000000000000000;
    uint256 public MAX_PER_TX = 5;
    using SafeMath for uint256;
    using Strings for uint256;
    event NFTMINTED(uint256 tokenId, address owner);
    /* ---- */


    constructor(uint64 subscriptionId) ERC721SUB("EtherLottos", "EL") VRFConsumerBaseV2(vrfCoordinator) {
    COORDINATOR = VRFCoordinatorV2Interface(vrfCoordinator);
    s_owner = msg.sender;
    s_subscriptionId = subscriptionId;
    }


  /* -- VRF Functions -- */
    function requestRandomWords() external onlyOwner {
    s_requestId = COORDINATOR.requestRandomWords(
      keyHash,
      s_subscriptionId,
      requestConfirmations,
      callbackGasLimit,
      numWords
    );
    }
    function fulfillRandomWords(
    uint256, /* requestId */
    uint256[] memory randomWords
    ) internal override {
    s_randomWords = randomWords;
    randomNumber = s_randomWords[0];
    }

    function setVRFCoordinator(address _newVRFCoordinator) external onlyOwner {
      vrfCoordinator = _newVRFCoordinator;
    }

    function setKeyhash(bytes32 _newKeyHash) external onlyOwner{
      keyHash = _newKeyHash;
    }

    function setCallBackGas(uint32 _newCallBackGas) external onlyOwner{
      callbackGasLimit = _newCallBackGas;
    }

     function setRequestConfirmations(uint16 _newRequestConfirmations) external onlyOwner{
      requestConfirmations = _newRequestConfirmations;
    }

    function changeSubscriptionId(uint64 _newSubscriptionID) external onlyOwner{
      s_subscriptionId = _newSubscriptionID;
    }
    /* ---- */

    /* -- Lottery Functions -- */
    /* Created by & Property of EtherLotto*/
    function selectAndRewardWinners() external payable onlyOwner nonReentrant {
    isTicketSalesActive= false;
    uint256 entriesCounter = totalSupply();
    uint256[] memory expandedValues;
    expandedValues = new uint256[](numberOfWinners);
    for (uint256 i = 0; i < numberOfWinners ; i++) {
        expandedValues[i] = uint256(keccak256(abi.encode(randomNumber, i)));
        expandedValues[i] = (expandedValues[i] % entriesCounter);
    }
    arrayofWinningTickets = expandedValues;
    pastWinningNumbers[currentWeek] = expandedValues;
    uint256 finalJackpot = address(this).balance;
    uint256 prizeFunds = finalJackpot/uint256(100)*(prizePercentagePerWinner);
    uint256 prizeFundsBoost = finalJackpot/uint256(100)*(prizePercentagePerWinnerBoost);
    for(uint256 i = 0; i < arrayofWinningTickets.length; i++){
        historyOfWinningAddresses[currentWeek].push(ownerOf(arrayofWinningTickets[i]));
        if(boost[currentWeek][arrayofWinningTickets[i]] == true){
          payable(ownerOf(arrayofWinningTickets[i])).transfer(prizeFundsBoost);
        }else{
           payable(ownerOf(arrayofWinningTickets[i])).transfer(prizeFunds);
        }
    }
    payable(ETLottoWallet).transfer(prizeFunds);
    }

    function startNextWeeksLottery() external onlyOwner{
      currentWeek++;
      indexTracker = 0;
      isTicketSalesActive = true;
    }

    function setLottoWallet(address _ETLottoWallet) external onlyOwner{
        ETLottoWallet = _ETLottoWallet;
    }

    function setPrizePercentagePerWinner(uint256 _newPrizePercentagePerWinner) external onlyOwner {
      prizePercentagePerWinner = _newPrizePercentagePerWinner;
    }

    function setAmountOfWinners(uint256 _newAmountofWinners) external onlyOwner {
        numberOfWinners = _newAmountofWinners;
    }

    function lastWeeksWinningNumbers() public view virtual returns (uint256[] memory) {
      return arrayofWinningTickets;
    }

    function lookupPastWinningNumbers(uint256 week) public view virtual returns (uint256[] memory){
      return pastWinningNumbers[week];
    }

    function lookupPastWinners(uint256 week) public view virtual returns (address[] memory){
      return historyOfWinningAddresses[week];
    }

     function isMultiplierActive(uint256 ticketID) public view virtual returns (bool){
      return boost[currentWeek][ticketID];
    }

    function checkMyNumbers(address yourWallet, uint256 week) public view virtual returns (bool){
      bool Winner = false;
      for(uint256 i = 0; i < numberOfWinners; i++){
        if(yourWallet == historyOfWinningAddresses[week][i]){
          Winner = true;
          break;
        }
      }
      return Winner;
    }

    function prizePool() public view virtual returns (uint256){
      //Repersented in WEI
      uint256 currentPrizePool = (3 * (address(this).balance/100*prizePercentagePerWinner));
      return currentPrizePool;
    }
    /*-----*/

    /* -- NFT Functions -- */
    
    function _baseURI() internal view virtual returns (string memory) {
        return baseURI;
      }

    function _ticketExpiredURI() internal view virtual returns (string memory) {
        return ticketExpiredURI;
      }
    
     function _ticketBoostURI() internal view virtual returns (string memory) {
        return ticketBoostURI;
      }
      
    function _price() internal view virtual returns (uint256) {
      return ticketPrice;
      }

    function setBaseURI(string memory _newBaseURI) public onlyOwner {
      baseURI = _newBaseURI;
      }
    
    function setTicketBoostURI(string memory _newBoostURI) public onlyOwner {
      ticketBoostURI = _newBoostURI;
      }

    function setExpiredURI(string memory _newExpiredURI) public onlyOwner {
      ticketExpiredURI = _newExpiredURI;
      }

    function setTicketPrice(uint256 _newTicketPrice) public onlyOwner {
      ticketPrice = _newTicketPrice;
      }

    function setMaxPerTX(uint256 _newMaxPerTX) public onlyOwner {
      MAX_PER_TX = _newMaxPerTX;
      }

    function activateTicketSale() external onlyOwner {
      isTicketSalesActive = !isTicketSalesActive;
      }
    /* Created by & Property of EtherLotto*/
    function exists(uint256 tokenId) public view returns (bool) {
      return _exists(tokenId);
    }
    
     function withdraw(address payable _to, uint _amount) public onlyOwner nonReentrant {
        _to.transfer(_amount);
    }

    function buyTicket(uint256 quantity) external payable {
      require(isTicketSalesActive, "Sale not Active");
      require(
        quantity > 0 && quantity <= MAX_PER_TX,
        "Can Mint only 5 per TX & Can't Mint Zero"
        );
        require(msg.value >= ticketPrice.mul(quantity),
         "0.001 eth Per Ticket"
        );
        _mint(msg.sender, quantity);
        }

     function tokenURI(uint256 tokenId)
        public
        view
        virtual
        override
        returns (string memory)
      {
    
        string memory currentBaseURI = _baseURI();
        string memory currentBoostURI = _ticketBoostURI();
        string memory currentExpiredURI = _ticketExpiredURI();

      if(tokenId >= indexTracker){
        return currentExpiredURI;
      }

      if(boost[currentWeek][tokenId] == true){
        return currentBoostURI;
      }

        return
          currentBaseURI;                
      }
  }

/* Created by & Property of EtherLotto*/
// File: @openzeppelin/contracts/security/ReentrancyGuard.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (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() {
        // On the first call to nonReentrant, _notEntered will be true
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

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

        _;

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

// File: @chainlink/contracts/src/v0.8/interfaces/VRFCoordinatorV2Interface.sol



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

interface VRFCoordinatorV2Interface {
  /**
   * @notice Get configuration relevant for making requests
   * @return minimumRequestConfirmations global min for request confirmations
   * @return maxGasLimit global max for request gas limit
   * @return s_provingKeyHashes list of registered key hashes
   */
  function getRequestConfig()
    external
    view
    returns (
      uint16,
      uint32,
      bytes32[] memory
    );

  /**
   * @notice Request a set of random words.
   * @param keyHash - Corresponds to a particular oracle job which uses
   * that key for generating the VRF proof. Different keyHash's have different gas price
   * ceilings, so you can select a specific one to bound your maximum per request cost.
   * @param subId  - The ID of the VRF subscription. Must be funded
   * with the minimum subscription balance required for the selected keyHash.
   * @param minimumRequestConfirmations - How many blocks you'd like the
   * oracle to wait before responding to the request. See SECURITY CONSIDERATIONS
   * for why you may want to request more. The acceptable range is
   * [minimumRequestBlockConfirmations, 200].
   * @param callbackGasLimit - How much gas you'd like to receive in your
   * fulfillRandomWords callback. Note that gasleft() inside fulfillRandomWords
   * may be slightly less than this amount because of gas used calling the function
   * (argument decoding etc.), so you may need to request slightly more than you expect
   * to have inside fulfillRandomWords. The acceptable range is
   * [0, maxGasLimit]
   * @param numWords - The number of uint256 random values you'd like to receive
   * in your fulfillRandomWords callback. Note these numbers are expanded in a
   * secure way by the VRFCoordinator from a single random value supplied by the oracle.
   * @return requestId - A unique identifier of the request. Can be used to match
   * a request to a response in fulfillRandomWords.
   */
  function requestRandomWords(
    bytes32 keyHash,
    uint64 subId,
    uint16 minimumRequestConfirmations,
    uint32 callbackGasLimit,
    uint32 numWords
  ) external returns (uint256 requestId);

  /**
   * @notice Create a VRF subscription.
   * @return subId - A unique subscription id.
   * @dev You can manage the consumer set dynamically with addConsumer/removeConsumer.
   * @dev Note to fund the subscription, use transferAndCall. For example
   * @dev  LINKTOKEN.transferAndCall(
   * @dev    address(COORDINATOR),
   * @dev    amount,
   * @dev    abi.encode(subId));
   */
  function createSubscription() external returns (uint64 subId);

  /**
   * @notice Get a VRF subscription.
   * @param subId - ID of the subscription
   * @return balance - LINK balance of the subscription in juels.
   * @return reqCount - number of requests for this subscription, determines fee tier.
   * @return owner - owner of the subscription.
   * @return consumers - list of consumer address which are able to use this subscription.
   */
  function getSubscription(uint64 subId)
    external
    view
    returns (
      uint96 balance,
      uint64 reqCount,
      address owner,
      address[] memory consumers
    );

  /**
   * @notice Request subscription owner transfer.
   * @param subId - ID of the subscription
   * @param newOwner - proposed new owner of the subscription
   */
  function requestSubscriptionOwnerTransfer(uint64 subId, address newOwner) external;

  /**
   * @notice Request subscription owner transfer.
   * @param subId - ID of the subscription
   * @dev will revert if original owner of subId has
   * not requested that msg.sender become the new owner.
   */
  function acceptSubscriptionOwnerTransfer(uint64 subId) external;

  /**
   * @notice Add a consumer to a VRF subscription.
   * @param subId - ID of the subscription
   * @param consumer - New consumer which can use the subscription
   */
  function addConsumer(uint64 subId, address consumer) external;

  /**
   * @notice Remove a consumer from a VRF subscription.
   * @param subId - ID of the subscription
   * @param consumer - Consumer to remove from the subscription
   */
  function removeConsumer(uint64 subId, address consumer) external;

  /**
   * @notice Cancel a subscription
   * @param subId - ID of the subscription
   * @param to - Where to send the remaining LINK to
   */
  function cancelSubscription(uint64 subId, address to) external;

  /*
   * @notice Check to see if there exists a request commitment consumers
   * for all consumers and keyhashes for a given sub.
   * @param subId - ID of the subscription
   * @return true if there exists at least one unfulfilled request for the subscription, false
   * otherwise.
   */
  function pendingRequestExists(uint64 subId) external view returns (bool);
}

// File: @chainlink/contracts/src/v0.8/VRFConsumerBaseV2.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.4;

/** ****************************************************************************
 * @notice Interface for contracts using VRF randomness
 * *****************************************************************************
 * @dev PURPOSE
 *
 * @dev Reggie the Random Oracle (not his real job) wants to provide randomness
 * @dev to Vera the verifier in such a way that Vera can be sure he's not
 * @dev making his output up to suit himself. Reggie provides Vera a public key
 * @dev to which he knows the secret key. Each time Vera provides a seed to
 * @dev Reggie, he gives back a value which is computed completely
 * @dev deterministically from the seed and the secret key.
 *
 * @dev Reggie provides a proof by which Vera can verify that the output was
 * @dev correctly computed once Reggie tells it to her, but without that proof,
 * @dev the output is indistinguishable to her from a uniform random sample
 * @dev from the output space.
 *
 * @dev The purpose of this contract is to make it easy for unrelated contracts
 * @dev to talk to Vera the verifier about the work Reggie is doing, to provide
 * @dev simple access to a verifiable source of randomness. It ensures 2 things:
 * @dev 1. The fulfillment came from the VRFCoordinator
 * @dev 2. The consumer contract implements fulfillRandomWords.
 * *****************************************************************************
 * @dev USAGE
 *
 * @dev Calling contracts must inherit from VRFConsumerBase, and can
 * @dev initialize VRFConsumerBase's attributes in their constructor as
 * @dev shown:
 *
 * @dev   contract VRFConsumer {
 * @dev     constructor(<other arguments>, address _vrfCoordinator, address _link)
 * @dev       VRFConsumerBase(_vrfCoordinator) public {
 * @dev         <initialization with other arguments goes here>
 * @dev       }
 * @dev   }
 *
 * @dev The oracle will have given you an ID for the VRF keypair they have
 * @dev committed to (let's call it keyHash). Create subscription, fund it
 * @dev and your consumer contract as a consumer of it (see VRFCoordinatorInterface
 * @dev subscription management functions).
 * @dev Call requestRandomWords(keyHash, subId, minimumRequestConfirmations,
 * @dev callbackGasLimit, numWords),
 * @dev see (VRFCoordinatorInterface for a description of the arguments).
 *
 * @dev Once the VRFCoordinator has received and validated the oracle's response
 * @dev to your request, it will call your contract's fulfillRandomWords method.
 *
 * @dev The randomness argument to fulfillRandomWords is a set of random words
 * @dev generated from your requestId and the blockHash of the request.
 *
 * @dev If your contract could have concurrent requests open, you can use the
 * @dev requestId returned from requestRandomWords to track which response is associated
 * @dev with which randomness request.
 * @dev See "SECURITY CONSIDERATIONS" for principles to keep in mind,
 * @dev if your contract could have multiple requests in flight simultaneously.
 *
 * @dev Colliding `requestId`s are cryptographically impossible as long as seeds
 * @dev differ.
 *
 * *****************************************************************************
 * @dev SECURITY CONSIDERATIONS
 *
 * @dev A method with the ability to call your fulfillRandomness method directly
 * @dev could spoof a VRF response with any random value, so it's critical that
 * @dev it cannot be directly called by anything other than this base contract
 * @dev (specifically, by the VRFConsumerBase.rawFulfillRandomness method).
 *
 * @dev For your users to trust that your contract's random behavior is free
 * @dev from malicious interference, it's best if you can write it so that all
 * @dev behaviors implied by a VRF response are executed *during* your
 * @dev fulfillRandomness method. If your contract must store the response (or
 * @dev anything derived from it) and use it later, you must ensure that any
 * @dev user-significant behavior which depends on that stored value cannot be
 * @dev manipulated by a subsequent VRF request.
 *
 * @dev Similarly, both miners and the VRF oracle itself have some influence
 * @dev over the order in which VRF responses appear on the blockchain, so if
 * @dev your contract could have multiple VRF requests in flight simultaneously,
 * @dev you must ensure that the order in which the VRF responses arrive cannot
 * @dev be used to manipulate your contract's user-significant behavior.
 *
 * @dev Since the block hash of the block which contains the requestRandomness
 * @dev call is mixed into the input to the VRF *last*, a sufficiently powerful
 * @dev miner could, in principle, fork the blockchain to evict the block
 * @dev containing the request, forcing the request to be included in a
 * @dev different block with a different hash, and therefore a different input
 * @dev to the VRF. However, such an attack would incur a substantial economic
 * @dev cost. This cost scales with the number of blocks the VRF oracle waits
 * @dev until it calls responds to a request. It is for this reason that
 * @dev that you can signal to an oracle you'd like them to wait longer before
 * @dev responding to the request (however this is not enforced in the contract
 * @dev and so remains effective only in the case of unmodified oracle software).
 */
abstract contract VRFConsumerBaseV2 {
  error OnlyCoordinatorCanFulfill(address have, address want);
  address private immutable vrfCoordinator;

  /**
   * @param _vrfCoordinator address of VRFCoordinator contract
   */
  constructor(address _vrfCoordinator) {
    vrfCoordinator = _vrfCoordinator;
  }

  /**
   * @notice fulfillRandomness handles the VRF response. Your contract must
   * @notice implement it. See "SECURITY CONSIDERATIONS" above for important
   * @notice principles to keep in mind when implementing your fulfillRandomness
   * @notice method.
   *
   * @dev VRFConsumerBaseV2 expects its subcontracts to have a method with this
   * @dev signature, and will call it once it has verified the proof
   * @dev associated with the randomness. (It is triggered via a call to
   * @dev rawFulfillRandomness, below.)
   *
   * @param requestId The Id initially returned by requestRandomness
   * @param randomWords the VRF output expanded to the requested number of words
   */
  function fulfillRandomWords(uint256 requestId, uint256[] memory randomWords) internal virtual;

  // rawFulfillRandomness is called by VRFCoordinator when it receives a valid VRF
  // proof. rawFulfillRandomness then calls fulfillRandomness, after validating
  // the origin of the call
  function rawFulfillRandomWords(uint256 requestId, uint256[] memory randomWords) external {
    if (msg.sender != vrfCoordinator) {
      revert OnlyCoordinatorCanFulfill(msg.sender, vrfCoordinator);
    }
    fulfillRandomWords(requestId, randomWords);
  }
}

// File: @openzeppelin/contracts/utils/math/SafeMath.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (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;
        }
    }
}

// File: docs.chain.link/samples/VRF/ERC721SUB.sol



// SPDX-License-Identifier: GPL-3.0-or-later

pragma solidity ^0.8.4;

import '@openzeppelin/contracts/token/ERC721/IERC721Receiver.sol';

error ApprovalCallerNotOwnerNorApproved();
error ApprovalQueryForNonexistentToken();
error ApproveToCaller();
error ApprovalToCurrentOwner();
error BalanceQueryForZeroAddress();
error MintedQueryForZeroAddress();
error MintToZeroAddress();
error MintZeroQuantity();
error OwnerIndexOutOfBounds();
error OwnerQueryForNonexistentToken();
error TokenIndexOutOfBounds();
error TransferCallerNotOwnerNorApproved();
error TransferFromIncorrectOwner();
error TransferToNonERC721ReceiverImplementer();
error TransferToZeroAddress();
error UnableDetermineTokenOwner();
error UnableGetTokenOwnerByIndex();
error URIQueryForNonexistentToken();

/**
 * Updated, minimalist and gas efficient version of OpenZeppelins ERC721 contract.
 * Includes the Metadata and  Enumerable extension.
 *
 * Assumes serials are sequentially minted starting at 0 (e.g. 0, 1, 2, 3..).
 * Does not support burning tokens
 *
 * @author EtherLottos
 * Credits: beskay0x, chiru-labs, solmate, transmissions11, nftchance, squeebo_nft and others
 */

abstract contract ERC721SUB {
    /*///////////////////////////////////////////////////////////////
                                 EVENTS
    //////////////////////////////////////////////////////////////*/

    event Transfer(address indexed from, address indexed to, uint256 indexed id);

    event Approval(address indexed owner, address indexed spender, uint256 indexed id);

    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);

    /*///////////////////////////////////////////////////////////////
                          METADATA STORAGE/LOGIC
    //////////////////////////////////////////////////////////////*/

    string public name;

    string public symbol;

    function tokenURI(uint256 tokenId) public view virtual returns (string memory);

    /*///////////////////////////////////////////////////////////////
                          ERC721 STORAGE
    //////////////////////////////////////////////////////////////*/

    // Array which maps token ID to address (index is tokenID)
    address[1000000000] internal _owners;
    uint256 public indexTracker;
    uint256 public currentWeek = 1; 
    mapping(uint256 => mapping(uint256 => bool)) public boost;
    

    // Mapping from token ID to approved address
    mapping(uint256 => address) private _tokenApprovals;

    // Mapping from owner to operator approvals
    mapping(address => mapping(address => bool)) private _operatorApprovals;

    /*///////////////////////////////////////////////////////////////
                              CONSTRUCTOR
    //////////////////////////////////////////////////////////////*/

    constructor(string memory _name, string memory _symbol) {
        name = _name;
        symbol = _symbol;
    }

    /*///////////////////////////////////////////////////////////////
                              ERC165 LOGIC
    //////////////////////////////////////////////////////////////*/

    function supportsInterface(bytes4 interfaceId) public view virtual returns (bool) {
        return
            interfaceId == 0x01ffc9a7 || // ERC165 Interface ID for ERC165
            interfaceId == 0x80ac58cd || // ERC165 Interface ID for ERC721
            interfaceId == 0x780e9d63 || // ERC165 Interface ID for ERC721Enumerable
            interfaceId == 0x5b5e139f; // ERC165 Interface ID for ERC721Metadata
    }

    /*///////////////////////////////////////////////////////////////
                       ERC721ENUMERABLE LOGIC
    //////////////////////////////////////////////////////////////*/

    /**
     * @dev See {IERC721Enumerable-totalSupply}.
     */
    function totalSupply() public view returns (uint256) {
        return indexTracker;
    }

    /**
     * @dev See {IERC721Enumerable-tokenOfOwnerByIndex}.
     * Dont call this function on chain from another smart contract, since it can become quite expensive
     */
    function tokenOfOwnerByIndex(address owner, uint256 index) public view virtual returns (uint256 tokenId) {
        if (index >= balanceOf(owner)) revert OwnerIndexOutOfBounds();

        uint256 count;
        uint256 qty = indexTracker;
        // Cannot realistically overflow, since we are using uint256
        unchecked {
            for (tokenId; tokenId < qty; tokenId++) {
                if (owner == ownerOf(tokenId)) {
                    if (count == index) return tokenId;
                    else count++;
                }
            }
        }

        revert UnableGetTokenOwnerByIndex();
    }

    /**
     * @dev See {IERC721Enumerable-tokenByIndex}.
     */
    function tokenByIndex(uint256 index) public view virtual returns (uint256) {
        if (index >= totalSupply()) revert TokenIndexOutOfBounds();
        return index;
    }

    function resetTokenIndex(uint256 _resetDigit) virtual public {
        indexTracker = _resetDigit;
    }

    /*///////////////////////////////////////////////////////////////
                              ERC721 LOGIC
    //////////////////////////////////////////////////////////////*/

    /**
     * @dev Iterates through _owners array, returns balance of address
     * It is not recommended to call this function from another smart contract
     * as it can become quite expensive -- call this function off chain instead.
     */
    function balanceOf(address owner) public view virtual returns (uint256) {
        if (owner == address(0)) revert BalanceQueryForZeroAddress();

        uint256 count;
        uint256 qty = indexTracker;
        // Cannot realistically overflow, since we are using uint256
        unchecked {
            for (uint256 i; i < qty; i++) {
                if (owner == ownerOf(i)) {
                    count++;
                }
            }
        }
        return count;
    }

    /**
     * @dev See {IERC721-ownerOf}.
     * Gas spent here starts off proportional to the maximum mint batch size.
     * It gradually moves to O(1) as tokens get transferred around in the collection over time.
     */
    function ownerOf(uint256 tokenId) public view virtual returns (address) {
        if (!_exists(tokenId)) revert OwnerQueryForNonexistentToken();

        // Cannot realistically overflow, since we are using uint256
        unchecked {
            for (tokenId; ; tokenId++) {
                if (_owners[tokenId] != address(0)) {
                    return _owners[tokenId];
                }
            }
        }

        revert UnableDetermineTokenOwner();
    }

    /**
     * @dev See {IERC721-approve}.
     */
    function approve(address to, uint256 tokenId) public virtual {
        address owner = ownerOf(tokenId);
        if (to == owner) revert ApprovalToCurrentOwner();

        if (msg.sender != owner && !isApprovedForAll(owner, msg.sender)) revert ApprovalCallerNotOwnerNorApproved();

        _tokenApprovals[tokenId] = to;
        emit Approval(owner, to, tokenId);
    }

    /**
     * @dev See {IERC721-getApproved}.
     */
    function getApproved(uint256 tokenId) public view virtual returns (address) {
        if (!_exists(tokenId)) revert ApprovalQueryForNonexistentToken();

        return _tokenApprovals[tokenId];
    }

    /**
     * @dev See {IERC721-setApprovalForAll}.
     */
    function setApprovalForAll(address operator, bool approved) public virtual {
        if (operator == msg.sender) revert ApproveToCaller();

        _operatorApprovals[msg.sender][operator] = approved;
        emit ApprovalForAll(msg.sender, operator, approved);
    }

    /**
     * @dev See {IERC721-isApprovedForAll}.
     */
    function isApprovedForAll(address owner, address operator) public view virtual returns (bool) {
        return _operatorApprovals[owner][operator];
    }

    /**
     * @dev See {IERC721-transferFrom}.
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public virtual {
        if (!_exists(tokenId)) revert OwnerQueryForNonexistentToken();
        if (ownerOf(tokenId) != from) revert TransferFromIncorrectOwner();
        if (to == address(0)) revert TransferToZeroAddress();

        bool isApprovedOrOwner = (msg.sender == from ||
            msg.sender == getApproved(tokenId) ||
            isApprovedForAll(from, msg.sender));
        if (!isApprovedOrOwner) revert TransferCallerNotOwnerNorApproved();

        // delete token approvals from previous owner
        delete _tokenApprovals[tokenId];
        _owners[tokenId] = to;
        boost[currentWeek][tokenId] = true;

        // if token ID below transferred one isnt set, set it to previous owner
        // if tokenid is zero, skip this to prevent underflow
        if (tokenId > 0 && _owners[tokenId - 1] == address(0)) {
            _owners[tokenId - 1] = from;
        }

        emit Transfer(from, to, tokenId);
    }

    /**
     * @dev See {IERC721-safeTransferFrom}.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 id
    ) public virtual {
        safeTransferFrom(from, to, id, '');
    }

    /**
     * @dev See {IERC721-safeTransferFrom}.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 id,
        bytes memory data
    ) public virtual {
        transferFrom(from, to, id);

        if (!_checkOnERC721Received(from, to, id, data)) revert TransferToNonERC721ReceiverImplementer();
    }

    /**
     * @dev Returns whether `tokenId` exists.
     */
    function _exists(uint256 tokenId) internal view virtual returns (bool) {
        return tokenId < indexTracker;
    }

    /**
     * @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target address.
     * The call is not executed if the target address is not a contract.
     *
     * @param from address representing the previous owner of the given token ID
     * @param to target address that will receive the tokens
     * @param tokenId uint256 ID of the token to be transferred
     * @param _data bytes optional data to send along with the call
     * @return bool whether the call correctly returned the expected magic value
     */
    function _checkOnERC721Received(
        address from,
        address to,
        uint256 tokenId,
        bytes memory _data
    ) private returns (bool) {
        if (to.code.length == 0) return true;

        try IERC721Receiver(to).onERC721Received(msg.sender, from, tokenId, _data) returns (bytes4 retval) {
            return retval == IERC721Receiver(to).onERC721Received.selector;
        } catch (bytes memory reason) {
            if (reason.length == 0) revert TransferToNonERC721ReceiverImplementer();

            assembly {
                revert(add(32, reason), mload(reason))
            }
        }
    }

    /*///////////////////////////////////////////////////////////////
                       INTERNAL MINT LOGIC
    //////////////////////////////////////////////////////////////*/

    /**
     * @dev check if contract confirms token transfer, if not - reverts
     * unlike the standard ERC721 implementation this is only called once per mint,
     * no matter how many tokens get minted, since it is useless to check this
     * requirement several times -- if the contract confirms one token,
     * it will confirm all additional ones too.
     * This saves us around 5k gas per additional mint
     */
    function _safeMint(address to, uint256 qty) internal virtual {
        _safeMint(to, qty, '');
    }

    function _safeMint(
        address to,
        uint256 qty,
        bytes memory data
    ) internal virtual {
        _mint(to, qty);

        if (!_checkOnERC721Received(address(0), to, indexTracker - 1, data))
            revert TransferToNonERC721ReceiverImplementer();
    }

    function _mint(address to, uint256 qty) internal virtual {
        if (to == address(0)) revert MintToZeroAddress();
        if (qty == 0) revert MintZeroQuantity();

        uint256 _currentIndex = indexTracker;

        // Cannot realistically overflow, since we are using uint256
        unchecked {
            for (uint256 i; i < qty - 1; i++) {
                if(_owners[indexTracker] != address(0)){
                   delete _owners[indexTracker];
                }
                indexTracker++;
                emit Transfer(address(0), to, _currentIndex + i);
            }
        }

        // set last index to receiver
        _owners[indexTracker] = to;
        indexTracker++;
        emit Transfer(address(0), to, _currentIndex + (qty - 1));
    }
}
// File: @openzeppelin/contracts/utils/Strings.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (utils/Strings.sol)

pragma solidity ^0.8.0;

/**
 * @dev String operations.
 */
library Strings {
    bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";
    uint8 private constant _ADDRESS_LENGTH = 20;

    /**
     * @dev Converts a `uint256` to its ASCII `string` decimal representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        // Inspired by OraclizeAPI's implementation - MIT licence
        // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol

        if (value == 0) {
            return "0";
        }
        uint256 temp = value;
        uint256 digits;
        while (temp != 0) {
            digits++;
            temp /= 10;
        }
        bytes memory buffer = new bytes(digits);
        while (value != 0) {
            digits -= 1;
            buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));
            value /= 10;
        }
        return string(buffer);
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
     */
    function toHexString(uint256 value) internal pure returns (string memory) {
        if (value == 0) {
            return "0x00";
        }
        uint256 temp = value;
        uint256 length = 0;
        while (temp != 0) {
            length++;
            temp >>= 8;
        }
        return toHexString(value, length);
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
     */
    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
        bytes memory buffer = new bytes(2 * length + 2);
        buffer[0] = "0";
        buffer[1] = "x";
        for (uint256 i = 2 * length + 1; i > 1; --i) {
            buffer[i] = _HEX_SYMBOLS[value & 0xf];
            value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        return string(buffer);
    }

    /**
     * @dev Converts an `address` with fixed length of 20 bytes to its not checksummed ASCII `string` hexadecimal representation.
     */
    function toHexString(address addr) internal pure returns (string memory) {
        return toHexString(uint256(uint160(addr)), _ADDRESS_LENGTH);
    }
}

// File: @openzeppelin/contracts/access/Ownable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (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 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/token/ERC721/IERC721Receiver.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC721/IERC721Receiver.sol)

pragma solidity ^0.8.0;

/**
 * @title ERC721 token receiver interface
 * @dev Interface for any contract that wants to support safeTransfers
 * from ERC721 asset contracts.
 */
interface IERC721Receiver {
    /**
     * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
     * by `operator` from `from`, this function is called.
     *
     * It must return its Solidity selector to confirm the token transfer.
     * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
     *
     * The selector can be obtained in Solidity with `IERC721Receiver.onERC721Received.selector`.
     */
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}

// File: @openzeppelin/contracts/utils/Context.sol



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

pragma solidity ^0.8.0;

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

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