ETH Price: $2,501.23 (+0.29%)

Transaction Decoder

Block:
17033067 at Apr-12-2023 04:20:11 PM +UTC
Transaction Fee:
0.002619616708159128 ETH $6.55
Gas Used:
109,042 Gas / 24.023923884 Gwei

Emitted Events:

293 TransparentUpgradeableProxy.0x92f1ba397f7880b9ea1626fce4e1ac466a8638050116cffba949f5261a97cac8( 0x92f1ba397f7880b9ea1626fce4e1ac466a8638050116cffba949f5261a97cac8, 0x0000000000000000000000001de7a1e23a8aea0ca3261874f3b895e4f9f8295b, 0000000000000000000000000000000000000000000000000000000000000001, 0000000000000000000000000000000000000000000000000000000000000001 )

Account State Difference:

  Address   Before After State Difference Code
0x1de7A1e2...4F9F8295b
0.36522887660481592 Eth
Nonce: 821
0.146609259896656792 Eth
Nonce: 822
0.218619616708159128
2.388668841918688109 Eth2.388679746118688109 Eth0.0000109042
0xa4f9a065...34ce1CA2F 306.047 Eth306.263 Eth0.216

Execution Trace

ETH 0.216 TransparentUpgradeableProxy.4051f740( )
  • ETH 0.216 Waitlist.reserve( _quantity=1, _maxQuantity=1, _batch=1, _holdingWallet=0x1de7A1e23A8AEa0Ca3261874f3B895e4F9F8295b, _signature=0xF6F94F69AD5056324EFB26E9D1B8694D34DA7CC72C521787D5C75D4D3DFFF9354CED5B06A941F1B7A5DDE5878F919607C305C0D7F4672FB08A4AF69EF2519BCF1B )
    • Null: 0x000...001.f27afbae( )
      File 1 of 2: TransparentUpgradeableProxy
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.8.0;
      import "@openzeppelin/contracts/proxy/beacon/BeaconProxy.sol";
      import "@openzeppelin/contracts/proxy/beacon/UpgradeableBeacon.sol";
      import "@openzeppelin/contracts/proxy/ERC1967/ERC1967Proxy.sol";
      import "@openzeppelin/contracts/proxy/transparent/TransparentUpgradeableProxy.sol";
      import "@openzeppelin/contracts/proxy/transparent/ProxyAdmin.sol";
      // Kept for backwards compatibility with older versions of Hardhat and Truffle plugins.
      contract AdminUpgradeabilityProxy is TransparentUpgradeableProxy {
          constructor(address logic, address admin, bytes memory data) payable TransparentUpgradeableProxy(logic, admin, data) {}
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.8.0;
      import "./IBeacon.sol";
      import "../Proxy.sol";
      import "../ERC1967/ERC1967Upgrade.sol";
      /**
       * @dev This contract implements a proxy that gets the implementation address for each call from a {UpgradeableBeacon}.
       *
       * The beacon address is stored in storage slot `uint256(keccak256('eip1967.proxy.beacon')) - 1`, so that it doesn't
       * conflict with the storage layout of the implementation behind the proxy.
       *
       * _Available since v3.4._
       */
      contract BeaconProxy is Proxy, ERC1967Upgrade {
          /**
           * @dev Initializes the proxy with `beacon`.
           *
           * If `data` is nonempty, it's used as data in a delegate call to the implementation returned by the beacon. This
           * will typically be an encoded function call, and allows initializating the storage of the proxy like a Solidity
           * constructor.
           *
           * Requirements:
           *
           * - `beacon` must be a contract with the interface {IBeacon}.
           */
          constructor(address beacon, bytes memory data) payable {
              assert(_BEACON_SLOT == bytes32(uint256(keccak256("eip1967.proxy.beacon")) - 1));
              _upgradeBeaconToAndCall(beacon, data, false);
          }
          /**
           * @dev Returns the current beacon address.
           */
          function _beacon() internal view virtual returns (address) {
              return _getBeacon();
          }
          /**
           * @dev Returns the current implementation address of the associated beacon.
           */
          function _implementation() internal view virtual override returns (address) {
              return IBeacon(_getBeacon()).implementation();
          }
          /**
           * @dev Changes the proxy to use a new beacon. Deprecated: see {_upgradeBeaconToAndCall}.
           *
           * If `data` is nonempty, it's used as data in a delegate call to the implementation returned by the beacon.
           *
           * Requirements:
           *
           * - `beacon` must be a contract.
           * - The implementation returned by `beacon` must be a contract.
           */
          function _setBeacon(address beacon, bytes memory data) internal virtual {
              _upgradeBeaconToAndCall(beacon, data, false);
          }
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.8.0;
      import "./IBeacon.sol";
      import "../../access/Ownable.sol";
      import "../../utils/Address.sol";
      /**
       * @dev This contract is used in conjunction with one or more instances of {BeaconProxy} to determine their
       * implementation contract, which is where they will delegate all function calls.
       *
       * An owner is able to change the implementation the beacon points to, thus upgrading the proxies that use this beacon.
       */
      contract UpgradeableBeacon is IBeacon, Ownable {
          address private _implementation;
          /**
           * @dev Emitted when the implementation returned by the beacon is changed.
           */
          event Upgraded(address indexed implementation);
          /**
           * @dev Sets the address of the initial implementation, and the deployer account as the owner who can upgrade the
           * beacon.
           */
          constructor(address implementation_) {
              _setImplementation(implementation_);
          }
          /**
           * @dev Returns the current implementation address.
           */
          function implementation() public view virtual override returns (address) {
              return _implementation;
          }
          /**
           * @dev Upgrades the beacon to a new implementation.
           *
           * Emits an {Upgraded} event.
           *
           * Requirements:
           *
           * - msg.sender must be the owner of the contract.
           * - `newImplementation` must be a contract.
           */
          function upgradeTo(address newImplementation) public virtual onlyOwner {
              _setImplementation(newImplementation);
              emit Upgraded(newImplementation);
          }
          /**
           * @dev Sets the implementation contract address for this beacon
           *
           * Requirements:
           *
           * - `newImplementation` must be a contract.
           */
          function _setImplementation(address newImplementation) private {
              require(Address.isContract(newImplementation), "UpgradeableBeacon: implementation is not a contract");
              _implementation = newImplementation;
          }
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.8.0;
      import "../Proxy.sol";
      import "./ERC1967Upgrade.sol";
      /**
       * @dev This contract implements an upgradeable proxy. It is upgradeable because calls are delegated to an
       * implementation address that can be changed. This address is stored in storage in the location specified by
       * https://eips.ethereum.org/EIPS/eip-1967[EIP1967], so that it doesn't conflict with the storage layout of the
       * implementation behind the proxy.
       */
      contract ERC1967Proxy is Proxy, ERC1967Upgrade {
          /**
           * @dev Initializes the upgradeable proxy with an initial implementation specified by `_logic`.
           *
           * If `_data` is nonempty, it's used as data in a delegate call to `_logic`. This will typically be an encoded
           * function call, and allows initializating the storage of the proxy like a Solidity constructor.
           */
          constructor(address _logic, bytes memory _data) payable {
              assert(_IMPLEMENTATION_SLOT == bytes32(uint256(keccak256("eip1967.proxy.implementation")) - 1));
              _upgradeToAndCall(_logic, _data, false);
          }
          /**
           * @dev Returns the current implementation address.
           */
          function _implementation() internal view virtual override returns (address impl) {
              return ERC1967Upgrade._getImplementation();
          }
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.8.0;
      import "../ERC1967/ERC1967Proxy.sol";
      /**
       * @dev This contract implements a proxy that is upgradeable by an admin.
       *
       * To avoid https://medium.com/nomic-labs-blog/malicious-backdoors-in-ethereum-proxies-62629adf3357[proxy selector
       * clashing], which can potentially be used in an attack, this contract uses the
       * https://blog.openzeppelin.com/the-transparent-proxy-pattern/[transparent proxy pattern]. This pattern implies two
       * things that go hand in hand:
       *
       * 1. If any account other than the admin calls the proxy, the call will be forwarded to the implementation, even if
       * that call matches one of the admin functions exposed by the proxy itself.
       * 2. If the admin calls the proxy, it can access the admin functions, but its calls will never be forwarded to the
       * implementation. If the admin tries to call a function on the implementation it will fail with an error that says
       * "admin cannot fallback to proxy target".
       *
       * These properties mean that the admin account can only be used for admin actions like upgrading the proxy or changing
       * the admin, so it's best if it's a dedicated account that is not used for anything else. This will avoid headaches due
       * to sudden errors when trying to call a function from the proxy implementation.
       *
       * Our recommendation is for the dedicated account to be an instance of the {ProxyAdmin} contract. If set up this way,
       * you should think of the `ProxyAdmin` instance as the real administrative interface of your proxy.
       */
      contract TransparentUpgradeableProxy is ERC1967Proxy {
          /**
           * @dev Initializes an upgradeable proxy managed by `_admin`, backed by the implementation at `_logic`, and
           * optionally initialized with `_data` as explained in {ERC1967Proxy-constructor}.
           */
          constructor(address _logic, address admin_, bytes memory _data) payable ERC1967Proxy(_logic, _data) {
              assert(_ADMIN_SLOT == bytes32(uint256(keccak256("eip1967.proxy.admin")) - 1));
              _changeAdmin(admin_);
          }
          /**
           * @dev Modifier used internally that will delegate the call to the implementation unless the sender is the admin.
           */
          modifier ifAdmin() {
              if (msg.sender == _getAdmin()) {
                  _;
              } else {
                  _fallback();
              }
          }
          /**
           * @dev Returns the current admin.
           *
           * NOTE: Only the admin can call this function. See {ProxyAdmin-getProxyAdmin}.
           *
           * TIP: To get this value clients can read directly from the storage slot shown below (specified by EIP1967) using the
           * https://eth.wiki/json-rpc/API#eth_getstorageat[`eth_getStorageAt`] RPC call.
           * `0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103`
           */
          function admin() external ifAdmin returns (address admin_) {
              admin_ = _getAdmin();
          }
          /**
           * @dev Returns the current implementation.
           *
           * NOTE: Only the admin can call this function. See {ProxyAdmin-getProxyImplementation}.
           *
           * TIP: To get this value clients can read directly from the storage slot shown below (specified by EIP1967) using the
           * https://eth.wiki/json-rpc/API#eth_getstorageat[`eth_getStorageAt`] RPC call.
           * `0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc`
           */
          function implementation() external ifAdmin returns (address implementation_) {
              implementation_ = _implementation();
          }
          /**
           * @dev Changes the admin of the proxy.
           *
           * Emits an {AdminChanged} event.
           *
           * NOTE: Only the admin can call this function. See {ProxyAdmin-changeProxyAdmin}.
           */
          function changeAdmin(address newAdmin) external virtual ifAdmin {
              _changeAdmin(newAdmin);
          }
          /**
           * @dev Upgrade the implementation of the proxy.
           *
           * NOTE: Only the admin can call this function. See {ProxyAdmin-upgrade}.
           */
          function upgradeTo(address newImplementation) external ifAdmin {
              _upgradeToAndCall(newImplementation, bytes(""), false);
          }
          /**
           * @dev Upgrade the implementation of the proxy, and then call a function from the new implementation as specified
           * by `data`, which should be an encoded function call. This is useful to initialize new storage variables in the
           * proxied contract.
           *
           * NOTE: Only the admin can call this function. See {ProxyAdmin-upgradeAndCall}.
           */
          function upgradeToAndCall(address newImplementation, bytes calldata data) external payable ifAdmin {
              _upgradeToAndCall(newImplementation, data, true);
          }
          /**
           * @dev Returns the current admin.
           */
          function _admin() internal view virtual returns (address) {
              return _getAdmin();
          }
          /**
           * @dev Makes sure the admin cannot access the fallback function. See {Proxy-_beforeFallback}.
           */
          function _beforeFallback() internal virtual override {
              require(msg.sender != _getAdmin(), "TransparentUpgradeableProxy: admin cannot fallback to proxy target");
              super._beforeFallback();
          }
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.8.0;
      import "./TransparentUpgradeableProxy.sol";
      import "../../access/Ownable.sol";
      /**
       * @dev This is an auxiliary contract meant to be assigned as the admin of a {TransparentUpgradeableProxy}. For an
       * explanation of why you would want to use this see the documentation for {TransparentUpgradeableProxy}.
       */
      contract ProxyAdmin is Ownable {
          /**
           * @dev Returns the current implementation of `proxy`.
           *
           * Requirements:
           *
           * - This contract must be the admin of `proxy`.
           */
          function getProxyImplementation(TransparentUpgradeableProxy proxy) public view virtual returns (address) {
              // We need to manually run the static call since the getter cannot be flagged as view
              // bytes4(keccak256("implementation()")) == 0x5c60da1b
              (bool success, bytes memory returndata) = address(proxy).staticcall(hex"5c60da1b");
              require(success);
              return abi.decode(returndata, (address));
          }
          /**
           * @dev Returns the current admin of `proxy`.
           *
           * Requirements:
           *
           * - This contract must be the admin of `proxy`.
           */
          function getProxyAdmin(TransparentUpgradeableProxy proxy) public view virtual returns (address) {
              // We need to manually run the static call since the getter cannot be flagged as view
              // bytes4(keccak256("admin()")) == 0xf851a440
              (bool success, bytes memory returndata) = address(proxy).staticcall(hex"f851a440");
              require(success);
              return abi.decode(returndata, (address));
          }
          /**
           * @dev Changes the admin of `proxy` to `newAdmin`.
           *
           * Requirements:
           *
           * - This contract must be the current admin of `proxy`.
           */
          function changeProxyAdmin(TransparentUpgradeableProxy proxy, address newAdmin) public virtual onlyOwner {
              proxy.changeAdmin(newAdmin);
          }
          /**
           * @dev Upgrades `proxy` to `implementation`. See {TransparentUpgradeableProxy-upgradeTo}.
           *
           * Requirements:
           *
           * - This contract must be the admin of `proxy`.
           */
          function upgrade(TransparentUpgradeableProxy proxy, address implementation) public virtual onlyOwner {
              proxy.upgradeTo(implementation);
          }
          /**
           * @dev Upgrades `proxy` to `implementation` and calls a function on the new implementation. See
           * {TransparentUpgradeableProxy-upgradeToAndCall}.
           *
           * Requirements:
           *
           * - This contract must be the admin of `proxy`.
           */
          function upgradeAndCall(TransparentUpgradeableProxy proxy, address implementation, bytes memory data) public payable virtual onlyOwner {
              proxy.upgradeToAndCall{value: msg.value}(implementation, data);
          }
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.8.0;
      /**
       * @dev This is the interface that {BeaconProxy} expects of its beacon.
       */
      interface IBeacon {
          /**
           * @dev Must return an address that can be used as a delegate call target.
           *
           * {BeaconProxy} will check that this address is a contract.
           */
          function implementation() external view returns (address);
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.8.0;
      /**
       * @dev This abstract contract provides a fallback function that delegates all calls to another contract using the EVM
       * instruction `delegatecall`. We refer to the second contract as the _implementation_ behind the proxy, and it has to
       * be specified by overriding the virtual {_implementation} function.
       *
       * Additionally, delegation to the implementation can be triggered manually through the {_fallback} function, or to a
       * different contract through the {_delegate} function.
       *
       * The success and return data of the delegated call will be returned back to the caller of the proxy.
       */
      abstract contract Proxy {
          /**
           * @dev Delegates the current call to `implementation`.
           *
           * This function does not return to its internall call site, it will return directly to the external caller.
           */
          function _delegate(address implementation) internal virtual {
              // solhint-disable-next-line no-inline-assembly
              assembly {
                  // Copy msg.data. We take full control of memory in this inline assembly
                  // block because it will not return to Solidity code. We overwrite the
                  // Solidity scratch pad at memory position 0.
                  calldatacopy(0, 0, calldatasize())
                  // Call the implementation.
                  // out and outsize are 0 because we don't know the size yet.
                  let result := delegatecall(gas(), implementation, 0, calldatasize(), 0, 0)
                  // Copy the returned data.
                  returndatacopy(0, 0, returndatasize())
                  switch result
                  // delegatecall returns 0 on error.
                  case 0 { revert(0, returndatasize()) }
                  default { return(0, returndatasize()) }
              }
          }
          /**
           * @dev This is a virtual function that should be overriden so it returns the address to which the fallback function
           * and {_fallback} should delegate.
           */
          function _implementation() internal view virtual returns (address);
          /**
           * @dev Delegates the current call to the address returned by `_implementation()`.
           *
           * This function does not return to its internall call site, it will return directly to the external caller.
           */
          function _fallback() internal virtual {
              _beforeFallback();
              _delegate(_implementation());
          }
          /**
           * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if no other
           * function in the contract matches the call data.
           */
          fallback () external payable virtual {
              _fallback();
          }
          /**
           * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if call data
           * is empty.
           */
          receive () external payable virtual {
              _fallback();
          }
          /**
           * @dev Hook that is called before falling back to the implementation. Can happen as part of a manual `_fallback`
           * call, or as part of the Solidity `fallback` or `receive` functions.
           *
           * If overriden should call `super._beforeFallback()`.
           */
          function _beforeFallback() internal virtual {
          }
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.8.2;
      import "../beacon/IBeacon.sol";
      import "../../utils/Address.sol";
      import "../../utils/StorageSlot.sol";
      /**
       * @dev This abstract contract provides getters and event emitting update functions for
       * https://eips.ethereum.org/EIPS/eip-1967[EIP1967] slots.
       *
       * _Available since v4.1._
       *
       * @custom:oz-upgrades-unsafe-allow delegatecall
       */
      abstract contract ERC1967Upgrade {
          // This is the keccak-256 hash of "eip1967.proxy.rollback" subtracted by 1
          bytes32 private constant _ROLLBACK_SLOT = 0x4910fdfa16fed3260ed0e7147f7cc6da11a60208b5b9406d12a635614ffd9143;
          /**
           * @dev Storage slot with the address of the current implementation.
           * This is the keccak-256 hash of "eip1967.proxy.implementation" subtracted by 1, and is
           * validated in the constructor.
           */
          bytes32 internal constant _IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;
          /**
           * @dev Emitted when the implementation is upgraded.
           */
          event Upgraded(address indexed implementation);
          /**
           * @dev Returns the current implementation address.
           */
          function _getImplementation() internal view returns (address) {
              return StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value;
          }
          /**
           * @dev Stores a new address in the EIP1967 implementation slot.
           */
          function _setImplementation(address newImplementation) private {
              require(Address.isContract(newImplementation), "ERC1967: new implementation is not a contract");
              StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value = newImplementation;
          }
          /**
           * @dev Perform implementation upgrade
           *
           * Emits an {Upgraded} event.
           */
          function _upgradeTo(address newImplementation) internal {
              _setImplementation(newImplementation);
              emit Upgraded(newImplementation);
          }
          /**
           * @dev Perform implementation upgrade with additional setup call.
           *
           * Emits an {Upgraded} event.
           */
          function _upgradeToAndCall(address newImplementation, bytes memory data, bool forceCall) internal {
              _setImplementation(newImplementation);
              emit Upgraded(newImplementation);
              if (data.length > 0 || forceCall) {
                  Address.functionDelegateCall(newImplementation, data);
              }
          }
          /**
           * @dev Perform implementation upgrade with security checks for UUPS proxies, and additional setup call.
           *
           * Emits an {Upgraded} event.
           */
          function _upgradeToAndCallSecure(address newImplementation, bytes memory data, bool forceCall) internal {
              address oldImplementation = _getImplementation();
              // Initial upgrade and setup call
              _setImplementation(newImplementation);
              if (data.length > 0 || forceCall) {
                  Address.functionDelegateCall(newImplementation, data);
              }
              // Perform rollback test if not already in progress
              StorageSlot.BooleanSlot storage rollbackTesting = StorageSlot.getBooleanSlot(_ROLLBACK_SLOT);
              if (!rollbackTesting.value) {
                  // Trigger rollback using upgradeTo from the new implementation
                  rollbackTesting.value = true;
                  Address.functionDelegateCall(
                      newImplementation,
                      abi.encodeWithSignature(
                          "upgradeTo(address)",
                          oldImplementation
                      )
                  );
                  rollbackTesting.value = false;
                  // Check rollback was effective
                  require(oldImplementation == _getImplementation(), "ERC1967Upgrade: upgrade breaks further upgrades");
                  // Finally reset to the new implementation and log the upgrade
                  _setImplementation(newImplementation);
                  emit Upgraded(newImplementation);
              }
          }
          /**
           * @dev Perform beacon upgrade with additional setup call. Note: This upgrades the address of the beacon, it does
           * not upgrade the implementation contained in the beacon (see {UpgradeableBeacon-_setImplementation} for that).
           *
           * Emits a {BeaconUpgraded} event.
           */
          function _upgradeBeaconToAndCall(address newBeacon, bytes memory data, bool forceCall) internal {
              _setBeacon(newBeacon);
              emit BeaconUpgraded(newBeacon);
              if (data.length > 0 || forceCall) {
                  Address.functionDelegateCall(IBeacon(newBeacon).implementation(), data);
              }
          }
          /**
           * @dev Storage slot with the admin of the contract.
           * This is the keccak-256 hash of "eip1967.proxy.admin" subtracted by 1, and is
           * validated in the constructor.
           */
          bytes32 internal constant _ADMIN_SLOT = 0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103;
          /**
           * @dev Emitted when the admin account has changed.
           */
          event AdminChanged(address previousAdmin, address newAdmin);
          /**
           * @dev Returns the current admin.
           */
          function _getAdmin() internal view returns (address) {
              return StorageSlot.getAddressSlot(_ADMIN_SLOT).value;
          }
          /**
           * @dev Stores a new address in the EIP1967 admin slot.
           */
          function _setAdmin(address newAdmin) private {
              require(newAdmin != address(0), "ERC1967: new admin is the zero address");
              StorageSlot.getAddressSlot(_ADMIN_SLOT).value = newAdmin;
          }
          /**
           * @dev Changes the admin of the proxy.
           *
           * Emits an {AdminChanged} event.
           */
          function _changeAdmin(address newAdmin) internal {
              emit AdminChanged(_getAdmin(), newAdmin);
              _setAdmin(newAdmin);
          }
          /**
           * @dev The storage slot of the UpgradeableBeacon contract which defines the implementation for this proxy.
           * This is bytes32(uint256(keccak256('eip1967.proxy.beacon')) - 1)) and is validated in the constructor.
           */
          bytes32 internal constant _BEACON_SLOT = 0xa3f0ad74e5423aebfd80d3ef4346578335a9a72aeaee59ff6cb3582b35133d50;
          /**
           * @dev Emitted when the beacon is upgraded.
           */
          event BeaconUpgraded(address indexed beacon);
          /**
           * @dev Returns the current beacon.
           */
          function _getBeacon() internal view returns (address) {
              return StorageSlot.getAddressSlot(_BEACON_SLOT).value;
          }
          /**
           * @dev Stores a new beacon in the EIP1967 beacon slot.
           */
          function _setBeacon(address newBeacon) private {
              require(
                  Address.isContract(newBeacon),
                  "ERC1967: new beacon is not a contract"
              );
              require(
                  Address.isContract(IBeacon(newBeacon).implementation()),
                  "ERC1967: beacon implementation is not a contract"
              );
              StorageSlot.getAddressSlot(_BEACON_SLOT).value = newBeacon;
          }
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.8.0;
      /**
       * @dev Collection of functions related to the address type
       */
      library Address {
          /**
           * @dev Returns true if `account` is a contract.
           *
           * [IMPORTANT]
           * ====
           * It is unsafe to assume that an address for which this function returns
           * false is an externally-owned account (EOA) and not a contract.
           *
           * Among others, `isContract` will return false for the following
           * types of addresses:
           *
           *  - an externally-owned account
           *  - a contract in construction
           *  - an address where a contract will be created
           *  - an address where a contract lived, but was destroyed
           * ====
           */
          function isContract(address account) internal view returns (bool) {
              // This method relies on extcodesize, which returns 0 for contracts in
              // construction, since the code is only stored at the end of the
              // constructor execution.
              uint256 size;
              // solhint-disable-next-line no-inline-assembly
              assembly { size := extcodesize(account) }
              return size > 0;
          }
          /**
           * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
           * `recipient`, forwarding all available gas and reverting on errors.
           *
           * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
           * of certain opcodes, possibly making contracts go over the 2300 gas limit
           * imposed by `transfer`, making them unable to receive funds via
           * `transfer`. {sendValue} removes this limitation.
           *
           * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
           *
           * IMPORTANT: because control is transferred to `recipient`, care must be
           * taken to not create reentrancy vulnerabilities. Consider using
           * {ReentrancyGuard} or the
           * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
           */
          function sendValue(address payable recipient, uint256 amount) internal {
              require(address(this).balance >= amount, "Address: insufficient balance");
              // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
              (bool success, ) = recipient.call{ value: amount }("");
              require(success, "Address: unable to send value, recipient may have reverted");
          }
          /**
           * @dev Performs a Solidity function call using a low level `call`. A
           * plain`call` is an unsafe replacement for a function call: use this
           * function instead.
           *
           * If `target` reverts with a revert reason, it is bubbled up by this
           * function (like regular Solidity function calls).
           *
           * Returns the raw returned data. To convert to the expected return value,
           * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
           *
           * Requirements:
           *
           * - `target` must be a contract.
           * - calling `target` with `data` must not revert.
           *
           * _Available since v3.1._
           */
          function functionCall(address target, bytes memory data) internal returns (bytes memory) {
            return functionCall(target, data, "Address: low-level call failed");
          }
          /**
           * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
           * `errorMessage` as a fallback revert reason when `target` reverts.
           *
           * _Available since v3.1._
           */
          function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
              return functionCallWithValue(target, data, 0, errorMessage);
          }
          /**
           * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
           * but also transferring `value` wei to `target`.
           *
           * Requirements:
           *
           * - the calling contract must have an ETH balance of at least `value`.
           * - the called Solidity function must be `payable`.
           *
           * _Available since v3.1._
           */
          function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
              return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
          }
          /**
           * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
           * with `errorMessage` as a fallback revert reason when `target` reverts.
           *
           * _Available since v3.1._
           */
          function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
              require(address(this).balance >= value, "Address: insufficient balance for call");
              require(isContract(target), "Address: call to non-contract");
              // solhint-disable-next-line avoid-low-level-calls
              (bool success, bytes memory returndata) = target.call{ value: value }(data);
              return _verifyCallResult(success, returndata, errorMessage);
          }
          /**
           * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
           * but performing a static call.
           *
           * _Available since v3.3._
           */
          function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
              return functionStaticCall(target, data, "Address: low-level static call failed");
          }
          /**
           * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
           * but performing a static call.
           *
           * _Available since v3.3._
           */
          function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
              require(isContract(target), "Address: static call to non-contract");
              // solhint-disable-next-line avoid-low-level-calls
              (bool success, bytes memory returndata) = target.staticcall(data);
              return _verifyCallResult(success, returndata, errorMessage);
          }
          /**
           * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
           * but performing a delegate call.
           *
           * _Available since v3.4._
           */
          function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
              return functionDelegateCall(target, data, "Address: low-level delegate call failed");
          }
          /**
           * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
           * but performing a delegate call.
           *
           * _Available since v3.4._
           */
          function functionDelegateCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
              require(isContract(target), "Address: delegate call to non-contract");
              // solhint-disable-next-line avoid-low-level-calls
              (bool success, bytes memory returndata) = target.delegatecall(data);
              return _verifyCallResult(success, returndata, errorMessage);
          }
          function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
              if (success) {
                  return returndata;
              } else {
                  // Look for revert reason and bubble it up if present
                  if (returndata.length > 0) {
                      // The easiest way to bubble the revert reason is using memory via assembly
                      // solhint-disable-next-line no-inline-assembly
                      assembly {
                          let returndata_size := mload(returndata)
                          revert(add(32, returndata), returndata_size)
                      }
                  } else {
                      revert(errorMessage);
                  }
              }
          }
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.8.0;
      /**
       * @dev Library for reading and writing primitive types to specific storage slots.
       *
       * Storage slots are often used to avoid storage conflict when dealing with upgradeable contracts.
       * This library helps with reading and writing to such slots without the need for inline assembly.
       *
       * The functions in this library return Slot structs that contain a `value` member that can be used to read or write.
       *
       * Example usage to set ERC1967 implementation slot:
       * ```
       * contract ERC1967 {
       *     bytes32 internal constant _IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;
       *
       *     function _getImplementation() internal view returns (address) {
       *         return StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value;
       *     }
       *
       *     function _setImplementation(address newImplementation) internal {
       *         require(Address.isContract(newImplementation), "ERC1967: new implementation is not a contract");
       *         StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value = newImplementation;
       *     }
       * }
       * ```
       *
       * _Available since v4.1 for `address`, `bool`, `bytes32`, and `uint256`._
       */
      library StorageSlot {
          struct AddressSlot {
              address value;
          }
          struct BooleanSlot {
              bool value;
          }
          struct Bytes32Slot {
              bytes32 value;
          }
          struct Uint256Slot {
              uint256 value;
          }
          /**
           * @dev Returns an `AddressSlot` with member `value` located at `slot`.
           */
          function getAddressSlot(bytes32 slot) internal pure returns (AddressSlot storage r) {
              assembly {
                  r.slot := slot
              }
          }
          /**
           * @dev Returns an `BooleanSlot` with member `value` located at `slot`.
           */
          function getBooleanSlot(bytes32 slot) internal pure returns (BooleanSlot storage r) {
              assembly {
                  r.slot := slot
              }
          }
          /**
           * @dev Returns an `Bytes32Slot` with member `value` located at `slot`.
           */
          function getBytes32Slot(bytes32 slot) internal pure returns (Bytes32Slot storage r) {
              assembly {
                  r.slot := slot
              }
          }
          /**
           * @dev Returns an `Uint256Slot` with member `value` located at `slot`.
           */
          function getUint256Slot(bytes32 slot) internal pure returns (Uint256Slot storage r) {
              assembly {
                  r.slot := slot
              }
          }
      }
      // SPDX-License-Identifier: MIT
      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 () {
              address msgSender = _msgSender();
              _owner = msgSender;
              emit OwnershipTransferred(address(0), msgSender);
          }
          /**
           * @dev Returns the address of the current owner.
           */
          function owner() public view virtual returns (address) {
              return _owner;
          }
          /**
           * @dev Throws if called by any account other than the owner.
           */
          modifier onlyOwner() {
              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 {
              emit OwnershipTransferred(_owner, address(0));
              _owner = 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");
              emit OwnershipTransferred(_owner, newOwner);
              _owner = newOwner;
          }
      }
      // SPDX-License-Identifier: MIT
      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) {
              this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
              return msg.data;
          }
      }
      

      File 2 of 2: Waitlist
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)
      pragma solidity ^0.8.0;
      import "../utils/ContextUpgradeable.sol";
      import "../proxy/utils/Initializable.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 OwnableUpgradeable is Initializable, ContextUpgradeable {
          address private _owner;
          event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
          /**
           * @dev Initializes the contract setting the deployer as the initial owner.
           */
          function __Ownable_init() internal onlyInitializing {
              __Ownable_init_unchained();
          }
          function __Ownable_init_unchained() internal onlyInitializing {
              _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);
          }
          /**
           * @dev This empty reserved space is put in place to allow future versions to add new
           * variables without shifting down storage in the inheritance chain.
           * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
           */
          uint256[49] private __gap;
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts (last updated v4.8.1) (proxy/utils/Initializable.sol)
      pragma solidity ^0.8.2;
      import "../../utils/AddressUpgradeable.sol";
      /**
       * @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
       * behind a proxy. Since proxied contracts do not make use of a constructor, it's common to move constructor logic to an
       * external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
       * function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
       *
       * The initialization functions use a version number. Once a version number is used, it is consumed and cannot be
       * reused. This mechanism prevents re-execution of each "step" but allows the creation of new initialization steps in
       * case an upgrade adds a module that needs to be initialized.
       *
       * For example:
       *
       * [.hljs-theme-light.nopadding]
       * ```
       * contract MyToken is ERC20Upgradeable {
       *     function initialize() initializer public {
       *         __ERC20_init("MyToken", "MTK");
       *     }
       * }
       * contract MyTokenV2 is MyToken, ERC20PermitUpgradeable {
       *     function initializeV2() reinitializer(2) public {
       *         __ERC20Permit_init("MyToken");
       *     }
       * }
       * ```
       *
       * TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
       * possible by providing the encoded function call as the `_data` argument to {ERC1967Proxy-constructor}.
       *
       * CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
       * that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
       *
       * [CAUTION]
       * ====
       * Avoid leaving a contract uninitialized.
       *
       * An uninitialized contract can be taken over by an attacker. This applies to both a proxy and its implementation
       * contract, which may impact the proxy. To prevent the implementation contract from being used, you should invoke
       * the {_disableInitializers} function in the constructor to automatically lock it when it is deployed:
       *
       * [.hljs-theme-light.nopadding]
       * ```
       * /// @custom:oz-upgrades-unsafe-allow constructor
       * constructor() {
       *     _disableInitializers();
       * }
       * ```
       * ====
       */
      abstract contract Initializable {
          /**
           * @dev Indicates that the contract has been initialized.
           * @custom:oz-retyped-from bool
           */
          uint8 private _initialized;
          /**
           * @dev Indicates that the contract is in the process of being initialized.
           */
          bool private _initializing;
          /**
           * @dev Triggered when the contract has been initialized or reinitialized.
           */
          event Initialized(uint8 version);
          /**
           * @dev A modifier that defines a protected initializer function that can be invoked at most once. In its scope,
           * `onlyInitializing` functions can be used to initialize parent contracts.
           *
           * Similar to `reinitializer(1)`, except that functions marked with `initializer` can be nested in the context of a
           * constructor.
           *
           * Emits an {Initialized} event.
           */
          modifier initializer() {
              bool isTopLevelCall = !_initializing;
              require(
                  (isTopLevelCall && _initialized < 1) || (!AddressUpgradeable.isContract(address(this)) && _initialized == 1),
                  "Initializable: contract is already initialized"
              );
              _initialized = 1;
              if (isTopLevelCall) {
                  _initializing = true;
              }
              _;
              if (isTopLevelCall) {
                  _initializing = false;
                  emit Initialized(1);
              }
          }
          /**
           * @dev A modifier that defines a protected reinitializer function that can be invoked at most once, and only if the
           * contract hasn't been initialized to a greater version before. In its scope, `onlyInitializing` functions can be
           * used to initialize parent contracts.
           *
           * A reinitializer may be used after the original initialization step. This is essential to configure modules that
           * are added through upgrades and that require initialization.
           *
           * When `version` is 1, this modifier is similar to `initializer`, except that functions marked with `reinitializer`
           * cannot be nested. If one is invoked in the context of another, execution will revert.
           *
           * Note that versions can jump in increments greater than 1; this implies that if multiple reinitializers coexist in
           * a contract, executing them in the right order is up to the developer or operator.
           *
           * WARNING: setting the version to 255 will prevent any future reinitialization.
           *
           * Emits an {Initialized} event.
           */
          modifier reinitializer(uint8 version) {
              require(!_initializing && _initialized < version, "Initializable: contract is already initialized");
              _initialized = version;
              _initializing = true;
              _;
              _initializing = false;
              emit Initialized(version);
          }
          /**
           * @dev Modifier to protect an initialization function so that it can only be invoked by functions with the
           * {initializer} and {reinitializer} modifiers, directly or indirectly.
           */
          modifier onlyInitializing() {
              require(_initializing, "Initializable: contract is not initializing");
              _;
          }
          /**
           * @dev Locks the contract, preventing any future reinitialization. This cannot be part of an initializer call.
           * Calling this in the constructor of a contract will prevent that contract from being initialized or reinitialized
           * to any version. It is recommended to use this to lock implementation contracts that are designed to be called
           * through proxies.
           *
           * Emits an {Initialized} event the first time it is successfully executed.
           */
          function _disableInitializers() internal virtual {
              require(!_initializing, "Initializable: contract is initializing");
              if (_initialized < type(uint8).max) {
                  _initialized = type(uint8).max;
                  emit Initialized(type(uint8).max);
              }
          }
          /**
           * @dev Returns the highest version that has been initialized. See {reinitializer}.
           */
          function _getInitializedVersion() internal view returns (uint8) {
              return _initialized;
          }
          /**
           * @dev Returns `true` if the contract is currently initializing. See {onlyInitializing}.
           */
          function _isInitializing() internal view returns (bool) {
              return _initializing;
          }
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts (last updated v4.8.0) (security/ReentrancyGuard.sol)
      pragma solidity ^0.8.0;
      import "../proxy/utils/Initializable.sol";
      /**
       * @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 ReentrancyGuardUpgradeable is Initializable {
          // 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;
          function __ReentrancyGuard_init() internal onlyInitializing {
              __ReentrancyGuard_init_unchained();
          }
          function __ReentrancyGuard_init_unchained() internal onlyInitializing {
              _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 This empty reserved space is put in place to allow future versions to add new
           * variables without shifting down storage in the inheritance chain.
           * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
           */
          uint256[49] private __gap;
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts (last updated v4.8.0) (utils/Address.sol)
      pragma solidity ^0.8.1;
      /**
       * @dev Collection of functions related to the address type
       */
      library AddressUpgradeable {
          /**
           * @dev Returns true if `account` is a contract.
           *
           * [IMPORTANT]
           * ====
           * It is unsafe to assume that an address for which this function returns
           * false is an externally-owned account (EOA) and not a contract.
           *
           * Among others, `isContract` will return false for the following
           * types of addresses:
           *
           *  - an externally-owned account
           *  - a contract in construction
           *  - an address where a contract will be created
           *  - an address where a contract lived, but was destroyed
           * ====
           *
           * [IMPORTANT]
           * ====
           * You shouldn't rely on `isContract` to protect against flash loan attacks!
           *
           * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
           * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
           * constructor.
           * ====
           */
          function isContract(address account) internal view returns (bool) {
              // This method relies on extcodesize/address.code.length, which returns 0
              // for contracts in construction, since the code is only stored at the end
              // of the constructor execution.
              return account.code.length > 0;
          }
          /**
           * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
           * `recipient`, forwarding all available gas and reverting on errors.
           *
           * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
           * of certain opcodes, possibly making contracts go over the 2300 gas limit
           * imposed by `transfer`, making them unable to receive funds via
           * `transfer`. {sendValue} removes this limitation.
           *
           * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
           *
           * IMPORTANT: because control is transferred to `recipient`, care must be
           * taken to not create reentrancy vulnerabilities. Consider using
           * {ReentrancyGuard} or the
           * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
           */
          function sendValue(address payable recipient, uint256 amount) internal {
              require(address(this).balance >= amount, "Address: insufficient balance");
              (bool success, ) = recipient.call{value: amount}("");
              require(success, "Address: unable to send value, recipient may have reverted");
          }
          /**
           * @dev Performs a Solidity function call using a low level `call`. A
           * plain `call` is an unsafe replacement for a function call: use this
           * function instead.
           *
           * If `target` reverts with a revert reason, it is bubbled up by this
           * function (like regular Solidity function calls).
           *
           * Returns the raw returned data. To convert to the expected return value,
           * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
           *
           * Requirements:
           *
           * - `target` must be a contract.
           * - calling `target` with `data` must not revert.
           *
           * _Available since v3.1._
           */
          function functionCall(address target, bytes memory data) internal returns (bytes memory) {
              return functionCallWithValue(target, data, 0, "Address: low-level call failed");
          }
          /**
           * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
           * `errorMessage` as a fallback revert reason when `target` reverts.
           *
           * _Available since v3.1._
           */
          function functionCall(
              address target,
              bytes memory data,
              string memory errorMessage
          ) internal returns (bytes memory) {
              return functionCallWithValue(target, data, 0, errorMessage);
          }
          /**
           * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
           * but also transferring `value` wei to `target`.
           *
           * Requirements:
           *
           * - the calling contract must have an ETH balance of at least `value`.
           * - the called Solidity function must be `payable`.
           *
           * _Available since v3.1._
           */
          function functionCallWithValue(
              address target,
              bytes memory data,
              uint256 value
          ) internal returns (bytes memory) {
              return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
          }
          /**
           * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
           * with `errorMessage` as a fallback revert reason when `target` reverts.
           *
           * _Available since v3.1._
           */
          function functionCallWithValue(
              address target,
              bytes memory data,
              uint256 value,
              string memory errorMessage
          ) internal returns (bytes memory) {
              require(address(this).balance >= value, "Address: insufficient balance for call");
              (bool success, bytes memory returndata) = target.call{value: value}(data);
              return verifyCallResultFromTarget(target, success, returndata, errorMessage);
          }
          /**
           * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
           * but performing a static call.
           *
           * _Available since v3.3._
           */
          function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
              return functionStaticCall(target, data, "Address: low-level static call failed");
          }
          /**
           * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
           * but performing a static call.
           *
           * _Available since v3.3._
           */
          function functionStaticCall(
              address target,
              bytes memory data,
              string memory errorMessage
          ) internal view returns (bytes memory) {
              (bool success, bytes memory returndata) = target.staticcall(data);
              return verifyCallResultFromTarget(target, success, returndata, errorMessage);
          }
          /**
           * @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
           * the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
           *
           * _Available since v4.8._
           */
          function verifyCallResultFromTarget(
              address target,
              bool success,
              bytes memory returndata,
              string memory errorMessage
          ) internal view returns (bytes memory) {
              if (success) {
                  if (returndata.length == 0) {
                      // only check isContract if the call was successful and the return data is empty
                      // otherwise we already know that it was a contract
                      require(isContract(target), "Address: call to non-contract");
                  }
                  return returndata;
              } else {
                  _revert(returndata, errorMessage);
              }
          }
          /**
           * @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
           * revert reason or using the provided one.
           *
           * _Available since v4.3._
           */
          function verifyCallResult(
              bool success,
              bytes memory returndata,
              string memory errorMessage
          ) internal pure returns (bytes memory) {
              if (success) {
                  return returndata;
              } else {
                  _revert(returndata, errorMessage);
              }
          }
          function _revert(bytes memory returndata, string memory errorMessage) private pure {
              // Look for revert reason and bubble it up if present
              if (returndata.length > 0) {
                  // The easiest way to bubble the revert reason is using memory via assembly
                  /// @solidity memory-safe-assembly
                  assembly {
                      let returndata_size := mload(returndata)
                      revert(add(32, returndata), returndata_size)
                  }
              } else {
                  revert(errorMessage);
              }
          }
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
      pragma solidity ^0.8.0;
      import "../proxy/utils/Initializable.sol";
      /**
       * @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 ContextUpgradeable is Initializable {
          function __Context_init() internal onlyInitializing {
          }
          function __Context_init_unchained() internal onlyInitializing {
          }
          function _msgSender() internal view virtual returns (address) {
              return msg.sender;
          }
          function _msgData() internal view virtual returns (bytes calldata) {
              return msg.data;
          }
          /**
           * @dev This empty reserved space is put in place to allow future versions to add new
           * variables without shifting down storage in the inheritance chain.
           * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
           */
          uint256[50] private __gap;
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts (last updated v4.8.0) (utils/cryptography/ECDSA.sol)
      pragma solidity ^0.8.0;
      import "../Strings.sol";
      /**
       * @dev Elliptic Curve Digital Signature Algorithm (ECDSA) operations.
       *
       * These functions can be used to verify that a message was signed by the holder
       * of the private keys of a given address.
       */
      library ECDSA {
          enum RecoverError {
              NoError,
              InvalidSignature,
              InvalidSignatureLength,
              InvalidSignatureS,
              InvalidSignatureV // Deprecated in v4.8
          }
          function _throwError(RecoverError error) private pure {
              if (error == RecoverError.NoError) {
                  return; // no error: do nothing
              } else if (error == RecoverError.InvalidSignature) {
                  revert("ECDSA: invalid signature");
              } else if (error == RecoverError.InvalidSignatureLength) {
                  revert("ECDSA: invalid signature length");
              } else if (error == RecoverError.InvalidSignatureS) {
                  revert("ECDSA: invalid signature 's' value");
              }
          }
          /**
           * @dev Returns the address that signed a hashed message (`hash`) with
           * `signature` or error string. This address can then be used for verification purposes.
           *
           * The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
           * this function rejects them by requiring the `s` value to be in the lower
           * half order, and the `v` value to be either 27 or 28.
           *
           * IMPORTANT: `hash` _must_ be the result of a hash operation for the
           * verification to be secure: it is possible to craft signatures that
           * recover to arbitrary addresses for non-hashed data. A safe way to ensure
           * this is by receiving a hash of the original message (which may otherwise
           * be too long), and then calling {toEthSignedMessageHash} on it.
           *
           * Documentation for signature generation:
           * - with https://web3js.readthedocs.io/en/v1.3.4/web3-eth-accounts.html#sign[Web3.js]
           * - with https://docs.ethers.io/v5/api/signer/#Signer-signMessage[ethers]
           *
           * _Available since v4.3._
           */
          function tryRecover(bytes32 hash, bytes memory signature) internal pure returns (address, RecoverError) {
              if (signature.length == 65) {
                  bytes32 r;
                  bytes32 s;
                  uint8 v;
                  // ecrecover takes the signature parameters, and the only way to get them
                  // currently is to use assembly.
                  /// @solidity memory-safe-assembly
                  assembly {
                      r := mload(add(signature, 0x20))
                      s := mload(add(signature, 0x40))
                      v := byte(0, mload(add(signature, 0x60)))
                  }
                  return tryRecover(hash, v, r, s);
              } else {
                  return (address(0), RecoverError.InvalidSignatureLength);
              }
          }
          /**
           * @dev Returns the address that signed a hashed message (`hash`) with
           * `signature`. This address can then be used for verification purposes.
           *
           * The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
           * this function rejects them by requiring the `s` value to be in the lower
           * half order, and the `v` value to be either 27 or 28.
           *
           * IMPORTANT: `hash` _must_ be the result of a hash operation for the
           * verification to be secure: it is possible to craft signatures that
           * recover to arbitrary addresses for non-hashed data. A safe way to ensure
           * this is by receiving a hash of the original message (which may otherwise
           * be too long), and then calling {toEthSignedMessageHash} on it.
           */
          function recover(bytes32 hash, bytes memory signature) internal pure returns (address) {
              (address recovered, RecoverError error) = tryRecover(hash, signature);
              _throwError(error);
              return recovered;
          }
          /**
           * @dev Overload of {ECDSA-tryRecover} that receives the `r` and `vs` short-signature fields separately.
           *
           * See https://eips.ethereum.org/EIPS/eip-2098[EIP-2098 short signatures]
           *
           * _Available since v4.3._
           */
          function tryRecover(
              bytes32 hash,
              bytes32 r,
              bytes32 vs
          ) internal pure returns (address, RecoverError) {
              bytes32 s = vs & bytes32(0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff);
              uint8 v = uint8((uint256(vs) >> 255) + 27);
              return tryRecover(hash, v, r, s);
          }
          /**
           * @dev Overload of {ECDSA-recover} that receives the `r and `vs` short-signature fields separately.
           *
           * _Available since v4.2._
           */
          function recover(
              bytes32 hash,
              bytes32 r,
              bytes32 vs
          ) internal pure returns (address) {
              (address recovered, RecoverError error) = tryRecover(hash, r, vs);
              _throwError(error);
              return recovered;
          }
          /**
           * @dev Overload of {ECDSA-tryRecover} that receives the `v`,
           * `r` and `s` signature fields separately.
           *
           * _Available since v4.3._
           */
          function tryRecover(
              bytes32 hash,
              uint8 v,
              bytes32 r,
              bytes32 s
          ) internal pure returns (address, RecoverError) {
              // EIP-2 still allows signature malleability for ecrecover(). Remove this possibility and make the signature
              // unique. Appendix F in the Ethereum Yellow paper (https://ethereum.github.io/yellowpaper/paper.pdf), defines
              // the valid range for s in (301): 0 < s < secp256k1n ÷ 2 + 1, and for v in (302): v ∈ {27, 28}. Most
              // signatures from current libraries generate a unique signature with an s-value in the lower half order.
              //
              // If your library generates malleable signatures, such as s-values in the upper range, calculate a new s-value
              // with 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 - s1 and flip v from 27 to 28 or
              // vice versa. If your library also generates signatures with 0/1 for v instead 27/28, add 27 to v to accept
              // these malleable signatures as well.
              if (uint256(s) > 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0) {
                  return (address(0), RecoverError.InvalidSignatureS);
              }
              // If the signature is valid (and not malleable), return the signer address
              address signer = ecrecover(hash, v, r, s);
              if (signer == address(0)) {
                  return (address(0), RecoverError.InvalidSignature);
              }
              return (signer, RecoverError.NoError);
          }
          /**
           * @dev Overload of {ECDSA-recover} that receives the `v`,
           * `r` and `s` signature fields separately.
           */
          function recover(
              bytes32 hash,
              uint8 v,
              bytes32 r,
              bytes32 s
          ) internal pure returns (address) {
              (address recovered, RecoverError error) = tryRecover(hash, v, r, s);
              _throwError(error);
              return recovered;
          }
          /**
           * @dev Returns an Ethereum Signed Message, created from a `hash`. This
           * produces hash corresponding to the one signed with the
           * https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`]
           * JSON-RPC method as part of EIP-191.
           *
           * See {recover}.
           */
          function toEthSignedMessageHash(bytes32 hash) internal pure returns (bytes32) {
              // 32 is the length in bytes of hash,
              // enforced by the type signature above
              return keccak256(abi.encodePacked("\\x19Ethereum Signed Message:\
      32", hash));
          }
          /**
           * @dev Returns an Ethereum Signed Message, created from `s`. This
           * produces hash corresponding to the one signed with the
           * https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`]
           * JSON-RPC method as part of EIP-191.
           *
           * See {recover}.
           */
          function toEthSignedMessageHash(bytes memory s) internal pure returns (bytes32) {
              return keccak256(abi.encodePacked("\\x19Ethereum Signed Message:\
      ", Strings.toString(s.length), s));
          }
          /**
           * @dev Returns an Ethereum Signed Typed Data, created from a
           * `domainSeparator` and a `structHash`. This produces hash corresponding
           * to the one signed with the
           * https://eips.ethereum.org/EIPS/eip-712[`eth_signTypedData`]
           * JSON-RPC method as part of EIP-712.
           *
           * See {recover}.
           */
          function toTypedDataHash(bytes32 domainSeparator, bytes32 structHash) internal pure returns (bytes32) {
              return keccak256(abi.encodePacked("\\x19\\x01", domainSeparator, structHash));
          }
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts (last updated v4.8.0) (utils/cryptography/MerkleProof.sol)
      pragma solidity ^0.8.0;
      /**
       * @dev These functions deal with verification of Merkle Tree proofs.
       *
       * The tree and the proofs can be generated using our
       * https://github.com/OpenZeppelin/merkle-tree[JavaScript library].
       * You will find a quickstart guide in the readme.
       *
       * WARNING: You should avoid using leaf values that are 64 bytes long prior to
       * hashing, or use a hash function other than keccak256 for hashing leaves.
       * This is because the concatenation of a sorted pair of internal nodes in
       * the merkle tree could be reinterpreted as a leaf value.
       * OpenZeppelin's JavaScript library generates merkle trees that are safe
       * against this attack out of the box.
       */
      library MerkleProof {
          /**
           * @dev Returns true if a `leaf` can be proved to be a part of a Merkle tree
           * defined by `root`. For this, a `proof` must be provided, containing
           * sibling hashes on the branch from the leaf to the root of the tree. Each
           * pair of leaves and each pair of pre-images are assumed to be sorted.
           */
          function verify(
              bytes32[] memory proof,
              bytes32 root,
              bytes32 leaf
          ) internal pure returns (bool) {
              return processProof(proof, leaf) == root;
          }
          /**
           * @dev Calldata version of {verify}
           *
           * _Available since v4.7._
           */
          function verifyCalldata(
              bytes32[] calldata proof,
              bytes32 root,
              bytes32 leaf
          ) internal pure returns (bool) {
              return processProofCalldata(proof, leaf) == root;
          }
          /**
           * @dev Returns the rebuilt hash obtained by traversing a Merkle tree up
           * from `leaf` using `proof`. A `proof` is valid if and only if the rebuilt
           * hash matches the root of the tree. When processing the proof, the pairs
           * of leafs & pre-images are assumed to be sorted.
           *
           * _Available since v4.4._
           */
          function processProof(bytes32[] memory proof, bytes32 leaf) internal pure returns (bytes32) {
              bytes32 computedHash = leaf;
              for (uint256 i = 0; i < proof.length; i++) {
                  computedHash = _hashPair(computedHash, proof[i]);
              }
              return computedHash;
          }
          /**
           * @dev Calldata version of {processProof}
           *
           * _Available since v4.7._
           */
          function processProofCalldata(bytes32[] calldata proof, bytes32 leaf) internal pure returns (bytes32) {
              bytes32 computedHash = leaf;
              for (uint256 i = 0; i < proof.length; i++) {
                  computedHash = _hashPair(computedHash, proof[i]);
              }
              return computedHash;
          }
          /**
           * @dev Returns true if the `leaves` can be simultaneously proven to be a part of a merkle tree defined by
           * `root`, according to `proof` and `proofFlags` as described in {processMultiProof}.
           *
           * CAUTION: Not all merkle trees admit multiproofs. See {processMultiProof} for details.
           *
           * _Available since v4.7._
           */
          function multiProofVerify(
              bytes32[] memory proof,
              bool[] memory proofFlags,
              bytes32 root,
              bytes32[] memory leaves
          ) internal pure returns (bool) {
              return processMultiProof(proof, proofFlags, leaves) == root;
          }
          /**
           * @dev Calldata version of {multiProofVerify}
           *
           * CAUTION: Not all merkle trees admit multiproofs. See {processMultiProof} for details.
           *
           * _Available since v4.7._
           */
          function multiProofVerifyCalldata(
              bytes32[] calldata proof,
              bool[] calldata proofFlags,
              bytes32 root,
              bytes32[] memory leaves
          ) internal pure returns (bool) {
              return processMultiProofCalldata(proof, proofFlags, leaves) == root;
          }
          /**
           * @dev Returns the root of a tree reconstructed from `leaves` and sibling nodes in `proof`. The reconstruction
           * proceeds by incrementally reconstructing all inner nodes by combining a leaf/inner node with either another
           * leaf/inner node or a proof sibling node, depending on whether each `proofFlags` item is true or false
           * respectively.
           *
           * CAUTION: Not all merkle trees admit multiproofs. To use multiproofs, it is sufficient to ensure that: 1) the tree
           * is complete (but not necessarily perfect), 2) the leaves to be proven are in the opposite order they are in the
           * tree (i.e., as seen from right to left starting at the deepest layer and continuing at the next layer).
           *
           * _Available since v4.7._
           */
          function processMultiProof(
              bytes32[] memory proof,
              bool[] memory proofFlags,
              bytes32[] memory leaves
          ) internal pure returns (bytes32 merkleRoot) {
              // This function rebuild the root hash by traversing the tree up from the leaves. The root is rebuilt by
              // consuming and producing values on a queue. The queue starts with the `leaves` array, then goes onto the
              // `hashes` array. At the end of the process, the last hash in the `hashes` array should contain the root of
              // the merkle tree.
              uint256 leavesLen = leaves.length;
              uint256 totalHashes = proofFlags.length;
              // Check proof validity.
              require(leavesLen + proof.length - 1 == totalHashes, "MerkleProof: invalid multiproof");
              // The xxxPos values are "pointers" to the next value to consume in each array. All accesses are done using
              // `xxx[xxxPos++]`, which return the current value and increment the pointer, thus mimicking a queue's "pop".
              bytes32[] memory hashes = new bytes32[](totalHashes);
              uint256 leafPos = 0;
              uint256 hashPos = 0;
              uint256 proofPos = 0;
              // At each step, we compute the next hash using two values:
              // - a value from the "main queue". If not all leaves have been consumed, we get the next leaf, otherwise we
              //   get the next hash.
              // - depending on the flag, either another value for the "main queue" (merging branches) or an element from the
              //   `proof` array.
              for (uint256 i = 0; i < totalHashes; i++) {
                  bytes32 a = leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++];
                  bytes32 b = proofFlags[i] ? leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++] : proof[proofPos++];
                  hashes[i] = _hashPair(a, b);
              }
              if (totalHashes > 0) {
                  return hashes[totalHashes - 1];
              } else if (leavesLen > 0) {
                  return leaves[0];
              } else {
                  return proof[0];
              }
          }
          /**
           * @dev Calldata version of {processMultiProof}.
           *
           * CAUTION: Not all merkle trees admit multiproofs. See {processMultiProof} for details.
           *
           * _Available since v4.7._
           */
          function processMultiProofCalldata(
              bytes32[] calldata proof,
              bool[] calldata proofFlags,
              bytes32[] memory leaves
          ) internal pure returns (bytes32 merkleRoot) {
              // This function rebuild the root hash by traversing the tree up from the leaves. The root is rebuilt by
              // consuming and producing values on a queue. The queue starts with the `leaves` array, then goes onto the
              // `hashes` array. At the end of the process, the last hash in the `hashes` array should contain the root of
              // the merkle tree.
              uint256 leavesLen = leaves.length;
              uint256 totalHashes = proofFlags.length;
              // Check proof validity.
              require(leavesLen + proof.length - 1 == totalHashes, "MerkleProof: invalid multiproof");
              // The xxxPos values are "pointers" to the next value to consume in each array. All accesses are done using
              // `xxx[xxxPos++]`, which return the current value and increment the pointer, thus mimicking a queue's "pop".
              bytes32[] memory hashes = new bytes32[](totalHashes);
              uint256 leafPos = 0;
              uint256 hashPos = 0;
              uint256 proofPos = 0;
              // At each step, we compute the next hash using two values:
              // - a value from the "main queue". If not all leaves have been consumed, we get the next leaf, otherwise we
              //   get the next hash.
              // - depending on the flag, either another value for the "main queue" (merging branches) or an element from the
              //   `proof` array.
              for (uint256 i = 0; i < totalHashes; i++) {
                  bytes32 a = leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++];
                  bytes32 b = proofFlags[i] ? leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++] : proof[proofPos++];
                  hashes[i] = _hashPair(a, b);
              }
              if (totalHashes > 0) {
                  return hashes[totalHashes - 1];
              } else if (leavesLen > 0) {
                  return leaves[0];
              } else {
                  return proof[0];
              }
          }
          function _hashPair(bytes32 a, bytes32 b) private pure returns (bytes32) {
              return a < b ? _efficientHash(a, b) : _efficientHash(b, a);
          }
          function _efficientHash(bytes32 a, bytes32 b) private pure returns (bytes32 value) {
              /// @solidity memory-safe-assembly
              assembly {
                  mstore(0x00, a)
                  mstore(0x20, b)
                  value := keccak256(0x00, 0x40)
              }
          }
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts (last updated v4.8.0) (utils/math/Math.sol)
      pragma solidity ^0.8.0;
      /**
       * @dev Standard math utilities missing in the Solidity language.
       */
      library Math {
          enum Rounding {
              Down, // Toward negative infinity
              Up, // Toward infinity
              Zero // Toward zero
          }
          /**
           * @dev Returns the largest of two numbers.
           */
          function max(uint256 a, uint256 b) internal pure returns (uint256) {
              return a > b ? a : b;
          }
          /**
           * @dev Returns the smallest of two numbers.
           */
          function min(uint256 a, uint256 b) internal pure returns (uint256) {
              return a < b ? a : b;
          }
          /**
           * @dev Returns the average of two numbers. The result is rounded towards
           * zero.
           */
          function average(uint256 a, uint256 b) internal pure returns (uint256) {
              // (a + b) / 2 can overflow.
              return (a & b) + (a ^ b) / 2;
          }
          /**
           * @dev Returns the ceiling of the division of two numbers.
           *
           * This differs from standard division with `/` in that it rounds up instead
           * of rounding down.
           */
          function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {
              // (a + b - 1) / b can overflow on addition, so we distribute.
              return a == 0 ? 0 : (a - 1) / b + 1;
          }
          /**
           * @notice Calculates floor(x * y / denominator) with full precision. Throws if result overflows a uint256 or denominator == 0
           * @dev Original credit to Remco Bloemen under MIT license (https://xn--2-umb.com/21/muldiv)
           * with further edits by Uniswap Labs also under MIT license.
           */
          function mulDiv(
              uint256 x,
              uint256 y,
              uint256 denominator
          ) internal pure returns (uint256 result) {
              unchecked {
                  // 512-bit multiply [prod1 prod0] = x * y. Compute the product mod 2^256 and mod 2^256 - 1, then use
                  // use the Chinese Remainder Theorem to reconstruct the 512 bit result. The result is stored in two 256
                  // variables such that product = prod1 * 2^256 + prod0.
                  uint256 prod0; // Least significant 256 bits of the product
                  uint256 prod1; // Most significant 256 bits of the product
                  assembly {
                      let mm := mulmod(x, y, not(0))
                      prod0 := mul(x, y)
                      prod1 := sub(sub(mm, prod0), lt(mm, prod0))
                  }
                  // Handle non-overflow cases, 256 by 256 division.
                  if (prod1 == 0) {
                      return prod0 / denominator;
                  }
                  // Make sure the result is less than 2^256. Also prevents denominator == 0.
                  require(denominator > prod1);
                  ///////////////////////////////////////////////
                  // 512 by 256 division.
                  ///////////////////////////////////////////////
                  // Make division exact by subtracting the remainder from [prod1 prod0].
                  uint256 remainder;
                  assembly {
                      // Compute remainder using mulmod.
                      remainder := mulmod(x, y, denominator)
                      // Subtract 256 bit number from 512 bit number.
                      prod1 := sub(prod1, gt(remainder, prod0))
                      prod0 := sub(prod0, remainder)
                  }
                  // Factor powers of two out of denominator and compute largest power of two divisor of denominator. Always >= 1.
                  // See https://cs.stackexchange.com/q/138556/92363.
                  // Does not overflow because the denominator cannot be zero at this stage in the function.
                  uint256 twos = denominator & (~denominator + 1);
                  assembly {
                      // Divide denominator by twos.
                      denominator := div(denominator, twos)
                      // Divide [prod1 prod0] by twos.
                      prod0 := div(prod0, twos)
                      // Flip twos such that it is 2^256 / twos. If twos is zero, then it becomes one.
                      twos := add(div(sub(0, twos), twos), 1)
                  }
                  // Shift in bits from prod1 into prod0.
                  prod0 |= prod1 * twos;
                  // Invert denominator mod 2^256. Now that denominator is an odd number, it has an inverse modulo 2^256 such
                  // that denominator * inv = 1 mod 2^256. Compute the inverse by starting with a seed that is correct for
                  // four bits. That is, denominator * inv = 1 mod 2^4.
                  uint256 inverse = (3 * denominator) ^ 2;
                  // Use the Newton-Raphson iteration to improve the precision. Thanks to Hensel's lifting lemma, this also works
                  // in modular arithmetic, doubling the correct bits in each step.
                  inverse *= 2 - denominator * inverse; // inverse mod 2^8
                  inverse *= 2 - denominator * inverse; // inverse mod 2^16
                  inverse *= 2 - denominator * inverse; // inverse mod 2^32
                  inverse *= 2 - denominator * inverse; // inverse mod 2^64
                  inverse *= 2 - denominator * inverse; // inverse mod 2^128
                  inverse *= 2 - denominator * inverse; // inverse mod 2^256
                  // Because the division is now exact we can divide by multiplying with the modular inverse of denominator.
                  // This will give us the correct result modulo 2^256. Since the preconditions guarantee that the outcome is
                  // less than 2^256, this is the final result. We don't need to compute the high bits of the result and prod1
                  // is no longer required.
                  result = prod0 * inverse;
                  return result;
              }
          }
          /**
           * @notice Calculates x * y / denominator with full precision, following the selected rounding direction.
           */
          function mulDiv(
              uint256 x,
              uint256 y,
              uint256 denominator,
              Rounding rounding
          ) internal pure returns (uint256) {
              uint256 result = mulDiv(x, y, denominator);
              if (rounding == Rounding.Up && mulmod(x, y, denominator) > 0) {
                  result += 1;
              }
              return result;
          }
          /**
           * @dev Returns the square root of a number. If the number is not a perfect square, the value is rounded down.
           *
           * Inspired by Henry S. Warren, Jr.'s "Hacker's Delight" (Chapter 11).
           */
          function sqrt(uint256 a) internal pure returns (uint256) {
              if (a == 0) {
                  return 0;
              }
              // For our first guess, we get the biggest power of 2 which is smaller than the square root of the target.
              //
              // We know that the "msb" (most significant bit) of our target number `a` is a power of 2 such that we have
              // `msb(a) <= a < 2*msb(a)`. This value can be written `msb(a)=2**k` with `k=log2(a)`.
              //
              // This can be rewritten `2**log2(a) <= a < 2**(log2(a) + 1)`
              // → `sqrt(2**k) <= sqrt(a) < sqrt(2**(k+1))`
              // → `2**(k/2) <= sqrt(a) < 2**((k+1)/2) <= 2**(k/2 + 1)`
              //
              // Consequently, `2**(log2(a) / 2)` is a good first approximation of `sqrt(a)` with at least 1 correct bit.
              uint256 result = 1 << (log2(a) >> 1);
              // At this point `result` is an estimation with one bit of precision. We know the true value is a uint128,
              // since it is the square root of a uint256. Newton's method converges quadratically (precision doubles at
              // every iteration). We thus need at most 7 iteration to turn our partial result with one bit of precision
              // into the expected uint128 result.
              unchecked {
                  result = (result + a / result) >> 1;
                  result = (result + a / result) >> 1;
                  result = (result + a / result) >> 1;
                  result = (result + a / result) >> 1;
                  result = (result + a / result) >> 1;
                  result = (result + a / result) >> 1;
                  result = (result + a / result) >> 1;
                  return min(result, a / result);
              }
          }
          /**
           * @notice Calculates sqrt(a), following the selected rounding direction.
           */
          function sqrt(uint256 a, Rounding rounding) internal pure returns (uint256) {
              unchecked {
                  uint256 result = sqrt(a);
                  return result + (rounding == Rounding.Up && result * result < a ? 1 : 0);
              }
          }
          /**
           * @dev Return the log in base 2, rounded down, of a positive value.
           * Returns 0 if given 0.
           */
          function log2(uint256 value) internal pure returns (uint256) {
              uint256 result = 0;
              unchecked {
                  if (value >> 128 > 0) {
                      value >>= 128;
                      result += 128;
                  }
                  if (value >> 64 > 0) {
                      value >>= 64;
                      result += 64;
                  }
                  if (value >> 32 > 0) {
                      value >>= 32;
                      result += 32;
                  }
                  if (value >> 16 > 0) {
                      value >>= 16;
                      result += 16;
                  }
                  if (value >> 8 > 0) {
                      value >>= 8;
                      result += 8;
                  }
                  if (value >> 4 > 0) {
                      value >>= 4;
                      result += 4;
                  }
                  if (value >> 2 > 0) {
                      value >>= 2;
                      result += 2;
                  }
                  if (value >> 1 > 0) {
                      result += 1;
                  }
              }
              return result;
          }
          /**
           * @dev Return the log in base 2, following the selected rounding direction, of a positive value.
           * Returns 0 if given 0.
           */
          function log2(uint256 value, Rounding rounding) internal pure returns (uint256) {
              unchecked {
                  uint256 result = log2(value);
                  return result + (rounding == Rounding.Up && 1 << result < value ? 1 : 0);
              }
          }
          /**
           * @dev Return the log in base 10, rounded down, of a positive value.
           * Returns 0 if given 0.
           */
          function log10(uint256 value) internal pure returns (uint256) {
              uint256 result = 0;
              unchecked {
                  if (value >= 10**64) {
                      value /= 10**64;
                      result += 64;
                  }
                  if (value >= 10**32) {
                      value /= 10**32;
                      result += 32;
                  }
                  if (value >= 10**16) {
                      value /= 10**16;
                      result += 16;
                  }
                  if (value >= 10**8) {
                      value /= 10**8;
                      result += 8;
                  }
                  if (value >= 10**4) {
                      value /= 10**4;
                      result += 4;
                  }
                  if (value >= 10**2) {
                      value /= 10**2;
                      result += 2;
                  }
                  if (value >= 10**1) {
                      result += 1;
                  }
              }
              return result;
          }
          /**
           * @dev Return the log in base 10, following the selected rounding direction, of a positive value.
           * Returns 0 if given 0.
           */
          function log10(uint256 value, Rounding rounding) internal pure returns (uint256) {
              unchecked {
                  uint256 result = log10(value);
                  return result + (rounding == Rounding.Up && 10**result < value ? 1 : 0);
              }
          }
          /**
           * @dev Return the log in base 256, rounded down, of a positive value.
           * Returns 0 if given 0.
           *
           * Adding one to the result gives the number of pairs of hex symbols needed to represent `value` as a hex string.
           */
          function log256(uint256 value) internal pure returns (uint256) {
              uint256 result = 0;
              unchecked {
                  if (value >> 128 > 0) {
                      value >>= 128;
                      result += 16;
                  }
                  if (value >> 64 > 0) {
                      value >>= 64;
                      result += 8;
                  }
                  if (value >> 32 > 0) {
                      value >>= 32;
                      result += 4;
                  }
                  if (value >> 16 > 0) {
                      value >>= 16;
                      result += 2;
                  }
                  if (value >> 8 > 0) {
                      result += 1;
                  }
              }
              return result;
          }
          /**
           * @dev Return the log in base 10, following the selected rounding direction, of a positive value.
           * Returns 0 if given 0.
           */
          function log256(uint256 value, Rounding rounding) internal pure returns (uint256) {
              unchecked {
                  uint256 result = log256(value);
                  return result + (rounding == Rounding.Up && 1 << (result * 8) < value ? 1 : 0);
              }
          }
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts (last updated v4.8.0) (utils/Strings.sol)
      pragma solidity ^0.8.0;
      import "./math/Math.sol";
      /**
       * @dev String operations.
       */
      library Strings {
          bytes16 private constant _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) {
              unchecked {
                  uint256 length = Math.log10(value) + 1;
                  string memory buffer = new string(length);
                  uint256 ptr;
                  /// @solidity memory-safe-assembly
                  assembly {
                      ptr := add(buffer, add(32, length))
                  }
                  while (true) {
                      ptr--;
                      /// @solidity memory-safe-assembly
                      assembly {
                          mstore8(ptr, byte(mod(value, 10), _SYMBOLS))
                      }
                      value /= 10;
                      if (value == 0) break;
                  }
                  return buffer;
              }
          }
          /**
           * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
           */
          function toHexString(uint256 value) internal pure returns (string memory) {
              unchecked {
                  return toHexString(value, Math.log256(value) + 1);
              }
          }
          /**
           * @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] = _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);
          }
      }
      //SPDX-License-Identifier: MIT
      pragma solidity ^0.8.19;
      interface INFT {
          function mint(
              uint256[] calldata _quantity,
              address[] calldata _address
          ) external payable;
          function balanceOf(address _owner) external view;
      }
      //SPDX-License-Identifier: MIT
      pragma solidity ^0.8.19;
      import "@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol";
      import "@openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol";
      import "@openzeppelin/contracts-upgradeable/security/ReentrancyGuardUpgradeable.sol";
      import "@openzeppelin/contracts/utils/cryptography/MerkleProof.sol";
      import "@openzeppelin/contracts/utils/cryptography/ECDSA.sol";
      import "./interfaces/INFT.sol";
      //  ===========================================================================================
      //  #     #               ######
      //  #     # ###### ###### #     #  ####  #    #  ####
      //  #     # #      #      #     # #    # ##   # #    #
      //  ####### #####  #####  #     # #    # # #  # #
      //  #     # #      #      #     # #    # #  # # #  ###
      //  #     # #      #      #     # #    # #   ## #    #
      //  #     # ###### ###### ######   ####  #    #  ####
      //
      //  Welcome to the geeky side of HeeDong. There may or may not be an easter egg in this code.
      //  If you find one, please let me know. I would love to hear from you.
      //  ===========================================================================================
      /**
       * @title HeeDongWaitlist
       * @author @loocurse
       * @author @0xBuooy (buooy.eth)
       * @dev in order for the contract to work, the following steps must be taken:
       * 1. set the signer address
       * 2. set the finance wallet address
       * 3. set the collection to mint
       * 4. set the batches
       * 5a. ensure for each batch, the maxReservedQuantity is more than the expected allowed
       * 5b. ensure for each batch, the maxTotalQuantity is more than the expected allowed
       * 6. start the waitlist
       * 7. end the waitlist
       * 8. start the refund
       * 9. end the refund
       * 10. mint the NFTs
       */
      contract Waitlist is
          Initializable,
          ReentrancyGuardUpgradeable,
          OwnableUpgradeable
      {
          using ECDSA for bytes32;
          INFT public collectionToMint;
          address public financeWalletAddress;
          address public signer;
          bytes32 private merkleRootForWonItemsCount;
          enum State {
              NOT_STARTED,
              WAITLIST_STARTED,
              WAITLIST_ENDED,
              REFUND_STARTED,
              REFUND_ENDED
          }
          State public state;
          struct Batch {
              uint256 price;
              uint32 startDateTime;
              uint32 endDateTime;
              uint32 padding1;
              uint16 maxTotalQuantity; // up to 65535
              uint16 totalReservedQuantity; // up to 65535
              uint8 maxReservedQuantity; // up to 255
              bool requiresSignature;
              uint8 padding2; // storage padding
              uint16 padding3; // storage padding
          }
          Batch[] public batches;
          struct Reserved {
              uint8 batch;
              uint8 quantity;
              address holdingWallet;
              uint80 timestamp;
          }
          mapping(uint8 => mapping(address => Reserved)) public participantReserved;
          mapping(address => bool) public isParticipantRefunded;
          address[] public participants;
          Reserved[] public reservations;
          //  ============================================================
          //  Events
          //  ============================================================
          event ParticipantEnteredWaitlist(
              address indexed participant,
              uint8 quantity,
              uint8 batch
          );
          event ParticipantRefunded(
              address indexed participant,
              uint256 amount,
              uint256[] indexed quantity
          );
          /// @custom:oz-upgrades-unsafe-allow constructor
          constructor() {
              _disableInitializers();
          }
          function initialize(address _signer) public initializer {
              ReentrancyGuardUpgradeable.__ReentrancyGuard_init();
              OwnableUpgradeable.__Ownable_init();
              signer = _signer;
          }
          //  ============================================================
          //  Reserve Management
          //  ============================================================
          function reserve(
              uint8 _quantity,
              uint8 _maxQuantity,
              uint8 _batch,
              address _holdingWallet,
              bytes memory _signature
          ) external payable nonReentrant {
              _mintChecker(_quantity, _maxQuantity, _batch, _signature);
              Reserved memory reservation = Reserved({
                  batch: _batch,
                  quantity: _quantity,
                  holdingWallet: _holdingWallet,
                  timestamp: uint80(block.timestamp)
              });
              participantReserved[_batch][msg.sender] = reservation;
              reservations.push(reservation);
              emit ParticipantEnteredWaitlist(_holdingWallet, _quantity, _batch);
              // increase the totalReservedQuantity of the batch
              batches[_batch].totalReservedQuantity += _quantity;
          }
          /// @dev checks if the participant has reserved
          /// @return reserved details
          function getParticipantReserved(
              uint8 _batch
          ) external view returns (Reserved memory) {
              return participantReserved[_batch][msg.sender];
          }
          function getReservations() external view returns (Reserved[] memory) {
              Reserved[] memory localReservations = new Reserved[](reservations.length);
              for (uint256 i; i < reservations.length; i++) {
                  localReservations[i] = reservations[i];
              }
              return localReservations;
          }
          //  ============================================================
          //  Won Items Count Verification
          //  ============================================================
          /// @dev returns the merkle root for the won items count
          /// @return merkle root for the won items count
          function getMerkleRootForWonItemsCount()
              external
              view
              onlyOwner
              returns (bytes32)
          {
              return merkleRootForWonItemsCount;
          }
          /// @dev sets the merkle root for the won items count
          /// @param _merkleRoot merkle root for the won items count
          function setMerkleRootForWonItemsCount(
              bytes32 _merkleRoot
          ) external onlyOwner {
              merkleRootForWonItemsCount = _merkleRoot;
          }
          /// @dev verifies the won items count
          /// @param proof merkle proof
          /// @param wonItemsCount won items count
          function verifyWonItemsCount(
              bytes32[] calldata proof,
              uint256[] calldata wonItemsCount
          ) public view returns (bool) {
              bytes32 leaf = keccak256(
                  bytes.concat(keccak256(abi.encode(msg.sender, wonItemsCount)))
              );
              return MerkleProof.verify(proof, merkleRootForWonItemsCount, leaf);
          }
          //  ============================================================
          //  Financial Management
          //  ============================================================
          /// @dev allows participant to refund to their wallet
          /// @param proof merkle proof
          /// @param wonItemsCount won items count
          function refund(
              bytes32[] calldata proof,
              uint256[] calldata wonItemsCount
          ) external nonReentrant {
              require(state == State.REFUND_STARTED, "Refund not started yet");
              require(!isParticipantRefunded[msg.sender], "Already refunded");
              require(
                  verifyWonItemsCount(proof, wonItemsCount),
                  "Wrong won items count"
              );
              uint256 totalRefundAmount;
              for (uint8 i; i < batches.length; i++) {
                  totalRefundAmount +=
                      (participantReserved[i][msg.sender].quantity -
                          wonItemsCount[i]) *
                      batches[i].price;
              }
              require(totalRefundAmount > 0, "No refund needed");
              isParticipantRefunded[msg.sender] = true;
              emit ParticipantRefunded(msg.sender, totalRefundAmount, wonItemsCount);
              _withdraw(msg.sender, totalRefundAmount);
          }
          /// @dev withdraw all proceeds to the finance wallet
          function withdrawAll() external onlyOwner {
              require(financeWalletAddress != address(0), "Finance wallet not set");
              require(state >= State.REFUND_ENDED, "Refund not ended");
              _withdraw(financeWalletAddress, address(this).balance);
          }
          /// @dev withdraws a fixed amount to the given address
          /// @param _address address to withdraw to
          /// @param _amount amount to withdraw
          function _withdraw(address _address, uint256 _amount) private {
              (bool success, ) = _address.call{value: _amount}("");
              require(success, "cant withdraw");
          }
          /// @dev sets the finance wallet address
          /// @param _financeWalletAddress address of the finance wallet
          function setFinanceWalletAddress(
              address _financeWalletAddress
          ) external onlyOwner {
              financeWalletAddress = _financeWalletAddress;
          }
          //  ============================================================
          //  Refund Management
          //  ============================================================
          function getIsParticipantRefunded(
              address participant
          ) external view returns (bool) {
              return isParticipantRefunded[participant];
          }
          function getRefundStatus()
              external
              view
              returns (address[] memory, bool[] memory)
          {
              bool[] memory _isParticipantRefunded = new bool[](participants.length);
              for (uint256 i; i < participants.length; i++) {
                  _isParticipantRefunded[i] = isParticipantRefunded[participants[i]];
              }
              return (participants, _isParticipantRefunded);
          }
          //  ============================================================
          //  Batch Management
          //  ============================================================
          /// @dev upserts the batch
          /// @param _batchIndex batch index
          /// @param _requiresSignature whether the batch requires a signature
          /// @param _maxReservedQuantity max mint quantity allowed for this batch
          /// @param _maxTotalQuantity maxmium total quantity of the batch that can be reserved
          /// @param _price price per item
          /// @param _startDateTime start date time
          /// @param _endDateTime end date time
          function setBatch(
              uint8 _batchIndex,
              bool _requiresSignature,
              uint8 _maxReservedQuantity,
              uint16 _maxTotalQuantity,
              uint256 _price,
              uint256 _startDateTime,
              uint256 _endDateTime
          ) external onlyOwner {
              // Checks if the batch index is out of range.
              // If so, it creates a new batch, that disregards the batch index
              if (batches.length <= _batchIndex) {
                  batches.push(
                      Batch({
                          requiresSignature: _requiresSignature,
                          padding1: 0,
                          padding2: 0,
                          padding3: 0,
                          maxTotalQuantity: _maxTotalQuantity,
                          maxReservedQuantity: _maxReservedQuantity,
                          price: _price,
                          startDateTime: uint32(_startDateTime),
                          endDateTime: uint32(_endDateTime),
                          totalReservedQuantity: 0
                      })
                  );
              } else {
                  batches[_batchIndex] = Batch({
                      requiresSignature: _requiresSignature,
                      maxTotalQuantity: _maxTotalQuantity,
                      maxReservedQuantity: _maxReservedQuantity,
                      price: _price,
                      startDateTime: uint32(_startDateTime),
                      endDateTime: uint32(_endDateTime),
                      totalReservedQuantity: 0,
                      padding1: 0,
                      padding2: 0,
                      padding3: 0
                  });
              }
          }
          function getBatches() external view returns (Batch[] memory) {
              Batch[] memory _batches = new Batch[](batches.length);
              for (uint256 i; i < batches.length; i++) {
                  _batches[i] = batches[i];
              }
              return _batches;
          }
          //  ============================================================
          //  Waitlist Checker
          //  ============================================================
          /// @dev sets the signer address
          /// @param _signer address of the signer
          function setSigner(address _signer) external onlyOwner {
              signer = _signer;
          }
          /// @dev checks if the mint is valid
          /// @param _quantity the quantity of the mint
          /// @param _maxQuantity the max quantity of the mint
          /// @param _batch the batch of the mint
          /// @param _signature the signature of the mint
          function _mintChecker(
              uint8 _quantity,
              uint8 _maxQuantity,
              uint8 _batch,
              bytes memory _signature
          ) internal {
              // =========================================================================
              // Batch Checks
              // =========================================================================
              require(state == State.WAITLIST_STARTED, "Not started yet");
              require(_batch < batches.length, "Batch does not exist");
              // checks if mint batch is active
              require(
                  batches[_batch].startDateTime <= block.timestamp,
                  "Batch not open yet"
              );
              require(
                  batches[_batch].endDateTime > block.timestamp,
                  "Batch is closed"
              );
              // =========================================================================
              // Quantity Checks
              // =========================================================================
              require(_quantity > 0, "Quantity must be > 0");
              // Checks if the user has already reserved
              require(
                  participantReserved[_batch][msg.sender].quantity == 0,
                  "Already reserved"
              );
              // checks if batch allows more reservations
              require(
                  batches[_batch].maxTotalQuantity >=
                      batches[_batch].totalReservedQuantity + _quantity,
                  "Exceeds batch total quantity"
              );
              require(
                  batches[_batch].maxReservedQuantity >= _quantity,
                  "Exceed batch max mint quantity"
              );
              // checks if max quantity is honoured
              require(_maxQuantity >= _quantity, "Exceed allowed max mint quantity");
              // =========================================================================
              // Finance Checks
              // =========================================================================
              // checks if sufficient eth is sent
              require(
                  msg.value == batches[_batch].price * _quantity,
                  "Insufficient funds"
              );
              // =========================================================================
              // Signature Checks
              // =========================================================================
              if (batches[_batch].requiresSignature) {
                  // checks if signature is valid
                  bytes32 messagehash = keccak256(
                      abi.encodePacked(_batch, _maxQuantity, msg.sender)
                  );
                  address _signer = messagehash.toEthSignedMessageHash().recover(
                      _signature
                  );
                  require(_signer == signer, "Invalid Signature");
              }
          }
          //  ============================================================
          //  Administrative Function
          //  ============================================================
          /// @dev sets the collectionToMint address
          /// @param _collectionAddress address of the collectionToMint contract
          function setCollection(address _collectionAddress) external onlyOwner {
              collectionToMint = INFT(_collectionAddress);
          }
          /// @dev sets the state
          /// @param _state state to set
          function setState(State _state) external onlyOwner {
              state = _state;
          }
      }