// File: contracts/RandomDistributor.sol



// SPDX-License-Identifier: MIT
// Copyright (c) 2022 Proof Holdings Inc
pragma solidity >=0.8.0 <0.9.0;

import "./NextShuffler.sol";
import "@divergencetech/ethier/contracts/random/PRNG.sol";
import "@openzeppelin/contracts/interfaces/IERC721.sol";
import "@openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol";

/**
@title RandomDistributor
@notice Randomly distributes a set of ERC721 tokens to a set of recipients.
@dev To allow for reuse behind a minimal proxy contract, this contract uses the
upgradeable pattern so has an initialize() function instead of a constructor.
 */
contract RandomDistributor is Initializable, OwnableUpgradeable, NextShuffler {
    using PRNG for PRNG.Source;

    /**
    @dev ERC721 token contract from which tokens are distributed.
     */
    IERC721 token;

    /**
    @dev Initializer in lieu of a constructor.
    @param _token The contract from which tokens will be distributed.
    @param numToDistribute Number of tokens that this RandomDistributor will
    distribute.
     */
    function initialize(IERC721 _token, uint256 numToDistribute)
        public
        initializer
    {
        token = _token;
        OwnableUpgradeable.__Ownable_init();
        NextShuffler.initialize(numToDistribute);
    }

    /**
    @dev A recipient address coupled with the number of tokens they receive.
     */
    struct Recipient {
        address receiver;
        uint96 count;
    }

    /**
    @dev Distributes tokens, randomly selected from the IDs, to the recipients.
    @param from The owner of the tokenIds; which must have allowed this contract
    with setApproveForAll().
    @param recipients Set of recipients receiving a random selection from
    ``tokenIds``, typically different on each call to distribute().
    @param tokenIds The IDs of the tokens to be transferred. These MUST be
    identical on each call to distribute().
     */
    function distribute(
        address from,
        Recipient[] calldata recipients,
        uint256[] calldata tokenIds
    ) external onlyOwner {
        require(
            tokenIds.length == numToShuffle,
            "RandomDistributor: tokenIds.length invalid"
        );

        uint256 shuffled_ = shuffled;
        uint256 numToShuffle_ = numToShuffle;
        {
            uint256 total = 0;
            for (uint256 i = 0; i < recipients.length; ++i) {
                total += uint256(recipients[i].count);
            }
            require(
                shuffled_ + total <= numToShuffle_,
                "RandomDistributor: too many distributed"
            );
            shuffled = shuffled_ + total;
        }

        IERC721 token_ = token;
        PRNG.Source src = PRNG.newSource(
            keccak256(
                abi.encode(
                    block.number,
                    block.coinbase,
                    recipients[0],
                    address(this)
                )
            )
        );

        // This comes straight from the ethier NextShuffler, modified to not
        // require multiple function calls.
        for (uint256 i = 0; i < recipients.length; ++i) {
            uint256 n = uint256(recipients[i].count);
            address to = recipients[i].receiver;

            for (uint256 j = 0; j < n; ++j) {
                uint256 next = src.readLessThan(numToShuffle_ - shuffled_) +
                    shuffled_;

                token_.transferFrom(from, to, tokenIds[_get(next)]);

                _set(next, _get(shuffled_));
                ++shuffled_;
            }
        }
    }
}

// File: @openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (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. Equivalent to `reinitializer(1)`.
     */
    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.
     *
     * `initializer` is equivalent to `reinitializer(1)`, so 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.
     *
     * 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.
     */
    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.
     */
    function _disableInitializers() internal virtual {
        require(!_initializing, "Initializable: contract is initializing");
        if (_initialized < type(uint8).max) {
            _initialized = type(uint8).max;
            emit Initialized(type(uint8).max);
        }
    }
}

// File: @openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol



// 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;
}

// File: @openzeppelin/contracts/interfaces/IERC721.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (interfaces/IERC721.sol)

pragma solidity ^0.8.0;

import "../token/ERC721/IERC721.sol";

// File: @divergencetech/ethier/contracts/random/PRNG.sol



// SPDX-License-Identifier: MIT
// Copyright (c) 2021 the ethier authors (github.com/divergencetech/ethier)
pragma solidity >=0.8.9 <0.9.0;

library PRNG {
    /**
    @notice A source of random numbers.
    @dev Pointer to a 2-word buffer of {carry || number, remaining unread
    bits}. however, note that this is abstracted away by the API and SHOULD NOT
    be used. This layout MUST NOT be considered part of the public API and
    therefore not relied upon even within stable versions.
     */
    type Source is uint256;

    /// @notice The biggest safe prime for modulus 2**128
    uint256 private constant MWC_FACTOR = 2**128 - 10408;

    /// @notice Layout within the buffer. 0x00 is the current (carry || number)
    uint256 private constant REMAIN = 0x20;

    /// @notice Mask for the 128 least significant bits
    uint256 private constant MASK_128_BITS = 0xffffffffffffffffffffffffffffffff;

    /**
    @notice Returns a new deterministic Source, differentiated only by the seed.
    @dev Use of PRNG.Source does NOT provide any unpredictability as generated
    numbers are entirely deterministic. Either a verifiable source of randomness
    such as Chainlink VRF, or a commit-and-reveal protocol MUST be used if
    unpredictability is required. The latter is only appropriate if the contract
    owner can be trusted within the specified threat model.
    @dev The 256bit seed is used to initialize carry || number
     */
    function newSource(bytes32 seed) internal pure returns (Source src) {
        assembly {
            src := mload(0x40)
            mstore(0x40, add(src, 0x40))
            mstore(src, seed)
            mstore(add(src, REMAIN), 128)
        }
        // DO NOT call _refill() on the new Source as newSource() is also used
        // by loadSource(), which implements its own state modifications. The
        // first call to read() on a fresh Source will induce a call to
        // _refill().
    }

    /**
    @dev Computes the next PRN in entropy using a lag-1 multiply-with-carry
    algorithm and resets the remaining bits to 128.
    `nextNumber = (factor * number + carry) mod 2**128`
    `nextCarry  = (factor * number + carry) //  2**128`
     */
    function _refill(Source src) private pure {
        assembly {
            let carryAndNumber := mload(src)
            let rand := and(carryAndNumber, MASK_128_BITS)
            let carry := shr(128, carryAndNumber)
            mstore(src, add(mul(MWC_FACTOR, rand), carry))
            mstore(add(src, REMAIN), 128)
        }
    }

    /**
    @notice Returns the specified number of bits <= 128 from the Source.
    @dev It is safe to cast the returned value to a uint<bits>.
     */
    function read(Source src, uint256 bits)
        internal
        pure
        returns (uint256 sample)
    {
        require(bits <= 128, "PRNG: max 128 bits");

        uint256 remain;
        assembly {
            remain := mload(add(src, REMAIN))
        }
        if (remain > bits) {
            return readWithSufficient(src, bits);
        }

        uint256 extra = bits - remain;
        sample = readWithSufficient(src, remain);
        assembly {
            sample := shl(extra, sample)
        }

        _refill(src);
        sample = sample | readWithSufficient(src, extra);
    }

    /**
    @notice Returns the specified number of bits, assuming that there is
    sufficient entropy remaining. See read() for usage.
     */
    function readWithSufficient(Source src, uint256 bits)
        private
        pure
        returns (uint256 sample)
    {
        assembly {
            let ent := mload(src)
            let rem := add(src, REMAIN)
            let remain := mload(rem)
            sample := shr(sub(256, bits), shl(sub(256, remain), ent))
            mstore(rem, sub(remain, bits))
        }
    }

    /// @notice Returns a random boolean.
    function readBool(Source src) internal pure returns (bool) {
        return read(src, 1) == 1;
    }

    /**
    @notice Returns the number of bits needed to encode n.
    @dev Useful for calling readLessThan() multiple times with the same upper
    bound.
     */
    function bitLength(uint256 n) internal pure returns (uint16 bits) {
        assembly {
            for {
                let _n := n
            } gt(_n, 0) {
                _n := shr(1, _n)
            } {
                bits := add(bits, 1)
            }
        }
    }

    /**
    @notice Returns a uniformly random value in [0,n) with rejection sampling.
    @dev If the size of n is known, prefer readLessThan(Source, uint, uint16) as
    it skips the bit counting performed by this version; see bitLength().
     */
    function readLessThan(Source src, uint256 n)
        internal
        pure
        returns (uint256)
    {
        return readLessThan(src, n, bitLength(n));
    }

    /**
    @notice Returns a uniformly random value in [0,n) with rejection sampling
    from the range [0,2^bits).
    @dev For greatest efficiency, the value of bits should be the smallest
    number of bits required to capture n; if this is not known, use
    readLessThan(Source, uint) or bitLength(). Although rejections are reduced
    by using twice the number of bits, this increases the rate at which the
    entropy pool must be refreshed with a call to `_refill`.

    TODO: benchmark higher number of bits for rejection vs hashing gas cost.
     */
    function readLessThan(
        Source src,
        uint256 n,
        uint16 bits
    ) internal pure returns (uint256 result) {
        // Discard results >= n and try again because using % will bias towards
        // lower values; e.g. if n = 13 and we read 4 bits then {13, 14, 15}%13
        // will select {0, 1, 2} twice as often as the other values.
        // solhint-disable-next-line no-empty-blocks
        for (result = n; result >= n; result = read(src, bits)) {}
    }

    /**
    @notice Returns the internal state of the Source.
    @dev MUST NOT be considered part of the API and is subject to change without
    deprecation nor warning. Only exposed for testing.
     */
    function state(Source src)
        internal
        pure
        returns (uint256 entropy, uint256 remain)
    {
        assembly {
            entropy := mload(src)
            remain := mload(add(src, REMAIN))
        }
    }

    /**
    @notice Stores the state of the Source in a 2-word buffer. See loadSource().
    @dev The layout of the stored state MUST NOT be considered part of the
    public API, and is subject to change without warning. It is therefore only
    safe to rely on stored Sources _within_ contracts, but not _between_ them.
     */
    function store(Source src, uint256[2] storage stored) internal {
        uint256 carryAndNumber;
        uint256 remain;
        assembly {
            carryAndNumber := mload(src)
            remain := mload(add(src, REMAIN))
        }
        stored[0] = carryAndNumber;
        stored[1] = remain;
    }

    /**
    @notice Recreates a Source from the state stored with store().
     */
    function loadSource(uint256[2] storage stored)
        internal
        view
        returns (Source)
    {
        Source src = newSource(bytes32(stored[0]));
        uint256 carryAndNumber = stored[0];
        uint256 remain = stored[1];

        assembly {
            mstore(src, carryAndNumber)
            mstore(add(src, REMAIN), remain)
        }
        return src;
    }
}

// File: contracts/NextShuffler.sol



// SPDX-License-Identifier: MIT
// Copyright (c) 2021 the ethier authors (github.com/divergencetech/ethier)
// Modifications (c) 2022 PROOF Holdings Inc
pragma solidity >=0.8.9 <0.9.0;

import "@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol";

/**
@notice Returns the next value in a shuffled list [0,n), amortising the shuffle
across all calls to _next(). Can be used for randomly allocating a set of tokens
but the caveats in `dev` docs MUST be noted.
@dev Although the final shuffle is uniformly random, it is entirely
deterministic if the seed to the PRNG.Source is known. This MUST NOT be used for
applications that require secure (i.e. can't be manipulated) allocation unless
parties who stand to gain from malicious use have no control over nor knowledge
of the seed at the time that their transaction results in a call to _next().
 */
contract NextShuffler is Initializable {
    /// @notice Total number of elements to shuffle.
    uint256 internal numToShuffle;

    /**
    @notice Initialize the contract, in lieu of a constructor.
    @param numToShuffle_ Total number of elements to shuffle.
     */
    function initialize(uint256 numToShuffle_) internal onlyInitializing {
        numToShuffle = numToShuffle_;
    }

    /**
    @dev Number of items already shuffled; i.e. number of historical calls to
    _next(). This is the equivalent of `i` in the Wikipedia description of the
    Fisher–Yates algorithm.
     */
    uint256 internal shuffled;

    /**
    @dev A sparse representation of the shuffled list [0,n). List items that
    have been shuffled are stored with their original index as the key and their
    new index + 1 as their value. Note that mappings with numerical values
    return 0 for non-existent keys so we MUST increment the new index to
    differentiate between a default value and a new index of 0. See _get() and
    _set().
     */
    mapping(uint256 => uint256) private _permutation;

    /**
    @notice Returns the current value stored in list index `i`, accounting for
    all historical shuffling.
     */
    function _get(uint256 i) internal view returns (uint256) {
        uint256 val = _permutation[i];
        return val == 0 ? i : val - 1;
    }

    /**
    @notice Sets the list index `i` to `val`, equivalent `arr[i] = val` in a
    standard Fisher–Yates shuffle.
     */
    function _set(uint256 i, uint256 val) internal {
        _permutation[i] = i == val ? 0 : val + 1;
    }
}

// File: @openzeppelin/contracts/token/ERC721/IERC721.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (token/ERC721/IERC721.sol)

pragma solidity ^0.8.0;

import "../../utils/introspection/IERC165.sol";

/**
 * @dev Required interface of an ERC721 compliant contract.
 */
interface IERC721 is IERC165 {
    /**
     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
     */
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
     */
    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
     */
    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);

    /**
     * @dev Returns the number of tokens in ``owner``'s account.
     */
    function balanceOf(address owner) external view returns (uint256 balance);

    /**
     * @dev Returns the owner of the `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function ownerOf(uint256 tokenId) external view returns (address owner);

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes calldata data
    ) external;

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
     * are aware of the ERC721 protocol to prevent tokens from being forever locked.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must have been allowed to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

    /**
     * @dev Transfers `tokenId` token from `from` to `to`.
     *
     * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

    /**
     * @dev Gives permission to `to` to transfer `tokenId` token to another account.
     * The approval is cleared when the token is transferred.
     *
     * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
     *
     * Requirements:
     *
     * - The caller must own the token or be an approved operator.
     * - `tokenId` must exist.
     *
     * Emits an {Approval} event.
     */
    function approve(address to, uint256 tokenId) external;

    /**
     * @dev Approve or remove `operator` as an operator for the caller.
     * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
     *
     * Requirements:
     *
     * - The `operator` cannot be the caller.
     *
     * Emits an {ApprovalForAll} event.
     */
    function setApprovalForAll(address operator, bool _approved) external;

    /**
     * @dev Returns the account approved for `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function getApproved(uint256 tokenId) external view returns (address operator);

    /**
     * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
     *
     * See {setApprovalForAll}
     */
    function isApprovedForAll(address owner, address operator) external view returns (bool);
}

// File: @openzeppelin/contracts-upgradeable/utils/AddressUpgradeable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (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 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");

        (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");

        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason 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 {
            // 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);
            }
        }
    }
}

// File: @openzeppelin/contracts-upgradeable/utils/ContextUpgradeable.sol



// 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;
}

// File: @openzeppelin/contracts/utils/introspection/IERC165.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)

pragma solidity ^0.8.0;

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