// File: /home/dave/proof/proof-seller/contracts/sellers/src/presets/TokenHolderAirdropper.sol



// SPDX-License-Identifier: MIT
// Copyright 2023 Proof Holdings Inc.
pragma solidity >=0.8.0 <0.9.0;

import {Math} from "openzeppelin-contracts/utils/math/Math.sol";
import {IERC721} from "openzeppelin-contracts/token/ERC721/IERC721.sol";

import {ISellable} from "proof/sellers/interfaces/ISellable.sol";
import {Seller} from "proof/sellers/base/Seller.sol";
import {ImmutableSellableCallbacker} from "proof/sellers/base/SellableCallbacker.sol";

interface IERC721WithTotalSupply is IERC721 {
    function totalSupply() external view returns (uint256);
}

/**
 * @notice Airdrops sellable tokens to the holders of another, non-burnable token contract.
 */
contract TokenHolderAirdropper is Seller, ImmutableSellableCallbacker {
    /**
     * @notice The token to airdrop to.
     */
    IERC721WithTotalSupply public immutable token;

    /**
     * @notice The number of sellable tokens that have been airdropped.
     */
    uint256 public numAirdropped;

    constructor(IERC721WithTotalSupply token_, ISellable sellable_) ImmutableSellableCallbacker(sellable_) {
        token = token_;
    }

    /**
     * @notice Airdrops a batch of sellable tokens to the holders of `token`.
     * @dev Iterates sequentially through the token IDs of `token`, picking up where the previous call left off, and
     * airdrops a sellable token to each holder.
     * @dev This function assumes that `token` is not burnable.
     * @param num The number of tokens to airdrop.
     */
    function airdrop(uint256 num) public virtual {
        uint256 tokenId = numAirdropped;
        // using the total supply us upper bound for tokenID assumes that `token` is not burnable.
        uint256 endTokenId = Math.min(tokenId + num, token.totalSupply());
        numAirdropped = endTokenId;

        while (tokenId < endTokenId) {
            _purchase(token.ownerOf(tokenId), 1, /* total cost */ 0, "");
            unchecked {
                ++tokenId;
            }
        }
    }
}

// File: /home/dave/.cache/bazel/_bazel_dave/b9a57168317213f9241a484d2ee2d038/external/openzeppelin-contracts_4-8-1/contracts/utils/math/Math.sol



// 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);
        }
    }
}

// File: /home/dave/.cache/bazel/_bazel_dave/b9a57168317213f9241a484d2ee2d038/external/openzeppelin-contracts_4-8-1/contracts/token/ERC721/IERC721.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (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: Note that the caller is responsible to confirm that the recipient is capable of receiving ERC721
     * or else they may be permanently lost. Usage of {safeTransferFrom} prevents loss, though the caller must
     * understand this adds an external call which potentially creates a reentrancy vulnerability.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

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

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

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

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

// File: /home/dave/proof/proof-seller/contracts/sellers/src/interfaces/ISellable.sol



// SPDX-License-Identifier: MIT
// Copyright 2023 PROOF Holdings Inc
pragma solidity >=0.8.0 <0.9.0;

/**
 * @notice Basic interface for a contract providing sellable content.
 */
interface ISellable {
    /**
     * @notice Handles the sale of sellable content.
     * @dev This is usually only callable by Sellers.
     */
    function handleSale(address to, uint64 num, bytes calldata data) external payable;
}

// File: /home/dave/proof/proof-seller/contracts/sellers/src/base/Seller.sol



// SPDX-License-Identifier: MIT
// Copyright 2023 PROOF Holdings Inc
pragma solidity >=0.8.0 <0.9.0;

import {ReentrancyGuard} from "openzeppelin-contracts/security/ReentrancyGuard.sol";
import {PurchaseExecuter} from "../interfaces/PurchaseExecuter.sol";

/**
 * @notice Abstract base contract for all `Seller`s.
 * @dev The intention of this contract is to provide an extensible base for various kinds of Seller modules that can be
 * flexibly composed to build more complex sellers - allowing effective code reuse.
 * Derived contracts are intended to implement their logic by overriding and extending the `_checkAndModifyPurchase` and
 * `_beforePurchase` hooks (calling the parent implementation(s) to compose logic). The former is intended to perform
 * manipulations and checks of the input data; the latter to update the internal state of the module.
 * Final sellers will compose these modules and expose an addition external purchase function for buyers.
 */

abstract contract Seller is PurchaseExecuter, ReentrancyGuard {
    uint256 internal constant _UNDEFINED_COST = type(uint256).max;

    /**
     * @notice Internal function handling a given purchase, performing checks and input manipulations depending on the
     * logic in the hooks.
     * @param to The receiver of the purchase
     * @param num Number of requested purchases
     * @param externalTotalCost Total cost of the purchase
     * @dev This function is intended to be wrapped in an external method for final sellers. Since we cannot foresee
     * what logic will be implemented in the hooks, we added a reentrancy guard for safety.
     */
    function _purchase(address to, uint64 num, uint256 externalTotalCost, bytes memory data)
        internal
        virtual
        nonReentrant
    {
        uint256 totalCost;
        (to, num, totalCost) = _checkAndModifyPurchase(to, num, externalTotalCost, data);
        _beforePurchase(to, num, totalCost, data);
        _executePurchase(to, num, totalCost, data);
    }

    // =================================================================================================================
    //                           Hooks
    // =================================================================================================================

    /**
     * @notice Hook that is called before handling a purchase (even before `_beforePurchase`)
     * @dev The intent of this hook is to manipulate the input data and perform  checks before actually handling the
     * purchase.
     * @param to The receiver of the purchase
     * @param num Number of requested purchases
     * @param totalCost Total cost of the purchase
     * @dev This function MUST return sensible values, since these will be used to perfom the purchase.
     */
    function _checkAndModifyPurchase(address to, uint64 num, uint256 totalCost, bytes memory)
        internal
        view
        virtual
        returns (address, uint64, uint256)
    {
        return (to, num, totalCost);
    }

    /**
     * @notice Hook that is called before handling a purchase.
     * @dev The intent of this hook is to update the internal state of the seller (module) if necessary.
     * It is critical that the updates happen here and not in `_checkAndModifyPurchase` because only after calling that
     * function the purchase parameters can be considered fixed.
     */
    function _beforePurchase(address to, uint64 num, uint256 totalCost, bytes memory data) internal virtual {
        // solhint-disable-line no-empty-blocks
    }
}

// File: /home/dave/proof/proof-seller/contracts/sellers/src/base/SellableCallbacker.sol



// SPDX-License-Identifier: MIT
// Copyright 2023 PROOF Holdings Inc
pragma solidity >=0.8.0 <0.9.0;

import {ISellable} from "../interfaces/ISellable.sol";
import {PurchaseExecuter} from "../interfaces/PurchaseExecuter.sol";

/**
 * @notice Executes a purchase by calling the purchase interface of a `ISellable`  contract.
 */
abstract contract SellableCallbacker is PurchaseExecuter {
    /**
     * @notice Emitted when the callback to the `ISellable` contract fails.
     */
    error CallbackFailed(bytes reason);

    function _sellable(address to, uint64 num, uint256 cost, bytes memory data) internal virtual returns (ISellable);

    /**
     * @notice Executes a purchase by calling the sale interface of a `ISellable` contract.
     */
    function _executePurchase(address to, uint64 num, uint256 cost, bytes memory data) internal virtual override {
        ISellable sellable = _sellable(to, num, cost, data);
        try sellable.handleSale{value: cost}(to, num, data) {}
        catch (bytes memory reason) {
            // TODO(dave): the reason is empty if the above call runs OutOfFund. Explore ways to bubble this up more cleanly.
            revert CallbackFailed(reason);
        }
    }
}

/**
 * @notice Executes a purchase by calling the purchase interface of a `ISellable`  contract.
 */
abstract contract ImmutableSellableCallbacker is SellableCallbacker {
    /**
     * @notice The `ISellable` contract that will be called to execute the purchase.
     */
    ISellable public immutable sellable;

    constructor(ISellable sellable_) {
        sellable = sellable_;
    }

    function _sellable(address, uint64, uint256, bytes memory) internal virtual override returns (ISellable) {
        return sellable;
    }
}

/**
 * @notice Executes a purchase by calling the purchase interface of a `ISellable`  contract.
 */
abstract contract SettableSellableCallbacker is SellableCallbacker {
    /**
     * @notice The `ISellable` contract that will be called to execute the purchase.
     */
    ISellable private _sellable_;

    function _sellable(address, uint64, uint256, bytes memory) internal virtual override returns (ISellable) {
        return _sellable_;
    }

    function _setSellable(ISellable sellable_) internal {
        _sellable_ = sellable_;
    }

    function sellable() public view returns (ISellable) {
        return _sellable_;
    }
}

// File: /home/dave/.cache/bazel/_bazel_dave/b9a57168317213f9241a484d2ee2d038/external/openzeppelin-contracts_4-8-1/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);
}

// File: /home/dave/.cache/bazel/_bazel_dave/b9a57168317213f9241a484d2ee2d038/external/openzeppelin-contracts_4-8-1/contracts/security/ReentrancyGuard.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (security/ReentrancyGuard.sol)

pragma solidity ^0.8.0;

/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 *
 * TIP: If you would like to learn more about reentrancy and alternative ways
 * to protect against it, check out our blog post
 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
 */
abstract contract ReentrancyGuard {
    // Booleans are more expensive than uint256 or any type that takes up a full
    // word because each write operation emits an extra SLOAD to first read the
    // slot's contents, replace the bits taken up by the boolean, and then write
    // back. This is the compiler's defense against contract upgrades and
    // pointer aliasing, and it cannot be disabled.

    // The values being non-zero value makes deployment a bit more expensive,
    // but in exchange the refund on every call to nonReentrant will be lower in
    // amount. Since refunds are capped to a percentage of the total
    // transaction's gas, it is best to keep them low in cases like this one, to
    // increase the likelihood of the full refund coming into effect.
    uint256 private constant _NOT_ENTERED = 1;
    uint256 private constant _ENTERED = 2;

    uint256 private _status;

    constructor() {
        _status = _NOT_ENTERED;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and making it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        _nonReentrantBefore();
        _;
        _nonReentrantAfter();
    }

    function _nonReentrantBefore() private {
        // On the first call to nonReentrant, _status will be _NOT_ENTERED
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

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

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

// File: /home/dave/proof/proof-seller/contracts/sellers/src/interfaces/PurchaseExecuter.sol



// SPDX-License-Identifier: MIT
// Copyright 2023 PROOF Holdings Inc
pragma solidity >=0.8.0 <0.9.0;

/**
 * @notice Interface to execute purchases in `Seller`s.
 * @dev This executes the final purchase. This can be anything from minting ERC721 tokens to transfering funds, etc.
 */
abstract contract PurchaseExecuter {
    function _executePurchase(address to, uint64 num, uint256 cost, bytes memory data) internal virtual;
}