Contract Source Code:

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (access/Ownable.sol)

pragma solidity ^0.8.0;

import "../utils/Context.sol";

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_msgSender());
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby disabling 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);
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.4) (utils/Context.sol)

pragma solidity ^0.8.0;

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

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

    function _contextSuffixLength() internal view virtual returns (uint256) {
        return 0;
    }
}

// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.0;

import "./EntropyStructs.sol";

interface EntropyEvents {
    event Registered(EntropyStructs.ProviderInfo provider);

    event Requested(EntropyStructs.Request request);
    event RequestedWithCallback(
        address indexed provider,
        address indexed requestor,
        uint64 indexed sequenceNumber,
        bytes32 userRandomNumber,
        EntropyStructs.Request request
    );

    event Revealed(
        EntropyStructs.Request request,
        bytes32 userRevelation,
        bytes32 providerRevelation,
        bytes32 blockHash,
        bytes32 randomNumber
    );
    event RevealedWithCallback(
        EntropyStructs.Request request,
        bytes32 userRandomNumber,
        bytes32 providerRevelation,
        bytes32 randomNumber
    );

    event ProviderFeeUpdated(address provider, uint128 oldFee, uint128 newFee);

    event ProviderUriUpdated(address provider, bytes oldUri, bytes newUri);

    event ProviderFeeManagerUpdated(
        address provider,
        address oldFeeManager,
        address newFeeManager
    );

    event Withdrawal(
        address provider,
        address recipient,
        uint128 withdrawnAmount
    );
}

// SPDX-License-Identifier: Apache 2

pragma solidity ^0.8.0;

contract EntropyStructs {
    struct ProviderInfo {
        uint128 feeInWei;
        uint128 accruedFeesInWei;
        // The commitment that the provider posted to the blockchain, and the sequence number
        // where they committed to this. This value is not advanced after the provider commits,
        // and instead is stored to help providers track where they are in the hash chain.
        bytes32 originalCommitment;
        uint64 originalCommitmentSequenceNumber;
        // Metadata for the current commitment. Providers may optionally use this field to help
        // manage rotations (i.e., to pick the sequence number from the correct hash chain).
        bytes commitmentMetadata;
        // Optional URI where clients can retrieve revelations for the provider.
        // Client SDKs can use this field to automatically determine how to retrieve random values for each provider.
        // TODO: specify the API that must be implemented at this URI
        bytes uri;
        // The first sequence number that is *not* included in the current commitment (i.e., an exclusive end index).
        // The contract maintains the invariant that sequenceNumber <= endSequenceNumber.
        // If sequenceNumber == endSequenceNumber, the provider must rotate their commitment to add additional random values.
        uint64 endSequenceNumber;
        // The sequence number that will be assigned to the next inbound user request.
        uint64 sequenceNumber;
        // The current commitment represents an index/value in the provider's hash chain.
        // These values are used to verify requests for future sequence numbers. Note that
        // currentCommitmentSequenceNumber < sequenceNumber.
        //
        // The currentCommitment advances forward through the provider's hash chain as values
        // are revealed on-chain.
        bytes32 currentCommitment;
        uint64 currentCommitmentSequenceNumber;
        // An address that is authorized to set / withdraw fees on behalf of this provider.
        address feeManager;
    }

    struct Request {
        // Storage slot 1 //
        address provider;
        uint64 sequenceNumber;
        // The number of hashes required to verify the provider revelation.
        uint32 numHashes;
        // Storage slot 2 //
        // The commitment is keccak256(userCommitment, providerCommitment). Storing the hash instead of both saves 20k gas by
        // eliminating 1 store.
        bytes32 commitment;
        // Storage slot 3 //
        // The number of the block where this request was created.
        // Note that we're using a uint64 such that we have an additional space for an address and other fields in
        // this storage slot. Although block.number returns a uint256, 64 bits should be plenty to index all of the
        // blocks ever generated.
        uint64 blockNumber;
        // The address that requested this random number.
        address requester;
        // If true, incorporate the blockhash of blockNumber into the generated random value.
        bool useBlockhash;
        // If true, the requester will be called back with the generated random value.
        bool isRequestWithCallback;
        // There are 2 remaining bytes of free space in this slot.
    }
}

// SPDX-License-Identifier: Apache 2
pragma solidity ^0.8.0;

import "./EntropyEvents.sol";

interface IEntropy is EntropyEvents {
    // Register msg.sender as a randomness provider. The arguments are the provider's configuration parameters
    // and initial commitment. Re-registering the same provider rotates the provider's commitment (and updates
    // the feeInWei).
    //
    // chainLength is the number of values in the hash chain *including* the commitment, that is, chainLength >= 1.
    function register(
        uint128 feeInWei,
        bytes32 commitment,
        bytes calldata commitmentMetadata,
        uint64 chainLength,
        bytes calldata uri
    ) external;

    // Withdraw a portion of the accumulated fees for the provider msg.sender.
    // Calling this function will transfer `amount` wei to the caller (provided that they have accrued a sufficient
    // balance of fees in the contract).
    function withdraw(uint128 amount) external;

    // Withdraw a portion of the accumulated fees for provider. The msg.sender must be the fee manager for this provider.
    // Calling this function will transfer `amount` wei to the caller (provided that they have accrued a sufficient
    // balance of fees in the contract).
    function withdrawAsFeeManager(address provider, uint128 amount) external;

    // As a user, request a random number from `provider`. Prior to calling this method, the user should
    // generate a random number x and keep it secret. The user should then compute hash(x) and pass that
    // as the userCommitment argument. (You may call the constructUserCommitment method to compute the hash.)
    //
    // This method returns a sequence number. The user should pass this sequence number to
    // their chosen provider (the exact method for doing so will depend on the provider) to retrieve the provider's
    // number. The user should then call fulfillRequest to construct the final random number.
    //
    // This method will revert unless the caller provides a sufficient fee (at least getFee(provider)) as msg.value.
    // Note that excess value is *not* refunded to the caller.
    function request(
        address provider,
        bytes32 userCommitment,
        bool useBlockHash
    ) external payable returns (uint64 assignedSequenceNumber);

    // Request a random number. The method expects the provider address and a secret random number
    // in the arguments. It returns a sequence number.
    //
    // The address calling this function should be a contract that inherits from the IEntropyConsumer interface.
    // The `entropyCallback` method on that interface will receive a callback with the generated random number.
    //
    // This method will revert unless the caller provides a sufficient fee (at least getFee(provider)) as msg.value.
    // Note that excess value is *not* refunded to the caller.
    function requestWithCallback(
        address provider,
        bytes32 userRandomNumber
    ) external payable returns (uint64 assignedSequenceNumber);

    // Fulfill a request for a random number. This method validates the provided userRandomness and provider's proof
    // against the corresponding commitments in the in-flight request. If both values are validated, this function returns
    // the corresponding random number.
    //
    // Note that this function can only be called once per in-flight request. Calling this function deletes the stored
    // request information (so that the contract doesn't use a linear amount of storage in the number of requests).
    // If you need to use the returned random number more than once, you are responsible for storing it.
    function reveal(
        address provider,
        uint64 sequenceNumber,
        bytes32 userRevelation,
        bytes32 providerRevelation
    ) external returns (bytes32 randomNumber);

    // Fulfill a request for a random number. This method validates the provided userRandomness
    // and provider's revelation against the corresponding commitment in the in-flight request. If both values are validated
    // and the requestor address is a contract address, this function calls the requester's entropyCallback method with the
    // sequence number, provider address and the random number as arguments. Else if the requestor is an EOA, it won't call it.
    //
    // Note that this function can only be called once per in-flight request. Calling this function deletes the stored
    // request information (so that the contract doesn't use a linear amount of storage in the number of requests).
    // If you need to use the returned random number more than once, you are responsible for storing it.
    //
    // Anyone can call this method to fulfill a request, but the callback will only be made to the original requester.
    function revealWithCallback(
        address provider,
        uint64 sequenceNumber,
        bytes32 userRandomNumber,
        bytes32 providerRevelation
    ) external;

    function getProviderInfo(
        address provider
    ) external view returns (EntropyStructs.ProviderInfo memory info);

    function getDefaultProvider() external view returns (address provider);

    function getRequest(
        address provider,
        uint64 sequenceNumber
    ) external view returns (EntropyStructs.Request memory req);

    function getFee(address provider) external view returns (uint128 feeAmount);

    function getAccruedPythFees()
        external
        view
        returns (uint128 accruedPythFeesInWei);

    function setProviderFee(uint128 newFeeInWei) external;

    function setProviderFeeAsFeeManager(
        address provider,
        uint128 newFeeInWei
    ) external;

    function setProviderUri(bytes calldata newUri) external;

    // Set manager as the fee manager for the provider msg.sender.
    // After calling this function, manager will be able to set the provider's fees and withdraw them.
    // Only one address can be the fee manager for a provider at a time -- calling this function again with a new value
    // will override the previous value. Call this function with the all-zero address to disable the fee manager role.
    function setFeeManager(address manager) external;

    function constructUserCommitment(
        bytes32 userRandomness
    ) external pure returns (bytes32 userCommitment);

    function combineRandomValues(
        bytes32 userRandomness,
        bytes32 providerRandomness,
        bytes32 blockHash
    ) external pure returns (bytes32 combinedRandomness);
}

// SPDX-License-Identifier: Apache 2
pragma solidity ^0.8.0;

abstract contract IEntropyConsumer {
    // This method is called by Entropy to provide the random number to the consumer.
    // It asserts that the msg.sender is the Entropy contract. It is not meant to be
    // override by the consumer.
    function _entropyCallback(
        uint64 sequence,
        address provider,
        bytes32 randomNumber
    ) external {
        address entropy = getEntropy();
        require(entropy != address(0), "Entropy address not set");
        require(msg.sender == entropy, "Only Entropy can call this function");

        entropyCallback(sequence, provider, randomNumber);
    }

    // getEntropy returns Entropy contract address. The method is being used to check that the
    // callback is indeed from Entropy contract. The consumer is expected to implement this method.
    // Entropy address can be found here - https://docs.pyth.network/entropy/contract-addresses
    function getEntropy() internal view virtual returns (address);

    // This method is expected to be implemented by the consumer to handle the random number.
    // It will be called by _entropyCallback after _entropyCallback ensures that the call is
    // indeed from Entropy contract.
    function entropyCallback(
        uint64 sequence,
        address provider,
        bytes32 randomNumber
    ) internal virtual;
}

// SPDX-License-Identifier: MIT
pragma solidity 0.8.19;
import "@openzeppelin/contracts/access/Ownable.sol";
import { IEntropyConsumer } from "@pythnetwork/entropy-sdk-solidity/IEntropyConsumer.sol";
import { IEntropy } from "@pythnetwork/entropy-sdk-solidity/IEntropy.sol";

contract TestPythCallback is IEntropyConsumer, Ownable {
    IEntropy entropy;
    error AmountOfEthSentIsTooSmall(uint256 sent, uint256 minimum);
    event RequestSent(uint256 requestId);
    event RequestFulfilled(uint64 requestId, address provider, bytes32 randomNumber);
    // @param entropyAddress The address of the entropy contract.
    constructor(address entropyAddress) {
        entropy = IEntropy(entropyAddress);
    }
    uint public response;
    // @param userRandomNumber The random number generated by the user.
    function requestRandomNumber(bytes32 userRandomNumber) external payable {
        // Get the default provider and the fee for the request
        (address entropyProvider, uint256 fee) = getEntropyFee();
        if (msg.value < fee) {
            revert AmountOfEthSentIsTooSmall(msg.value, fee);
        }
        // Request the random number with the callback
        uint64 sequenceNumber = entropy.requestWithCallback{ value: fee }(
            entropyProvider,
            userRandomNumber
        );
        emit RequestSent(sequenceNumber);
    }

    // @param sequenceNumber The sequence number of the request.
    // @param provider The address of the provider that generated the random number. If your app uses multiple providers, you can use this argument to distinguish which one is calling the app back.
    // @param randomNumber The generated random number.
    // This method is called by the entropy contract when a random number is generated.
    function entropyCallback(
        uint64 sequenceNumber,
        address provider,
        bytes32 randomNumber
    ) internal override {
        response = uint256(randomNumber);
        emit RequestFulfilled(sequenceNumber, provider, randomNumber);
    }

    // This method is required by the IEntropyConsumer interface.
    // It returns the address of the entropy contract which will call the callback.
    function getEntropy() internal view override returns (address) {
        return address(entropy);
    }

    function getEntropyFee() public view returns (address entropyProvider, uint256 fee) {
        entropyProvider = entropy.getDefaultProvider();
        fee = entropy.getFee(entropyProvider);
    }
}