DRBConsumerBase.sol

// SPDX-License-Identifier: MIT
pragma solidity 0.8.25;

import { IDRBCoordinator } from "../../interfaces/IDRBCoordinator.sol";
import "@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol";

/**
 * @notice Interface for contracts using VRF randomness
 * @dev USAGE
 *
 * @dev Consumer contracts must inherit from VRFConsumerBase, and can
 * @dev initialize Coordinator address in their constructor as
 */
abstract contract DRBConsumerBase {
    error OnlyCoordinatorCanFulfill(address have, address want);

    /// @dev The RNGCoordinator contract
    IDRBCoordinator internal i_drbCoordinator;

    /**
     * @param rngCoordinator The address of the RNGCoordinator contract
     */
    function __DRBConsumerBase_init(address rngCoordinator) internal {
        i_drbCoordinator = IDRBCoordinator(rngCoordinator);
    }

    /**
     * @return directFundingCost cost of funding
     * @return requestId The ID of the request
     * @dev Request Randomness to the Coordinator
     */
    function requestRandomness(uint16 security, uint16 mode, uint32 callbackGasLimit) internal returns (uint256 directFundingCost, uint256 requestId) {
       directFundingCost = i_drbCoordinator.calculateDirectFundingPrice(
            IDRBCoordinator.RandomWordsRequest({security: security, mode: mode, callbackGasLimit: callbackGasLimit})
        );
       requestId = i_drbCoordinator.requestRandomWordDirectFunding{value: directFundingCost}(
            IDRBCoordinator.RandomWordsRequest({security: security, mode: mode, callbackGasLimit: callbackGasLimit})
        );
    }

    /**
     * @param round The round of the randomness
     * @param hashedOmegaVal The hashed value of the random number
     * @dev Callback function for the Coordinator to call after the request is fulfilled.  Override this function in your contract
     */
    function fulfillRandomWords(
        uint256 round,
        uint256 hashedOmegaVal
    ) internal virtual;

    /**
     * @param requestId The round of the randomness
     * @param randomWord The random number
     * @dev Callback function for the Coordinator to call after the request is fulfilled. This function is called by the Coordinator
     */
    function rawFulfillRandomWords(
        uint256 requestId,
        uint256 randomWord
    ) external {
        if (msg.sender != address(i_drbCoordinator)) {
            revert OnlyCoordinatorCanFulfill(
                msg.sender,
                address(i_drbCoordinator)
            );
        }
        fulfillRandomWords(requestId, randomWord);
    }
}