dgf-prototype/ethereum/contracts/Rollup.sol

// SPDX-License-Identifier: Unlicense
pragma solidity ^0.8.24;

import "./core/DAO.sol";
import "./Availability.sol";

contract Rollup is Availability {
    struct BatchItem {
        address sender;
        address worker;
        uint stakeAmount;
        uint fee;
        string postId;
    }

    mapping(uint => BatchItem) public items;
    uint public itemCount;
    address public batchWorker;
    uint batchWorkerStakeIndex;
    uint public immutable batchInterval;
    uint public batchStart;
    uint lastWorkerReset;
    uint constant minResetInterval = 120;

    event BatchItemAdded(string postId, address sender, uint fee);
    event BatchWorkerAssigned(address batchWorker);

    constructor(DAO dao, uint batchInterval_) Availability(dao) {
        batchInterval = batchInterval_;
    }

    /// Instead of initiating a validation pool, call this method to include
    /// the stakes and fee in the next batch validation pool
    function addItem(
        address author,
        uint stakeAmount,
        string calldata postId
    ) public payable {
        BatchItem storage item = items[itemCount++];
        item.sender = msg.sender;
        item.worker = author;
        item.stakeAmount = stakeAmount;
        item.fee = msg.value;
        item.postId = postId;
        emit BatchItemAdded(postId, item.sender, item.fee);
    }

    /// To be called by the currently assigned batch worker,
    /// If no batch worker has been assigned this may be called by anybody,
    /// but it will only succeed if it is able to assign a new worker.
    function submitBatch(
        string calldata batchPostId,
        string[] calldata batchItems,
        uint poolDuration
    ) public returns (uint poolIndex) {
        if (batchWorker != address(0)) {
            require(
                msg.sender == batchWorker,
                "Batch result must be submitted by current batch worker"
            );
        }
        require(batchItems.length <= itemCount, "Batch size too large");
        // Make sure all batch items match
        for (uint i = 0; i < batchItems.length; i++) {
            require(
                keccak256(bytes(batchItems[i])) ==
                    keccak256(bytes(items[i].postId)),
                "Batch item mismatch"
            );
        }
        // initiate a validation pool for this batch
        uint fee;
        for (uint i = 0; i < batchItems.length; i++) {
            fee += items[i].fee;
        }
        poolIndex = dao.initiateValidationPool{value: fee}(
            batchPostId,
            poolDuration,
            [uint256(1), uint256(3)],
            [uint256(1), uint256(2)],
            100,
            true,
            false,
            ""
        );
        // Include all the availability stakes from the batched work
        for (uint i = 0; i < batchItems.length; i++) {
            dao.delegatedStakeOnValidationPool(
                poolIndex,
                items[i].worker,
                items[i].stakeAmount,
                true
            );
        }
        // Include availability stakes from the batch worker
        if (batchWorker != address(0)) {
            dao.delegatedStakeOnValidationPool(
                poolIndex,
                batchWorker,
                stakes[batchWorkerStakeIndex].amount,
                true
            );
        }
        if (batchItems.length < itemCount) {
            // Some items were added after this batch was computed.
            // Keep them in the queue to be included in the next batch.
            for (uint i = 0; i < itemCount - batchItems.length; i++) {
                items[i] = items[batchItems.length + i];
            }
            itemCount = itemCount - batchItems.length;
        } else {
            // Reset item count so we can start the next batch
            itemCount = 0;
        }
        // Select the next batch worker
        batchWorkerStakeIndex = assignWork();
        batchWorker = stakes[batchWorkerStakeIndex].worker;
        batchStart = block.timestamp;
        emit BatchWorkerAssigned(batchWorker);
    }

    /// If the batch worker fails to submit the batch, a new batch worker may be selected
    function resetBatchWorker() public {
        // TODO: Grace period after the current batch is due and before the worker can be replaced
        require(
            block.timestamp - batchStart > batchInterval,
            "Current batch interval has not yet elapsed"
        );
        require(itemCount > 0, "Current batch is empty");
        require(
            lastWorkerReset == 0 ||
                block.timestamp - lastWorkerReset >= minResetInterval,
            "Mininum reset interval has not elapsed since last batch worker reset"
        );
        // TODO: Submit a validation pool targeting a null post, and send the worker's availability stake
        // This gives the DAO an opportunity to police the failed work
        // Select a new batch worker
        batchWorkerStakeIndex = assignWork();
        batchWorker = stakes[batchWorkerStakeIndex].worker;
    }
}