// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;

import {ISequencerUptimeFeed} from "./../interfaces/ISequencerUptimeFeed.sol";

import {BaseValidator} from "../base/BaseValidator.sol";

import {IL1CrossDomainMessenger} from "@eth-optimism/contracts/L1/messaging/IL1CrossDomainMessenger.sol";

/// @title OptimismValidator - makes cross chain call to update the Sequencer Uptime Feed on L2
contract OptimismValidator is BaseValidator {
  string public constant override typeAndVersion = "OptimismValidator 1.1.0-dev";

  /// @param l1CrossDomainMessengerAddress address the L1CrossDomainMessenger contract address
  /// @param l2UptimeFeedAddr the address of the OptimismSequencerUptimeFeed contract address
  /// @param gasLimit the gasLimit to use for sending a message from L1 to L2
  constructor(
    address l1CrossDomainMessengerAddress,
    address l2UptimeFeedAddr,
    uint32 gasLimit
  ) BaseValidator(l1CrossDomainMessengerAddress, l2UptimeFeedAddr, gasLimit) {}

  /// @notice validate method sends an xDomain L2 tx to update Uptime Feed contract on L2.
  /// @dev A message is sent using the L1CrossDomainMessenger. This method is accessed controlled.
  /// @param currentAnswer new aggregator answer - value of 1 considers the sequencer offline.
  function validate(
    uint256 previousRoundId,
    int256 previousAnswer,
    uint256 currentRoundId,
    int256 currentAnswer
  ) external override checkAccess returns (bool) {
    // Encode the OptimismSequencerUptimeFeed call
    bytes4 selector = ISequencerUptimeFeed.updateStatus.selector;
    bool status = currentAnswer == ANSWER_SEQ_OFFLINE;
    uint64 timestamp = uint64(block.timestamp);
    // Encode `status` and `timestamp`
    bytes memory message = abi.encodeWithSelector(selector, status, timestamp);
    // Make the xDomain call
    IL1CrossDomainMessenger(L1_CROSS_DOMAIN_MESSENGER_ADDRESS).sendMessage(
      L2_UPTIME_FEED_ADDR, // target
      message,
      s_gasLimit
    );
    emit BaseValidator.ValidatedStatus(previousRoundId, previousAnswer, currentRoundId, currentAnswer);
    // return success
    return true;
  }
}