0x0000000000000000000000000000000000000900

interface IOlympusSystemEvents {
    event OrderAccepted(address indexed account, bytes32 indexed orderId);

    event OrderRejected(
        address indexed account,
        bytes32 indexed orderId,
        string reason
    );

    event OrderFilled(
        address indexed account,
        bytes32 indexed orderId,
        uint256 fillPrice,
        uint256 fillQuantity,
        uint256 remainingQuantity
    );

    // TradeExecuted is defined in IOlympusSystemEvents.sol but not yet
    // emitted by the system event encoder. Reserved for future use.
    // event TradeExecuted(bytes32 indexed orderId, uint256 price,
    //                     uint256 quantity, uint64 timestamp);

    event AssetLockConfirmed(
        address indexed account,
        string instrumentId,
        uint256 quantity
    );

    event AssetUnlockConfirmed(
        address indexed account,
        string instrumentId,
        uint256 quantity
    );
}

import "./IOlympusSystemEvents.sol";

contract OrderTracker {
    address constant SYSTEM = address(0x0900);

    // Subscribe to fills via event logs
    // Contracts cannot directly subscribe to events, but off-chain
    // indexers can filter for events from the system address
}

import { createPublicClient, http, parseAbiItem } from 'viem';

const client = createPublicClient({
  transport: http('http://localhost:8545'),
});

const SYSTEM_ADDRESS = '0x0000000000000000000000000000000000000900';

// Watch for OrderFilled events
const unwatch = client.watchEvent({
  address: SYSTEM_ADDRESS,
  event: parseAbiItem(
    'event OrderFilled(address indexed account, bytes32 indexed orderId, uint256 fillPrice, uint256 fillQuantity, uint256 remainingQuantity)'
  ),
  onLogs: (logs) => {
    for (const log of logs) {
      console.log('Fill:', {
        account: log.args.account,
        orderId: log.args.orderId,
        price: log.args.fillPrice,
        quantity: log.args.fillQuantity,
      });
    }
  },
});