server.ts

import express, { Request } from 'express';
import {
  createPublicClient,
  http,
  formatEther,
  getAddress
} from 'viem';
import { mainnet } from 'viem/chains';
import {
  getBalancesForAddresses,
  getBalancesForAllNotes
} from './balanceService';
import dotenv from 'dotenv';

dotenv.config();

const app = express();
const port = 8080;

const client = createPublicClient({
  chain: mainnet,
  transport: http(process.env.RPC)
});

async function getBlockNumberOrDefault(req: Request): Promise<bigint> {
  const blockNumberQuery = req.query['blockNumber'];
  if (
    blockNumberQuery &&
    (typeof blockNumberQuery !== 'string' || isNaN(parseInt(blockNumberQuery)))
  ) {
    throw new Error('Invalid block number');
  }
  if (!blockNumberQuery) {
    return await client.getBlockNumber();
  }
  return BigInt(blockNumberQuery);
}

function parseAddressesFromQuery(req: Request): `0x${string}`[] {
  const address = req.query['address'];
  let addresses: string[];
  if (typeof address === 'string') {
    addresses = [address];
  } else {
    addresses = address as string[];
  }
  const parsedAddresses = addresses.map((address) => getAddress(address));
  return parsedAddresses;
}

app.get('/', async (req, res) => {
  try {
    const blockNumber = await getBlockNumberOrDefault(req);

    let balances: Record<string, bigint>;

    if (req.query['address']) {
      let addresses: `0x${string}`[];
      try {
        addresses = parseAddressesFromQuery(req);
      } catch {
        res.status(400).json({ error: 'Invalid address' });
        return;
      }
      balances = await getBalancesForAddresses(client, addresses, blockNumber);
    } else {
      balances = await getBalancesForAllNotes(client, blockNumber);
    }

    const formattedBalances = Object.entries(balances).map(
      ([owner, balance]) => ({
        address: owner,
        effective_balance: parseFloat(formatEther(balance))
      })
    );

    res.status(200).json({ Result: formattedBalances });
  } catch (error) {
    console.log(error);
    res.status(500).json({ error: 'An error occurred while fetching data' });
  }
});

// Start the server
app.listen(port, () => {
  console.log(`Server is running on http://localhost:${port}`);
});