eth_newFilter - Linea RPC Method

async function monitorTokenTransfers(provider, tokenAddress) {
  // keccak256('Transfer(address,address,uint256)')
  const transferTopic = '0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef';

  const filterId = await provider.send('eth_newFilter', [{
    fromBlock: 'latest',
    address: tokenAddress,
    topics: [transferTopic]
  }]);

  console.log(`Monitoring ${tokenAddress} transfers...`);

  setInterval(async () => {
    try {
      const logs = await provider.send('eth_getFilterChanges', [filterId]);

      for (const log of logs) {
        const from = '0x' + log.topics[1].slice(26);
        const to = '0x' + log.topics[2].slice(26);
        const value = BigInt(log.data);

        console.log(`Transfer: ${from} -> ${to} (${value})`);
      }
    } catch (error) {
      if (error.message.includes('filter not found')) {
        console.log('Filter expired — application should recreate');
      }
    }
  }, 3000);

  return filterId;
}

async function monitorDeFiEvents(provider, dexRouterAddress) {
  // Watch for Swap and LiquidityAdded events
  const swapTopic = '0xd78ad95fa46c994b6551d0da85fc275fe613ce37657fb8d5e3d130840159d822';
  const syncTopic = '0x1c411e9a96e071241c2f21f7726b17ae89e3cab4c78be50e062b03a9fffbbad1';

  const filterId = await provider.send('eth_newFilter', [{
    fromBlock: 'latest',
    address: dexRouterAddress,
    topics: [[swapTopic, syncTopic]]  // OR matching — either event type
  }]);

  setInterval(async () => {
    const logs = await provider.send('eth_getFilterChanges', [filterId]);

    for (const log of logs) {
      const eventType = log.topics[0] === swapTopic ? 'SWAP' : 'SYNC';
      console.log(`${eventType} at block ${parseInt(log.blockNumber, 16)}`);
    }
  }, 2000);

  return filterId;
}

class FilterManager {
  constructor(provider) {
    this.provider = provider;
    this.filters = new Map();
  }

  async createFilter(name, filterParams, callback) {
    const filterId = await this.provider.send('eth_newFilter', [filterParams]);

    const filter = {
      id: filterId,
      params: filterParams,
      callback,
      interval: setInterval(() => this.poll(name), 3000),
      lastPoll: Date.now()
    };

    this.filters.set(name, filter);
    console.log(`Filter "${name}" created: ${filterId}`);
    return filterId;
  }

  async poll(name) {
    const filter = this.filters.get(name);
    if (!filter) return;

    try {
      const logs = await this.provider.send('eth_getFilterChanges', [filter.id]);
      filter.lastPoll = Date.now();

      if (logs.length > 0) {
        await filter.callback(logs);
      }
    } catch (error) {
      if (error.message.includes('filter not found')) {
        console.log(`Filter "${name}" expired — recreating...`);
        const newId = await this.provider.send('eth_newFilter', [filter.params]);
        filter.id = newId;
      }
    }
  }

  async removeFilter(name) {
    const filter = this.filters.get(name);
    if (!filter) return;

    clearInterval(filter.interval);
    await this.provider.send('eth_uninstallFilter', [filter.id]);
    this.filters.delete(name);
    console.log(`Filter "${name}" removed`);
  }

  async removeAll() {
    for (const name of this.filters.keys()) {
      await this.removeFilter(name);
    }
  }
}

// Usage
const manager = new FilterManager(provider);

await manager.createFilter('transfers', {
  fromBlock: 'latest',
  address: '0xe5D7C2a44FfDDf6b295A15c148167daaAf5Cf34f',
  topics: ['0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef']
}, (logs) => {
  console.log(`${logs.length} new transfer events`);
});

async function createFilterSafely(provider, params, maxRetries = 3) {
  for (let i = 0; i < maxRetries; i++) {
    try {
      const filterId = await provider.send('eth_newFilter', [params]);
      return filterId;
    } catch (error) {
      if (error.message.includes('block range too large')) {
        // Narrow the range — split in half
        const from = parseInt(params.fromBlock, 16);
        const to = parseInt(params.toBlock, 16);
        const mid = Math.floor((from + to) / 2);
        console.warn(`Block range too large — splitting at ${mid}`);
        throw new Error(`Split needed: ${from}-${mid} and ${mid + 1}-${to}`);
      }
      if (error.code === -32005 && i < maxRetries - 1) {
        const delay = Math.pow(2, i) * 1000;
        await new Promise(r => setTimeout(r, delay));
      } else {
        throw error;
      }
    }
  }
}