alchemy aa maxFeePerGas PriorityFeePerGas

import { hexToBigInt, parseGwei } from 'viem'
import { arbitrum } from 'viem/chains'

// https://github.com/wevm/viem/blob/2813fbd218a54c99d92f1e29e5ca1b2961a06071/src/account-abstraction/actions/bundler/prepareUserOperation.ts#L435-L456
export const getUserOperationFeesPerGas = async (publicClient) => {
  const url = publicClient.chain.rpcUrls.default.http[0]

  // https://docs.alchemy.com/reference/bundler-api-fee-logic

  // Recommended Actions for Calculating maxFeePerGas
  if (/alchemy/.test(url)) {
    ////////////////////////////////////////////////////////////////////////////////
    //                    alchemy  baseFeePerGas
    ////////////////////////////////////////////////////////////////////////////////
    const block = await publicClient.getBlock({
      blockTag: 'latest',
    })
    ////////////////////////////////////////////////////////////////////////////////
    //                    alchemy  baseFeePerGas buffer + PriorityFeePerGas buffer
    ////////////////////////////////////////////////////////////////////////////////
    let baseFeeBuffer = 110n
    let priorityFeePerGasBuffer = 110n
    // mainnet
    if (!publicClient.chain.testnet) {
      if (publicClient.chain.id === arbitrum.id) {
        baseFeeBuffer = 105n
        priorityFeePerGasBuffer = 100n
      } else {
        baseFeeBuffer = 150n
        priorityFeePerGasBuffer = 125n
      }
    }
    const response = await fetch(url, {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
      },
      body: JSON.stringify({
        jsonrpc: '2.0',
        method: 'rundler_maxPriorityFeePerGas',
        params: [],
        id: 1,
      }),
    }).then((response) => response.json())

    const rundler_maxPriorityFeePerGas = hexToBigInt(response.result)

    const baseFeePerGas = block.baseFeePerGas

    // biome-ignore format:
    const maxPriorityFeePerGas = priorityFeePerGasBuffer * rundler_maxPriorityFeePerGas

    const result = {
      maxFeePerGas:
        (baseFeeBuffer * baseFeePerGas) / 100n + maxPriorityFeePerGas / 100n,
      maxPriorityFeePerGas: maxPriorityFeePerGas / 100n,
    }

    return result
  }
  // other bundler providers
  return {}
}