# Defining the application
defmodule MyApp.Application do
  use Web3, rpc_endpoint: "<PATH_TO_RPC_ENDPOINT>"

  # middleware (optional)
  # middleware MyApp.Middleware.Logger

  # dispatch (optional)
  dispatch :eth_getBalance, args: 2

  # contract (optinnal)
  contract :FirstContract, contract_address: "0xdAC17F958D2ee523a2206206994597C13D831ec7", abi_path: "path_to_abi.json"
end

# Get latest block number
iex> MyApp.Application.eth_blockNumber
{:ok, 15034908}

# Get address balance.
iex> MyApp.Application.eth_getBalance("0xF4986360a6d873ea02F79eC3913be6845e0308A4", "latest")
{:ok, 0}

# Get multi-addresses balance.
iex> MyApp.Application.eth_getBalance(["0xF4986360a6d873ea02F79eC3913be6845e0308A4", "0xF4986360a6d873ea02F79eC3913be6845e0308A4"], "latest")
{:ok,
  %{
    errors: [],
    params: ["0xF4986360a6d873ea02F79eC3913be6845e0308A4", "0xF4986360a6d873ea02F79eC3913be6845e0308A4"],
    result: [0, 0]
  }
}

# Query Contract
iex> MyApp.Application.FirstContract.balanceOf_address_("0xF4986360a6d873ea02F79eC3913be6845e0308A4")
{:ok, 0}

# Make Transaction
iex> MyApp.Application.FirstContract.approve_address_uint256_(
  "0x0000000000000000000000000000000000000000", 
  10, 
  gas_price: 12_000_000_000, 
  gas_limit: 300_000, 
  chain_id: 1, 
  nonce: 1,
  priv_key: "xxxxxxxxxxxxxxxxxxxxxxx"
)

{:ok, true}