handle cast code for medium post

export_email.ex

@agent :export_email_state

def start_link() do
  GenServer.start_link(__MODULE__, %{}, [name: __MODULE__])
  Agent.start_link(fn -> Map.new end, name: @agent)
end
  
def handle_cast({:export_email, {data, email}}, state) do
  key = email
  job_status = Agent.get(@agent, fn agent_state -> Map.get(agent_state, key) end)
  try do
    case job_status do
      nil ->
        Agent.update(@agent, fn agent_state -> Map.put(agent_state, key, {:started, System.system_time(:millisecond)}) end)
        export_download_zip_email(data, email)
        Agent.update(@agent, fn agent_state -> Map.delete(agent_state, key) end)
        {:noreply, state}
      {:started, _} ->
        Logger.warn "Already in progress"
        {:noreply, state}
    end
  catch
    :error, error ->
      Logger.error "Error occured #{inspect error}"
      {:noreply, state}
  end
end