defmodule MessageServer.RemoteClient do
  require Logger

  alias MessageServer.{MessageRequest, ServerRegistry, Auth, MessageQueue}

  @spec send_message_to_server(String.t(), MessageRequest.t()) :: :ok | {:error, String.t()}
  def send_message_to_server(target_server_id, payload) do
    with {:ok, server_info} <- ServerRegistry.get_server_info(target_server_id),
         {:ok, serialized_payload} <- serialize_payload(payload),
         {:ok, response} <- make_request(server_info, serialized_payload) do
      handle_response(response)
    else
      {:error, :not_found} ->
        {:error, "Unknown server: #{target_server_id}"}

      {:error, reason} = error ->
        Logger.error("Failed to send message to server #{target_server_id}: #{reason}")
        MessageQueue.queue_message(target_server_id, payload)
        error
    end
  end

  @spec serialize_payload(MessageRequest.t()) :: {:ok, binary()} | {:error, String.t()}
  defp serialize_payload(payload) do
    try do
      serialized = :erlang.term_to_binary(payload)
      {:ok, serialized}
    rescue
      error -> {:error, "Serialization failed: #{inspect(error)}"}
    end
  end

  @spec make_request(map(), binary()) :: {:ok, Req.Response.t()} | {:error, String.t()}
  defp make_request(%{host: host, port: port}, serialized_payload) do
    url = "http://#{host}:#{port}/api/remote/messages"
    local_server_id = ServerRegistry.get_server_id()
    auth_token = Auth.generate_auth_token(local_server_id)

    case Req.post(url,
           body: serialized_payload,
           headers: [
             {"content-type", "application/octet-stream"},
             {"authorization", "Bearer #{auth_token}"}
           ]
         ) do
      {:ok, %Req.Response{status: status} = response} when status in 200..299 ->
        {:ok, response}

      {:ok, %Req.Response{status: status}} ->
        {:error, "HTTP #{status}"}

      {:error, reason} ->
        {:error, "Request failed: #{inspect(reason)}"}
    end
  end

  @spec handle_response(Req.Response.t()) :: :ok | {:error, String.t()}
  defp handle_response(%Req.Response{body: body}) do
    case body do
      %{"status" => "success"} -> :ok
      %{"error" => error} -> {:error, error}
      _ -> {:error, "Invalid response format"}
    end
  end
end