defmodule Golos.WS do
  alias Poison, as: JSON
  require Logger
  @moduledoc """
  Starts the WebSocket server for given ws URL. Received messages
  are forwarded to the sender pid
  """

  def start_link(url) do
    :crypto.start
    :ssl.start
    golos_wss_url = String.to_charlist(url)

    {:ok, sock_pid} = :websocket_client.start_link(golos_wss_url, __MODULE__, [])
    # websocket_client doesn't pass options to the gen_server, so registering manually
    Process.register(sock_pid, Golos.WS)
    {:ok, sock_pid}
  end


  def init([], _conn_state \\ []) do
    {:once, %{}}
  end

  def onconnect(_ws_req, state) do
    {:ok, state}
  end

  def ondisconnect({:remote, :closed}, state) do
    {:reconnect, state}
  end

  @doc """
  Closes the socket
  """
  def close(socket) do
    send(socket, :close)
  end

  @doc """
  Receives JSON encoded message from remote WS endpoint and
  forwards message to client sender process
  """
  def websocket_handle({:text, msg}, _conn_state, state) do
    data = JSON.decode!(msg)
    id = data["id"]
    {pid, params} = Golos.IdStore.get(id)
    send(pid, {:ws_response, {id, params, data}})

    {:ok, state}
  end

  @doc """
  Sends JSON encoded message to remote WS endpoint
  """
  def websocket_info({:send, msg}, _conn_state, state) do
    {:reply, {:text, json!(msg)}, state}
  end

  def websocket_info(:close, _conn_state, _state) do
    {:close, <<>>, "done"}
  end

  def websocket_terminate(_reason, _conn_state, _state) do
    :ok
  end

  defp json!(map), do: JSON.encode!(map)
end