defmodule WebSockex.Utils do
  @moduledoc false

  Code.ensure_loaded(:sys)

  # OTP

  def otp_release do
    :erlang.system_info(:otp_release) |> to_string() |> String.to_integer()
  end

  # Startup

  def spawn(link, conn, module, state, opts) do
    case List.keyfind(opts, :name, 0) do
      {:name, name} ->
        case whereis(name) do
          nil ->
            do_spawn(link, [self(), name, conn, module, state, opts])

          pid ->
            {:error, {:already_started, pid}}
        end

      nil ->
        do_spawn(link, [self(), conn, module, state, opts])
    end
  end

  defp do_spawn(:link, args) do
    :proc_lib.start_link(WebSockex, :init, args)
  end

  defp do_spawn(:no_link, args) do
    :proc_lib.start(WebSockex, :init, args)
  end

  # Named Processes

  def register({:global, name}), do: register({:via, :global, name})

  def register({:via, mod, name} = where_tup) do
    case mod.register_name(name, self()) do
      :yes -> true
      :no -> whereis(where_tup)
    end
  end

  def register(name) do
    try do
      Process.register(self(), name)
    catch
      :error, _ ->
        {:error, {:already_started, Process.whereis(name)}}
    end
  end

  def send({:global, name}, msg), do: WebSockex.Utils.send({:via, :global, name}, msg)

  def send({:via, mod, name}, msg) do
    mod.send(name, msg)
  end

  def send(dest, msg) do
    Kernel.send(dest, msg)
  end

  def whereis({:global, name}), do: whereis({:via, :global, name})

  def whereis({:via, mod, name}) do
    case mod.whereis_name(name) do
      :undefined -> nil
      other -> other
    end
  end

  def whereis(name), do: Process.whereis(name)

  # Debugging

  def sys_debug([], _, _), do: []

  def sys_debug(debug, event, state) do
    :sys.handle_debug(debug, &print_event/3, state, event)
  end

  if function_exported?(:sys, :get_log, 1) do
    def sys_log(debug), do: :sys.get_log(debug)
  else
    def sys_log(debug), do: :sys.get_debug(:log, debug, [])
  end

  defp print_event(io_dev, {:in, :frame, frame}, %{name: name}) do
    IO.puts(io_dev, "*DBG* #{inspect(name)} received frame: #{inspect(frame)}")
  end

  defp print_event(io_dev, {:in, :completed_fragment, frame}, %{name: name}) do
    IO.puts(io_dev, "*DBG* #{inspect(name)} completed fragmented frame: #{inspect(frame)}")
  end

  defp print_event(io_dev, {:in, :cast, msg}, %{name: name}) do
    IO.puts(io_dev, "*DBG* #{inspect(name)} received cast msg: #{inspect(msg)}")
  end

  defp print_event(io_dev, {:in, :msg, msg}, %{name: name}) do
    IO.puts(io_dev, "*DBG* #{inspect(name)} received msg: #{inspect(msg)}")
  end

  defp print_event(io_dev, {:reply, func, frame}, %{name: name}) do
    IO.puts(
      io_dev,
      "*DBG* #{inspect(name)} replying from #{inspect(func)} with #{inspect(frame)}"
    )
  end

  defp print_event(io_dev, {:close, :remote, :unexpected}, %{name: name}) do
    IO.puts(
      io_dev,
      "*DBG* #{inspect(name)} had the connection closed unexpectedly by the remote server"
    )
  end

  defp print_event(io_dev, {:close, :remote, reason}, %{name: name}) do
    IO.puts(io_dev, "*DBG* #{inspect(name)} closing with the remote reason: #{inspect(reason)}")
  end

  defp print_event(io_dev, {:close, :local, reason}, %{name: name}) do
    IO.puts(io_dev, "*DBG* #{inspect(name)} closing with local reason: #{inspect(reason)}")
  end

  defp print_event(io_dev, {:close, :error, error}, %{name: name}) do
    IO.puts(io_dev, "*DBG* #{inspect(name)} closing due to error: #{inspect(error)}")
  end

  defp print_event(io_dev, :closed, %{name: name}) do
    IO.puts(io_dev, "*DBG* #{inspect(name)} closed the connection sucessfully")
  end

  defp print_event(io_dev, :timeout_closed, %{name: name}) do
    IO.puts(
      io_dev,
      "*DBG* #{inspect(name)} forcefully closed the connection because the server was taking too long close"
    )
  end

  defp print_event(io_dev, {:socket_out, :close, :error}, %{name: name}) do
    IO.puts(io_dev, "*DBG* #{inspect(name)} sending error close frame: {:close, 1011, \"\"}")
  end

  defp print_event(io_dev, {:socket_out, :close, frame}, %{name: name}) do
    IO.puts(io_dev, "*DBG* #{inspect(name)} sending close frame: #{inspect(frame)}")
  end

  defp print_event(io_dev, {:socket_out, :sync_send, frame}, %{name: name}) do
    IO.puts(io_dev, "*DBG* #{inspect(name)} sending frame: #{inspect(frame)}")
  end

  defp print_event(io_dev, :reconnect, %{name: name}) do
    IO.puts(io_dev, "*DBG* #{inspect(name)} attempting to reconnect")
  end

  defp print_event(io_dev, :connect, %{name: name}) do
    IO.puts(io_dev, "*DBG* #{inspect(name)} attempting to connect")
  end

  defp print_event(io_dev, :connected, %{name: name}) do
    IO.puts(io_dev, "*DBG* #{inspect(name)} sucessfully connected")
  end

  defp print_event(io_dev, :reconnected, %{name: name}) do
    IO.puts(io_dev, "*DBG* #{inspect(name)} sucessfully reconnected")
  end

  def parse_debug_options(name, options) do
    case List.keyfind(options, :debug, 0) do
      {:debug, opts} ->
        try do
          :sys.debug_options(opts)
        catch
          _, _ ->
            :error_logger.format(~c"~p: ignoring bad debug options ~p~n", [name, opts])
            []
        end

      _ ->
        []
    end
  end
end