defmodule VegaLite.Convert.WxViewer do
  @moduledoc false

  cond do
    not Code.ensure_loaded?(:wx) ->
      def start(_html) do
        raise RuntimeError,
              "VegaLite.Convert.Viewer requires Erlang compilation to include the :wx module, but it's not available"
      end

    not Code.ensure_loaded?(:wxWebView) ->
      def start(_html) do
        raise RuntimeError,
              "VegaLite.Convert.Viewer requires Erlang compilation to include the :wxWebView module, but it's not available." <>
                " This module is available as of Erlang/OTP 24"
      end

    true ->
      @behaviour :wx_object

      @title "VegaLite graphic"
      @size {1000, 800}

      @doc """
      Creates a graphical window displaying the given HTML.

      Returns `{:ok, pid}` on success, where `pid` identifies
      the process managing the window widget.
      """
      @spec start(binary()) :: {:ok, pid()} | :error
      def start(html) do
        case :wx_object.start(__MODULE__, [html: html], []) do
          {:error, _reason} -> :error
          {:wx_ref, _id, _obj, pid} -> {:ok, pid}
        end
      end

      @impl true
      def init(opts) do
        html = opts[:html]

        wx = :wx.new()

        frame = :wxFrame.new(wx, -1, @title, size: @size)
        :wxFrame.connect(frame, :close_window)

        web_view = :wxWebView.new(frame, -1)
        :wxWebView.setPage(web_view, html, "")

        :wxFrame.center(frame)
        :wxFrame.show(frame)

        {frame, :no_state}
      end

      @impl true
      def handle_event({:wx, _id, _obj, _data, {:wxClose, :close_window}}, state) do
        {:stop, :normal, state}
      end
  end
end