livebook/lib/livebook_web/live/open_live/url_component.ex

defmodule LivebookWeb.OpenLive.UrlComponent do
  use LivebookWeb, :live_component

  alias Livebook.{Utils, Notebook}

  @impl true
  def mount(socket) do
    {:ok, assign(socket, url: "", error_message: nil)}
  end

  @impl true
  def update(assigns, socket) do
    if url = assigns[:url] do
      {:ok, do_import(socket, url)}
    else
      {:ok, socket}
    end
  end

  @impl true
  def render(assigns) do
    ~H"""
    <div class="flex-col space-y-5">
      <div :if={@error_message} class="error-box">
        <%= @error_message %>
      </div>
      <p class="text-gray-700" id="import-from-url">
        Paste the URL to a .livemd file, to a GitHub file, or to a Gist.
      </p>
      <.form
        :let={f}
        for={%{"url" => @url}}
        as={:data}
        phx-submit="import"
        phx-change="validate"
        phx-target={@myself}
        autocomplete="off"
      >
        <.text_field
          field={f[:url]}
          label="Notebook URL"
          autofocus
          aria-labelledby="import-from-url"
          spellcheck="false"
        />
        <button
          class="mt-5 button-base button-blue"
          type="submit"
          disabled={not Utils.valid_url?(@url)}
        >
          Import
        </button>
      </.form>
    </div>
    """
  end

  @impl true
  def handle_event("validate", %{"data" => %{"url" => url}}, socket) do
    {:noreply, assign(socket, url: url)}
  end

  def handle_event("import", %{"data" => %{"url" => url}}, socket) do
    {:noreply, do_import(socket, url)}
  end

  defp do_import(socket, url) do
    origin = Notebook.ContentLoader.url_to_location(url)

    origin
    |> Notebook.ContentLoader.fetch_content_from_location()
    |> case do
      {:ok, content} ->
        send(self(), {:import_source, content, [origin: origin]})
        socket

      {:error, message} ->
        assign(socket, url: url, error_message: Utils.upcase_first(message))
    end
  end
end