defmodule RogerUI.Web.QueuesPlug do
  @moduledoc """
  Handles endpoints for processing queues API calls

  Queues are managed in the UI trough API calls. These queues are presented, filtred, paused, resume, purged, among others operations
  by handlers herein described with Plug
  """
  require Logger
  alias RogerUI.Web.QueuesPlug.Router

  def init(opts), do: opts

  def call(conn, opts) do
    Router.call(conn, Router.init(opts))
  end

  defmodule Router do
    @moduledoc """
    Plug Router extension for QueuesPlug
    """

    @roger_api Application.get_env(:roger_ui, :roger_api, RogerUI.RogerApi)

    import Plug.Conn
    alias RogerUI.Web.Helpers.{Page, Response, Request, Filter}
    alias RogerUI.Queues
    use Plug.Router

    plug(:match)
    plug(:dispatch)

    defp filtered_queues(filter) do
      @roger_api.partitions()
      |> Queues.nodes_to_queues()
      |> Filter.call("qualified_queue_name", filter)
    end

    defp selected_queues([], filter), do: filtered_queues(filter)
    defp selected_queues(queues, _), do: queues

    defp action_over_queues(conn, action) do
      conn = Request.fill_params(conn)
      queues = Map.get(conn.params, "queues", [])
      filter = Map.get(conn.params, "filter", "")

      queues
      |> selected_queues(filter)
      |> Enum.each(fn q ->
        action.(q["partition_name"], Queues.normalize_name(q["queue_name"]))
      end)

      Response.no_content(conn, 207)
    end

    get "/:page_size/:page_number" do
      conn = Request.fill_params(conn)
      page_size = String.to_integer(page_size)
      page_number = String.to_integer(page_number)
      filter = Map.get(conn.params, "filter", "")

      queues =
        filter
        |> filtered_queues()
        |> Page.extract("queues", page_size, page_number)

      Response.json(conn, queues)
    end

    options("/pause", do: Response.no_content(conn, 207))
    put("/pause", do: action_over_queues(conn, &@roger_api.queue_pause/2))

    options("/resume", do: Response.no_content(conn, 207))
    put("/resume", do: action_over_queues(conn, &@roger_api.queue_resume/2))

    options("/purge", do: Response.no_content(conn, 207))
    put("/purge", do: action_over_queues(conn, &@roger_api.purge_queue/2))
  end
end