defmodule FrenzyWeb.PipelineController do
  use FrenzyWeb, :controller
  alias Frenzy.{Repo, Feed, PipelineStage}
  alias FrenzyWeb.Router.Helpers, as: Routes
  alias FrenzyWeb.Endpoint
  import Ecto.Query

  plug :user_owns_feed
  plug :user_owns_stage

  defp user_owns_feed(%Plug.Conn{path_params: %{"feed_id" => feed_id}} = conn, _opts) do
    user = conn.assigns[:user]

    feed = Repo.get(Feed, feed_id) |> Repo.preload(:pipeline_stages)

    if Enum.any?(user.groups, fn g -> g.id == feed.group_id end) do
      conn
      |> assign(:feed, feed)
    else
      conn
      |> put_flash(:error, "You do not have permission to access that resource.")
      |> redirect(to: Routes.group_path(Endpoint, :index))
      |> halt()
    end
  end

  defp user_owns_feed(conn, _opts), do: conn

  defp user_owns_stage(%Plug.Conn{path_params: %{"stage_id" => stage_id}} = conn, _opts) do
    feed = conn.assigns[:feed]

    stage = Repo.get(PipelineStage, stage_id)

    if stage.feed_id == feed.id do
      conn
      |> assign(:stage, stage)
    else
      conn
      |> put_flash(:error, "You do not have permission to access that resource.")
      |> redirect(to: Routes.group_path(Endpoint, :index))
      |> halt()
    end
  end

  defp user_owns_stage(conn, _opts), do: conn

  def edit(conn, %{"stage_id" => stage_id}) do
    feed = conn.assigns[:feed]
    stage = conn.assigns[:stage]
    {:ok, options_json} = Jason.encode(stage.options, pretty: true)

    changeset =
      PipelineStage.changeset(stage, %{
        options: options_json
      })

    render(conn, "edit.html", %{
      feed: feed,
      stage: stage,
      changeset: changeset
    })
  end

  def update(conn, %{"pipeline_stage" => %{"options" => options_json}}) do
    feed = conn.assigns[:feed]
    stage = conn.assigns[:stage]

    with {:ok, options} <- Jason.decode(options_json),
         {:ok, options} <-
           apply(String.to_existing_atom("Elixir." <> stage.module_name), :validate_opts, [
             options
           ]) do
      changeset = PipelineStage.changeset(stage, %{options: options})
      {:ok, _stage} = Repo.update(changeset)

      conn
      |> put_flash(:info, "Pipeline Stage updated")
      |> redirect(to: Routes.feed_path(Endpoint, :edit, feed.id))
    else
      result ->
        error_changeset = PipelineStage.changeset(stage, %{options: options_json})

        conn
        |> put_flash(:error, "Unable to update pipeline stage: #{inspect(result)}")
        |> render("edit.html", %{
          feed: feed,
          stage: stage,
          changeset: error_changeset
        })
    end
  end

  def new(conn, _params) do
    feed = conn.assigns[:feed]

    changeset =
      PipelineStage.changeset(%PipelineStage{}, %{
        index: feed.pipeline_stages |> Enum.count(),
        options: "{}"
      })

    render(conn, "new.html", %{
      feed: feed,
      changeset: changeset
    })
  end

  def create(conn, %{
        "pipeline_stage" =>
          %{
            "index" => index,
            "module_name" => module_name,
            "options" => options_json
          } = params
      }) do
    feed = conn.assigns[:feed]

    with {index, _} <- Integer.parse(index),
         module_atom <- String.to_existing_atom("Elixir." <> module_name),
         {:ok, options} <- Jason.decode(options_json),
         {:ok, options} <- apply(module_atom, :validate_opts, [options]) do
      changeset =
        Ecto.build_assoc(feed, :pipeline_stages, %{
          index: index,
          module_name: module_name,
          options: options
        })

      {:ok, _stage} = Repo.insert(changeset)

      conn
      |> put_flash(:info, "Pipeline Stage created")
      |> redirect(to: Routes.feed_path(Endpoint, :edit, feed.id))
    else
      result ->
        error_changeset = PipelineStage.changeset(%PipelineStage{}, params)

        conn
        |> put_flash(:error, "Unable to create pipeline stage: #{inspect(result)}")
        |> render("new.html", %{
          feed: feed,
          changeset: error_changeset
        })
    end
  end

  def delete(conn, _params) do
    feed = conn.assigns[:feed]
    stage = conn.assigns[:stage]
    {:ok, _stage} = Repo.delete(stage)

    conn
    |> put_flash(:info, "Pipeline Stage deleted")
    |> redirect(to: Routes.feed_path(Endpoint, :edit, feed.id))
  end
end