frenzy/lib/frenzy_web/controllers/group_controller.ex

defmodule FrenzyWeb.GroupController do
  use FrenzyWeb, :controller
  alias Frenzy.{Repo, Group, Feed}
  alias FrenzyWeb.Router.Helpers, as: Routes
  alias FrenzyWeb.Endpoint

  plug :user_owns_group

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

    group = Repo.get(Group, id)

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

  defp user_owns_group(conn, _opts), do: conn

  def index(conn, _params) do
    groups = conn.assigns[:user].groups
    render(conn, "index.html", groups: groups)
  end

  def show(conn, _params) do
    group = conn.assigns[:group] |> Repo.preload(:feeds)

    create_feed_changeset =
      Feed.changeset(
        %Feed{
          group_id: group.id
        },
        %{}
      )

    render(conn, "show.html", %{
      group: group,
      create_feed_changeset: create_feed_changeset
    })
  end

  def new(conn, _params) do
    changeset = Group.changeset(%Group{}, %{})

    render(conn, "new.html", changeset: changeset)
  end

  def create(conn, %{"group" => %{"title" => title}}) do
    user = conn.assigns[:user]
    title = title |> String.trim()

    if String.length(title) > 0 do
      changeset =
        Ecto.build_assoc(user, :groups, %{
          title: title
        })

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

      redirect(conn, to: Routes.group_path(Endpoint, :show, group.id))
    else
      conn
      |> put_flash(:error, "Group title must not be empty")
      |> redirect(to: Routes.group_path(Endpoint, :new))
    end
  end

  def delete(conn, _params) do
    group = conn.assigns[:group]

    {:ok, _} = Repo.delete(group)
    redirect(conn, to: Routes.group_path(Endpoint, :index))
  end
end