wiki/lib/wiki_web/controllers/page_controller.ex

defmodule WikiWeb.PageController do
  use WikiWeb, :controller

  alias Wiki.Content
  alias Wiki.Content.Page

  plug :get_page when action in [:show, :edit, :update, :delete]

  defp get_page(%Plug.Conn{path_params: %{"id" => id}} = conn, _opts) do
    case Content.get_page(id) do
      nil ->
        conn
        |> send_resp(404, "Not found")
        |> halt()

      page ->
        key = get_session(conn, :content_encryption_key)

        page = %Page{page | content_encryption_key: key}

        page =
          if action_name(conn) in [:show, :edit] do
            Page.decrypt_content(page)
          else
            page
          end

        assign(conn, :page, page)
    end
  end

  def index(conn, _params) do
    pages = Content.list_pages()
    render(conn, "index.html", pages: pages)
  end

  def new(conn, params) do
    changeset = Content.change_page(%Page{}, params, encrypt: false)
    render(conn, "new.html", changeset: changeset)
  end

  def create(conn, %{"page" => page_params}) do
    key = get_session(conn, :content_encryption_key)

    page_params =
      page_params
      |> Map.put("user_id", conn.assigns.current_user.id)
      |> Map.put("content_encryption_key", key)

    case Content.create_page(page_params) do
      {:ok, page} ->
        conn
        |> put_flash(:info, "Page created successfully.")
        |> redirect(to: Routes.page_path(conn, :show, page))

      {:error, %Ecto.Changeset{} = changeset} ->
        render(conn, "new.html", changeset: changeset)
    end
  end

  def show(conn, _params) do
    rendered_content = Content.Renderer.render(conn.assigns.page)
    render(conn, "show.html", page: conn.assigns.page, content: rendered_content)
  end

  def edit(conn, _params) do
    page = conn.assigns.page
    changeset = Content.change_page(page)
    render(conn, "edit.html", page: page, changeset: changeset)
  end

  def update(conn, %{"page" => page_params}) do
    page = conn.assigns.page

    case Content.update_page(page, page_params) do
      {:ok, page} ->
        conn
        |> put_flash(:info, "Page updated successfully.")
        |> redirect(to: Routes.page_path(conn, :show, page))

      {:error, %Ecto.Changeset{} = changeset} ->
        render(conn, "edit.html", page: page, changeset: changeset)
    end
  end

  def delete(conn, _params) do
    page = conn.assigns.page
    {:ok, _page} = Content.delete_page(page)

    conn
    |> put_flash(:info, "Page deleted successfully.")
    |> redirect(to: Routes.page_path(conn, :index))
  end
end