defmodule Flex.Application do
  use Application
  require Logger

  def start(_type, _args) do
    port = Application.get_env(:flex_web, :port, 4000)
    url = "http://localhost:#{port}"

    cowboy_options = [port: port, dispatch: dispatch()]

    children = [
      {Plug.Cowboy, scheme: :http, plug: Flex.Router, options: cowboy_options},
      Flex.PubSub,
      {Flex.HotReloader, [dirs: [controllers_path(), templates_path()]]},
      Flex.TemplateCache
    ]

    opts = [strategy: :one_for_one, name: Flex.Supervisor]

    Logger.info("Starting Flex application on #{url}")

    case Supervisor.start_link(children, opts) do
      {:ok, pid} ->
        Logger.info("Flex application started successfully on #{url}")
        {:ok, pid}

      {:error, {:shutdown, {:failed_to_start_child, {Plug.Cowboy, _}, reason}}} ->
        Logger.error("Failed to start Flex application: #{inspect(reason)}")
        {:error, reason}

      {:error, reason} ->
        Logger.error("Failed to start Flex application: #{inspect(reason)}")
        {:error, reason}
    end
  end

  @doc """
  Returns the dispatch configuration for Cowboy.
  """
  def dispatch do
    flex_router_opts = Flex.Router.init([])

    [
      {:_,
       [
         {"/ws/live_reload", Flex.LiveReload, []},
         {:_, Plug.Cowboy.Handler, {Flex.Router, flex_router_opts}}
       ]}
    ]
  end

  def controllers_path do
    Application.get_env(:flex_web, :controllers_path) ||
      raise "Flex :controllers_path is not configured"
  end

  def templates_path do
    Application.get_env(:flex_web, :templates_path) ||
      raise "Flex :templates_path is not configured"
  end

  @doc """
  Reloads all controllers. Useful for development and testing.
  """
  def reload_controllers do
    controllers_path()
    |> File.ls!()
    |> Enum.filter(&String.ends_with?(&1, "_controller.ex"))
    |> Enum.each(fn file ->
      module =
        file
        |> Path.rootname()
        |> Macro.camelize()
        |> (&"Elixir.#{&1}").()
        |> String.to_atom()

      :code.purge(module)
      :code.delete(module)
      Code.compile_file(Path.join(controllers_path(), file))
    end)

    # Clear the routes cache
    :persistent_term.erase(:flex_compiled_routes)

    # Reinitialize the router
    Flex.Router.init([])

    :ok
  end
end