defmodule RaxolWeb.TerminalChannel do
  @moduledoc """
  WebSocket channel for real-time terminal communication.

  This channel handles:
  - Terminal session initialization
  - Real-time input/output
  - Terminal resizing
  - Session management
  - Error handling
  """

  use RaxolWeb, :channel
  alias Raxol.Terminal.{Emulator, Renderer, Input}
  # alias Phoenix.Channel # Unused
  # alias Raxol.Terminal.Input.InputHandler # Unused (commented out call)
  # alias Phoenix.Socket # Unused

  @type t :: %__MODULE__{
          emulator: Emulator.t(),
          input: Input.t(),
          renderer: Renderer.t(),
          session_id: String.t(),
          user_id: String.t()
        }

  defstruct [:emulator, :input, :renderer, :session_id, :user_id]

  @impl true
  @dialyzer {:nowarn_function, join: 3}
  def join("terminal:" <> session_id, _params, socket) do
    if authorized?(socket) do
      emulator = Emulator.new(80, 24)
      input = Input.new()
      renderer = Renderer.new(emulator: emulator)

      state = %__MODULE__{
        emulator: emulator,
        input: input,
        renderer: renderer,
        session_id: session_id,
        user_id: socket.assigns.user_id
      }

      {:ok, assign(socket, :terminal_state, state)}
    else
      {:error, %{reason: "unauthorized"}}
    end
  end

  @impl true
  def handle_in("input", %{"data" => data}, socket) do
    state = socket.assigns.terminal_state
    # Process keyboard input using the Input module
    # We ignore the returned state for now, as we aren't using it elsewhere yet.
    _ = Input.process_keyboard(state.input, data)

    # Placeholder output for testing
    # Placeholder
    push(socket, "output", %{data: "Received: #{data}"})

    {:noreply, socket}
  end

  @impl true
  @dialyzer {:nowarn_function, handle_in: 3}
  def handle_in("resize", %{"width" => width, "height" => height}, socket) do
    state = socket.assigns.terminal_state
    emulator = Emulator.resize(state.emulator, width, height)
    # Renderer doesn't need explicit resizing; it uses the emulator's buffer
    renderer = state.renderer

    new_state = %{state | emulator: emulator, renderer: renderer}

    socket = assign(socket, :terminal_state, new_state)

    # Get updated cursor info after emulator resize
    {cursor_x, cursor_y} = Emulator.get_cursor_position(emulator)
    cursor_visible = Emulator.get_cursor_visible(emulator)

    {:reply, :ok,
     push(socket, "output", %{
       html: Renderer.render(renderer),
       cursor: %{
         x: cursor_x,
         y: cursor_y,
         visible: cursor_visible
       }
     })}
  end

  @impl true
  def handle_in("scroll", %{"offset" => _offset}, socket) do
    state = socket.assigns.terminal_state

    # Renderer doesn't need scroll offset; scrolling is handled by Emulator/ScreenBuffer
    # Just render the current state
    {:reply, :ok,
     push(socket, "output", %{
       html: Renderer.render(state.renderer)
     })}
  end

  @impl true
  def handle_in("theme", %{"theme" => theme}, socket) do
    state = socket.assigns.terminal_state
    renderer = Renderer.set_theme(state.renderer, theme)

    new_state = %{state | renderer: renderer}
    socket = assign(socket, :terminal_state, new_state)

    {:reply, :ok,
     push(socket, "output", %{
       html: Renderer.render(renderer)
     })}
  end

  @impl true
  def terminate(_reason, socket) do
    _state = socket.assigns.terminal_state
    # Clean up terminal session
    :ok
  end

  # Private functions

  defp authorized?(_socket) do
    # Implement authorization logic
    true
  end

  # Unused function
  # defp process_events(events, emulator, renderer) do
  #   Enum.reduce(events, {emulator, renderer}, fn event, {emu, ren} ->
  #     case event do
  #       {:text, text} ->
  #         {Emulator.process_input(emu, text), ren}
  #       {:control, :enter} ->
  #         {Emulator.process_input(emu, "\n"), ren}
  #       {:control, :backspace} ->
  #         {Emulator.process_input(emu, "\b"), ren}
  #       {:control, :tab} ->
  #         {Emulator.process_input(emu, "\t"), ren}
  #       {:escape, sequence} ->
  #         {Emulator.process_escape_sequence(emu, sequence), ren}
  #       {:mouse, event} ->
  #         {Emulator.process_mouse(emu, event), ren}
  #       _ ->
  #         {emu, ren}
  #     end
  #   end)
  # end

  # Keep the commented out original resize handler
  # @impl true
  # def handle_in(\"resize\", %{\"width\" => width, \"height\" => height}, socket) do
  # ... (rest of original handler)
  # end
end