defmodule BerrypodWeb.Shop.Page do
  @moduledoc """
  Unified shop LiveView that handles all shop pages.

  Using a single LiveView enables `patch` navigation between pages,
  preserving socket state (including editor state) across transitions.
  """

  use BerrypodWeb, :live_view

  alias BerrypodWeb.Shop.Pages

  # Map live_action atoms to page handler modules
  @page_modules %{
    home: Pages.Home,
    product: Pages.Product,
    collection: Pages.Collection,
    cart: Pages.Cart,
    contact: Pages.Contact,
    search: Pages.Search,
    orders: Pages.Orders,
    order_detail: Pages.OrderDetail,
    checkout_success: Pages.CheckoutSuccess,
    custom_page: Pages.CustomPage,
    # Content pages all use the same module
    about: Pages.Content,
    delivery: Pages.Content,
    privacy: Pages.Content,
    terms: Pages.Content
  }

  # Pages that need session data passed to init
  @session_pages [:orders, :order_detail]

  @impl true
  def mount(_params, session, socket) do
    # Store session for pages that need it (orders, order_detail)
    {:ok, assign(socket, :_session, session)}
  end

  @impl true
  def handle_params(params, uri, socket) do
    action = socket.assigns.live_action
    prev_action = socket.assigns[:_current_page_action]
    module = @page_modules[action]

    # Clean up previous page if needed (e.g., unsubscribe from PubSub)
    socket = maybe_cleanup_previous_page(socket, prev_action)

    socket =
      if action != prev_action do
        # Page type changed - call init
        socket = assign(socket, :_current_page_action, action)

        result =
          if action in @session_pages do
            module.init(socket, params, uri, socket.assigns._session)
          else
            module.init(socket, params, uri)
          end

        case result do
          {:noreply, socket} -> socket
          {:redirect, socket} -> socket
        end
      else
        socket
      end

    # After page init, sync editor state if editing and page changed
    socket = maybe_sync_editing_blocks(socket)

    # Always call handle_params for URL changes
    case module.handle_params(params, uri, socket) do
      {:noreply, socket} -> {:noreply, socket}
    end
  end

  # If editing and we navigated to a different page, reload editing_blocks
  defp maybe_sync_editing_blocks(socket) do
    page = socket.assigns[:page]
    editing = socket.assigns[:editing]
    editor_page_slug = socket.assigns[:editor_page_slug]

    if editing && page && page.slug != editor_page_slug do
      # Page changed while editing - reload editing state for the new page
      allowed = Berrypod.Pages.BlockTypes.allowed_for(page.slug)
      at_defaults = Berrypod.Pages.Defaults.matches_defaults?(page.slug, page.blocks)

      socket
      |> assign(:editing_blocks, page.blocks)
      |> assign(:editor_page_slug, page.slug)
      |> assign(:editor_dirty, false)
      |> assign(:editor_at_defaults, at_defaults)
      |> assign(:editor_history, [])
      |> assign(:editor_future, [])
      |> assign(:editor_expanded, MapSet.new())
      |> assign(:editor_allowed_blocks, allowed)
    else
      socket
    end
  end

  @impl true
  def handle_event(event, params, socket) do
    module = @page_modules[socket.assigns.live_action]

    case module.handle_event(event, params, socket) do
      :cont ->
        # Event not handled by page module, let hooks handle it
        {:noreply, socket}

      {:noreply, socket} ->
        {:noreply, socket}
    end
  end

  @impl true
  def handle_info(msg, socket) do
    module = @page_modules[socket.assigns.live_action]

    # Check if the module defines handle_info
    if function_exported?(module, :handle_info, 2) do
      case module.handle_info(msg, socket) do
        :cont -> {:noreply, socket}
        {:noreply, socket} -> {:noreply, socket}
      end
    else
      {:noreply, socket}
    end
  end

  @impl true
  def render(assigns) do
    # Cart page needs extra assigns computed at render time
    assigns =
      if assigns.live_action == :cart do
        Pages.Cart.compute_assigns(assigns)
      else
        assigns
      end

    ~H"""
    <BerrypodWeb.PageRenderer.render_page {assigns} />
    """
  end

  # Clean up previous page state when transitioning
  defp maybe_cleanup_previous_page(socket, :checkout_success) do
    Pages.CheckoutSuccess.cleanup(socket)
  end

  defp maybe_cleanup_previous_page(socket, _), do: socket
end