defmodule BerrypodWeb.PageEditorHook do
  @moduledoc """
  LiveView on_mount hook for the unified on-site editor.

  Mounted in the public_shop live_session. When an admin visits any shop
  page, this hook enables editing capabilities:

  1. **Page editing** — loads a working copy of the page's blocks, attaches
     event handlers for block manipulation
  2. **Theme editing** — provides live theme customisation on the actual shop

  The hook manages a tabbed editor panel with Page, Theme, and Settings tabs.
  Non-admin users are unaffected — the hook just assigns `editing: false`.

  ## Actions

  - `:mount_page_editor` — sets up editing assigns and attaches hooks
  """

  import Phoenix.Component, only: [assign: 3]
  import Phoenix.LiveView, only: [attach_hook: 4, push_navigate: 2]

  alias Berrypod.{Media, Settings}
  alias Berrypod.Pages
  alias Berrypod.Pages.{BlockEditor, BlockTypes, Defaults}
  alias Berrypod.Theme.{Contrast, CSSGenerator, Presets}

  def on_mount(:mount_page_editor, _params, _session, socket) do
    socket =
      socket
      # Page editing state
      |> assign(:editing, false)
      |> assign(:editing_blocks, nil)
      |> assign(:editor_page_slug, nil)
      |> assign(:editor_dirty, false)
      |> assign(:editor_at_defaults, true)
      |> assign(:editor_history, [])
      |> assign(:editor_future, [])
      |> assign(:editor_expanded, MapSet.new())
      |> assign(:editor_show_picker, false)
      |> assign(:editor_picker_filter, "")
      |> assign(:editor_allowed_blocks, nil)
      |> assign(:editor_live_region_message, nil)
      |> assign(:editor_current_path, nil)
      |> assign(:editor_sidebar_open, true)
      |> assign(:editor_sheet_state, :collapsed)
      |> assign(:editor_image_picker_block_id, nil)
      |> assign(:editor_image_picker_field_key, nil)
      |> assign(:editor_image_picker_images, [])
      |> assign(:editor_image_picker_search, "")
      |> assign(:editor_save_status, :idle)
      # Unified editor tab state (:page | :theme | :settings)
      |> assign(:editor_active_tab, :page)
      # Theme editing state
      |> assign(:theme_editing, false)
      |> assign(:theme_editor_settings, nil)
      |> assign(:theme_editor_active_preset, nil)
      |> assign(:theme_editor_logo_image, nil)
      |> assign(:theme_editor_header_image, nil)
      |> assign(:theme_editor_icon_image, nil)
      |> assign(:theme_editor_contrast_warning, :ok)
      |> assign(:theme_editor_customise_open, false)
      |> assign(:theme_editor_presets, Presets.all_with_descriptions())
      |> attach_hook(:editor_params, :handle_params, &handle_editor_params/3)
      |> attach_hook(:editor_events, :handle_event, &handle_editor_event/3)
      |> attach_hook(:editor_info, :handle_info, &handle_editor_info/2)

    {:cont, socket}
  end

  # ── handle_params: track current path and restore editor state ────

  defp handle_editor_params(params, uri, socket) do
    parsed = URI.parse(uri)

    socket =
      socket
      |> assign(:editor_current_path, parsed.path)
      |> maybe_restore_editor_state(params)

    {:cont, socket}
  end

  # Restore editor state from URL params on navigation
  # Only activates state if not already in the requested state (avoids loops)
  defp maybe_restore_editor_state(socket, params) do
    if socket.assigns.is_admin do
      requested_tab = params["edit"]
      current_tab = socket.assigns.editor_active_tab
      current_state = socket.assigns.editor_sheet_state

      # If already in the correct state, don't re-apply
      already_correct? =
        current_state == :open && requested_tab &&
          String.to_existing_atom(requested_tab) == current_tab

      if already_correct? do
        socket
      else
        case requested_tab do
          "theme" ->
            socket
            |> assign(:editor_sheet_state, :open)
            |> assign(:editor_active_tab, :theme)
            |> maybe_enter_theme_mode()

          "page" ->
            socket
            |> assign(:editor_sheet_state, :open)
            |> assign(:editor_active_tab, :page)
            |> maybe_enter_page_mode()

          "settings" ->
            socket
            |> assign(:editor_sheet_state, :open)
            |> assign(:editor_active_tab, :settings)
            |> maybe_enter_theme_mode()

          _ ->
            socket
        end
      end
    else
      socket
    end
  end

  defp maybe_enter_theme_mode(socket) do
    if socket.assigns.theme_editing do
      socket
    else
      load_theme_state(socket)
    end
  end

  defp maybe_enter_page_mode(socket) do
    if socket.assigns.editing do
      socket
    else
      if socket.assigns[:page] do
        enter_edit_mode(socket)
      else
        socket
      end
    end
  end

  # ── handle_info ─────────────────────────────────────────────────

  defp handle_editor_info(:editor_clear_save_status, socket) do
    {:halt, assign(socket, :editor_save_status, :idle)}
  end

  defp handle_editor_info(_msg, socket), do: {:cont, socket}

  # ── handle_event: editor_* events ────────────────────────────────

  # toggle_editing can be called even when not editing (to enter edit mode)
  defp handle_editor_event("editor_toggle_editing", _params, socket) do
    if socket.assigns.is_admin and socket.assigns[:page] do
      if socket.assigns.editing do
        {:halt, exit_edit_mode(socket)}
      else
        {:halt, enter_edit_mode(socket)}
      end
    else
      {:cont, socket}
    end
  end

  # set_sheet_state can be called even when not editing (from JS click-outside)
  defp handle_editor_event("editor_set_sheet_state", %{"state" => state_str}, socket) do
    if socket.assigns.is_admin do
      state = if state_str == "open", do: :open, else: :collapsed
      {:halt, assign(socket, :editor_sheet_state, state)}
    else
      {:cont, socket}
    end
  end

  # Tab switching for unified editor
  defp handle_editor_event("editor_set_tab", %{"tab" => tab_str}, socket) do
    if socket.assigns.is_admin do
      tab = String.to_existing_atom(tab_str)

      socket =
        case tab do
          :theme ->
            # Load theme state if not already loaded
            if socket.assigns.theme_editing do
              assign(socket, :editor_active_tab, :theme)
            else
              enter_theme_edit_mode(socket)
            end

          :page ->
            # Enter page edit mode if we have a page and aren't already editing
            socket = assign(socket, :editor_active_tab, :page)

            if socket.assigns[:page] && !socket.assigns.editing do
              enter_edit_mode(socket)
            else
              socket
            end

          :settings ->
            # Ensure theme state is loaded for settings that need it
            socket =
              if socket.assigns.theme_editing do
                socket
              else
                load_theme_state(socket)
              end

            assign(socket, :editor_active_tab, :settings)
        end

      {:halt, socket}
    else
      {:cont, socket}
    end
  end

  # Toggle theme editing mode
  defp handle_editor_event("editor_toggle_theme", _params, socket) do
    if socket.assigns.is_admin do
      if socket.assigns.theme_editing do
        {:halt, exit_theme_edit_mode(socket)}
      else
        {:halt, enter_theme_edit_mode(socket)}
      end
    else
      {:cont, socket}
    end
  end

  defp handle_editor_event("editor_" <> action, params, socket) do
    if socket.assigns.editing do
      handle_editor_action(action, params, socket)
    else
      {:cont, socket}
    end
  end

  # Theme editing events
  defp handle_editor_event("theme_" <> action, params, socket) do
    if socket.assigns.is_admin && socket.assigns.theme_editing do
      handle_theme_action(action, params, socket)
    else
      {:cont, socket}
    end
  end

  defp handle_editor_event(_event, _params, socket), do: {:cont, socket}

  # ── Block manipulation actions ───────────────────────────────────

  defp handle_editor_action("move_up", %{"id" => id}, socket) do
    case BlockEditor.move_up(socket.assigns.editing_blocks, id) do
      {:ok, new_blocks, message} ->
        {:halt, apply_mutation(socket, new_blocks, message, :reorder)}

      :noop ->
        {:halt, socket}
    end
  end

  defp handle_editor_action("move_down", %{"id" => id}, socket) do
    case BlockEditor.move_down(socket.assigns.editing_blocks, id) do
      {:ok, new_blocks, message} ->
        {:halt, apply_mutation(socket, new_blocks, message, :reorder)}

      :noop ->
        {:halt, socket}
    end
  end

  defp handle_editor_action("remove_block", %{"id" => id}, socket) do
    {:ok, new_blocks, message} = BlockEditor.remove_block(socket.assigns.editing_blocks, id)
    {:halt, apply_mutation(socket, new_blocks, message, :content)}
  end

  defp handle_editor_action("duplicate_block", %{"id" => id}, socket) do
    case BlockEditor.duplicate_block(socket.assigns.editing_blocks, id) do
      {:ok, new_blocks, message} ->
        {:halt, apply_mutation(socket, new_blocks, message, :content)}

      :noop ->
        {:halt, socket}
    end
  end

  defp handle_editor_action("add_block", %{"type" => type}, socket) do
    case BlockEditor.add_block(socket.assigns.editing_blocks, type) do
      {:ok, new_blocks, message} ->
        socket =
          socket
          |> apply_mutation(new_blocks, message, :content)
          |> assign(:editor_show_picker, false)

        {:halt, socket}

      :noop ->
        {:halt, socket}
    end
  end

  defp handle_editor_action("update_block_settings", params, socket) do
    block_id = params["block_id"]
    new_settings = params["block_settings"] || %{}

    case BlockEditor.update_settings(socket.assigns.editing_blocks, block_id, new_settings) do
      {:ok, new_blocks} ->
        {:halt, apply_mutation(socket, new_blocks, "Settings updated", :content)}

      :noop ->
        {:halt, socket}
    end
  end

  # ── Repeater actions ─────────────────────────────────────────────

  defp handle_editor_action(
         "repeater_add",
         %{"block-id" => block_id, "field" => field_key},
         socket
       ) do
    case BlockEditor.repeater_add(socket.assigns.editing_blocks, block_id, field_key) do
      {:ok, new_blocks, message} ->
        {:halt, apply_mutation(socket, new_blocks, message, :content)}

      :noop ->
        {:halt, socket}
    end
  end

  defp handle_editor_action(
         "repeater_remove",
         %{"block-id" => block_id, "field" => field_key, "index" => index_str},
         socket
       ) do
    index = String.to_integer(index_str)

    case BlockEditor.repeater_remove(socket.assigns.editing_blocks, block_id, field_key, index) do
      {:ok, new_blocks, message} ->
        {:halt, apply_mutation(socket, new_blocks, message, :content)}

      :noop ->
        {:halt, socket}
    end
  end

  defp handle_editor_action(
         "repeater_move",
         %{"block-id" => block_id, "field" => field_key, "index" => index_str, "dir" => dir},
         socket
       ) do
    index = String.to_integer(index_str)

    case BlockEditor.repeater_move(
           socket.assigns.editing_blocks,
           block_id,
           field_key,
           index,
           dir
         ) do
      {:ok, new_blocks, message} ->
        {:halt, apply_mutation(socket, new_blocks, message, :reorder)}

      :noop ->
        {:halt, socket}
    end
  end

  # ── UI state actions ─────────────────────────────────────────────

  defp handle_editor_action("toggle_expand", %{"id" => block_id}, socket) do
    expanded = socket.assigns.editor_expanded
    block = Enum.find(socket.assigns.editing_blocks, &(&1["id"] == block_id))
    block_name = BlockEditor.block_display_name(block)

    {new_expanded, action} =
      if MapSet.member?(expanded, block_id) do
        {MapSet.delete(expanded, block_id), "collapsed"}
      else
        {MapSet.put(expanded, block_id), "expanded"}
      end

    {:halt,
     socket
     |> assign(:editor_expanded, new_expanded)
     |> assign(:editor_live_region_message, "#{block_name} settings #{action}")}
  end

  defp handle_editor_action("toggle_sidebar", _params, socket) do
    {:halt, assign(socket, :editor_sidebar_open, !socket.assigns.editor_sidebar_open)}
  end

  defp handle_editor_action("show_picker", _params, socket) do
    {:halt,
     socket
     |> assign(:editor_show_picker, true)
     |> assign(:editor_picker_filter, "")}
  end

  defp handle_editor_action("hide_picker", _params, socket) do
    {:halt, assign(socket, :editor_show_picker, false)}
  end

  defp handle_editor_action("filter_picker", %{"value" => value}, socket) do
    {:halt, assign(socket, :editor_picker_filter, value)}
  end

  # ── Image picker actions ───────────────────────────────────────

  defp handle_editor_action(
         "show_image_picker",
         %{"block-id" => block_id, "field" => field_key},
         socket
       ) do
    images = Berrypod.Media.list_images()

    {:halt,
     socket
     |> assign(:editor_image_picker_block_id, block_id)
     |> assign(:editor_image_picker_field_key, field_key)
     |> assign(:editor_image_picker_images, images)
     |> assign(:editor_image_picker_search, "")}
  end

  defp handle_editor_action("hide_image_picker", _params, socket) do
    {:halt,
     socket
     |> assign(:editor_image_picker_block_id, nil)
     |> assign(:editor_image_picker_field_key, nil)}
  end

  defp handle_editor_action("image_picker_search", %{"value" => value}, socket) do
    {:halt, assign(socket, :editor_image_picker_search, value)}
  end

  defp handle_editor_action("pick_image", %{"image-id" => image_id}, socket) do
    block_id = socket.assigns.editor_image_picker_block_id
    field_key = socket.assigns.editor_image_picker_field_key

    case BlockEditor.update_settings(socket.assigns.editing_blocks, block_id, %{
           field_key => image_id
         }) do
      {:ok, new_blocks} ->
        socket =
          socket
          |> apply_mutation(new_blocks, "Image selected", :content)
          |> assign(:editor_image_picker_block_id, nil)
          |> assign(:editor_image_picker_field_key, nil)

        {:halt, socket}

      :noop ->
        {:halt, socket}
    end
  end

  defp handle_editor_action(
         "clear_image",
         %{"block-id" => block_id, "field" => field_key},
         socket
       ) do
    case BlockEditor.update_settings(socket.assigns.editing_blocks, block_id, %{
           field_key => ""
         }) do
      {:ok, new_blocks} ->
        {:halt, apply_mutation(socket, new_blocks, "Image cleared", :content)}

      :noop ->
        {:halt, socket}
    end
  end

  # ── Undo / redo ──────────────────────────────────────────────────

  defp handle_editor_action("undo", _params, socket) do
    case socket.assigns.editor_history do
      [prev | rest] ->
        future = [socket.assigns.editing_blocks | socket.assigns.editor_future]
        at_defaults = Defaults.matches_defaults?(socket.assigns.page.slug, prev)

        socket =
          socket
          |> assign(:editing_blocks, prev)
          |> assign(:editor_history, rest)
          |> assign(:editor_future, future)
          |> assign(:editor_dirty, true)
          |> assign(:editor_at_defaults, at_defaults)
          |> assign(:editor_live_region_message, "Undone")
          |> reload_block_data(prev)

        {:halt, socket}

      [] ->
        {:halt, socket}
    end
  end

  defp handle_editor_action("redo", _params, socket) do
    case socket.assigns.editor_future do
      [next | rest] ->
        history = [socket.assigns.editing_blocks | socket.assigns.editor_history]
        at_defaults = Defaults.matches_defaults?(socket.assigns.page.slug, next)

        socket =
          socket
          |> assign(:editing_blocks, next)
          |> assign(:editor_history, history)
          |> assign(:editor_future, rest)
          |> assign(:editor_dirty, true)
          |> assign(:editor_at_defaults, at_defaults)
          |> assign(:editor_live_region_message, "Redone")
          |> reload_block_data(next)

        {:halt, socket}

      [] ->
        {:halt, socket}
    end
  end

  # ── Page actions ─────────────────────────────────────────────────

  defp handle_editor_action("save", _params, socket) do
    %{page: page, editing_blocks: blocks} = socket.assigns

    case Pages.save_page(page.slug, %{title: page.title, blocks: blocks}) do
      {:ok, _saved_page} ->
        updated_page = Pages.get_page(page.slug)
        at_defaults = Defaults.matches_defaults?(page.slug, updated_page.blocks)
        Process.send_after(self(), :editor_clear_save_status, 2500)

        socket =
          socket
          |> assign(:page, updated_page)
          |> assign(:editing_blocks, updated_page.blocks)
          |> assign(:editor_dirty, false)
          |> assign(:editor_at_defaults, at_defaults)
          |> assign(:editor_history, [])
          |> assign(:editor_future, [])
          |> assign(:editor_save_status, :saved)

        {:halt, socket}

      {:error, _changeset} ->
        {:halt, assign(socket, :editor_save_status, :error)}
    end
  end

  defp handle_editor_action("reset_defaults", _params, socket) do
    slug = socket.assigns.page.slug
    default_blocks = Berrypod.Pages.Defaults.for_slug(slug).blocks

    # Treat reset like any other mutation: push to history, mark dirty
    {:halt, apply_mutation(socket, default_blocks, "Reset to defaults", :content)}
  end

  defp handle_editor_action("done", _params, socket) do
    path = socket.assigns.editor_current_path || "/"
    {:halt, push_navigate(socket, to: path)}
  end

  # Catch-all for unknown editor actions
  defp handle_editor_action(_action, _params, socket), do: {:halt, socket}

  # ── Theme editing actions ───────────────────────────────────────────

  # Settings stored outside the theme JSON (site_name, site_description)
  @standalone_settings ~w(site_name site_description)

  defp handle_theme_action("apply_preset", %{"preset" => preset_name}, socket) do
    preset_atom = String.to_existing_atom(preset_name)

    case Settings.apply_preset(preset_atom) do
      {:ok, theme_settings} ->
        generated_css =
          CSSGenerator.generate(theme_settings, &BerrypodWeb.Endpoint.static_path/1)

        header_image = socket.assigns.theme_editor_header_image
        contrast_warning = compute_header_contrast(theme_settings, header_image)

        socket =
          socket
          # Update editor state
          |> assign(:theme_editor_settings, theme_settings)
          |> assign(:theme_editor_active_preset, preset_atom)
          |> assign(:theme_editor_contrast_warning, contrast_warning)
          # Update shop state so layout reflects changes live
          |> assign(:theme_settings, theme_settings)
          |> assign(:generated_css, generated_css)

        {:halt, socket}

      {:error, _} ->
        {:halt, socket}
    end
  end

  defp handle_theme_action(
         "update_setting",
         %{"field" => field, "setting_value" => value},
         socket
       )
       when field in @standalone_settings do
    Settings.put_setting(field, value, "string")
    # Also update the main assigns so ThemeHook sees the change
    {:halt, assign(socket, String.to_existing_atom(field), value)}
  end

  defp handle_theme_action(
         "update_setting",
         %{"field" => field, "setting_value" => value},
         socket
       ) do
    field_atom = String.to_existing_atom(field)
    update_theme_setting(socket, %{field_atom => value}, field)
  end

  defp handle_theme_action("update_setting", %{"field" => field} = params, socket)
       when field in @standalone_settings do
    value = params[field]

    if value do
      Settings.put_setting(field, value, "string")
      {:halt, assign(socket, String.to_existing_atom(field), value)}
    else
      {:halt, socket}
    end
  end

  defp handle_theme_action("update_setting", %{"field" => field} = params, socket) do
    value = params[field] || params["#{field}_text"] || params["value"]

    if value do
      field_atom = String.to_existing_atom(field)
      update_theme_setting(socket, %{field_atom => value}, field)
    else
      {:halt, socket}
    end
  end

  defp handle_theme_action("update_color", %{"field" => field, "value" => value}, socket) do
    field_atom = String.to_existing_atom(field)
    update_theme_setting(socket, %{field_atom => value}, field)
  end

  defp handle_theme_action("toggle_setting", %{"field" => field}, socket) do
    field_atom = String.to_existing_atom(field)
    current_value = Map.get(socket.assigns.theme_editor_settings, field_atom)
    new_value = !current_value

    # Prevent turning off show_site_name when there's no logo
    if field_atom == :show_site_name && new_value == false && !has_valid_logo?(socket) do
      {:halt, socket}
    else
      update_theme_setting(socket, %{field_atom => new_value}, field)
    end
  end

  defp handle_theme_action("toggle_customise", _params, socket) do
    {:halt,
     assign(socket, :theme_editor_customise_open, !socket.assigns.theme_editor_customise_open)}
  end

  defp handle_theme_action("remove_logo", _params, socket) do
    if logo = socket.assigns.theme_editor_logo_image do
      Media.delete_image(logo)
    end

    {:ok, theme_settings} =
      Settings.update_theme_settings(%{logo_image_id: nil, show_site_name: true})

    generated_css = CSSGenerator.generate(theme_settings)

    socket =
      socket
      |> assign(:theme_editor_logo_image, nil)
      |> assign(:logo_image, nil)
      |> assign(:theme_editor_settings, theme_settings)
      |> assign(:generated_css, generated_css)

    {:halt, socket}
  end

  defp handle_theme_action("remove_header", _params, socket) do
    if header = socket.assigns.theme_editor_header_image do
      Media.delete_image(header)
    end

    Settings.update_theme_settings(%{header_image_id: nil})

    socket =
      socket
      |> assign(:theme_editor_header_image, nil)
      |> assign(:header_image, nil)
      |> assign(:theme_editor_contrast_warning, :ok)

    {:halt, socket}
  end

  defp handle_theme_action("remove_icon", _params, socket) do
    if icon = socket.assigns.theme_editor_icon_image do
      Media.delete_image(icon)
    end

    Settings.update_theme_settings(%{icon_image_id: nil})

    socket =
      socket
      |> assign(:theme_editor_icon_image, nil)
      |> assign(:icon_image, nil)

    {:halt, socket}
  end

  # Catch-all for unknown theme actions
  defp handle_theme_action(_action, _params, socket), do: {:halt, socket}

  # Helper to update a theme setting and regenerate CSS
  defp update_theme_setting(socket, attrs, field) do
    case Settings.update_theme_settings(attrs) do
      {:ok, theme_settings} ->
        generated_css =
          CSSGenerator.generate(theme_settings, &BerrypodWeb.Endpoint.static_path/1)

        active_preset = Presets.detect_preset(theme_settings)

        socket =
          socket
          # Update editor state
          |> assign(:theme_editor_settings, theme_settings)
          |> assign(:theme_editor_active_preset, active_preset)
          |> maybe_recompute_contrast(field)
          # Update shop state so layout reflects changes live
          |> assign(:theme_settings, theme_settings)
          |> assign(:generated_css, generated_css)

        {:halt, socket}

      {:error, _} ->
        {:halt, socket}
    end
  end

  defp maybe_recompute_contrast(socket, field)
       when field in ["mood", "header_background_enabled"] do
    header_image = socket.assigns.theme_editor_header_image
    theme_settings = socket.assigns.theme_editor_settings
    contrast_warning = compute_header_contrast(theme_settings, header_image)
    assign(socket, :theme_editor_contrast_warning, contrast_warning)
  end

  defp maybe_recompute_contrast(socket, _field), do: socket

  defp has_valid_logo?(socket) do
    socket.assigns.theme_editor_settings.show_logo &&
      socket.assigns.theme_editor_logo_image != nil
  end

  # ── Private helpers ──────────────────────────────────────────────

  defp enter_edit_mode(socket) do
    page = socket.assigns.page
    allowed = BlockTypes.allowed_for(page.slug)
    at_defaults = Defaults.matches_defaults?(page.slug, page.blocks)

    socket
    |> assign(:editing, true)
    |> 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_show_picker, false)
    |> assign(:editor_picker_filter, "")
    |> assign(:editor_allowed_blocks, allowed)
    |> assign(:editor_live_region_message, nil)
    |> assign(:editor_sidebar_open, true)
    |> assign(:editor_sheet_state, :open)
    |> assign(:editor_image_picker_block_id, nil)
    |> assign(:editor_image_picker_field_key, nil)
    |> assign(:editor_image_picker_images, [])
    |> assign(:editor_image_picker_search, "")
    |> assign(:editor_save_status, :idle)
  end

  defp exit_edit_mode(socket) do
    socket
    |> assign(:editing, false)
    |> assign(:editing_blocks, nil)
    |> assign(:editor_page_slug, nil)
    |> assign(:editor_dirty, false)
    |> assign(:editor_history, [])
    |> assign(:editor_future, [])
    |> assign(:editor_expanded, MapSet.new())
    |> assign(:editor_show_picker, false)
    |> assign(:editor_picker_filter, "")
    |> assign(:editor_allowed_blocks, nil)
    |> assign(:editor_live_region_message, nil)
    |> assign(:editor_sidebar_open, true)
    |> assign(:editor_image_picker_block_id, nil)
    |> assign(:editor_image_picker_field_key, nil)
    |> assign(:editor_image_picker_images, [])
    |> assign(:editor_image_picker_search, "")
    |> assign(:editor_save_status, :idle)
  end

  defp apply_mutation(socket, new_blocks, message, type) do
    history =
      [socket.assigns.editing_blocks | socket.assigns.editor_history] |> Enum.take(50)

    at_defaults = Defaults.matches_defaults?(socket.assigns.page.slug, new_blocks)

    socket =
      socket
      |> assign(:editing_blocks, new_blocks)
      |> assign(:editor_history, history)
      |> assign(:editor_future, [])
      |> assign(:editor_dirty, true)
      |> assign(:editor_at_defaults, at_defaults)
      |> assign(:editor_live_region_message, message)

    case type do
      :content -> reload_block_data(socket, new_blocks)
      :reorder -> socket
    end
  end

  defp reload_block_data(socket, blocks) do
    extra = Pages.load_block_data(blocks, socket.assigns)
    Enum.reduce(extra, socket, fn {key, value}, acc -> assign(acc, key, value) end)
  end

  # ── Theme editing helpers ───────────────────────────────────────────

  # Load theme state without changing tabs (for settings tab that needs theme data)
  defp load_theme_state(socket) do
    theme_settings = Settings.get_theme_settings()

    generated_css =
      CSSGenerator.generate(theme_settings, &BerrypodWeb.Endpoint.static_path/1)

    active_preset = Presets.detect_preset(theme_settings)

    logo_image = Media.get_logo()
    header_image = Media.get_header()
    icon_image = Media.get_icon()

    contrast_warning = compute_header_contrast(theme_settings, header_image)

    socket
    |> assign(:theme_editing, true)
    |> assign(:theme_editor_settings, theme_settings)
    |> assign(:theme_editor_active_preset, active_preset)
    |> assign(:theme_editor_logo_image, logo_image)
    |> assign(:theme_editor_header_image, header_image)
    |> assign(:theme_editor_icon_image, icon_image)
    |> assign(:theme_editor_contrast_warning, contrast_warning)
    |> assign(:theme_editor_customise_open, false)
    # Update both editor and shop state
    |> assign(:theme_settings, theme_settings)
    |> assign(:generated_css, generated_css)
    |> assign(:editor_sheet_state, :open)
  end

  defp enter_theme_edit_mode(socket) do
    socket
    |> load_theme_state()
    |> assign(:editor_active_tab, :theme)
  end

  defp exit_theme_edit_mode(socket) do
    socket
    |> assign(:theme_editing, false)
    |> assign(:theme_editor_settings, nil)
    |> assign(:theme_editor_active_preset, nil)
    |> assign(:theme_editor_contrast_warning, :ok)
    |> assign(:theme_editor_customise_open, false)
  end

  defp compute_header_contrast(theme_settings, header_image) do
    if theme_settings.header_background_enabled && header_image do
      text_color = Contrast.text_color_for_mood(theme_settings.mood)
      colors = Contrast.parse_dominant_colors(header_image.dominant_colors)
      Contrast.analyze_header_contrast(colors, text_color)
    else
      :ok
    end
  end
end