defmodule BerrypodWeb.Admin.Pages.Editor do
  use BerrypodWeb, :live_view

  alias Berrypod.Pages
  alias Berrypod.Pages.{BlockTypes, Defaults}

  @impl true
  def mount(%{"slug" => slug}, _session, socket) do
    page = Pages.get_page(slug)
    allowed_blocks = BlockTypes.allowed_for(slug)

    {:ok,
     socket
     |> assign(:page_title, page.title)
     |> assign(:slug, slug)
     |> assign(:page_data, page)
     |> assign(:blocks, page.blocks)
     |> assign(:allowed_blocks, allowed_blocks)
     |> assign(:dirty, false)
     |> assign(:show_picker, false)
     |> assign(:picker_filter, "")
     |> assign(:expanded, MapSet.new())
     |> assign(:live_region_message, nil)}
  end

  @impl true
  def handle_event("move_up", %{"id" => block_id}, socket) do
    blocks = socket.assigns.blocks
    idx = Enum.find_index(blocks, &(&1["id"] == block_id))

    if idx && idx > 0 do
      block = Enum.at(blocks, idx)
      block_name = block_display_name(block)
      new_pos = idx

      new_blocks =
        blocks
        |> List.delete_at(idx)
        |> List.insert_at(idx - 1, block)

      {:noreply,
       socket
       |> assign(:blocks, new_blocks)
       |> assign(:dirty, true)
       |> assign(:live_region_message, "#{block_name} moved to position #{new_pos}")}
    else
      {:noreply, socket}
    end
  end

  def handle_event("move_down", %{"id" => block_id}, socket) do
    blocks = socket.assigns.blocks
    idx = Enum.find_index(blocks, &(&1["id"] == block_id))

    if idx && idx < length(blocks) - 1 do
      block = Enum.at(blocks, idx)
      block_name = block_display_name(block)
      new_pos = idx + 2

      new_blocks =
        blocks
        |> List.delete_at(idx)
        |> List.insert_at(idx + 1, block)

      {:noreply,
       socket
       |> assign(:blocks, new_blocks)
       |> assign(:dirty, true)
       |> assign(:live_region_message, "#{block_name} moved to position #{new_pos}")}
    else
      {:noreply, socket}
    end
  end

  def handle_event("remove_block", %{"id" => block_id}, socket) do
    block = Enum.find(socket.assigns.blocks, &(&1["id"] == block_id))
    block_name = block_display_name(block)
    new_blocks = Enum.reject(socket.assigns.blocks, &(&1["id"] == block_id))

    {:noreply,
     socket
     |> assign(:blocks, new_blocks)
     |> assign(:dirty, true)
     |> assign(:live_region_message, "#{block_name} removed")}
  end

  def handle_event("duplicate_block", %{"id" => block_id}, socket) do
    blocks = socket.assigns.blocks
    idx = Enum.find_index(blocks, &(&1["id"] == block_id))

    if idx do
      original = Enum.at(blocks, idx)

      copy = %{
        "id" => Defaults.generate_block_id(),
        "type" => original["type"],
        "settings" => original["settings"] || %{}
      }

      block_name = block_display_name(original)
      new_blocks = List.insert_at(blocks, idx + 1, copy)

      {:noreply,
       socket
       |> assign(:blocks, new_blocks)
       |> assign(:dirty, true)
       |> assign(:live_region_message, "#{block_name} duplicated")}
    else
      {:noreply, socket}
    end
  end

  def handle_event("toggle_expand", %{"id" => block_id}, socket) do
    expanded = socket.assigns.expanded
    block = Enum.find(socket.assigns.blocks, &(&1["id"] == block_id))
    block_name = 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

    {:noreply,
     socket
     |> assign(:expanded, new_expanded)
     |> assign(:live_region_message, "#{block_name} settings #{action}")}
  end

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

    # Find the block and its schema to coerce types
    block = Enum.find(socket.assigns.blocks, &(&1["id"] == block_id))

    if block do
      schema =
        case BlockTypes.get(block["type"]) do
          %{settings_schema: s} -> s
          _ -> []
        end

      coerced = coerce_settings(new_settings, schema)

      new_blocks =
        Enum.map(socket.assigns.blocks, fn b ->
          if b["id"] == block_id do
            Map.put(b, "settings", Map.merge(b["settings"] || %{}, coerced))
          else
            b
          end
        end)

      {:noreply,
       socket
       |> assign(:blocks, new_blocks)
       |> assign(:dirty, true)}
    else
      {:noreply, socket}
    end
  end

  def handle_event("show_picker", _params, socket) do
    {:noreply,
     socket
     |> assign(:show_picker, true)
     |> assign(:picker_filter, "")}
  end

  def handle_event("hide_picker", _params, socket) do
    {:noreply, assign(socket, :show_picker, false)}
  end

  def handle_event("filter_picker", %{"value" => value}, socket) do
    {:noreply, assign(socket, :picker_filter, value)}
  end

  def handle_event("add_block", %{"type" => type}, socket) do
    block_def = BlockTypes.get(type)

    if block_def do
      # Build default settings from schema
      default_settings =
        block_def
        |> Map.get(:settings_schema, [])
        |> Enum.into(%{}, fn field -> {field.key, field.default} end)

      new_block = %{
        "id" => Defaults.generate_block_id(),
        "type" => type,
        "settings" => default_settings
      }

      {:noreply,
       socket
       |> assign(:blocks, socket.assigns.blocks ++ [new_block])
       |> assign(:dirty, true)
       |> assign(:show_picker, false)
       |> assign(:live_region_message, "#{block_def.name} added")}
    else
      {:noreply, socket}
    end
  end

  def handle_event("save", _params, socket) do
    %{slug: slug, blocks: blocks, page_data: page_data} = socket.assigns

    case Pages.save_page(slug, %{title: page_data.title, blocks: blocks}) do
      {:ok, _page} ->
        {:noreply,
         socket
         |> assign(:dirty, false)
         |> put_flash(:info, "Page saved")}

      {:error, _changeset} ->
        {:noreply, put_flash(socket, :error, "Failed to save page")}
    end
  end

  def handle_event("reset_defaults", _params, socket) do
    slug = socket.assigns.slug
    :ok = Pages.reset_page(slug)
    page = Pages.get_page(slug)

    {:noreply,
     socket
     |> assign(:blocks, page.blocks)
     |> assign(:dirty, false)
     |> put_flash(:info, "Page reset to defaults")}
  end

  @impl true
  def render(assigns) do
    ~H"""
    <div id="page-editor" phx-hook="DirtyGuard" data-dirty={to_string(@dirty)}>
      <.link
        navigate={~p"/admin/pages"}
        class="text-sm font-normal text-base-content/60 hover:underline"
      >
        &larr; Pages
      </.link>
      <.header>
        {@page_data.title}
        <:actions>
          <button
            phx-click="reset_defaults"
            data-confirm="Reset this page to its default layout? Your changes will be lost."
            class="admin-btn admin-btn-sm admin-btn-ghost"
          >
            Reset to defaults
          </button>
          <button
            phx-click="save"
            class={["admin-btn admin-btn-sm admin-btn-primary", !@dirty && "opacity-50"]}
            disabled={!@dirty}
          >
            Save
          </button>
        </:actions>
      </.header>

      <%!-- ARIA live region for screen reader announcements --%>
      <div aria-live="polite" aria-atomic="true" class="sr-only">
        {if @live_region_message, do: @live_region_message}
      </div>

      <%!-- Unsaved changes indicator --%>
      <p :if={@dirty} class="admin-badge admin-badge-warning mt-4">
        Unsaved changes
      </p>

      <%!-- Block list --%>
      <div class="block-list" role="list" aria-label="Page blocks">
        <.block_card
          :for={{block, idx} <- Enum.with_index(@blocks)}
          block={block}
          idx={idx}
          total={length(@blocks)}
          expanded={@expanded}
        />

        <div :if={@blocks == []} class="block-list-empty">
          <p>No blocks on this page yet.</p>
        </div>
      </div>

      <%!-- Add block button --%>
      <div class="block-actions">
        <button phx-click="show_picker" class="admin-btn admin-btn-outline block-add-btn">
          <.icon name="hero-plus" class="size-4" /> Add block
        </button>
      </div>

      <%!-- Block picker modal --%>
      <.block_picker
        :if={@show_picker}
        allowed_blocks={@allowed_blocks}
        filter={@picker_filter}
      />
    </div>
    """
  end

  defp block_card(assigns) do
    block_type = BlockTypes.get(assigns.block["type"])
    has_settings = has_settings?(assigns.block)
    expanded = MapSet.member?(assigns.expanded, assigns.block["id"])

    assigns =
      assigns
      |> assign(:block_type, block_type)
      |> assign(:has_settings, has_settings)
      |> assign(:is_expanded, expanded)

    ~H"""
    <div
      class={["block-card", @is_expanded && "block-card-expanded"]}
      role="listitem"
      aria-label={"#{@block_type && @block_type.name || @block["type"]}, position #{@idx + 1} of #{@total}"}
      id={"block-#{@block["id"]}"}
    >
      <div class="block-card-header">
        <span class="block-card-position">{@idx + 1}</span>

        <span class="block-card-icon">
          <.icon name={(@block_type && @block_type.icon) || "hero-puzzle-piece"} class="size-5" />
        </span>

        <span class="block-card-name">
          {(@block_type && @block_type.name) || @block["type"]}
        </span>

        <span class="block-card-controls">
          <button
            :if={@has_settings}
            phx-click="toggle_expand"
            phx-value-id={@block["id"]}
            class={[
              "admin-btn admin-btn-ghost admin-btn-icon admin-btn-sm",
              @is_expanded && "block-edit-btn-active"
            ]}
            aria-label={"Edit #{@block_type && @block_type.name} settings"}
            aria-expanded={to_string(@is_expanded)}
            aria-controls={"block-settings-#{@block["id"]}"}
            id={"block-edit-btn-#{@block["id"]}"}
          >
            <.icon name="hero-cog-6-tooth-mini" class="size-4" />
          </button>
          <button
            phx-click="move_up"
            phx-value-id={@block["id"]}
            class="admin-btn admin-btn-ghost admin-btn-icon admin-btn-sm"
            aria-label={"Move #{@block_type && @block_type.name} up"}
            disabled={@idx == 0}
          >
            <.icon name="hero-chevron-up-mini" class="size-4" />
          </button>
          <button
            phx-click="move_down"
            phx-value-id={@block["id"]}
            class="admin-btn admin-btn-ghost admin-btn-icon admin-btn-sm"
            aria-label={"Move #{@block_type && @block_type.name} down"}
            disabled={@idx == @total - 1}
          >
            <.icon name="hero-chevron-down-mini" class="size-4" />
          </button>
          <button
            phx-click="duplicate_block"
            phx-value-id={@block["id"]}
            class="admin-btn admin-btn-ghost admin-btn-icon admin-btn-sm"
            aria-label={"Duplicate #{@block_type && @block_type.name}"}
          >
            <.icon name="hero-document-duplicate-mini" class="size-4" />
          </button>
          <button
            phx-click="remove_block"
            phx-value-id={@block["id"]}
            class="admin-btn admin-btn-ghost admin-btn-icon admin-btn-sm block-remove-btn"
            aria-label={"Remove #{@block_type && @block_type.name}"}
            data-confirm={"Remove #{@block_type && @block_type.name}?"}
          >
            <.icon name="hero-trash-mini" class="size-4" />
          </button>
        </span>
      </div>

      <.block_settings_form
        :if={@is_expanded}
        block={@block}
        schema={@block_type.settings_schema}
      />
    </div>
    """
  end

  defp block_settings_form(assigns) do
    settings = settings_with_defaults(assigns.block)
    assigns = assign(assigns, :settings, settings)

    ~H"""
    <div class="block-card-settings" id={"block-settings-#{@block["id"]}"}>
      <form phx-change="update_block_settings">
        <input type="hidden" name="block_id" value={@block["id"]} />

        <div class="block-settings-fields">
          <.block_field
            :for={field <- @schema}
            field={field}
            value={@settings[field.key]}
            block_id={@block["id"]}
          />
        </div>
      </form>
    </div>
    """
  end

  defp block_field(%{field: %{type: :select}} = assigns) do
    ~H"""
    <div class="admin-fieldset">
      <label>
        <span class="admin-label">{@field.label}</span>
        <select
          name={"block_settings[#{@field.key}]"}
          id={"block-#{@block_id}-#{@field.key}"}
          class="admin-select"
          phx-debounce="blur"
        >
          {Phoenix.HTML.Form.options_for_select(@field.options, to_string(@value))}
        </select>
      </label>
    </div>
    """
  end

  defp block_field(%{field: %{type: :textarea}} = assigns) do
    ~H"""
    <div class="admin-fieldset">
      <label>
        <span class="admin-label">{@field.label}</span>
        <textarea
          name={"block_settings[#{@field.key}]"}
          id={"block-#{@block_id}-#{@field.key}"}
          class="admin-textarea"
          rows="3"
          phx-debounce="300"
        >{@value}</textarea>
      </label>
    </div>
    """
  end

  defp block_field(%{field: %{type: :number}} = assigns) do
    ~H"""
    <div class="admin-fieldset">
      <label>
        <span class="admin-label">{@field.label}</span>
        <input
          type="number"
          name={"block_settings[#{@field.key}]"}
          id={"block-#{@block_id}-#{@field.key}"}
          value={@value}
          class="admin-input"
          phx-debounce="blur"
        />
      </label>
    </div>
    """
  end

  defp block_field(%{field: %{type: :json}} = assigns) do
    json_str =
      case assigns.value do
        val when is_list(val) or is_map(val) -> Jason.encode!(val, pretty: true)
        val when is_binary(val) -> val
        _ -> "[]"
      end

    assigns = assign(assigns, :json_str, json_str)

    ~H"""
    <div class="admin-fieldset">
      <label>
        <span class="admin-label">{@field.label}</span>
        <textarea
          name={"block_settings[#{@field.key}]"}
          id={"block-#{@block_id}-#{@field.key}"}
          class="admin-textarea block-settings-json"
          rows="4"
          readonly
          aria-readonly="true"
        >{@json_str}</textarea>
        <p class="block-settings-hint">JSON data — editing coming soon</p>
      </label>
    </div>
    """
  end

  defp block_field(assigns) do
    ~H"""
    <div class="admin-fieldset">
      <label>
        <span class="admin-label">{@field.label}</span>
        <input
          type="text"
          name={"block_settings[#{@field.key}]"}
          id={"block-#{@block_id}-#{@field.key}"}
          value={@value}
          class="admin-input"
          phx-debounce="300"
        />
      </label>
    </div>
    """
  end

  defp block_picker(assigns) do
    filter = String.downcase(assigns.filter)

    filtered =
      assigns.allowed_blocks
      |> Enum.filter(fn {_type, def} ->
        filter == "" or String.contains?(String.downcase(def.name), filter)
      end)
      |> Enum.sort_by(fn {_type, def} -> def.name end)

    assigns = assign(assigns, :filtered_blocks, filtered)

    ~H"""
    <div class="block-picker-overlay" phx-click="hide_picker">
      <div class="block-picker" phx-click-away="hide_picker">
        <div class="block-picker-header">
          <h3>Add a block</h3>
          <button
            phx-click="hide_picker"
            class="admin-btn admin-btn-ghost admin-btn-icon admin-btn-sm"
            aria-label="Close"
          >
            <.icon name="hero-x-mark" class="size-5" />
          </button>
        </div>

        <input
          type="text"
          placeholder="Filter blocks..."
          value={@filter}
          phx-keyup="filter_picker"
          phx-key=""
          class="admin-input block-picker-search"
          autofocus
        />

        <div class="block-picker-grid">
          <button
            :for={{type, def} <- @filtered_blocks}
            phx-click="add_block"
            phx-value-type={type}
            class="block-picker-item"
          >
            <.icon name={def.icon} class="size-5" />
            <span>{def.name}</span>
          </button>

          <p :if={@filtered_blocks == []} class="block-picker-empty">
            No matching blocks.
          </p>
        </div>
      </div>
    </div>
    """
  end

  defp block_display_name(nil), do: "Block"

  defp block_display_name(block) do
    case BlockTypes.get(block["type"]) do
      %{name: name} -> name
      _ -> block["type"]
    end
  end

  defp coerce_settings(params, schema) do
    type_map = Map.new(schema, fn field -> {field.key, field} end)

    Map.new(params, fn {key, value} ->
      case type_map[key] do
        %{type: :number, default: default} ->
          {key, parse_number(value, default)}

        _ ->
          {key, value}
      end
    end)
  end

  defp parse_number(value, default) when is_binary(value) do
    case Integer.parse(value) do
      {n, ""} -> n
      _ -> default
    end
  end

  defp parse_number(value, _default) when is_integer(value), do: value
  defp parse_number(_value, default), do: default

  defp has_settings?(block) do
    case BlockTypes.get(block["type"]) do
      %{settings_schema: [_ | _]} -> true
      _ -> false
    end
  end

  defp settings_with_defaults(block) do
    schema =
      case BlockTypes.get(block["type"]) do
        %{settings_schema: s} -> s
        _ -> []
      end

    defaults = Map.new(schema, fn field -> {field.key, field.default} end)
    Map.merge(defaults, block["settings"] || %{})
  end
end