defmodule BerrypodWeb.Components.SeoPreview do
  @moduledoc """
  SEO preview component showing how pages appear in search results and social cards.

  Provides live-updating previews as users edit page titles and descriptions,
  with character count indicators showing optimal lengths.
  """

  use Phoenix.Component

  @doc """
  Renders the full SEO preview panel with Google and social previews.
  """
  attr :title, :string, required: true
  attr :description, :string, default: ""
  attr :url, :string, required: true
  attr :og_image, :string, default: nil
  attr :site_name, :string, required: true

  def seo_preview(assigns) do
    ~H"""
    <div class="seo-preview">
      <.google_preview title={@title} description={@description} url={@url} site_name={@site_name} />
      <.social_preview
        title={@title}
        description={@description}
        url={@url}
        image={@og_image}
        site_name={@site_name}
      />
      <.character_counts title={@title} description={@description} />
    </div>
    """
  end

  @doc """
  Google search result preview mockup.
  """
  attr :title, :string, required: true
  attr :description, :string, default: ""
  attr :url, :string, required: true
  attr :site_name, :string, required: true

  def google_preview(assigns) do
    # Truncate title at ~60 chars, description at ~160 chars
    truncated_title = truncate(assigns.title, 60)
    truncated_desc = truncate(assigns.description || "", 160)

    # Build breadcrumb-style URL
    breadcrumb = build_breadcrumb(assigns.url, assigns.site_name)

    assigns =
      assigns
      |> assign(:truncated_title, truncated_title)
      |> assign(:truncated_desc, truncated_desc)
      |> assign(:breadcrumb, breadcrumb)

    ~H"""
    <div class="seo-preview-section">
      <div class="seo-preview-label">Google search preview</div>
      <div class="seo-google-preview">
        <div class="seo-google-breadcrumb">{@breadcrumb}</div>
        <div class="seo-google-title">{@truncated_title}</div>
        <div class="seo-google-description">{@truncated_desc}</div>
      </div>
    </div>
    """
  end

  @doc """
  Social media card preview (Facebook/Twitter style).
  """
  attr :title, :string, required: true
  attr :description, :string, default: ""
  attr :url, :string, required: true
  attr :image, :string, default: nil
  attr :site_name, :string, required: true

  def social_preview(assigns) do
    truncated_title = truncate(assigns.title, 70)
    truncated_desc = truncate(assigns.description || "", 100)
    domain = extract_domain(assigns.url)

    assigns =
      assigns
      |> assign(:truncated_title, truncated_title)
      |> assign(:truncated_desc, truncated_desc)
      |> assign(:domain, domain)

    ~H"""
    <div class="seo-preview-section">
      <div class="seo-preview-label">Social card preview</div>
      <div class="seo-social-preview">
        <div class="seo-social-image">
          <%= if @image do %>
            <img src={@image} alt="" />
          <% else %>
            <div class="seo-social-image-placeholder">
              <span>No image set</span>
            </div>
          <% end %>
        </div>
        <div class="seo-social-content">
          <div class="seo-social-domain">{@domain}</div>
          <div class="seo-social-title">{@truncated_title}</div>
          <div class="seo-social-description">{@truncated_desc}</div>
        </div>
      </div>
    </div>
    """
  end

  @doc """
  Character count indicators for title and description.
  """
  attr :title, :string, required: true
  attr :description, :string, default: ""

  def character_counts(assigns) do
    title_len = String.length(assigns.title || "")
    desc_len = String.length(assigns.description || "")

    title_status = title_status(title_len)
    desc_status = desc_status(desc_len)

    assigns =
      assigns
      |> assign(:title_len, title_len)
      |> assign(:desc_len, desc_len)
      |> assign(:title_status, title_status)
      |> assign(:desc_status, desc_status)

    ~H"""
    <div class="seo-char-counts">
      <div class="seo-char-count" data-status={@title_status}>
        <span class="seo-char-label">Title</span>
        <span class="seo-char-value">{@title_len}/60</span>
        <span class="seo-char-indicator"></span>
      </div>
      <div class="seo-char-count" data-status={@desc_status}>
        <span class="seo-char-label">Description</span>
        <span class="seo-char-value">{@desc_len}/160</span>
        <span class="seo-char-indicator"></span>
      </div>
    </div>
    """
  end

  # Title: green ≤60, yellow 61-70, red >70
  defp title_status(len) when len <= 60, do: "good"
  defp title_status(len) when len <= 70, do: "warning"
  defp title_status(_), do: "error"

  # Description: green 120-155, yellow 100-119 or 156-160, red <100 or >160
  defp desc_status(len) when len >= 120 and len <= 155, do: "good"
  defp desc_status(len) when len >= 100 and len <= 160, do: "warning"
  defp desc_status(_), do: "error"

  defp truncate(nil, _max), do: ""
  defp truncate("", _max), do: ""

  defp truncate(text, max) when byte_size(text) > max do
    String.slice(text, 0, max - 3) <> "..."
  end

  defp truncate(text, _max), do: text

  defp build_breadcrumb(url, site_name) do
    case URI.parse(url) do
      %URI{path: path} when is_binary(path) ->
        parts =
          path
          |> String.split("/", trim: true)
          |> Enum.take(2)

        if parts == [] do
          site_name
        else
          site_name <> " › " <> Enum.join(parts, " › ")
        end

      _ ->
        site_name
    end
  end

  defp extract_domain(url) do
    case URI.parse(url) do
      %URI{host: host} when is_binary(host) -> host
      _ -> "example.com"
    end
  end
end