defmodule LabelmakerWeb.LabelsController do
  use LabelmakerWeb, :controller
  alias LabelmakerWeb.Constants

  @label_dir Path.join(:code.priv_dir(:labelmaker), "static/labels")

  def index(conn, params) do
    page = parse_page(params["page"])
    all_labels = list_labels()
    total_count = length(all_labels)
    total_pages = ceil(total_count / Constants.labels_per_page())

    # Ensure page is within valid range
    page = max(1, min(page, max(total_pages, 1)))

    labels = paginate(all_labels, page)

    render(conn, :index,
      labels: labels,
      page: page,
      total_pages: total_pages,
      total_count: total_count,
      per_page: Constants.labels_per_page()
    )
  end

  defp parse_page(nil), do: 1

  defp parse_page(page_str) do
    case Integer.parse(page_str) do
      {page, _} when page > 0 -> page
      _ -> 1
    end
  end

  defp paginate(labels, page) do
    labels
    |> Enum.drop((page - 1) * Constants.labels_per_page())
    |> Enum.take(Constants.labels_per_page())
  end

  defp list_labels do
    case File.ls(@label_dir) do
      {:ok, files} ->
        files
        |> Enum.filter(&String.ends_with?(&1, ".png"))
        |> Enum.map(fn filename ->
          filepath = Path.join(@label_dir, filename)
          stat = File.stat!(filepath)

          %{
            filename: filename,
            filepath: filepath,
            size: stat.size,
            modified: stat.mtime,
            url: "/labels/#{filename}"
          }
        end)
        |> Enum.sort_by(& &1.modified, :desc)

      {:error, :enoent} ->
        # Directory doesn't exist yet
        []

      {:error, _reason} ->
        []
    end
  end
end