defmodule ComponentsElixir.QRCode do
  @moduledoc """
  QR Code generation and parsing for storage locations.

  Provides functionality to generate QR codes for storage locations
  and parse them back to retrieve location information.
  """

  @doc """
  Generates a QR code data string for a storage location.

  Format: SL:{level}:{qr_code}:{parent_qr_or_ROOT}

  ## Examples

      iex> location = %StorageLocation{level: 1, qr_code: "ABC123", parent: nil}
      iex> ComponentsElixir.QRCode.generate_qr_data(location)
      "SL:1:ABC123:ROOT"

      iex> parent = %StorageLocation{qr_code: "SHELF1"}
      iex> drawer = %StorageLocation{level: 2, qr_code: "DRAW01", parent: parent}
      iex> ComponentsElixir.QRCode.generate_qr_data(drawer)
      "SL:2:DRAW01:SHELF1"
  """
  def generate_qr_data(storage_location) do
    parent_code =
      case storage_location.parent do
        nil -> "ROOT"
        parent -> parent.qr_code
      end

    "SL:#{storage_location.level}:#{storage_location.qr_code}:#{parent_code}"
  end

  @doc """
  Parses a QR code string and extracts components.

  ## Examples

      iex> ComponentsElixir.QRCode.parse_qr_data("SL:1:ABC123:ROOT")
      {:ok, %{level: 1, code: "ABC123", parent: "ROOT"}}

      iex> ComponentsElixir.QRCode.parse_qr_data("invalid")
      {:error, :invalid_format}
  """
  def parse_qr_data(qr_string) do
    case String.split(qr_string, ":") do
      ["SL", level_str, code, parent] ->
        case Integer.parse(level_str) do
          {level, ""} ->
            {:ok, %{level: level, code: code, parent: parent}}
          _ ->
            {:error, :invalid_level}
        end
      _ ->
        {:error, :invalid_format}
    end
  end

  @doc """
  Validates if a string looks like a storage location QR code.

  ## Examples

      iex> ComponentsElixir.QRCode.valid_storage_qr?("SL:1:ABC123:ROOT")
      true

      iex> ComponentsElixir.QRCode.valid_storage_qr?("COMP:12345")
      false
  """
  def valid_storage_qr?(qr_string) do
    case parse_qr_data(qr_string) do
      {:ok, _} -> true
      _ -> false
    end
  end

  @doc """
  Generates a printable label data structure for a storage location.

  This could be used to generate PDF labels or send to a label printer.
  """
  def generate_label_data(storage_location) do
    qr_data = generate_qr_data(storage_location)

    %{
      qr_code: qr_data,
      name: storage_location.name,
      path: storage_location.path,
      level: storage_location.level,
      description: storage_location.description
    }
  end

  @doc """
  Generates multiple QR codes for disambiguation testing.

  This is useful for testing multi-QR detection scenarios.
  """
  def generate_test_codes(storage_locations) when is_list(storage_locations) do
    Enum.map(storage_locations, &generate_qr_data/1)
  end
end