arcana

defmodule Arcana.FileParser.PDF.Poppler do
  @moduledoc """
  PDF parser using poppler's `pdftotext` command.

  This is the default PDF parser for Arcana. It requires the `pdftotext`
  command from the Poppler library to be installed on the system.

  ## Installation

      # macOS
      brew install poppler

      # Ubuntu/Debian
      apt-get install poppler-utils

      # Fedora
      dnf install poppler-utils

  ## Options

    * `:layout` - Preserve original text layout (default: true)

  """

  @behaviour Arcana.FileParser.PDF

  @doc """
  Checks if `pdftotext` is available on the system.

  ## Examples

      iex> Arcana.FileParser.PDF.Poppler.available?()
      true  # or false if poppler not installed

  """
  def available? do
    case System.find_executable("pdftotext") do
      nil -> false
      _path -> true
    end
  end

  @doc """
  Returns false - Poppler requires a file path, not binary content.
  """
  def supports_binary?, do: false

  @impl true
  def parse(path, opts) when is_binary(path) do
    cond do
      not available?() -> {:error, :poppler_not_available}
      not File.exists?(path) -> {:error, :file_not_found}
      true -> extract_text(path, opts)
    end
  end

  defp extract_text(path, opts) do
    layout = Keyword.get(opts, :layout, true)
    args = build_args(path, layout)

    case System.cmd("pdftotext", args, stderr_to_stdout: true) do
      {text, 0} ->
        {:ok, String.trim(text)}

      {error_output, _code} ->
        {:error, {:pdftotext_failed, error_output}}
    end
  end

  defp build_args(path, layout) do
    base_args = if layout, do: ["-layout"], else: []
    base_args ++ [path, "-"]
  end
end