defmodule CSVLoader do
  @moduledoc """
  Loads test cases from CSV files.
  """

  @doc """
  Loads test cases from a CSV file.
  
  ## Parameters
    - csv_path: Path to the CSV file
  
  ## Returns
    List of test case maps
  """
  def load(csv_path) do
    if !File.exists?(csv_path) do
      raise "CSV file not found: #{csv_path}"
    end

    csv_path
    |> File.stream!()
    |> Stream.map(&String.trim/1)
    |> Stream.reject(&(&1 == ""))
    |> Enum.to_list()
    |> parse_csv()
  end

  defp parse_csv([header_line | data_lines]) do
    headers = parse_csv_line(header_line)
    
    Enum.map(data_lines, fn line ->
      values = parse_csv_line(line)
      
      headers
      |> Enum.zip(values)
      |> Enum.into(%{}, fn {key, value} ->
        {String.to_atom(key), value}
      end)
    end)
  end

  defp parse_csv([]), do: []

  defp parse_csv_line(line) do
    # Simple CSV parser (handles basic cases without quoted fields with commas)
    String.split(line, ",")
    |> Enum.map(&String.trim/1)
  end

  @doc """
  Loads test cases and filters by specific test IDs if provided.
  """
  def load_with_filter(csv_path, test_ids \\ nil) do
    test_cases = load(csv_path)
    
    if test_ids && test_ids != [] do
      Enum.filter(test_cases, fn tc ->
        Enum.member?(test_ids, tc.test_id)
      end)
    else
      test_cases
    end
  end
end