defmodule Mv.Config do
  @moduledoc """
  Configuration helper functions for the application.

  Provides centralized access to configuration values to avoid
  magic strings/atoms scattered throughout the codebase.
  """

  @doc """
  Returns whether SQL sandbox mode is enabled.

  SQL sandbox mode is typically enabled in test environments
  to allow concurrent database access in tests.

  ## Returns

    - `true` if SQL sandbox is enabled
    - `false` otherwise
  """
  @spec sql_sandbox?() :: boolean()
  def sql_sandbox? do
    Application.get_env(:mv, :sql_sandbox, false)
  end

  @doc """
  Returns the maximum file size for CSV imports in bytes.

  Reads the `max_file_size_mb` value from the CSV import configuration
  and converts it to bytes.

  ## Returns

    - Maximum file size in bytes (default: 10_485_760 bytes = 10 MB)

  ## Examples

      iex> Mv.Config.csv_import_max_file_size_bytes()
      10_485_760
  """
  @spec csv_import_max_file_size_bytes() :: non_neg_integer()
  def csv_import_max_file_size_bytes do
    max_file_size_mb = get_csv_import_config(:max_file_size_mb, 10)
    max_file_size_mb * 1024 * 1024
  end

  @doc """
  Returns the maximum number of rows allowed in CSV imports.

  Reads the `max_rows` value from the CSV import configuration.

  ## Returns

    - Maximum number of rows (default: 1000)

  ## Examples

      iex> Mv.Config.csv_import_max_rows()
      1000
  """
  @spec csv_import_max_rows() :: pos_integer()
  def csv_import_max_rows do
    get_csv_import_config(:max_rows, 1000)
  end

  @doc """
  Returns the maximum file size for CSV imports in megabytes.

  Reads the `max_file_size_mb` value from the CSV import configuration.

  ## Returns

    - Maximum file size in megabytes (default: 10)

  ## Examples

      iex> Mv.Config.csv_import_max_file_size_mb()
      10
  """
  @spec csv_import_max_file_size_mb() :: pos_integer()
  def csv_import_max_file_size_mb do
    get_csv_import_config(:max_file_size_mb, 10)
  end

  # Helper function to get CSV import config values
  defp get_csv_import_config(key, default) do
    Application.get_env(:mv, :csv_import, [])
    |> Keyword.get(key, default)
    |> parse_and_validate_integer(default)
  end

  # Parses and validates integer configuration values.
  #
  # Accepts:
  # - Integer values (passed through)
  # - String integers (e.g., "1000") - parsed to integer
  # - Invalid values (e.g., "abc", nil) - falls back to default
  #
  # Always clamps the result to a minimum of 1 to ensure positive values.
  #
  # Note: We don't log warnings for unparseable values because:
  # - These functions may be called frequently (e.g., on every request)
  # - Logging would create excessive log spam
  # - The fallback to default provides a safe behavior
  # - Configuration errors should be caught during deployment/testing
  defp parse_and_validate_integer(value, _default) when is_integer(value) do
    max(1, value)
  end

  defp parse_and_validate_integer(value, default) when is_binary(value) do
    case Integer.parse(value) do
      {int, _remainder} -> max(1, int)
      :error -> default
    end
  end

  defp parse_and_validate_integer(_value, default) do
    default
  end
end