mitgliederverwaltung/lib/mv/config.ex

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

  @doc """
  Returns the maximum number of rows allowed in PDF exports.

  Reads the `row_limit` value from the PDF export configuration.

  ## Returns

    - Maximum number of rows (default: 5000)

  ## Examples

      iex> Mv.Config.pdf_export_row_limit()
      5000
  """
  @spec pdf_export_row_limit() :: pos_integer()
  def pdf_export_row_limit do
    get_pdf_export_config(:row_limit, 5000)
  end

  # Helper function to get PDF export config values
  defp get_pdf_export_config(key, default) do
    Application.get_env(:mv, :pdf_export, [])
    |> Keyword.get(key, default)
    |> parse_and_validate_integer(default)
  end

  # ---------------------------------------------------------------------------
  # Vereinfacht accounting software integration
  # ENV variables take priority; fallback to Settings from database.
  # ---------------------------------------------------------------------------

  @doc """
  Returns the Vereinfacht API base URL.

  Reads from `VEREINFACHT_API_URL` env first, then from Settings.
  """
  @spec vereinfacht_api_url() :: String.t() | nil
  def vereinfacht_api_url do
    env_or_setting("VEREINFACHT_API_URL", :vereinfacht_api_url)
  end

  @doc """
  Returns the Vereinfacht API key (Bearer token).

  Reads from `VEREINFACHT_API_KEY` env first, then from Settings.
  """
  @spec vereinfacht_api_key() :: String.t() | nil
  def vereinfacht_api_key do
    env_or_setting("VEREINFACHT_API_KEY", :vereinfacht_api_key)
  end

  @doc """
  Returns the Vereinfacht club ID for multi-tenancy.

  Reads from `VEREINFACHT_CLUB_ID` env first, then from Settings.
  """
  @spec vereinfacht_club_id() :: String.t() | nil
  def vereinfacht_club_id do
    env_or_setting("VEREINFACHT_CLUB_ID", :vereinfacht_club_id)
  end

  @doc """
  Returns true if Vereinfacht is fully configured (URL, API key, and club ID all set).
  """
  @spec vereinfacht_configured?() :: boolean()
  def vereinfacht_configured? do
    present?(vereinfacht_api_url()) and present?(vereinfacht_api_key()) and
      present?(vereinfacht_club_id())
  end

  @doc """
  Returns true if any Vereinfacht ENV variable is set (used to gray out Settings UI).
  """
  @spec vereinfacht_env_configured?() :: boolean()
  def vereinfacht_env_configured? do
    System.get_env("VEREINFACHT_API_URL") != nil or
      System.get_env("VEREINFACHT_API_KEY") != nil or
      System.get_env("VEREINFACHT_CLUB_ID") != nil
  end

  defp env_or_setting(env_key, setting_key) do
    case System.get_env(env_key) do
      nil -> get_vereinfacht_from_settings(setting_key)
      value -> trim_nil(value)
    end
  end

  defp get_vereinfacht_from_settings(key) do
    case Mv.Membership.get_settings() do
      {:ok, settings} -> settings |> Map.get(key) |> trim_nil()
      {:error, _} -> nil
    end
  end

  defp trim_nil(nil), do: nil

  defp trim_nil(s) when is_binary(s) do
    t = String.trim(s)
    if t == "", do: nil, else: t
  end

  @doc """
  Returns the URL to view a finance contact (e.g. in Vereinfacht frontend or API).

  Uses the configured API base URL and appends /finance-contacts/{id}.
  Can be extended later with a dedicated frontend URL setting.
  """
  @spec vereinfacht_contact_view_url(String.t()) :: String.t() | nil
  def vereinfacht_contact_view_url(contact_id) when is_binary(contact_id) do
    base = vereinfacht_api_url()

    if present?(base),
      do: base |> String.trim_trailing("/") |> then(&"#{&1}/finance-contacts/#{contact_id}"),
      else: nil
  end

  defp present?(nil), do: false
  defp present?(s) when is_binary(s), do: String.trim(s) != ""
  defp present?(_), do: false
end