defmodule PgbConnectionReaper do
  @moduledoc false
  alias PgbConnectionReaper.{Config, Reaper}

  @doc """
  Starts the PgbConnectionReaper with the given repos and options.

  ## Parameters
  - repos: A list of Ecto repo modules to monitor.
  - opts: A keyword list of options:
    - :frequency - Interval between disconnections in milliseconds (default: 5 minutes)
    - :graceful_window - Time allowed for graceful disconnection in milliseconds (default: 2 minutes)

  ## Returns
  - `{:ok, pid}`: If the Reaper starts successfully.
  - `{:error, reason}`: If there's an error starting the Reaper
  """
  @spec start_link([module()], keyword()) :: Supervisor.on_start()
  def start_link(repos, opts \\ []) when is_list(repos) do
    name = Keyword.get(opts, :name, __MODULE__)

    config = %Config{
      repos: repos,
      frequency: Keyword.get(opts, :frequency, :timer.minutes(5)),
      graceful_window: Keyword.get(opts, :graceful_window, :timer.minutes(2))
    }

    Reaper.start_link(config, name: name)
  end

  @doc """
  Returns a child specification for starting the PgbConnectionReaper
  under a supervisor.
  """
  def child_spec({repos, opts}) when is_list(opts), do: build_child_spec(repos, opts)
  def child_spec([repos, opts]) when is_list(opts), do: build_child_spec(repos, opts)
  def child_spec([repos]), do: build_child_spec(repos, [])

  defp build_child_spec(repos, opts) do
    name = Keyword.get(opts, :name, __MODULE__)

    %{
      id: name,
      start: {__MODULE__, :start_link, [repos, opts]},
      type: :worker
    }
  end
end