vibe

defmodule Vibe.Gateway.Telegram.Backend do
  @moduledoc """
  Telegram implementation of the generic gateway backend contract.

  The backend ties together Telegram config, update normalization, authorization,
  and outbound adapter selection while keeping ExGram and Bot API semantics out
  of the generic gateway runtime.
  """

  @behaviour Vibe.Gateway.Backend

  alias Vibe.Gateway.Message
  alias Vibe.Gateway.Telegram.{Adapter, Authorization, Config, Polling, Update}

  @impl true
  def load_config(opts), do: Config.load(opts)

  @impl true
  def normalize(update, %Config{} = config) do
    Update.normalize(update,
      bot_id: Map.get(config, :bot_id),
      bot_username: Map.get(config, :bot_username)
    )
  end

  @impl true
  def authorized?(%Message{} = message, trigger, %Config{} = config) do
    Authorization.authorized?(message.source, config) and
      Authorization.trigger_allowed?(message.source, trigger, config)
  end

  @impl true
  def outbound_adapter(%Config{}), do: Adapter

  @impl true
  def child_specs(%Config{method: :polling} = config, runtime) do
    [
      %{
        id: :telegram_polling,
        start: {Polling, :start_link, [[config: config, runtime: runtime, name: polling_name()]]}
      }
    ]
  end

  def child_specs(%Config{}, _runtime), do: []

  defp polling_name,
    do: {:via, Registry, {Vibe.Registry, {:gateway_transport, :telegram_polling}}}
end