defmodule Remedy.Gateway do
  @moduledoc """
  Exposes functions for gateway interraction.
  """

  use Supervisor
  alias Remedy.API
  alias Remedy.Gateway.{EventBroadcaster, EventBuffer, SessionSupervisor}
  require Logger

  @doc false
  def info do
    {:ok, %{shards: shards, url: "wss://" <> url}} = API.get_gateway_bot()

    %{url: url, shards: shards}
  end

  @doc false
  def num_shards do
    %{shards: shards} = info()
    shards
  end

  @doc false
  def start_link(_args) do
    %{url: _url, shards: _shards} = state = info()

    Supervisor.start_link(__MODULE__, state, name: __MODULE__)
  end

  @doc false
  def init(%{url: url, shards: shards}) do
    children =
      [
        EventBroadcaster,
        EventBuffer
      ] ++ shard_workers(url, shards)

    Supervisor.init(children, strategy: :one_for_one, max_restarts: 3, max_seconds: 60)
  end

  defp shard_workers(gateway, shards),
    do: for(shard <- 0..(shards - 1), into: [], do: shard_worker(gateway, shard))

  defp shard_worker(gateway, shard),
    do: Supervisor.child_spec({SessionSupervisor, %{gateway: gateway, shard: shard}}, id: shard)
end