defmodule Polymarket.WebSocket.SocketSupervisor do
  @moduledoc """
  Dynamic supervisor for all websocket connections to polymarket.

  A single websocket can only hold so many asset ids, so sharding is required to
  make sure we can subscribe to more assets than a single connection allows.
  """
  use DynamicSupervisor

  alias Polymarket.WebSocket

  @doc false
  @spec start_link(term()) :: Supervisor.on_start()
  def start_link(init_arg) do
    DynamicSupervisor.start_link(__MODULE__, init_arg, name: __MODULE__)
  end

  @impl true
  def init(_init_arg) do
    DynamicSupervisor.init(strategy: :one_for_one)
  end

  @doc """
  Adds a new websocket connection to the supervisor.

  Accepts the same options as `Polymarket.WebSocket.start_link/1` (for example
  `handler:`) to inject a custom event handler.

  Connections are `:temporary` children: a dead connection is not restarted,
  because the restarted process would carry a new pid and no subscriptions,
  invisible to whoever opened it. Owners are expected to monitor the returned
  pid and open a replacement themselves.
  """
  @spec add_connection(keyword()) :: DynamicSupervisor.on_start_child()
  def add_connection(opts \\ []) do
    DynamicSupervisor.start_child(
      __MODULE__,
      Supervisor.child_spec({WebSocket, opts}, restart: :temporary)
    )
  end
end