defmodule ThousandIsland.TelemetryCollector do
  @moduledoc false

  use GenServer

  def start_link(event_types) do
    GenServer.start_link(__MODULE__, event_types)
  end

  def record_event(event, measurements, metadata, pid) do
    GenServer.cast(pid, {:event, event, measurements, metadata})
  end

  def get_events(pid) do
    GenServer.call(pid, :get_events)
  end

  def init(event_types) do
    :telemetry.attach_many("#{__MODULE__}.trace", event_types, &record_event/4, self())
    {:ok, []}
  end

  def handle_cast({:event, event, measurements, metadata}, events) do
    {:noreply, [{event, measurements, metadata} | events]}
  end

  def handle_call(:get_events, _from, events) do
    {:reply, Enum.reverse(events), events}
  end
end