defmodule SyncDispatch do
  @moduledoc "README.md"
             |> File.read!()
             |> String.split("<!-- MDOC !-->")
             |> Enum.fetch!(1)

  alias SyncDispatch.HandlerTable

  @type handler_function :: (list(atom()), term(), term() -> any())

  @doc """
  Executes an event and any handlers that are attached to the event name. `data`
  can be any term().
  """
  @spec execute(list(atom()), term()) :: :ok | no_return()
  def execute(event, data) do
    handlers = HandlerTable.handlers_for_event(event)

    for {handler, event, config} <- handlers do
      handler.(event, data, config)
    end

    :ok
  end

  @doc """
  Attaches a function to an event. The provided id is used for idempotence.
  Different handlers should use unique handler ids.
  """
  @spec attach(term(), list(atom()), handler_function(), term()) :: :ok | {:error, %SyncDispatch.AttachError{}}
  def attach(id, event, fun, config \\ nil) do
    HandlerTable.insert(id, event, fun, config)
  end
end