dbus

defmodule Dbus.Db do
  require Logger
  alias Dbus.Redis, as: R

  def kill() do
    Logger.info("Removing all topics and messages...")
    R.q!(["SMEMBERS", "topics"]) |> Enum.map(&unregister(&1))
    R.q(["DEL", "topics"])
    Logger.debug("DONE, Removing all topics and messages.")
  end

  def register(topic) do
    was_added = R.q!(["SADD", "topics", topic]) == "1"
    if was_added do
      Logger.info("Registered topic #{topic}.")
    else
      Logger.debug("Topic #{topic}, already registered.")
    end
  end

  def unregister(topic) do
    was_removed = R.q!(["SREM", "topics", topic]) == "1"
    if was_removed do
      R.q!(["DEL",
            topic_id(topic),
            total_id(topic),
            num_processed_id(topic),
            num_failed_id(topic),
            recent_processed_id(topic),
            recent_failed_id(topic),
            last_total_id(topic),
            last_size_id(topic),
            tock_id(topic)])
      Logger.info("Unregistered topic #{topic}, and removed all messages.")
    else
      Logger.debug("Topic #{topic} does not exist, nothing to unregister.")
    end
  end

  def topics_id(), do: "topics"
  def topic_id(topic), do: "topics.#{topic}"
  def total_id(topic), do: "topics.#{topic}.num-total"
  def num_processed_id(topic), do: "topics.#{topic}.num-processed"
  def num_failed_id(topic), do: "topics.#{topic}.num-failed"
  def recent_processed_id(topic), do: "topics.#{topic}.recent-processed"
  def recent_failed_id(topic), do: "topics.#{topic}.recent-failed"
  def last_total_id(topic), do: "topics.#{topic}.num-last-processed"
  def last_size_id(topic), do: "topics.#{topic}.num-last-count"
  def tock_id(topic), do: "topics.#{topic}.tock"

  def to_i(""), do: 0
  def to_i(:undefined), do: 0
  def to_i(num) when is_integer(num), do: num
  def to_i(num) when is_binary(num), do: num |> String.to_integer

end