neiam /gitgud

defmodule GitGud.Federation.Workers.Retention do
  @moduledoc """
  Periodic pruner for federation audit data.

  Three independently configurable retention windows:

      config :git_gud, GitGud.Federation.Workers.Retention,
        inbox_deliveries_days: 90,
        outbound_deliveries_days: 30,
        remote_activities_days: 365

  Any value of `nil` (or absence of the key) disables pruning for that
  bucket. Local-generated activities (`is_local: true`) are *never*
  pruned automatically — they're the audit trail for what we
  published.

  Schedule via Oban Cron, e.g.:

      config :git_gud, Oban,
        plugins: [
          {Oban.Plugins.Cron, crontab: [
            {"@daily", GitGud.Federation.Workers.Retention}
          ]}
        ]
  """

  use Oban.Worker, queue: :default, max_attempts: 3

  import Ecto.Query, warn: false

  alias GitGud.Federation.Activity
  alias GitGud.Federation.InboxDelivery
  alias GitGud.Federation.OutboundDelivery
  alias GitGud.Repo

  @impl Oban.Worker
  def perform(_job) do
    opts = Application.get_env(:git_gud, __MODULE__, [])

    prune_table(InboxDelivery, Keyword.get(opts, :inbox_deliveries_days))
    prune_table(OutboundDelivery, Keyword.get(opts, :outbound_deliveries_days))
    prune_remote_activities(Keyword.get(opts, :remote_activities_days))

    :ok
  end

  defp prune_table(_schema, nil), do: 0
  defp prune_table(_schema, n) when not is_integer(n), do: 0

  defp prune_table(schema, days) when is_integer(days) and days > 0 do
    cutoff = DateTime.utc_now() |> DateTime.add(-days * 86_400, :second)

    {count, _} =
      Repo.delete_all(from r in schema, where: r.inserted_at < ^cutoff)

    count
  end

  defp prune_remote_activities(nil), do: 0
  defp prune_remote_activities(n) when not is_integer(n), do: 0

  defp prune_remote_activities(days) when is_integer(days) and days > 0 do
    cutoff = DateTime.utc_now() |> DateTime.add(-days * 86_400, :second)

    {count, _} =
      Repo.delete_all(
        from a in Activity,
          where: a.is_local == false and a.inserted_at < ^cutoff
      )

    count
  end

  @doc """
  Run all prunes immediately (for tests + manual ops via
  `mix gitgud.federation.prune`).
  """
  def run_now do
    perform(%Oban.Job{args: %{}})
  end
end