bikoret/vav_pipeline/lib/vav_pipeline/application.ex

defmodule VavPipeline.Application do
  @moduledoc """
  OTP Application for the Vav Pipeline.

  Starts the supervision tree with:
  - Repo (L3 PostgreSQL — oral tradition persistence)
  - Chatzotzrot (silver trumpets — signal system)
  - AreiMiklat (cities of refuge — protection protocol)
  - EglahArufah (accountability for unknown harm)
  - Bikurim (first fruits — release protocol)
  - MannaLedger (consumption tracking and anti-hoarding enforcement)
  - HaltMonitor (esh tamid — cardinal sin detection)
  - ShabbatTimer (mandatory cessation monitor)
  - Bandit HTTP server (bigdei kodesh — the garments)
  - ShoreshEnginePort (Erlang Port to Haskell engine, if binary found)
  - TalmudicEngineSocket (Unix socket to Prolog engine)

  Step 14 (Architecture §4): Component connections supervised.
  The port and socket are optional — the pipeline degrades gracefully
  if external engines are not available (clients fall back to stubs).
  """

  use Application

  require Logger

  @impl true
  def start(_type, _args) do
    shoresh_binary = Application.get_env(:vav_pipeline, :shoresh_engine_binary, "shoresh-engine")
    shoresh_cwd = Application.get_env(:vav_pipeline, :shoresh_engine_cwd, nil)
    talmudic_socket = Application.get_env(:vav_pipeline, :talmudic_socket_path, "/tmp/shorashim/talmudic.sock")
    korban_socket = Application.get_env(:vav_pipeline, :korban_socket_path, "/tmp/shorashim/korban.sock")

    children =
      [
        {VavPipeline.Chatzotzrot, []},
        # Tablet 38 — reads the scroll and hashes it; everything that asks
        # "is L1 intact?" is answered from this reading.
        {VavPipeline.L1Integrity, []},
        {VavPipeline.AreiMiklat, []},
        {VavPipeline.EglahArufah, []},
        {VavPipeline.Bikurim, []},
        {VavPipeline.MannaLedger, []},
        {VavPipeline.HaltMonitor, []},
        {VavPipeline.UrimVTumim, []},
        {VavPipeline.ShabbatTimer, []},
        {VavPipeline.VoiceMonitor, []},
        {VavPipeline.MachtzitHaShekel, []},
        # Tablet 30 — the index that lets a question name its own verse
        {VavPipeline.L1Index, []},
        {VavPipeline.BigdeiKodesh.Mishmar, []}
      ]
      |> maybe_add_http_server()
      |> maybe_add_repo()
      |> maybe_add_shoresh_port(shoresh_binary, shoresh_cwd)
      |> maybe_add_talmudic_socket(talmudic_socket)
      |> maybe_add_korban_socket(korban_socket)

    opts = [strategy: :one_for_one, name: VavPipeline.Supervisor]
    result = Supervisor.start_link(children, opts)

    # Doorpost startup verification (vehaya §3.1, item 1).
    # Devarim 11:18 — corporate inscription is the load-bearing
    # input to threshold practice. The corporate text must be
    # identifiable at startup; drift detected here gets surfaced
    # via Logger.error AND chatzotzrot :assembly_leaders so
    # operators are alerted before any reception fires. We do NOT
    # refuse to boot — dev environments routinely have spec drift
    # during active editing — but we make the drift visible.
    verify_doorpost_at_startup()

    result
  end

  defp verify_doorpost_at_startup do
    case VavPipeline.Doorpost.verify_identity() do
      :ok ->
        Logger.info("Doorpost: spec identity verified — corporate text holds")

      {:error, reason} ->
        Logger.error("DOORPOST_DRIFT_AT_STARTUP: #{reason}")

        if Process.whereis(VavPipeline.Chatzotzrot) do
          VavPipeline.Chatzotzrot.signal(:assembly_leaders,
            reason: "Doorpost drift detected at startup: " <> reason
          )
        end
    end
  end

  defp maybe_add_http_server(children) do
    port = Application.get_env(:vav_pipeline, :http_port, 4000)

    if port do
      children ++ [{Bandit, plug: VavPipeline.BigdeiKodesh.Router, port: port}]
    else
      children
    end
  end

  defp maybe_add_repo(children) do
    repo_config = Application.get_env(:vav_pipeline, VavPipeline.Repo)

    cond do
      is_nil(repo_config) ->
        Logger.warning("VavPipeline.Repo: no config found — running without L3 persistence")
        children

      repo_config[:start] == false ->
        Logger.info("VavPipeline.Repo: start disabled — running without L3 persistence")
        children

      true ->
        [VavPipeline.Repo | children]
    end
  end

  defp maybe_add_shoresh_port(children, binary, cwd) do
    case System.find_executable(binary) do
      nil ->
        Logger.warning("ShoreshEnginePort: binary '#{binary}' not in PATH — running without Haskell engine")
        children

      path ->
        children ++ [{VavPipeline.ShoreshEnginePort, [binary: path, cwd: cwd]}]
    end
  end

  # The Korban Processor's door (Construction §3.9) — connects lazily on
  # the first bedikah; nothing is examined if it is not there.
  defp maybe_add_korban_socket(children, socket_path) do
    children ++ [{VavPipeline.KorbanProcessorSocket, [socket_path: socket_path]}]
  end

  defp maybe_add_talmudic_socket(children, socket_path) do
    # Always add the socket client — it connects lazily on first request
    children ++ [{VavPipeline.TalmudicEngineSocket, [socket_path: socket_path]}]
  end
end