#+TITLE: The Metabolic Loop (loop.lisp)
#+AUTHOR: Amr
#+FILETAGS: :harness:loop:
#+STARTUP: content

* The Metabolic Loop (loop.lisp)
** Architectural Intent: The Heartbeat
The Metabolic Loop is the high-level coordinator of the OpenCortex. It orchestrates the flow of energy (information) through the system by calling the three metabolic stages in sequence:
1. **Perceive:** Sensory intake.
2. **Reason:** Cognitive processing.
3. **Act:** Physical side-effects.

** Package and Variables
The loop requires thread-safe interrupt handling to ensure that the agent can be stopped gracefully without leaving the Lisp image in an inconsistent state.

#+begin_src lisp :tangle ../src/loop.lisp
(in-package :opencortex)

(defvar *interrupt-flag* nil)
(defvar *interrupt-lock* (bt:make-lock "harness-interrupt-lock"))
(defvar *heartbeat-thread* nil)
#+end_src

** The Metabolic Pipeline
The `process-signal` function is the core metabolic processor. It iterates through the Perceive-Reason-Act gates until the signal is fully processed or an error state is reached. We have refined the error handling to ensure that memory rollbacks only occur on critical system failures, preventing transient tool errors from wiping short-term cognitive state.

#+begin_src lisp :tangle ../src/loop.lisp
(defun process-signal (signal)
  "The entry point to the Metabolic Pipeline: Perceive -> Reason -> Act."
  (let ((current-signal signal))
    (loop while current-signal do
      (let ((depth (getf current-signal :depth 0)))
        (when (> depth 10) (harness-log "METABOLISM ERROR: Max depth reached.") (return nil))
        (when (bt:with-lock-held (*interrupt-lock*) *interrupt-flag*)
          (harness-log "METABOLISM: Interrupted.")
          (bt:with-lock-held (*interrupt-lock*) (setf *interrupt-flag* nil))
          (return nil))
        (handler-case
            (progn
              (setf current-signal (perceive-gate current-signal))
              (setf current-signal (reason-gate current-signal))
              (setf current-signal (act-gate current-signal)))
          (error (c)
            (let ((sensor (ignore-errors (getf (getf current-signal :payload) :sensor))))
              (harness-log "METABOLISM CRASH [~a]: ~a" (or sensor :unknown) c)
              ;; Only rollback on critical errors, not standard tool or loop errors
              (unless (member sensor '(:loop-error :tool-error :syntax-error))
                (harness-log "CRITICAL ERROR: Initiating Micro-Rollback.")
                (rollback-memory 0))
              (if (or (> depth 2) (member sensor '(:loop-error :tool-error)))
                  (setf current-signal nil)
                  (setf current-signal (list :type :EVENT :depth (1+ depth) :reply-stream (getf current-signal :reply-stream)
                                             :payload (list :sensor :loop-error :message (format nil "~a" c) :depth depth)))))))))))
#+end_src

** Heartbeat Mechanism
The heartbeat ensures the agent remains "alive" even in the absence of external stimuli, allowing for latent reflection and periodic maintenance. The interval is externalized to the `HEARTBEAT_INTERVAL` environment variable.

#+begin_src lisp :tangle ../src/loop.lisp
(defun start-heartbeat ()
  "Starts the background heartbeat thread. Interval is loaded from HEARTBEAT_INTERVAL."
  (let ((interval (or (ignore-errors (parse-integer (uiop:getenv "HEARTBEAT_INTERVAL"))) 60)))
    (setf *heartbeat-thread* 
          (bt:make-thread 
           (lambda () 
             (loop 
               (sleep interval) 
               ;; inject-stimulus is synchronous for heartbeats, preventing accumulation.
               (inject-stimulus (list :type :EVENT :payload (list :sensor :heartbeat :unix-time (get-universal-time)))))) 
           :name "opencortex-heartbeat"))))
#+end_src

** Main Entry Point
The `main` function initializes the environment, loads skills, and starts the heartbeat. It now includes a graceful shutdown handler for `SIGINT` (Ctrl+C) and uses `DAEMON_SLEEP_INTERVAL` to control its idle rhythm.

#+begin_src lisp :tangle ../src/loop.lisp
(defun main ()
  "Entry point for the Skeleton MVP. Handles initialization and graceful shutdown."
  (let* ((home (uiop:getenv "HOME"))
         (env-file (uiop:merge-pathnames* ".local/share/opencortex/.env" (uiop:ensure-directory-pathname home))))
    (when (uiop:file-exists-p env-file) (cl-dotenv:load-env env-file)))
  
  (initialize-actuators)
  (initialize-all-skills)
  (start-heartbeat)
  
  ;; Graceful shutdown handler for SBCL
  #+sbcl
  (sb-sys:enable-interrupt sb-unix:sigint 
                           (lambda (sig code scp) 
                             (declare (ignore sig code scp)) 
                             (harness-log "SHUTDOWN: SIGINT received. Exiting...")
                             (uiop:quit 0)))

  (let ((sleep-interval (or (ignore-errors (parse-integer (uiop:getenv "DAEMON_SLEEP_INTERVAL"))) 3600)))
    (loop 
      (when (bt:with-lock-held (*interrupt-lock*) *interrupt-flag*) (return))
      (sleep sleep-interval))))
#+end_src
