(in-package :opencortex)

(defvar *interrupt-flag* nil
  "Atomic flag set by signal handlers to trigger graceful shutdown.
  Using a dedicated variable avoids race conditions in interrupt handling.")

(defvar *interrupt-lock* (bt:make-lock "harness-interrupt-lock")
  "Mutex protecting *interrupt-flag* access.
  Locking is required because SBCL's interrupt handlers run in uncertain contexts.")

(defvar *heartbeat-thread* nil
  "Handle to the heartbeat thread, allowing explicit termination on shutdown.")

(defun process-signal (signal)
  "The entry point to the Metabolic Pipeline: Perceive -> Reason -> Act.

  SIGNAL is a property list with the following structure:
  - :type - :EVENT, :REQUEST, :RESPONSE, etc.
  - :payload - The actual content (sensor data, approved actions, etc.)
  - :meta - Metadata including source, session, reply stream
  - :depth - Recursion depth counter (starts at 0)
  - :status - Processing status (:perceived, :reasoned, :acted)

  Returns NIL when processing is complete, or a new signal for feedback loop."

  (let ((current-signal signal))
    (loop while current-signal do

      ;; Depth limiting prevents infinite recursion from feedback loops
      (let ((depth (getf current-signal :depth 0))
            (meta (getf current-signal :meta)))
        (when (> depth 10)
          (harness-log "METABOLISM ERROR: Max recursion depth reached.")
          (return nil))

        ;; Check for graceful shutdown interrupt
        (when (bt:with-lock-held (*interrupt-lock*) *interrupt-flag*)
          (harness-log "METABOLISM: Interrupted by shutdown signal.")
          (bt:with-lock-held (*interrupt-lock*) (setf *interrupt-flag* nil))
          (return nil))

        ;; The three-stage pipeline wrapped in error handling
        (handler-case
            (progn
              ;; Stage 1: Perceive - normalize sensory input
              (setf current-signal (perceive-gate current-signal))

              ;; Stage 2: Reason - generate and verify action proposals
              (setf current-signal (reason-gate current-signal))

              ;; Stage 3: Act - execute approved actions
              (let ((feedback (act-gate current-signal)))
                (if feedback
                    ;; Action generated a feedback signal - continue processing
                    (progn
                      ;; Preserve metadata from original signal
                      (unless (getf feedback :meta)
                        (setf (getf feedback :meta) meta))
                      (setf current-signal feedback))
                    ;; No feedback - pipeline complete
                    (setf current-signal nil))))

          ;; Error recovery with differentiated response
          (error (c)
            (let ((sensor (ignore-errors (getf (getf current-signal :payload) :sensor))))
              (harness-log "METABOLISM CRASH [~a]: ~a" (or sensor :unknown) c)

              ;; Only rollback memory on critical errors, not transient tool failures
              ;; This prevents losing recent context due to a single bad API call
              (unless (member sensor '(:loop-error :tool-error :syntax-error))
                (harness-log "CRITICAL ERROR: Initiating Micro-Rollback.")
                (rollback-memory 0))

              ;; At deep recursion or known error types, terminate gracefully
              (if (or (> depth 2) (member sensor '(:loop-error :tool-error)))
                  (setf current-signal nil)
                  ;; Otherwise, convert error to a loop-error signal for retry
                  (setf current-signal
                        (list :type :EVENT
                              :depth (1+ depth)
                              :meta meta
                              :payload (list :sensor :loop-error
                                           :message (format nil "~a" c)
                                           :depth depth)))))))))))

(defvar *auto-save-interval* 300
  "Interval in seconds between automatic memory saves.
  Defaults to 300 seconds (5 minutes). Set via MEMORY_AUTO_SAVE_INTERVAL env var.")

(defvar *heartbeat-save-counter* 0
  "Tracks heartbeats since last save, used to calculate auto-save timing.")

(defun start-heartbeat ()
  "Starts the background heartbeat thread.

  The heartbeat runs in a dedicated thread to avoid blocking the main
  signal processing loop. Each heartbeat:

  1. Injects a :HEARTBEAT signal into the metabolic pipeline
  2. Checks if memory should be auto-saved (based on interval ratio)

  Configuration via environment:
  - HEARTBEAT_INTERVAL: Seconds between heartbeats (default: 60)
  - MEMORY_AUTO_SAVE_INTERVAL: Seconds between auto-saves (default: 300)"

  (let ((interval (or (ignore-errors (parse-integer (uiop:getenv "HEARTBEAT_INTERVAL"))) 60))
        (auto-save (or (ignore-errors (parse-integer (uiop:getenv "MEMORY_AUTO_SAVE_INTERVAL"))) *auto-save-interval*)))
    (setf *auto-save-interval* auto-save)
    (setf *heartbeat-save-counter* 0)

    (setf *heartbeat-thread*
          (bt:make-thread
           (lambda ()
             (loop
               ;; Wait for interval
               (sleep interval)

               ;; Update counter and check if it's time to save
               (incf *heartbeat-save-counter*)
               (when (>= *heartbeat-save-counter* (/ *auto-save-interval* interval))
                 (setf *heartbeat-save-counter* 0)
                 (save-memory-to-disk))

               ;; Inject heartbeat signal - this runs through the full pipeline
               ;; allowing the agent to do latent reflection even with no input
               (inject-stimulus
                 (list :type :EVENT
                       :payload (list :sensor :heartbeat
                                    :unix-time (get-universal-time)))))

            :name "opencortex-heartbeat")))))

(defvar *shutdown-save-enabled* t
  "When T, save memory to disk on graceful shutdown.
  Disable for testing or when memory persistence is handled externally.")

(defun main ()
  "Entry point for OpenCortex. Initializes the system and enters idle loop.

  Startup sequence:
  1. Load environment from ~/.local/share/opencortex/.env
  2. Restore memory from disk (if snapshot exists)
  3. Initialize actuators (shell, cli, system)
  4. Load all skills from SKILLS_DIR
  5. Start heartbeat thread
  6. Register SIGINT handler for graceful shutdown
  7. Enter idle loop (sleeps in DAEMON_SLEEP_INTERVAL chunks)

  The idle loop checks for interrupts and saves memory before exit."

  ;; Step 1: Load environment variables from standard location
  (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)))

  ;; Step 2: Crash recovery - load memory from previous snapshot
  (load-memory-from-disk)

  ;; Step 3-4: Initialize actuators and load skills
  (initialize-actuators)
  (initialize-all-skills)

  ;; Step 5: Start the heartbeat
  (start-heartbeat)

  ;; Step 6: Register graceful shutdown handler
  ;; SBCL-specific: catches Ctrl+C (SIGINT) and saves before exit
  #+sbcl
  (sb-sys:enable-interrupt sb-unix:sigint
                           (lambda (sig code scp)
                             (declare (ignore sig code scp))
                             (harness-log "SHUTDOWN: SIGINT received. Saving memory...")
                             (when *shutdown-save-enabled*
                               (save-memory-to-disk))
                             (uiop:quit 0)))

  ;; Step 7: Idle loop - sleep in chunks, checking for interrupts
  (let ((sleep-interval (or (ignore-errors
                              (parse-integer (uiop:getenv "DAEMON_SLEEP_INTERVAL")))
                            3600)))
    (loop
      ;; Check for interrupt before each sleep cycle
      (when (bt:with-lock-held (*interrupt-lock*) *interrupt-flag*)
        (harness-log "SHUTDOWN: Interrupt flag set. Saving memory...")
        (when *shutdown-save-enabled*
          (save-memory-to-disk))
        (return))

      ;; Sleep in configured intervals (default: 1 hour)
      (sleep sleep-interval))))