;;;; cl-scopes/util/async - utilities for asynchronous (concurrent / parallel) operations

(defpackage :scopes/util/async
  (:use :common-lisp)
  (:local-nicknames (:util :scopes/util)
                    (:lp :lparallel)
                    (:lpq :lparallel.queue))
  (:export #:startup #:shutdown
           #:task #:make-task #:start #:restart #:stop #:kill #:status #:logdata
           #:mailbox #:send #:receive))

(in-package :scopes/util/async)

(when (not (boundp '+quit-message+)) 
  (defconstant +quit-message+ (gensym "QUIT")))

(when (null lp:*kernel*)
  (setf lp:*kernel* (lp:make-kernel 2)))

(defclass task ()
  ((job :accessor job :initform nil)
   (taskid :reader taskid :initform (gensym "TSK"))
   (channel :reader channel :initform (lp:make-channel))
   (mailbox :reader mailbox :initarg :mailbox)
   (status :accessor status :initform :new)
   (logdata :accessor logdata :initform nil)))

(defun make-task ()
  (make-instance 'task))

(defun standard-job (tsk &key (startup #'noop) (teardown #'noop) handle-message)
  (let ((mb (mailbox tsk)))
    (startup tsk)
    (if mb
      (loop 
        (let ((msg (lpq:pop-queue mb)))
          (if (eq msg +quit-message+)
            (return-from nil)
            (handle-message tsk msg)))))
    (teardown tsk)))

(defun noop (&rest params))