;;;; -*- Mode: Lisp; Syntax: ANSI-Common-Lisp; Base: 10; Package: wol -*-
;;;; *************************************************************************
;;;; FILE IDENTIFICATION
;;;;
;;;; Name:          sessions.lisp
;;;; Purpose:       Session handler
;;;; Programmer:    Kevin M. Rosenberg
;;;; Date Started:  July 2003
;;;;
;;;; $Id: sessions.lisp,v 1.3 2003/07/16 20:40:43 kevin Exp $
;;;;
;;;; This file and Wol are Copyright (c) 2003 by Kevin M. Rosenberg
;;;; *************************************************************************

(in-package #:wol)


(defun make-new-session-id ()
  (random-string :length 24 :set :lower-alphanumeric))

(defun ensure-websession (key req ent method)
  "Find or make websession for key"
  (let ((sessions (sessions (session-master (entity-project ent)))))
    ;; if sessions doesn't exist, then project is not session enabled
    (when sessions
      (cond 
       ((null key)
	(make-websession req ent method))
       (t
	(maphash
	 (lambda (k v)
	   (declare (ignore k))
	   (when (equal key (websession-key v))
	     (setf (websession-lastref v) (get-universal-time))
	     (return-from ensure-websession v)))
	 sessions)
	(make-websession req ent method))))))

  
(defun make-websession (req ent method)
  (let* ((key (random-string :length 24 :set :lower-alphanumeric))
	 (sess (make-instance 'websession
		 :key key
		 :lastref (get-universal-time)
		 :lifetime (lifetime (session-master (entity-project ent)))
		 :method method))
	 (hash (sessions (session-master (entity-project ent)))))
    (when hash
      (setf (gethash key hash) sess)
      (setf (websession-from-req req) sess)
      sess)))

(defun compute-session (req ent)
  (awhen (and (request-plist req)
	      (getf (request-plist req) :session-id))
	 (setf (websession-from-req req) 
	   (ensure-websession it req ent :uri))))



;;; Reap expired sessions


(defun start-reaper ()
  (process-run-function "wol-reaper"
    (lambda () (reap-sessions) (kmrcl::process-sleep *reap-interval*))))

(defun reap-sessions ()
  (cmsg-c :debug "Reaping")
  (dolist (expired (find-expired-sessions))
    (flush-expired expired)))

(defun find-expired-sessions ()
  (loop for s in (all-sessions)
	when (is-session-expired (car s))
	collect s))

(defun all-sessions (&aux s)
  (maphash
   (lambda (name proj)
     (declare (ignore name))
     (let* ((sm (session-master proj))
	    (sessions (when sm (sessions sm))))
       (when sessions
	 (maphash
	  (lambda (k v)
	    (declare (ignore k))
	   (push (cons v proj) s))
	  sessions))))
   *active-projects*)
  s)

(defmethod flush-expired (s)
  (let ((sessions (sessions (session-master (cdr s)))))
    (remhash (car s) sessions)
    (add-log-entry (cdr s) "flush expired session: key=~A" (websession-key (car s)))))

(defun is-session-expired (ws)
  (> (get-universal-time)  (+ (websession-lastref ws)
			      (websession-lifetime ws))))