;;;; -*- 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 1.4 2003/08/08 23:40:13 kevin Exp $
;;;;
;;;; This file and Wol are Copyright (c) 2003 by Kevin M. Rosenberg
;;;; *************************************************************************

(in-package #:wol)


#||
(awhen (and session-id (find-websession session-id ent))
       (setf (websession-from-req req) it)
       (setf (websession-method it) :url))
||#

(defun find-websession (key ent)
  (let ((sessions (sessions (session-master (entity-project ent)))))
    (maphash
     (lambda (k v)
       (declare (ignore k))
       (when (equal key (websession-key v))
	 (setf (websession-lastref v) (get-universal-time))
	 (return-from find-websession v)))
     sessions)
    nil))

(defun is-session-enabled (ent)
  (not (null (sessions (session-master (entity-project ent))))))

  
(defun make-websession (req ent)
  (let* ((key (random-string :length +length-session-id+
			     :set :lower-alphanumeric))
	 (sess (make-instance 'websession
		 :key key
		 :lastref (get-universal-time)
		 :lifetime (lifetime (session-master (entity-project ent)))
		 :method :try-cookie))
	 (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)
  (when (is-session-enabled ent)
    (let ((key (cookie-session-key ent (request-cookies req)))
	  (has-cookie-key nil)
	  (has-url-key nil))
      (if key
	  (setq has-cookie-key t)
	(when (setq key (url-session-key (request-raw-uri req)))
	  (setq has-url-key t)))
      (let* ((found-session (when key (find-websession key ent)))
	     (session (aif found-session it (make-websession req ent)))) 
	(setf (websession-from-req req) session)
	(when found-session
	  (if has-cookie-key
	      (setf (websession-method session) :cookies)
	    (when has-url-key
	      (setf (websession-method session) :url))))
	session))))
  

;;; 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))))

(defun is-raw-session-id (str)
  (and (stringp str)
       (> (length str) 2)
       (char= #\~ (schar str 0) (schar str (1- (length str))))))

(defun raw-session-id->session-id (str)
  (subseq str 1 (1- (length str))))