;;;; -*- 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
;;;;
;;;; $Id$
;;;;
;;;; This file and Wol are Copyright (c) 2003 by Kevin M. Rosenberg
;;;; *************************************************************************

(in-package #:wol)


(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 url-session-id)
  (when (is-session-enabled ent)
    (let* ((cookie-session-id (cookie-session-key ent (request-cookies req)))
           (session-id (or url-session-id cookie-session-id))
           (found-session (when session-id
                            (find-websession session-id ent)))
           (session (aif found-session
                         it
                         (make-websession req ent))))
      (cond
        (cookie-session-id
         (setf (websession-method session) :cookies))
        (url-session-id
         (setf (websession-method session) :url)))
      (setf (websession-from-req req) 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))))