Megatest

;; Copyright 2006-2012, Matthew Welland.
;; 
;;  This program is made available under the GNU GPL version 2.0 or
;;  greater. See the accompanying file COPYING for details.
;; 
;;  This program is distributed WITHOUT ANY WARRANTY; without even the
;;  implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
;;  PURPOSE.

(require-extension (srfi 18) extras tcp s11n)

(use sqlite3 srfi-1 posix regex regex-case srfi-69 hostinfo md5 message-digest)
(import (prefix sqlite3 sqlite3:))

(use nanomsg)

(declare (unit nmsg-transport))

(declare (uses common))
(declare (uses db))
(declare (uses tests))
(declare (uses tasks)) ;; tasks are where stuff is maintained about what is running.
(declare (uses server))

(include "common_records.scm")
(include "db_records.scm")

;; Transition to pub --> sub with pull <-- push
;;
;;   1. client sends request to server via push to the pull port
;;   2. server puts request in queue or processes immediately as appropriate
;;   3. server puts responses from completed requests into pub port 
;;
;; TODO
;;
;; Done Tested
;; [x]  [ ]    1. Add columns pullport pubport to servers table
;; [x]  [ ]    2. Add rm of monitor.db if older than 11/12/2012 
;; [x]  [ ]    3. Add create of pullport and pubport with finding of available ports
;; [x]  [ ]    4. Add client compose of request
;; [x]  [ ]        - name of client: testname/itempath-test_id-hostname 
;; [x]  [ ]        - name of request: callname, params
;; [x]  [ ]        - request key: f(clientname, callname, params)
;; [x]  [ ]    5. Add processing of subscription hits
;; [x]  [ ]        - done when get key 
;; [x]  [ ]        - return results
;; [x]  [ ]    6. Add timeout processing
;; [x]  [ ]        - after 60 seconds
;; [ ]  [ ]            i. check server alive, connect to new if necessary
;; [ ]  [ ]           ii. resend request
;; [ ]  [ ]    7. Turn self ping back on

(define (nmsg-transport:make-server-url hostport)
  (if (not hostport)
      #f
      (conc "tcp://" (car hostport) ":" (cadr hostport))))

(define *server-loop-heart-beat* (current-seconds))
(define *heartbeat-mutex* (make-mutex))

;;======================================================================
;; S E R V E R
;;======================================================================

(define-inline (nmsgsock:get-pub  dat)(vector-ref dat 0))
(define-inline (nmsgsock:get-pull dat)(vector-ref dat 1))
(define-inline (nmsgsock:set-pub! dat s)(vector-set! dat s 0))
(define-inline (nmsgsock:set-pull! dat s)(vector-set! dat s 0))

(define (nmsg-transport:run hostn)
  (debug:print 2 "Attempting to start the server ...")
  (if (not *toppath*)
      (if (not (launch:setup-for-run))
	  (begin
	    (debug:print 0 "ERROR: cannot find megatest.config, cannot start server, exiting")
	    (exit))))
  (let* ((db              (open-db)) ;; here we *do not* want to be opening and closing the db
	 (nmsg-sdat1       #f)
	 (nmsg-sdat2       #f)
	 (pull-socket     #f)
	 (pub-socket      #f)
	 (p1              #f)
	 (p2              #f)
	 (nmsg-sockets-dat #f)
	 (iface           (if (string=? "-" hostn)
			      "*" ;; (get-host-name) 
			      hostn))
	 (hostname        (get-host-name))
	 (ipaddrstr       (let ((ipstr (if (string=? "-" hostn)
					   (string-intersperse (map number->string (u8vector->list (hostname->ip hostname))) ".")
					   #f)))
			    (if ipstr ipstr hostname)))
	 (last-run       0))
    (set! nmsg-sockets-dat (nmsg-transport:setup-ports ipaddrstr (if (args:get-arg "-port")
			    (string->number (args:get-arg "-port"))
							    (+ 5000 (random 1001)))))

    (set! nmsg-sdat1    (car   nmsg-sockets-dat))
    (set! pull-socket  (cadr  nmsg-sdat1)) ;; (iface s  port)
    (set! p1           (caddr nmsg-sdat1))
    
    (set! nmsg-sdat2    (cadr  nmsg-sockets-dat))
    (set! pub-socket   (cadr  nmsg-sdat2))
    (set! p2           (caddr nmsg-sdat2))

    (set! *cache-on* #t)

    (set! *runremote* (vector pull-socket pub-socket)) ;; overloading the use of *runremote* BUG!?

    ;; what to do when we quit
    ;;
;;     (on-exit (lambda ()
;; 	       (if (and *toppath* *server-info*)
;; 		   (open-run-close tasks:server-deregister-self tasks:open-db (car *server-info*))
;; 		   (let loop () 
;; 		     (let ((queue-len 0))
;; 		       (thread-sleep! (random 5))
;; 		       (mutex-lock! *incoming-mutex*)
;; 		       (set! queue-len (length *incoming-data*))
;; 		       (mutex-unlock! *incoming-mutex*)
;; 		       (if (> queue-len 0)
;; 			   (begin
;; 			     (debug:print-info 0 "Queue not flushed, waiting ...")
;; 			     (loop))))))))

    ;; The heavy lifting
    ;;
    ;; make-vector-record cdb packet client-sig qtype immediate query-sig params qtime
    ;;
    (debug:print-info 11 "Server setup complete, start listening for messages")
    (let loop ((queue-lst '()))
      (let* ((rawmsg (receive-message* pull-socket))
	     (packet (db:string->obj rawmsg))
	     (qtype  (cdb:packet-get-qtype packet)))
	(debug:print-info 12 "server=> received packet=" packet)
	(if (not (member qtype '(sync ping)))
	    (begin
	      (mutex-lock! *heartbeat-mutex*)
	      (set! *last-db-access* (current-seconds))
	      (mutex-unlock! *heartbeat-mutex*)))
	(if #t ;; (cdb:packet-get-immediate packet) ;; process immediately or put in queue
	    (begin
	      (db:process-queue-item db packet)
	      ;; (open-run-close db:process-queue #f pub-socket (cons packet queue-lst))
	      
	      (loop '()))
	    (loop (cons packet queue-lst)))))))

;; run nmsg-transport:keep-running in a parallel thread to monitor that the db is being 
;; used and to shutdown after sometime if it is not.
;;
(define (nmsg-transport:keep-running)
  ;; if none running or if > 20 seconds since 
  ;; server last used then start shutdown
  ;; This thread waits for the server to come alive
  (let* ((server-info (let loop ()
			(let ((sdat #f))
			  (mutex-lock! *heartbeat-mutex*)
			  (set! sdat *server-info*)
			  (mutex-unlock! *heartbeat-mutex*)
			  (if sdat sdat
			      (begin
				(debug:print 12 "WARNING: server not started yet, waiting few seconds before trying again")
				(sleep 4)
				(loop))))))
	 (iface       (cadr server-info))
	 (pullport    (caddr server-info))
	 (pubport     (cadddr server-info)) ;; id interface pullport pubport)
	 ;; (nmsg-sockets (nmsg-transport:client-connect iface pullport pubport))
	 (last-access 0))
    (debug:print-info 11 "heartbeat started for nmsg server on " iface " " pullport " " pubport)
    (let loop ((count 0))
      (thread-sleep! 4) ;; no need to do this very often
      ;; NB// sync currently does NOT return queue-length
      ;; GET REAL QUEUE LENGTH FROM THE VARIABLE
      (let ((queue-len 0)) ;; FOR NOW DO NOT DO THIS (cdb:client-call nmsg-sockets 'sync #t 1)))
      ;; (print "Server running, count is " count)
	(if (< count 1) ;; 3x3 = 9 secs aprox
	    (loop (+ count 1)))

	;; NOTE: Get rid of this mechanism! It really is not needed...
	(open-run-close tasks:server-update-heartbeat tasks:open-db (car server-info))

	;; (if ;; (or (> numrunning 0) ;; stay alive for two days after last access
	(mutex-lock! *heartbeat-mutex*)
	(set! last-access *last-db-access*)
	(mutex-unlock! *heartbeat-mutex*)
	(if (> (+ last-access
		  ;; (* 50 60 60)    ;; 48 hrs
		  ;; 60              ;; one minute
		  ;; (* 60 60)       ;; one hour
		  (* 45 60)          ;; 45 minutes, until the db deletion bug is fixed.
		  )
	       (current-seconds))
	    (begin
	      (debug:print-info 2 "Server continuing, seconds since last db access: " (- (current-seconds) last-access))
	      (loop 0))
	    (begin
	      (debug:print-info 0 "Starting to shutdown the server.")
	      ;; need to delete only *my* server entry (future use)
	      (set! *time-to-exit* #t)
	      (open-run-close tasks:server-deregister-self tasks:open-db (get-host-name))
	      (thread-sleep! 1)
	      (debug:print-info 0 "Max cached queries was " *max-cache-size*)
	      (debug:print-info 0 "Server shutdown complete. Exiting")
	      (exit)))))))

(define (nmsg-transport:find-free-port-and-open iface s port stype #!key (trynum 50))
  (let ((s (if s s (make-socket stype)))
        (p (if (number? port) port 5555))
        (old-handler (current-exception-handler)))
    (handle-exceptions
     exn
     (begin
       (debug:print 0 "Failed to bind to port " p ", trying next port")
       (debug:print 0 "   EXCEPTION: " ((condition-property-accessor 'exn 'message) exn))
       ;; (old-handler)
       ;; (print-call-chain)
       (if (> trynum 0)
           (nmsg-transport:find-free-port-and-open iface s (+ p 1) trynum: (- trynum 1))
           (debug:print-info 0 "Tried ports up to " p 
                             " but all were in use. Please try a different port range by starting the server with parameter \" -port N\" where N is the starting port number to use"))
       (exit)) ;; To exit or not? That is the question.
     (let ((nmsg-url (conc "tcp://" iface ":" p)))
       (debug:print 2 "Trying to start server on " nmsg-url)
       (bind-socket s nmsg-url)
       (list iface s port)))))

(define (nmsg-transport:setup-ports ipaddrstr startport)
  (let* ((s1 (nmsg-transport:find-free-port-and-open ipaddrstr #f startport 'pull))
         (p1 (caddr s1))
         (s2 (nmsg-transport:find-free-port-and-open ipaddrstr #f (+ 1 (if p1 p1 (+ startport 1))) 'pub))
         (p2 (caddr s2)))
    (set! *runremote* #f)
    (debug:print 0 "Server started on " ipaddrstr " ports " p1 " and " p2)
    (mutex-lock! *heartbeat-mutex*)
    (set! *server-info* (open-run-close tasks:server-register 
					tasks:open-db 
					(current-process-id) 
					ipaddrstr p1 
					0 
					'live
					'nmsg
					pubport: p2))
    (debug:print-info 11 "*server-info* set to " *server-info*)
    (mutex-unlock! *heartbeat-mutex*)
    (list s1 s2)))

(define (nmsg-transport:mk-signature)
  (message-digest-string (md5-primitive) 
			 (with-output-to-string
			   (lambda ()
			     (write (list (current-directory)
					  (argv)))))))

;;======================================================================
;; S E R V E R   U T I L I T I E S 
;;======================================================================

;;======================================================================
;; C L I E N T S
;;======================================================================

;; 
(define (nmsg-transport:client-socket-connect iface port #!key (context #f)(type 'req)(subscriptions '()))
  (debug:print-info 3 "client-connect " iface ":" port ", type=" type ", subscriptions=" subscriptions)
  (let ((connect-ok #f)
	(nmsg-socket (if context 
			(make-socket type context)
			(make-socket type)))
	(conurl     (nmsg-transport:make-server-url (list iface port))))
    (if (socket? nmsg-socket)
     (begin
	  ;; first apply subscriptions
	  (for-each (lambda (subscription)
		      (debug:print 2 "Subscribing to " subscription)
		      (socket-option-set! nmsg-socket 'subscribe subscription))
		    subscriptions)
	  (connect-socket nmsg-socket conurl)
	  nmsg-socket)
	(begin
	  (debug:print 0 "ERROR: Failed to open socket to " conurl)
	  #f))))

(define (nmsg-transport:client-connect iface pullport pubport)
  (let* ((push-socket (nmsg-transport:client-socket-connect iface pullport type: 'push))
	 (sub-socket  (nmsg-transport:client-socket-connect iface pubport
						    type: 'sub
						    subscriptions: (list (client:get-signature) "all")))
	 (nmsg-sockets (vector push-socket sub-socket))
	 (login-res   #f))
    (debug:print-info 11 "nmsg-transport:client-connect started. Next is login")
    (set! login-res (client:login serverdat nmsg-sockets))
    (if (and (not (null? login-res))
	     (car login-res))
	(begin
	  (debug:print-info 2 "Logged in and connected to " iface ":" pullport "/" pubport ".")
	  (set! *runremote* nmsg-sockets)
	  nmsg-sockets)
	(begin
	  (debug:print-info 2 "Failed to login or connect to " conurl)
	  (set! *runremote* #f)
	  #f))))

;; run nmsg-transport:keep-running in a parallel thread to monitor that the db is being 
;; used and to shutdown after sometime if it is not.
;;
(define (nmsg-transport:keep-running)
  ;; if none running or if > 20 seconds since 
  ;; server last used then start shutdown
  ;; This thread waits for the server to come alive
  (let* ((server-info (let loop ()
                        (let ((sdat #f))
                          (mutex-lock! *heartbeat-mutex*)
                          (set! sdat *runremote*)
                          (mutex-unlock! *heartbeat-mutex*)
                          (if sdat sdat
                              (begin
                                (sleep 4)
                                (loop))))))
         (iface       (car server-info))
         (port        (cadr server-info))
         (last-access 0)
	 (tdb         (tasks:open-db))
	 (spid        (tasks:server-get-server-id tdb #f iface port #f)))
    (print "Keep-running got server pid " spid ", using iface " iface " and port " port)
    (let loop ((count 0))
      (thread-sleep! 4) ;; no need to do this very often
      ;; NB// sync currently does NOT return queue-length
      (let () ;; (queue-len (cdb:client-call server-info 'sync #t 1)))
      ;; (print "Server running, count is " count)
        (if (< count 1) ;; 3x3 = 9 secs aprox
            (loop (+ count 1)))
        
        ;; NOTE: Get rid of this mechanism! It really is not needed...
        (tasks:server-update-heartbeat tdb spid)
      
        ;; (if ;; (or (> numrunning 0) ;; stay alive for two days after last access
        (mutex-lock! *heartbeat-mutex*)
        (set! last-access *last-db-access*)
        (mutex-unlock! *heartbeat-mutex*)
        (if (> (+ last-access
                  ;; (* 50 60 60)    ;; 48 hrs
                  ;; 60              ;; one minute
                  ;; (* 60 60)       ;; one hour
                  (* 45 60)          ;; 45 minutes, until the db deletion bug is fixed.
                  )
               (current-seconds))
            (begin
              (debug:print-info 2 "Server continuing, seconds since last db access: " (- (current-seconds) last-access))
              (loop 0))
            (begin
              (debug:print-info 0 "Starting to shutdown the server.")
              ;; need to delete only *my* server entry (future use)
              (set! *time-to-exit* #t)
              (tasks:server-deregister-self tdb (get-host-name))
              (thread-sleep! 1)
              (debug:print-info 0 "Max cached queries was " *max-cache-size*)
              (debug:print-info 0 "Server shutdown complete. Exiting")
              (exit)))))))

;; all routes though here end in exit ...
(define (nmsg-transport:launch)
  (if (not *toppath*)
      (if (not (launch:setup-for-run))
	  (begin
	    (debug:print 0 "ERROR: cannot find megatest.config, exiting")
	    (exit))))
  (debug:print-info 2 "Starting nmsg server")
  (if *toppath* 
      (let* (;; (th1 (make-thread (lambda ()
	     ;;      	       (let ((server-info #f))
	     ;;      		 ;; wait for the server to be online and available
	     ;;      		 (let loop ()
	     ;;			   (debug:print-info 2 "Waiting for the server to come online before starting heartbeat")
	     ;;      		   (thread-sleep! 2)
	     ;;      		   (mutex-lock! *heartbeat-mutex*)
	     ;;      		   (set! server-info *server-info* )
	     ;;      		   (mutex-unlock! *heartbeat-mutex*)
	     ;;      		   (if (not server-info)(loop)))
	     ;;			 (debug:print 2 "Server alive, starting self-ping")
	     ;;      		 (nmsg-transport:self-ping server-info)
	     ;;      		 ))
	     ;;      	     "Self ping"))
	     (th2 (make-thread (lambda ()
				 (nmsg-transport:run 
				  (if (args:get-arg "-server")
				      (args:get-arg "-server")
				      "-"))) "Server run"))
	     ;; (th3 (make-thread (lambda ()(nmsg-transport:keep-running)) "Keep running"))
	     )
	(set! *client-non-blocking-mode* #t)
	;; (thread-start! th1)
	(thread-start! th2)
	;; (thread-start! th3)
	(set! *didsomething* #t)
	;; (thread-join! th3)
	(thread-join! th2)
	)
      (debug:print 0 "ERROR: Failed to setup for megatest")))

(define (nmsg-transport:client-signal-handler signum)
  (handle-exceptions
   exn
   (debug:print " ... exiting ...")
   (let ((th1 (make-thread (lambda ()
			     (if (not *received-response*)
				 (receive-message* *runremote*))) ;; flush out last call if applicable
			   "eat response"))
	 (th2 (make-thread (lambda ()
			     (debug:print 0 "ERROR: Received ^C, attempting clean exit. Please be patient and wait a few seconds before hitting ^C again.")
			     (thread-sleep! 3) ;; give the flush three seconds to do it's stuff
			     (debug:print 0 "       Done.")
			     (exit 4))
			   "exit on ^C timer")))
     (thread-start! th2)
     (thread-start! th1)
     (thread-join! th2))))

(define (nmsg-transport:client-launch)
  (set-signal-handler! signal/int nmsg-transport:client-signal-handler)
   (if (nmsg-transport:client-setup)
       (debug:print-info 2 "connected as client")
       (begin
	 (debug:print 0 "ERROR: Failed to connect as client")
	 (exit))))

;;======================================================================
;; Defunct functions
;;======================================================================

;; ping a server and return number of clients or #f (if no response)
;; NOT IN USE!
(define (nmsg-transport:ping host port #!key (secs 10)(return-socket #f))
  (cdb:use-non-blocking-mode
   (lambda ()
     (let* ((res #f)
	    (th1 (make-thread
		  (lambda ()
		    (let* ((nmsg-context (make-context 1))
			   (nmsg-socket  (nmsg-transport:client-connect host port context: nmsg-context)))
		      (if nmsg-socket
			  (if (nmsg-transport:client-login nmsg-socket)
			      (let ((numclients (cdb:num-clients nmsg-socket)))
				(if (not return-socket)
				    (begin
				      (nmsg-transport:client-logout nmsg-socket)
				      (close-socket  nmsg-socket)))
				(set! res (list #t numclients (if return-socket nmsg-socket #f))))
			      (begin
				;; (close-socket nmsg-socket)
				(set! res (list #f "CAN'T LOGIN" #f))))
			  (set! res (list #f "CAN'T CONNECT" #f)))))
		  "Ping: th1"))
	    (th2 (make-thread
		  (lambda ()
		    (let loop ((count 1))
		      (debug:print-info 1 "Ping " count " server on " host " at port " port)
		      (thread-sleep! 2)
		      (if (< count (/ secs 2))
			  (loop (+ count 1))))
		    ;; (thread-terminate! th1)
		    (set! res (list #f "TIMED OUT" #f)))
		  "Ping: th2")))
       (thread-start! th2)
       (thread-start! th1)
       (handle-exceptions
	exn
	(set! res (list #f "TIMED OUT" #f))
	(thread-join! th1 secs))
       res))))

;; (define (nmsg-transport:self-ping server-info)
;;   ;; server-info: server-id interface pullport pubport
;;   (let ((iface    (list-ref server-info 1))
;; 	(pullport (list-ref server-info 2))
;; 	(pubport  (list-ref server-info 3)))
;;     (nmsg-transport:client-connect iface pullport pubport)
;;     (let loop ()
;;       (thread-sleep! 2)
;;       (cdb:client-call *runremote* 'ping #t)
;;       (debug:print 4 "nmsg-transport:self-ping - I'm alive on " iface ":" pullport "/" pubport "!")
;;       (mutex-lock! *heartbeat-mutex*)
;;       (set! *server-loop-heart-beat* (current-seconds))
;;       (mutex-unlock! *heartbeat-mutex*)
;;       (loop))))
    
(define (nmsg-transport:reply pubsock target query-sig success/fail result)
  (debug:print-info 11 "nmsg-transport:reply target=" target ", result=" result)
  (send-message pubsock target send-more: #t)
  (send-message pubsock (db:obj->string (vector success/fail query-sig result))))

(use nanomsg srfi-18 sqlite3 numbers)

(define resp (nn-socket 'rep))

(use zmq posix numbers)

(define cname "Bob")
(define runtime 10)
(let ((args (argv)))
  (if (< (length args) 3)
      (begin
	(print "Usage: mockupclient clientname runtime")
	(exit))
      (begin
	(set! cname (cadr args))
	(set! runtime (string->number (caddr args))))))
      
;; (define start-delay (/ (random 100) 9))
;; (define runtime     (+ 1 (/ (random 200) 2)))

(print "Starting client " cname " with runtime " runtime)

(include "mockupclientlib.scm")

(set! endtime (+ (current-seconds) runtime))

;; first ping the server to ensure we have a connection
(if (server-ping cname 5)
    (print "SUCCESS: Client " cname " connected to server")
    (begin
      (print "ERROR: Client " cname " failed ping of server, exiting")
      (exit)))

(let loop ()
  (let ((x (random 15))
	(varname (list-ref (list "hello" "goodbye" "saluton" "kiaorana")(random 4))))
    (case x
      ;; ((1)(dbaccess cname 'sync "nodat"    #f))
      ((2 3 4 5)(dbaccess cname 'set varname (random 999)))
      ((6 7 8 9 10)(print cname ": Get \"" varname "\" " (dbaccess cname 'get varname #f)))
      (else
       (thread-sleep! 0.011)))
    (if (< (current-seconds) endtime)
	(loop))))

(print "Client " cname " all done!!")

(define reqs (nn-socket 'req))

(connect-socket reqs "tcp://localhost:6563")

(thread-sleep! 0.2)

(define (server-ping cname timeout)
  (let ((msg     (conc cname ":ping:" timeout))
	(maxtime (+ (current-seconds) timeout)))
    (print "pinging server from " cname " with timeout " timeout)
    (let loop ((res   #f))
      (if (< maxtime (current-seconds))
	  #f ;; failed to ping
	  (if (equal? res "Got ping")
	      #t
	      (begin
		(print "Ping received from server " res)
		(send-message push msg)
		(thread-sleep! 0.1)
		(loop (receive-message sub non-blocking: #t))))))))
  
(define (dbaccess cname cmd var val #!key (numtries 20))
  (let* ((msg (conc cname ":" cmd ":" (if val (conc var " " val) var)))
	 (res #f)
	 (mtx1 (make-mutex))
	 (do-access (lambda ()
		      (let ((tmpres #f))
			(print "Sending msg: " msg)
			(send-message push msg)
			(print "Message " msg " sent")
			(print "Client " cname " waiting for response to " msg)
			(print "Client " cname " received address " (receive-message* sub))
			(set! tmpres (receive-message* sub))
			(mutex-lock! mtx1)
			(set! res tmpres)
			(mutex-unlock! mtx1))))
	 (th1 (make-thread do-access "do access"))
	 (th2 (make-thread (lambda ()
			     (let ((result #f))
			       (mutex-lock! mtx1)
			       (set! result res)
			       (mutex-unlock! mtx1)
			       (thread-sleep! 5)
			       (if (not result)
				   (if (> numtries 0)
				       (begin
					 (print "WARNING: access timed out for " cname ", trying again. Trys remaining=" numtries)
					 (dbaccess cname cmd var val numtries: (- numtries 1)))
				       (begin
					 (print "ERROR: dbaccess timed out. Exiting")
					 (exit)))))
			     "timeout thread"))))
    (thread-start! th1)
    (thread-start! th2)
    (thread-join! th1)
    (if res (print "SUCCESS: received " res " with " numtries " remaining possible attempts"))
    res))

;; pub/sub with envelope address
;; Note that if you don't insert a sleep, the server will crash with SIGPIPE as soon
;; as a client disconnects.  Also a remaining client may receive tons of
;; messages afterward.

(use nanomsg srfi-18 sqlite3 numbers)

(define resp (nn-socket 'rep))
(define cname "server")
(define total-db-accesses 0)
(define start-time (current-seconds))

(nn-bind resp  "tcp://*:6563")

(thread-sleep! 0.2)

(define (open-db)
  (let* ((dbpath    "mockup.db")
	 (dbexists  (file-exists? dbpath))
	 (db        (open-database dbpath)) ;; (never-give-up-open-db dbpath))
	 (handler   (make-busy-timeout 10)))
    (set-busy-handler! db handler)
    (if (not dbexists)
	(for-each
	 (lambda (stmt)
	   (execute db stmt))
	 (list
	  "PRAGMA SYNCHRONOUS=0;"
	  "CREATE TABLE clients (id INTEGER PRIMARY KEY,name TEXT,num_accesses INTEGER DEFAULT 0);"
	  "CREATE TABLE vars    (var TEXT,val TEXT,CONSTRAINT vars_constraint UNIQUE (var));")))
    db))

(define cid-cache (make-hash-table))

(define (get-client-id db cname)
  (let ((cid (hash-table-ref/default cid-cache cname #f)))
    (if cid 
	cid
	(begin
	  (execute db "INSERT OR REPLACE INTO clients (name) VALUES(?);" cname)
	  (for-each-row 
	   (lambda (id)
	     (set! cid id))
	   db
	   "SELECT id FROM clients WHERE name=?;" cname)
	  (hash-table-set! cid-cache cname cid)
	  (set! total-db-accesses (+ total-db-accesses 2))
	  cid))))

(define (count-client db cname)
  (let ((cid (get-client-id db cname)))
    (execute db "UPDATE clients SET num_accesses=num_accesses+1 WHERE id=?;" cid)
    (set! total-db-accesses (+ total-db-accesses 1))
    ))

(define db (open-db))
;; (define queuelst '())
;; (define mx1 (make-mutex))

(define max-queue-len 0)

(define (process-queue queuelst)
  (let ((queuelen (length queuelst)))
    (if (> queuelen max-queue-len)
	(set! max-queue-len queuelen))
    (for-each
     (lambda (item)
       (let ((cname (vector-ref item 1))
	     (clcmd (vector-ref item 2))
	     (cdata (vector-ref item 3)))
	 (send-message pub cname send-more: #t)
	 (send-message pub (case clcmd
			     ((sync)
			      (conc queuelen))
			     ((set)
			      (set! total-db-accesses (+ total-db-accesses 1))
			      (apply execute db "INSERT OR REPLACE INTO vars (var,val) VALUES (?,?);" (string-split cdata))
			      "ok")
			     ((get)
			      (set! total-db-accesses (+ total-db-accesses 1))
			      (let ((res "noval"))
				(for-each-row
				 (lambda (val)
				   (set! res val))
				 db 
				 "SELECT val FROM vars WHERE var=?;" cdata)
				res))
			     (else (conc "unk cmd: " clcmd))))))
     queuelst)))

;; SERVER THREAD
(define th1 (make-thread 
	     (lambda ()
	       (let ((last-run 0)) ;; current-seconds when run last
		 (let loop ((queuelst '()))
		   (let* ((indat (receive-message* pull))
			  (parts (string-split indat ":"))
			  (cname (car parts))                   ;; client name
			  (clcmd (string->symbol (cadr parts))) ;; client cmd
			  (cdata (caddr parts))                 ;; client data
			  (svect (vector (current-seconds) cname clcmd cdata))) ;; record for the queue
		     ;; (print "Server received message: " indat)
		     (count-client db cname)
		     (case clcmd
		       ((ping)
			(print "Got ping from " cname)
			(send-message pub cname send-more: #t)
			(send-message pub "Got ping")
			(loop queuelst))
		       ((sync) ;; just process the queue
			(print "Got sync from " cname)
			(process-queue (cons svect queuelst))
			(loop '()))
		       ((get)
			(process-queue (cons svect queuelst))
			(loop '()))
		       (else
			(loop (cons svect queuelst))))))))
	     "server thread"))

(include "mockupclientlib.scm")

;; SYNC THREAD
;; send a sync to the pull port
(define th2 (make-thread
	     (lambda ()
	       (let ((last-action-time (current-seconds)))
		 (let loop ()
		   (thread-sleep! 5)
		   (let ((queuelen (string->number (dbaccess "server" 'sync "nada" #f)))
			 (last-action-delta #f))
		     (if (> queuelen 1)(set! last-action-time (current-seconds)))
		     (set! last-action-delta (- (current-seconds) last-action-time))
		     (print "Server: Got queuelen=" queuelen ", last-action-delta=" last-action-delta)
		     (if (< last-action-delta 60)
			 (loop)
			 (print "Server exiting, 25 seconds since last access"))))))
	     "sync thread"))

(thread-start! th1)
(thread-start! th2)
(thread-join! th2)

(let* ((run-time       (- (current-seconds) start-time))
       (queries/second (/  total-db-accesses run-time)))
  (print "Server exited! Total db accesses=" total-db-accesses " in " run-time " seconds for " queries/second " queries/second with max queue length of: " max-queue-len))

;; watch nanomsg's pipeline load-balancer in action.
(use nanomsg)

(define push (nn-socket 'push))
(define pull1 (nn-socket 'pull))
(define pull2 (nn-socket 'pull))

(nn-bind    push  "inproc://test")
(nn-connect pull1 "inproc://test")
(nn-connect pull2 "inproc://test")

(nn-send push "a")
(nn-send push "b")
(nn-send push "c")
(nn-send push "d")

(define ((th sock))
  (print (current-thread) ": " (nn-recv sock))
  (print (current-thread) ": " (nn-recv sock))
  (print (current-thread) " is done"))

(thread-start! (th pull1))
(thread-start! (th pull2))

(thread-sleep! 1)

;; watch nanomsg's pipeline load-balancer in action.
(use nanomsg)

(define req   (nn-socket 'req))
(define rep   (nn-socket 'rep))

(nn-bind    rep  "inproc://test")
(nn-connect req  "inproc://test")

(define (client-send-receive soc msg)
  (nn-send soc msg)
  (nn-recv soc))

(define ((server soc))
  (let loop ((msg-in (nn-recv soc)))
    (if (not (equal? msg-in "quit"))
	(begin
	  (nn-send soc (conc "hello " msg-in))
	  (loop (nn-recv soc))))))

(thread-start! (server rep))

(print (client-send-receive req "Matt"))
(print (client-send-receive req "Tom"))

;; (client-send-receive req "quit")

(nn-close req)
(nn-close rep)
(exit)