#lang racket/base

(require racket/match)
(require racket/tcp)
(require racket/port)
(require minimart)
(require minimart/drivers/timer)
(require logbook)
(require racket/cmdline)

(define server-entry-name #f)
(define server-entry-type #f)

(command-line #:program "echo-server.rkt"
	      #:once-each
	      ["--logbook-entry-name" name
	       "set logbook entry name to use when recording run statistics"
	       (set! server-entry-name name)]
	      ["--logbook-entry-type" type
	       "set logbook entry type to use"
	       (set! server-entry-type type)])

(when (not server-entry-type)
  (error 'echo-server "Please supply the --logbook-entry-type command-line argument."))

(define L (default-logbook))
(define E (logbook-entry L "minimart" server-entry-name server-entry-type))
(define Tmem (logbook-table E "server-memory-use" #:column-spec '(time-seconds memory-use)))
(define Tconn (logbook-table E "server-connections" #:column-spec '(time-seconds connection-count)))

(define connection-count 0)
(define first-connection-seen? #f)

(define statistics-poll-interval 2000)

(define (statistician)
  (list (spawn (lambda (e s)
		 (match e
		   [(message (timer-expired 'statistician now) _ _)
		    ;; (collect-garbage)
		    ;; (collect-garbage)
		    ;; (collect-garbage)
		    (write-logbook-datum! Tmem (list (/ now 1000.0) (current-memory-use)))
		    (write-logbook-datum! Tconn (list (/ now 1000.0) connection-count))
		    (when (and first-connection-seen? (zero? connection-count))
		      (exit 0))
		    (transition s
		      (send (set-timer 'statistician statistics-poll-interval 'relative)))]
		   [_ #f]))
	       #f
	       (sub (timer-expired 'statistician ?)))
	(send (set-timer 'statistician statistics-poll-interval 'relative))))

(define (listener port-number)
  (spawn (lambda (e s)
	   (match e
	     [(message (event _ (list (list in out))) _ _)
	      (transition s (connection in out))]
	     [_ #f]))
	 #f
	 (sub (event (tcp-accept-evt (tcp-listen port-number 128 #t)) ?)
              #:meta-level 1)))

(define (connection in out)
  (set! connection-count (+ connection-count 1))
  (set! first-connection-seen? #t)
  (spawn (lambda (e s)
	   (match e
	     [(message (event _ (list (? eof-object?))) _ _)
	      (close-input-port in)
	      (close-output-port out)
	      (set! connection-count (- connection-count 1))
	      (transition s (quit))]
	     [(message (event _ (list line)) _ _)
	      (fprintf out "~a\n" line)
	      (flush-output out)
	      (transition s '())]
	     [_ #f]))
	 #f
	 (sub (event (read-line-evt in 'any) ?)
              #:meta-level 1)))

(run-ground (listener 5999)
	    (spawn-timer-driver)
	    (statistician))