;;;; remote-mailbox-client.scm
;;;; Kon Lovett, Sep '09

;; Issues
;;
;; - Currently the client input port is unused.

(module remote-mailbox-client

(;export
  ;;common
  ;parameters
  remote-mailbox-default-tcp-port-no
  remote-mailbox-default-expected-size
  remote-mailbox-default-hostname
  ;;client
  ;parameters
  remote-mailbox-default-connect
  ;operations
  make-remote-mailbox
  remote-mailbox?
  remote-mailbox-name
  remote-mailbox-hostname
  remote-mailbox-tcp-port-no
  remote-mailbox-connected?
  drop-remote-mailbox!
  drop-remote-mailboxes!
  remote-mailboxes
  remote-mailbox-send!)

(import scheme
  (chicken base)
  (chicken type)
  (chicken tcp)
  (only (chicken string) conc)
  (only (srfi 18) make-mutex mutex-name)
  (only moremacros ->boolean define-warning-parameter)
  (only type-errors warning-argument-type)
  mailbox
  synch-open
  (only type-checks-basic define-check+error-type)
  (only (check-errors sys) check-procedure)
  remote-mailbox-adapter
  remote-mailbox-packet
  remote-mailbox-common)

(include-relative "remote-mailbox.types")

(define-type remote-mailbox (struct remote-mailbox))

(: remote-mailbox-default-connect (#!optional (or false procedure) -> procedure))

(: make-remote-mailbox (mailbox-name #!rest -> remote-mailbox))
(: remote-mailbox? (* -> boolean : remote-mailbox))
(: remote-mailbox-connected? (remote-mailbox -> boolean))
(: remote-mailbox-name (remote-mailbox -> mailbox-name))
(: remote-mailbox-hostname (remote-mailbox -> hostname))
(: remote-mailboxes (-> (list-of remote-mailbox)))
(: drop-remote-mailbox! (remote-mailbox -> void))
(: drop-remote-mailboxes! (-> void))
(: remote-mailbox-send! (remote-mailbox * -> void))

(: remote-mailbox-ref (symbol ((or false symbol) -> (or false remote-mailbox)) -> (or false remote-mailbox)))
(: remote-mailbox-delete! (symbol -> void))
(: remote-mailbox-values (-> (list-of remote-mailbox)))

(: make-remote-mailbox-key (mailbox-name hostname tcp-port-no -> symbol))

(: checked-make-remote-mailbox (symbol mailbox-name hostname tcp-port-no procedure -> remote-mailbox))

;;; Support

(define remote-mailbox-ref)
(define remote-mailbox-delete!)
(define remote-mailbox-values)
(let ((+rmtmbx-map+ (make-symbol-map)))
  (set! remote-mailbox-ref
    (lambda (key f) (symbol-map-ref +rmtmbx-map+ key f)))
  (set! remote-mailbox-delete!
    (lambda (key) (symbol-map-delete! +rmtmbx-map+ key)))
  (set! remote-mailbox-values
    (lambda () (symbol-map-values +rmtmbx-map+))) )

(define-record-type remote-mailbox
  (*make-remote-mailbox name hstnam prtnum serializer connect mutex input output)
  *remote-mailbox?
  (name remote-mailbox-name remote-mailbox-name-set!)
  (hstnam remote-mailbox-hostname)
  (prtnum remote-mailbox-tcp-port-no)
  (serializer remote-mailbox-serializer)
  (connect remote-mailbox-connect)
  (mutex remote-mailbox-mutex)
  (input remote-mailbox-input-port remote-mailbox-input-port-set!)
  (output remote-mailbox-output-port remote-mailbox-output-port-set!) )

(define (invalidate-remote-mailbox! rmb)
  (remote-mailbox-name-set! rmb #f) )

(define (valid-remote-mailbox? rmb)
  (->boolean (remote-mailbox-name rmb)) )

(define (remote-mailbox-key rmb)
  (mutex-name (remote-mailbox-mutex rmb)) )

(define (make-remote-mailbox-key name hostname tcp-port-no)
  (string->symbol (conc name #\@ hostname (if tcp-port-no (conc #\: tcp-port-no) ""))) )

(define (checked-make-remote-mailbox loc name hostname tcp-port-no connect)
  (let* ((tcp-port-no (and tcp-port-no
                           (check-tcp-port-no loc tcp-port-no 'tcp-port-no)))
         (key (make-remote-mailbox-key (check-mailbox-name loc name)
                                       (check-hostname loc hostname)
                                       tcp-port-no)) )
    (remote-mailbox-ref key
                        (lambda (def)
                          (assert (not def) loc "cannot redefine mailbox" key def)
                          (*make-remote-mailbox name hostname tcp-port-no
                                                (serializer)
                                                (check-procedure loc connect)
                                                (make-mutex key)
                                                #f #f))) ) )

(define (*remote-mailbox-connected? rmb)
  (->boolean (remote-mailbox-output-port rmb)) )

(define (connection/remote-mailbox rmb)
  (if (*remote-mailbox-connected? rmb)
    (remote-mailbox-output-port rmb)
    ;else make a connection
    (let-values (((in out) (let ((connect (remote-mailbox-connect rmb))
                                 (tcp-port-no (remote-mailbox-tcp-port-no rmb)) )
                             ;Allow hostname to carry service/portno
                             (if (not tcp-port-no)
                                 (connect (remote-mailbox-hostname rmb))
                                 (connect (remote-mailbox-hostname rmb) tcp-port-no)))) )
      (remote-mailbox-input-port-set! rmb in)
      (remote-mailbox-output-port-set! rmb out)
      out ) ) )

(define (close-remote-mailbox-connection! rmb)
  (close-input-port (remote-mailbox-input-port rmb))
  (remote-mailbox-input-port-set! rmb #f)
  (close-output-port (remote-mailbox-output-port rmb))
  (remote-mailbox-output-port-set! rmb #f)
  (invalidate-remote-mailbox! rmb) )

(define (*drop-remote-mailbox! rmb)
  (%record-synch rmb remote-mailbox
    (close-remote-mailbox-connection! rmb)
    (remote-mailbox-delete! (remote-mailbox-key rmb)) ) )

;;; Exported

;; Parameters

(define (remote-mailbox-connector? x)
  (or (not x) (procedure? x)) )

(define-warning-parameter remote-mailbox-default-connect tcp-connect remote-mailbox-connector
  ;ugh, automagic identifier injection
  (unless obj (set! obj tcp-connect)) )

;; Operations

(define (make-remote-mailbox name
          #!key
          (hostname (remote-mailbox-default-hostname))
          (tcp-port-no (remote-mailbox-default-tcp-port-no))
          (connect (remote-mailbox-default-connect)))
  (checked-make-remote-mailbox 'make-remote-mailbox name hostname tcp-port-no connect) )

(define (remote-mailbox? obj)
  (and (*remote-mailbox? obj) (valid-remote-mailbox? obj)) )

(define-check+error-type remote-mailbox)

(define (remote-mailbox-connected? rmb)
  (*remote-mailbox-connected? (check-remote-mailbox 'remote-mailbox-connected? rmb)) )

(define (drop-remote-mailbox! rmb)
  (*drop-remote-mailbox! (check-remote-mailbox 'drop-remote-mailbox! rmb)) )

(define (drop-remote-mailboxes!)
  (for-each (cut *drop-remote-mailbox! <>) (remote-mailbox-values)) )

(define (remote-mailboxes)
  (remote-mailbox-values) )

(define (remote-mailbox-send! rmb val)
  (%record-synch (check-remote-mailbox 'remote-mailbox-send! rmb) remote-mailbox
    (let ((out (connection/remote-mailbox rmb))
          (req (make-remote-mailbox-packet (remote-mailbox-name rmb) val)) )
      (parameterize ((serializer (remote-mailbox-serializer rmb)))
        (serialize req out) ) ) ) )

) ;module remote-mailbox-client