! Copyright (C) 2005, 2006 Slava Pestov.
! See http://factorcode.org/license.txt for BSD license.
IN: gadgets
USING: hashtables kernel math namespaces sequences ;

TUPLE: timer object delay next ;

C: timer ( object delay initial -- timer )
    [ >r millis + r> set-timer-next ] keep
    [ set-timer-delay ] keep
    [ set-timer-object ] keep ;

GENERIC: tick ( object -- )

: timers \ timers get-global ;

: init-timers ( -- ) H{ } clone \ timers set-global ;

: add-timer ( object delay initial -- )
    pick >r <timer> r> timers set-hash ;

: remove-timer ( object -- ) timers remove-hash ;

: advance-timer ( ms timer -- )
    [ timer-delay + ] keep set-timer-next ;

: do-timer ( ms timer -- )
    dup timer-next pick <=
    [ [ advance-timer ] keep timer-object tick ] [ 2drop ] if ;

: do-timers ( -- )
    millis timers hash-values [ do-timer ] each-with ;