! Copyright (C) 2005, 2006 Slava Pestov.
! See http://factorcode.org/license.txt for BSD license.
IN: gadgets
USING: alien arrays errors freetype gadgets-layouts
gadgets-theme generic io kernel lists math memory namespaces
opengl prettyprint queues sequences sequences strings styles
threads ;

DEFER: redraw-world

! The world gadget is the top level gadget that all (visible)
! gadgets are contained in. The current world is stored in the
! world variable. The invalid slot is a list of gadgets that
! need to be layout.
TUPLE: world glass status handle ;

: add-layer ( gadget -- )
    world get add-gadget ;

C: world ( dim -- world )
    <stack> over set-delegate
    [ set-gadget-dim ] keep
    t over set-gadget-root? ;

: hide-glass ( -- )
    f world get dup world-glass unparent set-world-glass ;

: show-glass ( gadget -- )
    hide-glass
    <gadget> dup add-layer dup world get set-world-glass
    dupd add-gadget prefer ;

! Status bar protocol
GENERIC: set-message ( string/f status -- )

M: f set-message 2drop ;

: show-message ( string/f -- )
    #! Show a message in the status bar.
    world get world-status set-message ;

: relevant-help ( -- string )
    hand get hand-gadget
    parents [ gadget-help ] map [ ] find nip ;

: update-help ( -- )
    #! Update mouse-over help message.
    relevant-help show-message ;

: under-hand ( -- seq )
    #! A sequence whose first element is the world and last is
    #! the current gadget, with all parents in between.
    hand get hand-gadget parents reverse-slice ;

: hand-grab ( -- gadget )
    hand get rect-loc world get pick-up ;

: update-hand-gadget ( -- )
    hand-grab hand get set-hand-gadget ;

: move-hand ( loc -- )
    under-hand >r hand get set-rect-loc
    update-hand-gadget
    under-hand r> hand-gestures update-help ;

: update-hand ( -- )
    #! Called when a gadget is removed or added.
    hand get rect-loc move-hand ;

: ui-title
    [ "Factor " % version % " - " % image % ] "" make ;

: world-step ( -- )
    do-timers
    invalid queue-empty? >r layout-queued r>
    [ update-hand world get redraw-world ] unless ;