%D \module
%D   [       file=page-mis,
%D        version=2008.11.17, % was part of page-flt.tex / 2000.10.20
%D          title=\CONTEXT\ Page Macros,
%D       subtitle=Misc Float Things,
%D         author=Hans Hagen,
%D           date=\currentdate,
%D      copyright={PRAGMA ADE \& \CONTEXT\ Development Team}]
%C
%C This module is part of the \CONTEXT\ macro||package and is
%C therefore copyrighted by \PRAGMA. See mreadme.pdf for
%C details.

\writestatus{loading}{ConTeXt Page Macros / Misc Float Things}

\registerctxluafile{page-mis}{1.001}

\unprotect

\newif\ifmarginblocks

\def\dosetupmarginblocks[#1]%
  {\getparameters[\??mb][#1]%
   \doifelse\@@mbstate\v!start
     {\showmessage\m!layouts4\empty
      \marginblockstrue
      \let\somenextfloat\dosomenextfloat
      \let\startmarginblock\dostartmarginblock
      \let\stopmarginblock\dostopmarginblock}%
     {\showmessage\m!layouts5\empty
      \marginblocksfalse
      \def\somenextfloat[##1]%
        {\someelsefloat[##1,\v!here]}%
      \let\startmarginblock\dontstartmargeblok
      \let\stopmarginblock\dontstopmargeblok}}

\unexpanded\def\setupmarginblocks
  {\dosingleargument\dosetupmarginblocks}

\newbox\marginbox

\def\dosomenextfloat[#1]%
  {\global\setbox\marginbox\vbox
     {\hsize\@@mbwidth
      \unvcopy\marginbox
      \ifvoid\marginbox\else\expandafter\@@mbinbetween\fi
      \box\floatbox\filbreak}%
  \ifdim\ht\marginbox>\textheight
  % \dosavefloatinfo
  \else
    \doinsertfloatinfo
  \fi}

\newbox\preparedmarginbox

\def\reshapemargin
  {\ifdim\ht\preparedmarginbox>\zeropoint
     \beginofshapebox
     \unvbox\preparedmarginbox
     \endofshapebox
     \reshapebox
       {\box\shapebox}%
     \setbox\preparedmarginbox\vbox to \textheight
       {\@@mbtop
        \flushshapebox
        \@@mbbottom}%
   \fi}

\unexpanded\def\placerightmarginblock
  {\hskip\rightmarginwidth}

\unexpanded\def\placeleftmarginblock
  {\hskip\leftmarginwidth}

\def\checkmarginblocks
  {\ifvoid\marginbox\else\docheckmarginblocks\fi}

\def\docheckmarginblocks % erg inefficient
  {\setbox\preparedmarginbox\vbox
     {\forgetall
      \splittopskip\topskip
      \ifvoid\marginbox\else
        \ifdim\ht\marginbox>\textheight
          \vsplit\marginbox to \textheight
        \else
          \unvbox\marginbox
        \fi
      \fi}%
   \reshapemargin
   \setbox\preparedmarginbox\vbox
      {\@@mbbefore\box\preparedmarginbox\@@mbafter}%
   \def\rightmarginbox
     {\unexpanded\def\placerightmarginblock
        {\setbox\preparedmarginbox\hbox to \rightmarginwidth
           {\@@mbleft\box\preparedmarginbox\@@mbright}%
         \vsmashbox\preparedmarginbox
         \box\preparedmarginbox}}%
   \def\leftmarginbox
     {\unexpanded\def\placeleftmarginblock
        {\setbox\preparedmarginbox\hbox to \leftmarginwidth
           {\@@mbright\box\preparedmarginbox\@@mbleft}%
         \vsmashbox\preparedmarginbox
         \box\preparedmarginbox}}%
   \processaction % traag
     [\@@mblocation]
     [ \v!inmargin=>\doifbothsidesoverruled\rightmarginbox\rightmarginbox\leftmarginbox,
         \v!middle=>\doifbothsidesoverruled\rightmarginbox\leftmarginbox\rightmarginbox,
           \v!left=>\leftmarginbox,
          \v!right=>\rightmarginbox,
        \s!unknown=>\setbox\preparedmarginbox\emptyhbox]}

\def\dostartmarginblock % 2 maal \vbox ivm \unvbox elders
  {\global\setbox\marginbox\vtop\bgroup\vbox\bgroup
     \hsize\@@mbwidth
     \ifvoid\marginbox\else
       \unvbox\marginbox
       \@@mbinbetween
     \fi
     \setupalign[\@@mbalign]%
     \dostartattributes\??mb\c!style\c!color{}%
     \begstrut\ignorespaces}

\def\dostopmarginblock
  {\unskip\endstrut
   \dostopattributes
   \egroup
   \egroup}

\def\dontstartmargeblok
  {\@@mbbefore
   \bgroup
   \dostartattributes\??mb\c!style\c!color\empty}

\def\dontstopmargeblok
  {\dostopattributes
   \egroup
   \@@mbafter}

\setupmarginblocks
  [\c!state=\v!start,
   \c!location=\v!inmargin,
   \c!width=\rightmarginwidth,
   \c!style=,
   \c!color=,
   \c!align=,
   \c!left=,
   \c!right=,
   \c!top=,
   \c!inbetween=\blank,
   \c!bottom=\vfill,
   \c!before=,
   \c!after=]

% postponing

\newevery\everytopofpage\relax

\appendtoks   \the\everytopofpage          \to\everystarttext
\appendtoks\global\everytopofpage\emptytoks\to\everystoptext

% \startpostponing [pagenumber] [+pageoffset]
%
% \startpostponing[2]
%   PAGE 2 \blank
% \stoppostponing
%
% \startpostponing[+1]
%   PAGE +1 \blank
% \stoppostponing
%
% \startpostponing[+2]
%   PAGE +2 \blank
% \stoppostponing
%
% \starttext \dorecurse{4}{\input tufte \page} \stoptext

%D There is no real need to use \LUA\ here but the bookkeeping
%D is somewhat easier and we also can erase buffers easier when
%D we keep a local cache, especially as we can flush per page.

\newif   \ifinpostponing                  % prevents nesting
\newcount\postponed_page_blocks_next_page % set at the lua end

\unexpanded\setvalue{\e!start\v!postponing}%
  {\bgroup
   \obeylines
   \doifnextoptionalelse{\egroup\postponed_page_block_start}{\egroup\postponed_page_block_start[0]}}

\unexpanded\setvalue{\e!stop\v!postponing}%
  {\ctxcommand{registerpostponedblock("\currentpostponedpage")}\relax}

\def\postponed_page_block_start[#1]%
  {\edef\currentpostponedpage{#1}%
   \dostartbuffer[postponedblock][\e!start\v!postponing][\e!stop\v!postponing]}

% officially we should flush again after a flush as there can be new future pages
% but that will be looked into when we run into it

\unexpanded\def\postponed_page_block_flush
  {\bgroup
   \inpostponingtrue                  % for old times sake
   \global\pagetotal\zeropoint        % here? still needed? (was after flush pagefloats)
   \the\everytopofpage\relax
  %\flushrestfloats
   \doflushpagefloats
   \setnormalcatcodes                 % postponing in verbatim
   \restoreglobalbodyfont             % otherwise problems inside split verbatim
   \ctxcommand{flushpostponedblocks()}%
   \relax
   \doflushfloats                     % new but potential dangerous, maybe we need a classification
   \egroup}                           % of blocks: with and without flush

\def\doflushpostponedblocks
  {\ifinpostponing
     % probably a nested flush
   \else\ifnum\postponed_page_blocks_next_page=\zerocount
     % nothing in cache
   \else\ifnum\postponed_page_blocks_next_page<\zerocount
     % generic cache
     \postponed_page_block_flush
   \else\ifnum\postponed_page_blocks_next_page>\realpageno
     % future content
   \else
     % pending content
     \postponed_page_block_flush
   \fi\fi\fi\fi}

\def\doflushpostponedcontent % called in page-one
  {\bgroup
   \setsystemmode\v!postponing
   \the\everytopofpage
  %\flushrestfloats
   \doflushpagefloats
   \doflushpostponedblocks
   \egroup}

\protect \endinput