%D \module
%D   [       file=chem-ini,
%D        version=2009.05.13,
%D       subtitle=Chemistry,
%D         author=Hans Hagen,
%D           date=\currentdate,
%D      copyright=\PRAGMA]
%C
%C This module is part of the \CONTEXT\ macro||package and is
%C therefore copyrighted by \PRAGMA. See mreadme.pdf for
%C details.

%D This module in incomplete and experimental. Eventually this code
%D will replace \PPCHTEX.

\writestatus{loading}{ConTeXt Chemistry Macros / Structure}

\registerctxluafile{chem-str}{1.001}

% We have a slightly different interface. This is unchanged:
%
% \startchemical[axis=on]
%     \chemical[SIX,ROT2,B,R6,SUB1,FIVE,ROT1,B][1]
% \stopchemical
%
% Here we use chemicalformula instead, so no longer a mix:
%
% \startchemicalformula
%     \chemical{H_2}{top}{bottom}
%     \chemical{PLUS}{top}{bottom}
%     \chemical{O}{top}{bottom}
%     \chemical{GIVES}{top}{bottom}
%     \chemical{H_2O}{top}{bottom}
% \stopchemicalformula
%
% \startchemicalformula
%     \chemical{H_2}
%     \chemical{PLUS}
%     \chemical{O}
%     \chemical{GIVES}
%     \chemical{H_2O}
% \stopchemicalformula
%
% The inline variant has only one argument:
%
% \chemical{H_2,PLUS,O,GIVES,H_2O}

% todo: seven | eight | frontsix | fontfive | carbon | newmans | chair

\unprotect

\unexpanded\def\setupchemical
  {\dosingleempty\dosetupchemical}

\def\dosetupchemical
  {\getparameters[\??cm]}

\let\setupchemicals\setupchemical

\unexpanded\def\setupchemicalframed
  {\dosingleempty\dosetupchemicalframed}

\def\dosetupchemicalframed
  {\getparameters[\??cm:\c!frame]}

\def\chemicalparameter#1{\csname\??cm#1\endcsname}

\unexpanded\def\definechemical
  {\dosingleargument\dodefinechemical} % global

\def\dodefinechemical[#1]#2%
  {\startnointerference
   \ctxlua{chemicals.undefine("#1")}%
   \def\chemical{\dodoubleempty\dostructurechemical}%
   \def\dostructurechemical[##1][##2]{\ctxlua{chemicals.define("#1",\!!bs##1\!!es,\!!bs\detokenize{##2}\!!es)}}%
   #2% flush
   \stopnointerference}

\unexpanded\def\definechemicalsymbol
  {\dodoubleempty\dodefinechemicalsymbol}

\def\dodefinechemicalsymbol[#1][#2]%
  {\setvalue{\??cm::#1}{#2}}

\def\chemicalsymbol[#1]%
  {\getvalue{\??cm::#1}}

% size (small medium big)

\def\dosetchemicaltext
  {\dosetfontattribute \??cm\c!style
   \dosetcolorattribute\??cm\c!color}

\def\dochemicaltext#1%
  {\dosetchemicaltext\strut#1} % maybe also \setstrut

\edef\chemicaltoplocation{t}
\edef\chemicalbotlocation{b}

\def\dochemicaltext#1% in ppchtex we had a more clever alignment
  {\dosetchemicaltext\strut#1} % maybe also \setstrut

\def\dochemicaltext#1%
  {\mathematics{\dosetchemicaltext\strut\ifcase\currentxfontsize\or\scriptstyle\or\scriptscriptstyle\fi#1}}

\newconditional\indisplaychemical

\unexpanded\def\startchemical
  {\dosingleempty\dostartchemical}

\setvalue{\??cm:\c!size:\v!small }{\txx}
\setvalue{\??cm:\c!size:\v!medium}{\tx}
\setvalue{\??cm:\c!size:\v!big   }{}

\newtoks       \everychemical
\newtoks       \everystructurechemical
\newtoks       \withchemicalbox
\newbox        \chemicalbox
\newconditional\somechemicaltext
\newdimen      \chemicalwidth
\newdimen      \chemicalheight
\newdimen      \chemicaldepth

\def\dostartchemical[#1]%
  {\ifmmode\vcenter\else\vbox\fi
   \bgroup
   \dontcomplain
   \settrue\indisplaychemical
   \forgetall
   \getparameters[\??cm][#1]%
   \the\everystructurechemical
   \setbox\chemicalbox\hbox\bgroup
   \ctxlua{chemicals.start {
     width  = "\chemicalparameter\c!width",
     height = "\chemicalparameter\c!height",
     left   =  \chemicalparameter\c!left,
     right  =  \chemicalparameter\c!right,
     top    =  \chemicalparameter\c!top,
     bottom =  \chemicalparameter\c!bottom,
     scale  = "\chemicalparameter\c!scale",
     axis   = "\chemicalparameter\c!axis",
     offset = "\the\dimexpr.25em\relax",
   } }%
   \startnointerference}

\unexpanded\def\stopchemical
  {\stopnointerference
   \ctxlua{chemicals.stop()}%
   \egroup
   \chemicalwidth \wd\chemicalbox
   \chemicalheight\ht\chemicalbox
   \chemicaldepth \dp\chemicalbox
   \the\withchemicalbox
   \doifelsenothing{\chemicalparameter\c!frame}\handlechemicalframednop\handlechemicalframedyes
   \egroup}

\def\handlechemicalframedyes
  {\localframed%
     [\??cm:\c!frame]%
     [\c!frame=\chemicalparameter\c!frame,\c!align=\v!normal,\c!strut=\v!no]{\vbox{\box\chemicalbox\vss}}} % remove depth

\def\handlechemicalframednop
  {\localframed%
     [\??cm:\c!frame]%
     [\c!align=\v!normal,\c!strut=\v!no]{\vbox{\box\chemicalbox\vss}}} % remove depth

\let\startstructurechemical\startchemical
\let\stopstructurechemical \stopchemical

\unexpanded\def\structurechemical
  {\dotripleempty\dostructurechemical}

\appendtoks
    \let\chemical\structurechemical
\to\everystructurechemical

\def\dostructurechemical
  {\ifthirdargument
     \expandafter\dostructurechemicalthree
   \else
     \expandafter\dostructurechemicaltwo
   \fi}

\def\dostructurechemicalthree[#1][#2][#3]%
  {\writestatus\m!chemicals{hyperlinked chemicals not yet supported}% todo reference, for the moment ignored
   \ctxlua{chemicals.component(\!!bs#2\!!es, \!!bs\detokenize{#3}\!!es, { % maybe also pass first two args this way
     rulethickness = "\the\dimexpr\chemicalparameter\c!rulethickness\relax", % todo: scaled points
     rulecolor     = "\MPcolor{\chemicalparameter\c!rulecolor}" % we can precalculate this for speedup
    } ) }%
   \ignorespaces}

\def\dostructurechemicaltwo[#1][#2]%
  {\ctxlua{chemicals.component(\!!bs#1\!!es,\!!bs\detokenize{#2}\!!es, { % maybe also pass first two args this way
     rulethickness = "\the\dimexpr\chemicalparameter\c!rulethickness\relax", % todo: scaled points
     rulecolor     = "\MPcolor{\chemicalparameter\c!rulecolor}" % we can precalculate this for speedup
    } ) }%
   \ignorespaces}

\appendtoks
    \setbox\chemicalbox\hbox{\raise\MPlly\onebasepoint\box\chemicalbox}%
    \chemicalwidth \wd\chemicalbox
    \chemicalheight\ht\chemicalbox
    \chemicaldepth \dp\chemicalbox
\to \withchemicalbox

% kind of compatible, but text sizes instead of math sizes (i.e. tx is larger than scriptsize)

\appendtoks
   \edef\chemicalbodyfont{\chemicalparameter\c!bodyfont}%
   \doifnot\chemicalbodyfont\fontbody{\switchtobodyfont[\chemicalbodyfont]}% \fontbody is not expanded (yet)
   \getvalue{\??cm:\c!size:\chemicalparameter\c!size}%
% \to \everystructurechemical
\to \everychemical

\def\chemicaltoptext#1{\global\settrue\somechemicaltext\gdef\thetoptext{#1}\ignorespaces}
\def\chemicalbottext#1{\global\settrue\somechemicaltext\gdef\thebottext{#1}\ignorespaces}
\def\chemicalmidtext#1{\global\settrue\somechemicaltext\gdef\themidtext{#1}\ignorespaces}

\appendtoks
    \let\toptext\chemicaltoptext \glet\thetoptext\empty
    \let\bottext\chemicalbottext \glet\thebottext\empty
    \let\midtext\chemicalmidtext \glet\themidtext\empty
    \global\setfalse\somechemicaltext
\to \everystructurechemical

\def\doaddchemicaltexts
  {\setbox2\hbox to \chemicalwidth{\strut\hss\hbox{\strut\themidtext}\hss}%
   \setbox4\hbox to \chemicalwidth{\strut\hss\hbox{\strut\thetoptext}\hss}%
   \setbox6\hbox to \chemicalwidth{\strut\hss\hbox{\strut\thebottext}\hss}%
   \setbox\chemicalbox\hbox \bgroup
     \box\chemicalbox
     \hskip-\chemicalwidth
     \raise\chemicalheight\hbox{\lower\ht4\box4}%
     \hskip-\chemicalwidth
     \lower.5\dimexpr\ht2-\dp2\relax\box2%
     \hskip-\chemicalwidth
     \lower\chemicaldepth \hbox{\raise\dp6\box6}%
     \hss
   \egroup} % text on top of chemicals

\appendtoks
    \ifconditional\somechemicaltext
      \doaddchemicaltexts
      \chemicalwidth \wd\chemicalbox
      \chemicalheight\ht\chemicalbox
      \chemicaldepth \dp\chemicalbox
    \fi
\to \withchemicalbox

% todo: enspace or emspace

\definechemicalsymbol[space]       [\enspace\quad\enspace]
\definechemicalsymbol[plus]        [\enspace+\enspace]
\definechemicalsymbol[minus]       [\enspace-\enspace]
\definechemicalsymbol[gives]       [\dochemicalarrow\xrightarrow]
\definechemicalsymbol[equilibrium] [\dochemicalarrow\xrightoverleftarrow]
\definechemicalsymbol[mesomeric]   [\dochemicalarrow\xleftrightarrow]
\definechemicalsymbol[opencomplex] [\mathematics{\Bigg[}] % not yet ok
\definechemicalsymbol[closecomplex][\mathematics{\Bigg]}] % not yet ok

\definechemicalsymbol[SPACE]       [{\chemicalsymbol[space]}]
\definechemicalsymbol[PLUS]        [{\chemicalsymbol[plus]}]
\definechemicalsymbol[MINUS]       [{\chemicalsymbol[minus]}]
\definechemicalsymbol[GIVES]       [{\chemicalsymbol[gives]}]
\definechemicalsymbol[EQUILIBRIUM] [{\chemicalsymbol[equilibrium]}]
\definechemicalsymbol[MESOMERIC]   [{\chemicalsymbol[mesomeric]}]
\definechemicalsymbol[OPENCOMPLEX] [{\chemicalsymbol[opencomplex]}]
\definechemicalsymbol[CLOSECOMPLEX][{\chemicalsymbol[closecomplex]}]

\def\dochemicalarrow#1#2#3%
  {\enspace
   \mathematics{#1%
     {\strut\hbox \!!spread 2em{\hss\ctxlua{chemicals.inline(\!!bs#2\!!es)}\hss}}%
     {\strut\hbox \!!spread 2em{\hss\ctxlua{chemicals.inline(\!!bs#3\!!es)}\hss}}}%
   \enspace}

% special macros (probably needs some more work)

\def\dochemicaltop#1#2#3#4%
  {\begingroup
   \setbox0\hbox{\tx\setstrut\strut#3}%
   \setbox2\hbox{\setstrut\strut\molecule{#4}}%
   \setbox0\hbox{\raise\dimexpr\dp0+\ht2\relax\hbox to \wd2{#1\box0#2}}%
   \smashbox0
   \hbox{\box0\box2}%
   \endgroup}%

\def\dochemicalbottom#1#2#3#4%
  {\begingroup
   \setbox0\hbox{\tx\setstrut\strut#3}%
   \setbox2\hbox{\setstrut\strut#4}%
   \setbox0\hbox{\lower\dimexpr\dp2+\ht0\relax\hbox to \wd2{#1\box0#2}}%
   \smashbox0
   \hbox{\box0\box2}%
   \endgroup}%

\unexpanded\def\chemicalleft#1#2%
  {\begingroup
   \hbox{\llap{\tx\setstrut\strut#1}\setstrut\strut#2}%
   \endgroup}%

\unexpanded\def\chemicalright#1#2%
  {\begingroup
   \hbox{\setstrut\strut#2\rlap{\tx\setstrut\strut#1}}%
   \endgroup}%

\unexpanded\def\chemicaltop            {\dochemicaltop    \hss   \hss  }
\unexpanded\def\chemicallefttop        {\dochemicaltop    \relax \hss  }
\unexpanded\def\chemicalrighttop       {\dochemicaltop    \hss   \relax}
\unexpanded\def\chemicalbottom         {\dochemicalbottom \hss   \hss  }
\unexpanded\def\chemicalleftbottom     {\dochemicalbottom \relax \hss  }
\unexpanded\def\chemicalrightbottom    {\dochemicalbottom \hss   \relax}

\unexpanded\def\chemicaltopleft      #1{\chemicalleft {\chemicalrighttop   {#1}{}}}
\unexpanded\def\chemicalbottomleft   #1{\chemicalleft {\chemicalrightbottom{#1}{}}}
\unexpanded\def\chemicaltopright     #1{\chemicalright{\chemicallefttop    {#1}{}}}
\unexpanded\def\chemicalbottomright  #1{\chemicalright{\chemicalleftbottom {#1}{}}}

\unexpanded\def\chemicalcentered     #1{\setbox\scratchbox\hbox{C}\hbox to \wd\scratchbox{\setstrut\strut\hss#1\hss}}
\unexpanded\def\chemicalleftcentered #1{\setbox\scratchbox\hbox{C}\hbox to \wd\scratchbox{\setstrut\strut    #1\hss}}
\unexpanded\def\chemicalrightcentered#1{\setbox\scratchbox\hbox{C}\hbox to \wd\scratchbox{\setstrut\strut\hss#1}}

\let\chemicalsmashedmiddle\chemicalcentered
\let\chemicalsmashedleft  \chemicalleftcentered
\let\chemicalsmashedright \chemicalrightcentered

\unexpanded\def\chemicaloxidation#1#2#3%
  {\chemicaltop{\txx\ifcase#2\relax0\else#1\uppercase\expandafter{\romannumeral#2}\fi}{#3}}

\unexpanded\def\chemicaloxidationplus {\dotriplegroupempty\chemicaloxidation{\textplus }} % {} needed!
\unexpanded\def\chemicaloxidationminus{\dotriplegroupempty\chemicaloxidation{\textminus}} % {} needed!
\unexpanded\def\chemicalforeveropen   {\dotriplegroupempty\chemicalleft     {$\big[$}} % {} needed!
\unexpanded\def\chemicalforeverclose  {\dotriplegroupempty\chemicalright    {$\big]$}} % {} needed!
\unexpanded\def\chemicaloxidationone  {\chemicaloxidation\relax1}
\unexpanded\def\chemicaloxidationtwo  {\chemicaloxidation\relax2}
\unexpanded\def\chemicaloxidationthree{\chemicaloxidation\relax3}
\unexpanded\def\chemicaloxidationfour {\chemicaloxidation\relax4}
\unexpanded\def\chemicaloxidationfive {\chemicaloxidation\relax5}
\unexpanded\def\chemicaloxidationsix  {\chemicaloxidation\relax6}
\unexpanded\def\chemicaloxidationseven{\chemicaloxidation\relax7}

\appendtoks
   \let \+\chemicaloxidationplus
   \let \-\chemicaloxidationminus
   \let \[\chemicalforeveropen
   \let \]\chemicalforeverclose
   \let \1\chemicaloxidationone
   \let \2\chemicaloxidationtwo
   \let \3\chemicaloxidationthree
   \let \4\chemicaloxidationfour
   \let \5\chemicaloxidationfive
   \let \6\chemicaloxidationsix
   \let \7\chemicaloxidationseven
   \let \X\chemicaltighttext
   \let \T\chemicaltop
   \let \B\chemicalbottom
   \let \L\chemicalleft
   \let\LC\chemicalleftcentered
   \let \R\chemicalright
   \let\RC\chemicalrightcentered
   \let\TL\chemicaltopleft
   \let\BL\chemicalbottomleft
   \let\TR\chemicaltopright
   \let\BR\chemicalbottomright
   \let\LT\chemicallefttop
   \let\LB\chemicalleftbottom
   \let\RT\chemicalrighttop
   \let\RB\chemicalrightbottom
   \let\SL\chemicalsmashedleft
   \let\SM\chemicalsmashedmiddle
   \let\SR\chemicalsmashedright
\to \everychemical

\appendtoks
    \the\everychemical
\to \everystructurechemical

% inline

\unexpanded\def\chemical
  {\ifinformula
     \expandafter\displaychemical
   \else
     \expandafter\inlinechemical
   \fi}

\def\displaychemical
  {\dotriplegroupempty\dodisplaychemical}

\def\dodisplaychemical#1#2#3% todo:
  {\the\everychemical \everychemical\emptytoks
   \quad
   \vcenter\bgroup
     \ifthirdargument
       \ifsecondargument
         \halign{&\hss##\hss\cr#2\cr\molecule{#1}\cr#3\cr}%
       \else
         \halign{&\hss##\hss\cr\molecule{#1}\cr#2\cr}%
       \fi
     \else
       \hbox{\molecule{#1}}%
     \fi
   \egroup
   \quad}

\def\inlinechemical#1%
  {\dontleavehmode\hbox{\ctxlua{chemicals.inline(\!!bs#1\!!es)}}}

\def\chemicalbondrule{\hbox{\vrule\!!height.75ex\!!depth-\dimexpr.75ex-\linewidth\relax\!!width1em\relax}}

\definechemicalsymbol[i:space]       [\enspace\quad\enspace]
\definechemicalsymbol[i:plus]        [\enspace\mathematics{+}\enspace]
\definechemicalsymbol[i:minus]       [\enspace\mathematics{-}\enspace]
\definechemicalsymbol[i:gives]       [\enspace\mathematics{\xrightarrow{}{}}\enspace]
\definechemicalsymbol[i:equilibrium] [\enspace\mathematics{\xrightpverleftarrow{}{}}\enspace]
\definechemicalsymbol[i:mesomeric]   [\enspace\mathematics{\xleftrightarrow{}{}}\enspace]
\definechemicalsymbol[i:single]      [\chemicalbondrule]
\definechemicalsymbol[i:tripple]     [\hbox{\lower.5ex\chemicalbondrule\hskip-1em\raise.5ex\chemicalbondrule}]
\definechemicalsymbol[i:double]      [\hbox{\chemicalbondrule\hskip-1em\lower.5ex\chemicalbondrule\hskip-1em\raise.5ex\chemicalbondrule}]

\def\chemicalsinglebond {\chemicalsymbol[i:single]}
\def\chemicaldoublebond {\chemicalsymbol[i:tripple]}
\def\chemicaltriplebond {\chemicalsymbol[i:double]}
\def\chemicalgives      {\chemicalsymbol[i:gives]}
\def\chemicalmesomeric  {\chemicalsymbol[i:mesomeric]}
\def\chemicalequilibrium{\chemicalsymbol[i:equilibrium]}
\def\chemicalsplus      {\chemicalsymbol[i:plus]}
\def\chemicalsminus     {\chemicalsymbol[i:minus]}
\def\chemicalsspace     {\chemicalsymbol[i:space]}
\def\chemicalinline   #1{#1}

% display

\newconditional\formulachemicalhastop
\newconditional\formulachemicalhasbot

\newtoks\formulachemicaltop
\newtoks\formulachemicalmid
\newtoks\formulachemicalbot

\newif\ifinchemicalformula

\unexpanded\def\startchemicalformula
  {\mathortext\vcenter\vbox\bgroup
   \forgetall
   \inchemicalformulatrue
   \the\everychemical
   \everychemical\emptytoks
   \formulachemicaltop\emptytoks % not needed
   \formulachemicalmid\emptytoks % not needed
   \formulachemicalbot\emptytoks % not needed
   \let\chemical\formulachemical
   \setfalse\formulachemicalhastop
   \setfalse\formulachemicalhasbot }

\unexpanded\def\stopchemicalformula
  {\tabskip1em\relax
   \nointerlineskip
   \ifconditional\formulachemicalhastop
     \ifconditional\formulachemicalhasbot
       \halign{&\hss##\hss\cr\the\formulachemicaltop\cr\the\formulachemicalmid\cr\the\formulachemicalbot\cr}%
     \else
       \halign{&\hss##\hss\cr\the\formulachemicaltop\cr\the\formulachemicalmid\cr}%
     \fi
   \else
     \ifconditional\formulachemicalhasbot
       \halign{&\hss##\hss\cr\the\formulachemicalmid\cr\the\formulachemicalbot\cr}%
     \else
       \halign{&\hss##\hss\cr\the\formulachemicalmid\cr}%
     \fi
   \fi
   \egroup}

\unexpanded\def\formulachemical
  {\relax\dotriplegroupempty\doformulachemical}

\def\doformulachemical#1#2#3%
  {\ifthirdargument
     \doifelsenothing{#2}\noformulachemicaltop{\doformulachemicaltop{#2}}%
     \doifelsenothing{#3}\noformulachemicalbot{\doformulachemicalbot{#3}}%
   \else\ifsecondargument
     \noformulachemicaltop
     \doifelsenothing{#2}\noformulachemicalbot{\doformulachemicalbot{#2}}%
   \else
     \noformulachemicaltop
     \noformulachemicalbot
   \fi\fi
   \formulachemicalmid\expandafter{\the\formulachemicalmid\dodochemicalformulamid{#1}&}}

\def\noformulachemicaltop  {\formulachemicaltop\expandafter{\the\formulachemicaltop&}}
\def\noformulachemicalbot  {\formulachemicalbot\expandafter{\the\formulachemicalbot&}}
\def\doformulachemicaltop#1{\formulachemicaltop\expandafter{\the\formulachemicaltop\dodochemicalformulatop{#1}&}\settrue\formulachemicalhastop}
\def\doformulachemicalbot#1{\formulachemicalbot\expandafter{\the\formulachemicalbot\dodochemicalformulabot{#1}&}\settrue\formulachemicalhasbot}

\def\dodochemicalformulamid#1%
  {\ifcsname\??cm::\detokenize{#1}\endcsname\csname\??cm::\detokenize{#1}\expandafter\endcsname\else\molecule{#1}\fi{}{}}

\def\dodochemicalformulatop#1{\strut#1}
\def\dodochemicalformulabot#1{\strut#1}

% gone: state option resolution offset (now frame offset) alternative

\setupchemicalframed
  [\c!align=\v!normal,
   \c!strut=\v!no,
   \c!offset=\v!overlay,
   \c!frame=off]

\setupchemical
  [\c!frame=,
   \c!width=0,
   \c!height=0,
   \c!left=0,
   \c!right=0,
   \c!top=0,
   \c!bottom=0,
   \c!bodyfont=\the\bodyfontsize,
   \c!scale=\v!medium,
   \c!size=\v!medium,
   \c!textsize=\v!big,
   \c!axis=\v!off,
   \c!style=\rm,
   \c!location=,
   \c!color=,
   \c!rulethickness=\linewidth,
   \c!rulecolor=,
   \c!factor=1]

\protect \endinput