%D \module
%D   [     file=t-lua-widow-control,
%D      version=3.0.0, %%version
%D        title=lua-widow-control,
%D     subtitle=\ConTeXt module for lua-widow-control,
%D       author=Max Chernoff,
%D         date=2022-11-22, %%dashdate
%D    copyright=Max Chernoff,
%D      license=MPL-2.0+,
%D          url=https://github.com/gucci-on-fleek/lua-widow-control]
\startmodule[lua-widow-control]
\unprotect

% Preliminaries
\installnamespace{lwc}

\installswitchcommandhandler \????lwc {lwc} \????lwc

% Set up the options
\newdimen\lwc_emergency_stretch
\newdimen\lwc_draft_offset
\newcount\lwc_max_cost

\starttexdefinition lwc_set_parameters
    \lwc_emergency_stretch=\lwcparameter{emergencystretch}
    \lwc_draft_offset=\lwcparameter{draftoffset}

    \doifelse{\lwcparameter{\c!state}}\v!start{
        \lwc_enable
    }{
        \lwc_disable
    }

    \lwc_debug{\lwcparameter{debug}}

    \doif{\lwcparameter{draft}}\v!start{
        \setlwcparameter{showcosts}{\v!start}
        \setlwcparameter{showcolours}{\v!start}
    }

    \doif{\lwcparameter{draft}}\v!stop{
        \setlwcparameter{showcosts}{\v!stop}
        \setlwcparameter{showcolours}{\v!stop}
    }

    \lwc_show_costs{\lwcparameter{showcosts}}
    \lwc_show_colours{\lwcparameter{showcolours}}

    \lwc_nobreak{\lwcparameter{nobreak}}

    \lwc_max_cost=\lwcparameter{maxcost}

    % We can't just set the penalties because they will be reset automatically
    % at \\starttext.
    \startsetups[*default]
        \directsetup{*reset}

        \clubpenalty=\lwcparameter{orphanpenalty}
        \widowpenalty=\lwcparameter{widowpenalty}
        \displaywidowpenalty=\lwcparameter{widowpenalty}
        \brokenpenalty=\lwcparameter{brokenpenalty}
    \stopsetups

    \startsetups[grid][*default]
        \directsetup{*reset}

        \clubpenalty=\lwcparameter{orphanpenalty}
        \widowpenalty=\lwcparameter{widowpenalty}
        \displaywidowpenalty=\lwcparameter{widowpenalty}
        \brokenpenalty=\lwcparameter{brokenpenalty}
    \stopsetups

    \setups[*default]
\stoptexdefinition

% Load the main Lua file
\ctxloadluafile{lua-widow-control}

% Define the presets
\definelwc[default][
    emergencystretch=3em,
    maxcost=2147483647,
    nobreak=keep,
    orphanpenalty=1,
    widowpenalty=1,
    brokenpenalty=1,
]

\definelwc[strict][
    emergencystretch=0pt,
    maxcost=5000,
    nobreak=warn,
    widowpenalty=1,
    orphanpenalty=1,
    brokenpenalty=1,
]

\definelwc[balanced][
    emergencystretch=1em,
    maxcost=10000
    nobreak=keep,
    widowpenalty=500,
    orphanpenalty=500,
    brokenpenalty=500,
]

% Set up the default options
\setuplwc[
    \c!state=\v!start,
    debug=\v!stop,
    draft=,
    showcosts=\v!stop,
    showcolours=\v!stop,
    draftoffset=1in,
]

\setuplwc[default]

\appendtoks
    \ifcase\lwcsetupmode
        % can't happen
    \or % \setuplwc[name][key=value]
      \ifx\previouslwc\currentlwc
        \let\currentlwc\currentlwc
        \lwc_set_parameters
      \fi
    \or % \setuplwc[key=value]
      \let\currentlwc\previouslwc
      \lwc_set_parameters
    \or % \setuplwc[name]
      \glet\currentlwc\currentlwc % global
      \lwc_set_parameters
    \fi
\to \everysetuplwc

\lwc_set_parameters

% Here, we enable font expansion/contraction. It isn't strictly necessary for
% \lwc/'s functionality; however, it is required for the
% lengthened paragraphs to not have terrible spacing.
\definefontfeature[default][default][expansion=quality]
\setupalign[hz]

% Expansion of some parts of the document, such as section headings, is quite
% undesirable, so we'll disable \lwc/ for certain commands.
% We should only reenable \lwc/ at the end if it was already enabled.
\newcount\lwc_disable_count

\define\lwc_patch_pre{%
    \lwc_if_enabled%
        \advance\lwc_disable_count by 1%
        \setuplwc[\c!state=\v!stop]%
    \fi%
}

\define\lwc_patch_post{
    \ifnum\lwc_disable_count>0\relax%
        \setuplwc[\c!state=\v!start]%
        \advance\lwc_disable_count by -1%
    \fi%
}

% Add the default patches
\prependtoks\lwc_patch_pre\to\everybeforesectionheadhandle % Sectioning
\prependtoks\lwc_patch_post\to\everyaftersectionheadhandle

% Make the commands public
\let\iflwc=\lwc_if_enabled

\protect
\stopmodule