% Single entry point for the feature subsystem.
% Feature ids map directly to module files through the centralized catalog.

\RequirePackage{expl3}
\RequirePackage{xparse}
\RequirePackage{import}

\makeatletter
\@ifundefined{ifNextSystemInstalled}
  {\newif\ifNextSystemInstalled\NextSystemInstalledfalse}
  {}
\providecommand{\NextSystemRoot}{}
\newcommand{\FeatureModuleRoot}{}
\ifNextSystemInstalled
  \edef\FeatureModuleRoot{modules/features/}
\else
  \ifx\import@path\@undefined
    \edef\FeatureModuleRoot{./modules/features/}
  \else
    \edef\FeatureModuleRoot{\import@path}
    \StrSubstitute{\FeatureModuleRoot}{core/system/../features/}{modules/features/}[\FeatureModuleRoot]
    \StrSubstitute{\FeatureModuleRoot}{core/features/}{modules/features/}[\FeatureModuleRoot]
    \StrSubstitute{\FeatureModuleRoot}{package/../}{ }[\FeatureModuleRoot]
    \StrSubstitute{\FeatureModuleRoot}{ }{}[\FeatureModuleRoot]
  \fi
\fi
\makeatother

\providecommand{\NextCitationBiblatexOptions}{%
  backend=biber,
  style=apa,
  sorting=nyt,
  sortcites=true,
  doi=true,
  isbn=false,
  url=true
}

\makeatletter
\newcommand{\SetCitationBiblatexOptions}[1]{%
  \@ifpackageloaded{biblatex}
    {%
      \PackageError{feature-citations}
        {Citation style options must be set before biblatex is loaded}
        {Call this command before loading the citations feature.}%
    }
    {\def\NextCitationBiblatexOptions{#1}}%
}
\makeatother

\providecommand{\NextMathFontSelection}{auto}
\newcommand{\UseMathFont}[1]{%
  \def\NextMathFontSelection{#1}%
}

\ExplSyntaxOn

\NewDocumentCommand{\UseCitationStyle}{m}
  {
    \str_case_e:nnF { \str_uppercase:n {#1} }
      {
        { APA }
          {
            \SetCitationBiblatexOptions
              {
                backend=biber,
                style=apa,
                sorting=nyt,
                sortcites=true,
                doi=true,
                isbn=false,
                url=true
              }
          }
        { GB }
          {
            \SetCitationBiblatexOptions
              {
                backend=biber,
                style=gb7714-2015,
                sorting=none,
                sortcites=true,
                doi=true,
                isbn=false,
                url=true
              }
          }
        { NUMERIC }
          {
            \SetCitationBiblatexOptions
              {
                backend=biber,
                style=numeric,
                sorting=none,
                sortcites=true,
                doi=true,
                isbn=false,
                url=true
              }
          }
        { AUTHOR-YEAR }
          {
            \SetCitationBiblatexOptions
              {
                backend=biber,
                style=authoryear,
                sorting=nyt,
                sortcites=true,
                giveninits=true,
                uniquename=init,
                maxnames=3,
                maxbibnames=99,
                doi=true,
                isbn=false,
                url=true
              }
          }
        { AUTHORYEAR }
          {
            \SetCitationBiblatexOptions
              {
                backend=biber,
                style=authoryear,
                sorting=nyt,
                sortcites=true,
                giveninits=true,
                uniquename=init,
                maxnames=3,
                maxbibnames=99,
                doi=true,
                isbn=false,
                url=true
              }
          }
      }
      {
        \PackageError{feature-citations}
          {Unknown~citation~style~`#1`}
          {Use~APA,~GB,~numeric,~or~author-year.}
      }
  }

\prop_new:N \g__feature_catalog_path_prop
\prop_new:N \g__feature_catalog_loaded_prop

\cs_new_protected:Npn \__feature_catalog_register:nn #1#2
  { \prop_put:Nnn \g__feature_catalog_path_prop {#1} {#2} }

\NewDocumentCommand{\FeatureCatalogEntry}{m m}
  { \__feature_catalog_register:nn {#1} {#2} }

\cs_new_protected:Npn \__feature_use:n #1
  {
    \prop_if_in:NnTF \g__feature_catalog_path_prop {#1}
      {
        \prop_if_in:NnTF \g__feature_catalog_loaded_prop {#1}
          { }
          {
            \prop_get:NnN \g__feature_catalog_path_prop {#1} \l_tmpa_tl
            \use:x { \exp_not:N \input { \FeatureModuleRoot \tl_use:N \l_tmpa_tl } }
            \prop_put:Nnn \g__feature_catalog_loaded_prop {#1} { loaded }
          }
      }
      {
        \PackageError{feature-catalog}
          {Unknown~feature~id~`#1`}
          {Register~the~feature~in~catalog/impe-features-catalog.tex.}
      }
  }

\NewDocumentCommand{\UseFeature}{m}
  { \__feature_use:n {#1} }

\NewDocumentCommand{\UseFeatures}{m}
  { \clist_map_inline:nn {#1} { \__feature_use:n {##1} } }

\ExplSyntaxOff

\ifNextSystemInstalled
  \input{catalog/impe-features-catalog.tex}
\else
  \subimport{../../catalog/}{impe-features-catalog.tex}
\fi