%% Copyright (C) 2020 Eduardo C. Lourenço de Lima
%%
%% This work may be distributed and/or modified under the
%% conditions of the LaTeX Project Public License, either
%% version 1.3 of this license or (at your option) any later
%% version.  The latest version of this license is in
%%
%%   http://www.latex-project.org/lppl.txt
%%
%% and version 1.3 or later is part of all distributions of LaTeX
%% version 2005/12/01 or later.
%%
%\NeedsTeXFormat{LaTeX2e}[1996/06/01]
\RequirePackage{expl3}
\RequirePackage{xparse}
\ProvidesExplPackage {classics} {2020/02/03} {0.1a} {Cite classic works}

\tl_new:N  \g_classics_style_range_separator_tl
\tl_new:N  \g_classics_style_separator_tl

\tl_set:Nn \g_classics_style_range_separator_tl {--}
\tl_set:Nn \g_classics_style_separator_tl   {|}

\bool_new:N \g__classics_plural_prefix_bool

\cs_generate_variant:Nn \seq_set_split:Nnn     {cVn}

% * [<range separator>] {<basename>} {<code>}

\NewDocumentCommand \newclassic {somm}
 {

  \seq_new:c      {g_classics_#3_style_seq}
  \tl_new:c       {g_classics_#3_range_separator_tl}

  \IfValueTF {#2}
   {\tl_set:cn      {g_classics_#3_range_separator_tl} {#2}}
   {\tl_set:cn      {g_classics_#3_range_separator_tl} {\tl_use:N \g_classics_style_range_separator_tl}}

  \classics_style_set:nn {#3} {#4}

% * (<last page>) [<title>] {<page>} [<section>]

  \exp_after:wN \NewDocumentCommand \cs:w #3\cs_end: { sd()omO{}O{}O{}O{}O{} }
   {

    %Title: Typeset the optional title
    \IfValueT  {##3}
     {
      \group_begin:
      \frenchspacing \classics_title_format:n {##3}
      \tl_if_blank:nTF {##4} {}{~}
      \group_end:
     }

    %Range: Typeset page when last page is provided only if they differ
    \bool_if:nTF { (! #1) && \str_if_eq_p:ee{##2}{##4} }
     {
      \classics_style_map:nnnnnnn{#3}  {} {##5}{##6}{##7}{##8}{##9}
     }
     {
      \classics_style_map:nnnnnnn{#3}{##4}{##5}{##6}{##7}{##8}{##9}
     }

    %Starred:
    \IfBooleanT {##1} {\tl_use:c {g_classics_#3_range_separator_tl}\cs:w #3\cs_end:(##4)}

   }
 }

% {<code>}

\NewDocumentCommand \DeclareClassicWorkFormat {m} {\cs_set:Npn \classics_title_format:n ##1 {#1}}

% {<string>}

\cs_new:Npn \classics_title_format:n #1 {\textit{#1}}

% {<basename>} {<string>}

\cs_new:Npn \classics_style_set:nn #1#2
 {
  \seq_set_split:cVn {g_classics_#1_style_seq} \g_classics_style_separator_tl {#2}
 }

% {<basename>} {<value>}

\cs_new:Npn \classics_style_map:nnnnnnn #1#2#3#4#5#6#7
 {
    \seq_set_split:Nnn \l_tmpa_seq {} {{#2} {#3} {#4} {#5} {#6} {#7}}

    \cs_generate_variant:Nn \seq_mapthread_function:NNN {cNN}
    \seq_mapthread_function:cNN {g_classics_#1_style_seq} \l_tmpa_seq  \classics_style_apply:nn
 }

% {<style>} {<value>}

\cs_new:Npn \classics_style_apply:nn #1#2
 {
    \tl_if_blank:nTF {#2}
     {}
     {
       \cs_set:Npn \__classics_style_apply:n ##1 {#1}
       \__classics_style_apply:n {#2}
     }
 }

% {<code>}

\cs_new:Npn \__classics_style_apply:n #1 {}

% ********************************** Misc *************************************

\NewDocumentCommand \classicsalph  {m} {\int_to_alph:n {#1}}
\NewDocumentCommand \classicsAlph  {m} {\int_to_Alph:n {#1}}
\NewDocumentCommand \classicsroman {m} {\int_to_roman:n{#1}}
\NewDocumentCommand \classicsRoman {m} {\int_to_Roman:n{#1}}

% ------------------------------ Plural prefix --------------------------------

% {<command>} {<singular>} {<plural>} {<and>}

\NewDocumentCommand \newpagination {mmmm}
 {
% \exp_after:wN \NewDocumentCommand \cs:w #1\cs_end: {m}
 \NewDocumentCommand #1 {m}
  {
   \classics_plural_prefix:nnnn {#2} {#3} {#4} {##1}
   {~##1}
  }
 }

% {<singular>} {<plural>} {<and>} {<string>}

\cs_new:Npn \classics_plural_prefix:nnnn #1#2#3#4
 {
  \bool_set_false:N \g__classics_plural_prefix_bool

  \tl_if_in:nnT {#4} {#3} {\bool_set_true:N \g__classics_plural_prefix_bool}
  \tl_if_in:nnT {#4} {-}  {\bool_set_true:N \g__classics_plural_prefix_bool}
  \tl_if_in:nnT {#4} {,}  {\bool_set_true:N \g__classics_plural_prefix_bool}

  \bool_if:nTF \g__classics_plural_prefix_bool {#2} {#1}
 }

\endinput