% Display commands emitted by plainnatbn, abbrvnatbn and unsrtnatbn.
% Part of latexbangla, LPPL 1.3c or later; copyright 2026 Adib Hasan.
% English fallbacks come from the selected style. Native terms share the
% biblatex vocabulary; this adapter neither loads biblatex nor selects a style.
\prg_new_conditional:Npnn \__latexbangla_native_bibliography: {TF}
  {
    \str_case_e:nnF {\languagename}
      {{bengali}{\prg_return_true:}{assamese}{\prg_return_true:}}
      {\prg_return_false:}
  }
\NewDocumentCommand \latexbanglabibstring {m m}
  {
    \__latexbangla_native_bibliography:TF
      {\prop_item:cn {g__latexbangla_bibliography_\languagename _prop}{#1}}
      {#2}
  }
\tl_new:N \l__latexbangla_natbib_output_tl
\tl_new:N \l__latexbangla_natbib_date_tl
\tl_new:N \l__latexbangla_natbib_link_tl
\tl_new:N \l__latexbangla_natbib_edition_number_tl
\tl_new:N \l__latexbangla_natbib_edition_display_tl
\prop_const_from_keyval:Nn \c__latexbangla_bibtex_editions_prop
  {first=1,second=2,third=3,fourth=4,fifth=5,sixth=6,seventh=7,eighth=8,ninth=9,tenth=10}
\cs_generate_variant:Nn \prop_get:NnNTF {NeNTF}
\NewDocumentCommand\latexbanglabibnumber{m}
  {
    \group_begin:
    % Only the style-generated suffix marker is localized. Authored letters
    % in a page identifier or version remain literal input.
    \regex_match:nnT{[০-৯]}{#1}
      {\cs_set_eq:NN \__latexbangla_natbib_original_suffix:n \natexlab
       \cs_set:Npn\natexlab ##1
        {\__latexbangla_natbib_original_suffix:n
          {\__latexbangla_bibliography_native_text:n
            {\__latexbangla_bibliography_native_suffix:n{\int_from_alph:n{##1}}}}}}
    \tl_set:Nn \l__latexbangla_natbib_output_tl {#1}
    \__latexbangla_bibliography_select_fonts:N \l__latexbangla_natbib_output_tl
    \tl_use:N \l__latexbangla_natbib_output_tl
    \group_end:
  }
\NewDocumentCommand\latexbanglabibedition{m}
  {
    \group_begin:
    \tl_set:Nn \l__latexbangla_natbib_edition_display_tl {#1}
    \__latexbangla_native_bibliography:TF
      {\prop_get:NeNTF \c__latexbangla_bibtex_editions_prop
         {\str_lowercase:n{#1}}\l__latexbangla_natbib_edition_display_tl
         {}{\tl_set:Nn\l__latexbangla_natbib_edition_display_tl{#1}}}{}
    \tl_set_eq:NN\l__latexbangla_natbib_edition_number_tl\l__latexbangla_natbib_edition_display_tl
    \__latexbangla_bibliography_normalize:N \l__latexbangla_natbib_edition_number_tl
    \exp_args:NnV\regex_match:nnTF{\A[0-9]+(st|nd|rd|th)?\Z}\l__latexbangla_natbib_edition_number_tl
      {
        \regex_replace_once:nnN{(st|nd|rd|th)\Z}{}\l__latexbangla_natbib_edition_number_tl
        \regex_replace_once:nnN{(st|nd|rd|th)\Z}{}\l__latexbangla_natbib_edition_display_tl
        \exp_args:NV\latexbanglabibnumber\l__latexbangla_natbib_edition_display_tl
        \__latexbangla_bibliography_ordinal_suffix:nnn
          {\g__latexbangla_language_tl}{#1}{\l__latexbangla_natbib_edition_number_tl}
      }
      {#1}
    \nobreakspace\latexbanglabibstring{edition}{edition}
    \group_end:
  }
\NewDocumentCommand \latexbanglabibvolume {m m}
  {\__latexbangla_native_bibliography:TF
    {\tl_if_empty:nF{#2}{\emph{#2},~}
     \latexbanglabibstring{volume}{volume}\nobreakspace\latexbanglabibnumber{#1}}
    {volume\nobreakspace\latexbanglabibnumber{#1}
     \tl_if_empty:nF{#2}{~of~\emph{#2}}}}
\NewDocumentCommand \latexbanglabibseriesseparator {}
  {\__latexbangla_native_bibliography:TF {,~}{~of~}}

% The .bbl marks these styles in the aux file so citations preceding the
% bibliography also preserve the input script on the next normal LaTeX pass.
\bool_new:N \g__latexbangla_natbib_localized_bool
\NewDocumentCommand \latexbanglanatbibactive {}
  {\bool_gset_true:N \g__latexbangla_natbib_localized_bool}
\NewDocumentCommand \latexbanglanatbibstyle {}
  {
    \latexbanglanatbibactive
    \if@filesw
      \immediate\write\@auxout{\string\latexbanglanatbibactive}
    \fi
  }
\cs_new_protected:Npn \__latexbangla_natbib_suffix:N #1
  {
    \int_step_inline:nn {26}
      {\regex_replace_all:eeN
        {\int_to_alph:n{##1}}{\__latexbangla_bibliography_native_suffix:n{##1}} #1}
  }
% Normalize only the parser input; comparisons retain the displayed year.
\cs_new_protected:Npn \__latexbangla_natbib_parse_date:
  {
    \bool_if:NT \g__latexbangla_natbib_localized_bool
      {
        \exp_args:NnV \regex_match:nnT {[০-৯]} \NAT@date
          {
            % Parse with ASCII digits, then restore the source year used in
            % comparisons. Different displayed scripts remain distinct groups.
            \tl_set_eq:NN \l__latexbangla_natbib_date_tl \NAT@date
            \__latexbangla_bibliography_normalize:N \l__latexbangla_natbib_date_tl
            \exp_after:wN\NAT@parse@date\l__latexbangla_natbib_date_tl??????@@
            \tl_set:Ne \NAT@year {\tl_range:Nnn\NAT@date{1}{\tl_count:N\NAT@year}}
            \__latexbangla_natbib_suffix:N \NAT@date
            \__latexbangla_natbib_suffix:N \NAT@exlab
          }
      }
  }
% Keep raw dates in natbib's comparisons; select fonts at the printing boundary.
\cs_new_protected:Npn \__latexbangla_natbib_print:N #1
  {
    \group_begin:
    \tl_set_eq:NN \l__latexbangla_natbib_output_tl #1
    \bool_if:NT \g__latexbangla_natbib_localized_bool
      {\__latexbangla_bibliography_select_fonts:N \l__latexbangla_natbib_output_tl}
    \tl_use:N \l__latexbangla_natbib_output_tl
    \group_end:
  }
\cs_new_protected:Npn \__latexbangla_natbib_install:
  {
    \cs_new_eq:NN \__latexbangla_natbib_hyper:n \NAT@hyper@
    \cs_set_protected:Npn \NAT@hyper@ ##1
      {
        \bool_if:NTF \g__latexbangla_natbib_localized_bool
          {
            \group_begin:
            \tl_set:Nn \l__latexbangla_natbib_link_tl {##1}
            \tl_replace_all:Nnn \l__latexbangla_natbib_link_tl
              {\NAT@date}{\__latexbangla_natbib_print:N\NAT@date}
            \tl_replace_all:Nnn \l__latexbangla_natbib_link_tl
              {\NAT@exlab}{\__latexbangla_natbib_print:N\NAT@exlab}
            \exp_args:NV \__latexbangla_natbib_hyper:n \l__latexbangla_natbib_link_tl
            \group_end:
          }
          {\__latexbangla_natbib_hyper:n{##1}}
      }
  }
\cs_new_eq:NN \latexbangla@natbibprintdate \__latexbangla_natbib_print:N
\ExplSyntaxOff
\newcommand*\latexbangla@patchnatbibdate{%
  \begingroup\ExplSyntaxOff
  \patchcmd{\NAT@test}{\else \NAT@date}
    {\else \latexbangla@natbibprintdate\NAT@date}%
    {\global\let\NAT@test\NAT@test}%
    {\PackageError{latexbangla}{Cannot patch natbib date output}%
      {Check the installed natbib version.}}%
  \endgroup}
\ExplSyntaxOn
\AddToHook{package/natbib/after}[latexbangla/natbib-dates]
  {
    \clist_map_inline:nn {plainnat,abbrvnat,unsrtnat}
      {\cs_if_exist:cF {bibstyle@#1bn}
        {\cs_new_eq:cc {bibstyle@#1bn}{bibstyle@#1}}}
    \AddToHook{cmd/NAT@parse/after}[latexbangla/natbib-dates]
      {\__latexbangla_natbib_parse_date:}
    \__latexbangla_natbib_install:
    \latexbangla@patchnatbibdate
  }
\endinput