% Source-script rendering for biblatex fields and generated year suffixes.
% Part of latexbangla, LPPL 1.3c or later; copyright 2026 Adib Hasan.
\ExplSyntaxOn
\file_input:n {code/references/latexbangla-biblatex-input.tex}

\tl_new:N \l__latexbangla_biblatex_field_tl
\tl_new:N \l__latexbangla_biblatex_source_tl
\tl_new:N \l__latexbangla_biblatex_output_tl
\tl_new:N \l__latexbangla_biblatex_run_tl
\seq_new:N \l__latexbangla_biblatex_source_runs_seq
\seq_new:N \l__latexbangla_biblatex_output_parts_seq
\int_new:N \l__latexbangla_biblatex_run_int
% Resolve virtual label fields to the original date component, including
% legacy year fields. Annotations then follow Biber's inheritance machinery.
\cs_new_protected:Npn \__latexbangla_biblatex_source:n #1
  {
    \tl_set:Ne \l__latexbangla_biblatex_field_tl {#1}
    \regex_replace_once:nnN {\Alabel} {} \l__latexbangla_biblatex_field_tl
    \str_if_eq:eeF {#1}{\l__latexbangla_biblatex_field_tl}
      {
        \tl_set:Ne \l_tmpa_tl {\thefield{labeldatesource}}
        \str_if_eq:VnT \l_tmpa_tl {year}{\tl_clear:N \l_tmpa_tl}
        \tl_put_left:NV \l__latexbangla_biblatex_field_tl \l_tmpa_tl
      }
    % The public getter prints its result and cannot assign a token list.
    % Isolate the read of biblatex's annotation storage here.
    \tl_clear:N \l__latexbangla_biblatex_source_tl
    \cs_if_exist:cT
      {abx@annotation@literal@field@\l__latexbangla_biblatex_field_tl @latexbangla-input}
      {\tl_set:Ne \l__latexbangla_biblatex_source_tl
        {\use:c{abx@annotation@literal@field@\l__latexbangla_biblatex_field_tl @latexbangla-input}}}
  }
% Restore script per numeric run, retaining punctuation and formatting tokens.
% Right alignment accounts for removed leading zeros and shortened ranges.
\cs_new_protected:Npn \__latexbangla_biblatex_restore:nn #1#2
  {
    \group_begin:
    \__latexbangla_biblatex_source:n {#1}
    \protected@edef \l__latexbangla_biblatex_output_tl {#2}
    \tl_if_empty:NTF \l__latexbangla_biblatex_source_tl
      {\tl_use:N \l__latexbangla_biblatex_output_tl}
      {
        \regex_extract_all:nVN {[0-9০-৯]+}
          \l__latexbangla_biblatex_source_tl \l__latexbangla_biblatex_source_runs_seq
        \regex_split:nVN {([0-9]+)}
          \l__latexbangla_biblatex_output_tl \l__latexbangla_biblatex_output_parts_seq
        \int_zero:N \l__latexbangla_biblatex_run_int
        \seq_map_indexed_inline:Nn \l__latexbangla_biblatex_output_parts_seq
          {
            \int_if_even:nTF {##1}
              {
                \int_incr:N \l__latexbangla_biblatex_run_int
                \tl_set:Ne \l__latexbangla_biblatex_run_tl
                  {\seq_item:Nn \l__latexbangla_biblatex_source_runs_seq {\l__latexbangla_biblatex_run_int}}
                \int_step_inline:nn {\tl_count:n{##2}}
                  {
                    \tl_set:Ne \l_tmpa_tl
                      {\tl_item:Nn \l__latexbangla_biblatex_run_tl
                        {\int_max:nn{1}{\tl_count:N\l__latexbangla_biblatex_run_tl-\tl_count:n{##2}+####1}}}
                    \regex_match:nVTF {[০-৯]} \l_tmpa_tl
                      {\__latexbangla_bibliography_native_text:n{\char_generate:nn {"09E6+\tl_item:nn{##2}{####1}}{12}}}
                      {\tl_item:nn{##2}{####1}}
                  }
              }
              {##2}
          }
      }
    \group_end:
  }
\cs_generate_variant:Nn \regex_extract_all:nnN {nVN}
\cs_generate_variant:Nn \regex_split:nnN {nVN}
\cs_new_protected:Npn \__latexbangla_bibliography_digits:n #1
  {\__latexbangla_biblatex_restore:nn {\currentfield}{#1}}
% Print the restored number, then choose its suffix from the original field.
\cs_new_protected:Npn \__latexbangla_bibliography_ordinal:nn #1#2
  {
    \group_begin:
    \__latexbangla_biblatex_source:n {\currentfield}
    \__latexbangla_biblatex_restore:nn {\currentfield}{\int_eval:n{#2}}
    \__latexbangla_bibliography_ordinal_suffix:nVn
      {#1}\l__latexbangla_biblatex_source_tl{#2}
    \group_end:
  }
\cs_new_protected:Npn \__latexbangla_biblatex_date_component:nn #1#2
  {
    \group_begin:
    \protected@edef \l__latexbangla_biblatex_output_tl {\thefield{#2}}
    \tl_if_empty:NF \l__latexbangla_biblatex_output_tl
      {
        \exp_args:NV \ifinteger \l__latexbangla_biblatex_output_tl
          {
            \tl_set:Ne \l__latexbangla_biblatex_output_tl {\int_eval:n{\l__latexbangla_biblatex_output_tl}}
            \iftoggle{blx@datezeros}
              {\tl_put_left:Ne \l__latexbangla_biblatex_output_tl
                {\prg_replicate:nn{\int_max:nn{0}{#1-\tl_count:N\l__latexbangla_biblatex_output_tl}}{0}}}{}
          }{}
        \__latexbangla_biblatex_restore:nn {#2}{\l__latexbangla_biblatex_output_tl}
      }
    \group_end:
  }
% A generated suffix follows the script of the year it is attached to.
\cs_new_protected:Npn \__latexbangla_biblatex_suffix:n #1
  {
    \group_begin:
    \iffieldundef{labelendyear}
      {\__latexbangla_biblatex_source:n{labelyear}}
      {\__latexbangla_biblatex_source:n{labelendyear}}
    \regex_match:nVTF {[০-৯]} \l__latexbangla_biblatex_source_tl
      {\__latexbangla_bibliography_native_text:n{\__latexbangla_bibliography_native_suffix:n{#1}}}{\mknumalph{#1}}
    \group_end:
  }
\DeclareFieldFormat{extradate}{\iffieldnums{labelyear}
  {\__latexbangla_biblatex_suffix:n{#1}}{\mkbibparens{\__latexbangla_biblatex_suffix:n{#1}}}}
% Patch numeric output sites in the standard English formatters, retaining
% their wording and date order. Catcode-safe aliases allow etoolbox patches.
\cs_new_protected:Npn\__latexbangla_biblatex_field_number:w\thefield#1\q_stop#2
  {\__latexbangla_biblatex_date_component:nn{#2}{#1}}
\cs_new_eq:NN \latexbangla@bibdigits \__latexbangla_bibliography_digits:n
\cs_new_protected:Npn\latexbangla@bibstripzeros#1
  {\__latexbangla_biblatex_field_number:w#1\q_stop{0}}
\cs_new_protected:Npn\latexbangla@bibmonthday#1
  {\__latexbangla_biblatex_field_number:w#1\q_stop{2}}
\cs_new_protected:Npn\latexbangla@bibyear#1
  {\__latexbangla_biblatex_field_number:w#1\q_stop{4}}
% Wrap existing English formats rather than replacing their style-specific
% labels or punctuation. Missing entry-type formats retain normal fallback.
\cs_new_protected:Npn \__latexbangla_biblatex_wrap_field:nn #1#2
  {
    \cs_if_exist:cT {abx@ffd@#1@#2}
      {
        \cs_if_exist:cF {latexbangla@savedformat@#1@#2}
          {\cs_set_eq:cc {latexbangla@savedformat@#1@#2}{abx@ffd@#1@#2}}
        \DeclareFieldFormat[#1]{#2}
          {\use:c{latexbangla@savedformat@#1@#2}
            {\__latexbangla_bibliography_digits:n{##1}}}
      }
  }
% Page formatters must inspect the raw value to choose singular/plural labels.
% Restore digits at their output callback; custom formats keep their own text.
\cs_new_protected:Npn \__latexbangla_biblatex_wrap_pages:nN #1#2
  {
    \cs_if_exist:cF {latexbangla@savedformat@*@#1}
      {\cs_set_eq:cc {latexbangla@savedformat@*@#1}{abx@ffd@*@#1}}
    \cs_set_eq:cc {abx@ffd@*@#1}{latexbangla@savedformat@*@#1}
    \exp_args:Nc \patchcmd {abx@ffd@*@#1}
      {#2[bookpagination]{##1}}
      {#2[bookpagination][\latexbangla@bibdigits]{##1}}
      {}{\__latexbangla_biblatex_wrap_field:nn {*}{#1}}
  }
\cs_new_protected:Npn \__latexbangla_biblatex_install_english:
  {
    \patchcmd\mkbibdatelong{\stripzeros}{\latexbangla@bibstripzeros}{}{}
    \patchcmd\mkbibdatelong{\stripzeros}{\latexbangla@bibstripzeros}{}{}
    \patchcmd\mkbibdateshort{\mkdayzeros}{\latexbangla@bibmonthday}{}{}
    \patchcmd\mkbibdateshort{\mkmonthzeros}{\latexbangla@bibmonthday}{}{}
    \patchcmd\mkbibdateshort{\mkyearzeros}{\latexbangla@bibyear}{}{}
    \cs_set_protected:Npn\mkbibordinal ##1
      {\__latexbangla_bibliography_ordinal:nn{\g__latexbangla_language_tl}{##1}}
    \__latexbangla_biblatex_wrap_pages:nN {pages}\mkpageprefix
    \__latexbangla_biblatex_wrap_pages:nN {pagetotal}\mkpagetotal
    % These standard formats do not parse their value; retain their labels.
    \clist_map_inline:nn {volume,volumes,number,part,chapter,version}
      {
        \__latexbangla_biblatex_wrap_field:nn {*}{##1}
        \__latexbangla_biblatex_wrap_field:nn {article}{##1}
        \__latexbangla_biblatex_wrap_field:nn {periodical}{##1}
      }
  }
\DefineBibliographyExtras{english}{\__latexbangla_biblatex_install_english:}
\ExplSyntaxOff
\endinput