%
% Copyright (c) 2024 Zeping Lee
% Released under the LaTeX Project Public License v1.3c License.
% Repository: https://github.com/xkwxdyy/exam-zh
%            https://gitee.com/xkwxdyy/exam-zh (mirror)
%

\NeedsTeXFormat{LaTeX2e}

\RequirePackage{expl3}
\RequirePackage{xparse}
\RequirePackage { xcolor }

\ProvidesExplPackage {exam-zh-choices} {2026-07-12} {v0.3.0}
  {exam-zh choices module}

\RequirePackage { exam-zh-counter }

\dim_new:N \l__examzh_choices_column_sep_dim
\int_new:N \l__examzh_choices_columns_int
\tl_new:N \l__examzh_choices_label_tl
\tl_new:N \l__examzh_choices_label_pos_tl
\tl_new:N \l__examzh_choices_label_align_tl
\dim_new:N \l__examzh_choices_label_sep_dim
\dim_new:N \l__examzh_choices_label_width_dim
\int_new:N \l__examzh_choices_max_columns_int
\skip_new:N \l__examzh_choices_item_line_sep_skip
\dim_new:N \l__examzh_choices_left_indent_dim
\dim_new:N \l__examzh_choices_right_indent_dim
\bool_new:N \l__examzh_choices_show_answer_bool
\tl_new:N \l__examzh_choices_answer_color_tl

\keys_define:nn { exam-zh }
  { choices .meta:nn = { exam-zh / choices } {#1} }

\keys_define:nn { exam-zh / choices }
  {
    column-sep  .dim_set:N = \l__examzh_choices_column_sep_dim ,
    columns     .int_set:N = \l__examzh_choices_columns_int ,
    label       .tl_set:N  = \l__examzh_choices_label_tl ,
    label-pos   .choices:nn =
      { auto , top-left , left , bottom }
      { \tl_set_eq:NN \l__examzh_choices_label_pos_tl \l_keys_choice_tl } ,
    label-align .tl_set:N = \l__examzh_choices_label_align_tl ,
    label-sep   .dim_set:N = \l__examzh_choices_label_sep_dim ,
    label-width .dim_set:N = \l__examzh_choices_label_width_dim ,
    max-columns .int_set:N = \l__examzh_choices_max_columns_int ,
    index       .int_set:N = \l__examzh_choices_item_index_int,
    % 环境上方的额外距离
    top-sep .skip_set:N = \l__examzh_choices_top_sep_skip,
    % 环境下方的额外距离
    bottom-sep .skip_set:N = \l__examzh_choices_bottom_sep_skip,
    % 若不是单行排版，则可以控制行之间的额外间距
    linesep .skip_set:N = \l__examzh_choices_line_sep_skip,
    % 多行选项内部相邻文本行的额外间距
    item-linesep .skip_set:N = \l__examzh_choices_item_line_sep_skip,
    left-indent .dim_set:N = \l__examzh_choices_left_indent_dim,
    right-indent .dim_set:N = \l__examzh_choices_right_indent_dim,
    margin .meta:n = { left-indent = #1, right-indent = #1 },
    show-answer .bool_set:N = \l__examzh_choices_show_answer_bool,
    answer-color .tl_set:N = \l__examzh_choices_answer_color_tl
  }

\keys_set:nn { exam-zh / choices }
  {
    column-sep  = 1em ,
    columns     = 0 ,
    label       = \Alph*. ,
    label-pos   = auto ,
    label-align = left ,
    label-sep   = .5em ,
    label-width = 0pt ,
    max-columns = 4 ,
    index       = 1,
    top-sep     = 0pt,
    bottom-sep  = 0pt,
    linesep     = 0pt plus .5ex,
    item-linesep = 0pt,
    left-indent  = 0pt,
    right-indent = 0pt,
    show-answer = false,
    answer-color = red
  }

\NewDocumentCommand \setchoices { m }
  { \keys_set:nn { exam-zh / choices } {#1} }


\tl_new:N \l__examzh_choices_counters_tl

\NewDocumentCommand \AddChoicesCounter { m m }
  % #1: \Alph（用户接口）
  % #2: \@Alph（具体实现的命令或函数（开发层））
  {
    \__examzh_counter_register:NNNnn
      \l__examzh_choices_counters_tl #1 #2 { choices }
      { \l__examzh_choices_index_int }
  }

\AddChoicesCounter \arabic \@arabic
\AddChoicesCounter \alph   \@alph
\AddChoicesCounter \Alph   \@Alph
\AddChoicesCounter \roman  \@roman
\AddChoicesCounter \Roman  \@Roman


\dim_new:N \l__examzh_choices_total_width_dim
\seq_new:N \l__examzh_choices_seq

\cs_new_protected:Npn \__examzh_choices_set_total_width:
  {
    \dim_set:Nn \l__examzh_choices_total_width_dim
      {
        \linewidth - \leftskip - \rightskip
        - \l__examzh_choices_left_indent_dim
        - \l__examzh_choices_right_indent_dim
      }
  }

\NewDocumentEnvironment { choices } { O { } +b }
  {
    \keys_set:nn { exam-zh / choices } {#1}
    \par \nopagebreak
    % 严格禁止孤行和寡行
    \int_set:Nn \clubpenalty { 10000 }
    \int_set:Nn \widowpenalty { 10000 }
    % 尽量避免在选项中间换行
    \int_set:Nn \interlinepenalty { 301 }
    \vspace* { \l__examzh_choices_top_sep_skip }
    \noindent
    \dim_compare:nNnF { \l__examzh_choices_left_indent_dim } = { 0pt }
      { \skip_horizontal:N \l__examzh_choices_left_indent_dim }
    \__examzh_choices_set_total_width:
    \int_zero:N \l__examzh_choices_columns_int
    \dim_zero:N \l__examzh_choices_label_width_dim
  }
  {
    % 用 \item 分割选项
    \seq_set_split:Nnn \l__examzh_choices_seq { \item } {#2}
    % 把第一个空项去掉
    \seq_if_empty:NF \l__examzh_choices_seq
      { \seq_pop_left:NN \l__examzh_choices_seq \l_tmpa_tl }
    % 收集正确的选项
    \__examzh_choices_collect_correct_choices:N   
      \l__examzh_choices_seq
    % 计算标签和选项内容的最大自然宽度
    \__examzh_choices_calc_max_width:N \l__examzh_choices_seq
    % label-pos = auto 时自动选择标签位置
    \__examzh_choices_set_auto_label_pos:
    % 如果用户没有声明列数，计算合适的列数
    % 「学习点」从默认值是否被改变来测试用户是否输入
    % 用户没有输入的话就采用自动计算列数
    \int_compare:nNnT { \l__examzh_choices_columns_int } < {1}
      { \__examzh_choices_calc_columns: }
    % 解决 columns 无效的问题
    \keys_set:nn { exam-zh / choices } {#1}
    % 计算每个选项内容的宽度 \l__examzh_choices_item_width_dim
    \__examzh_choices_calc_item_width:
    % 输出选项
    \__examzh_print_choices:N \l__examzh_choices_seq
    % 输出正确选项
    % \__examzh_print_correctchoice:
    \vspace* { \l__examzh_choices_bottom_sep_skip }
  }

% 用来存正确选项的序号（entry）
\seq_new:N \l__examzh_choices_correct_choices_label_seq
% 用来存正确选项的内容
\seq_new:N \l__examzh_choices_correct_choices_item_seq
% 用来存正确选项在当前 choices 环境中的序号
\seq_new:N \l__examzh_choices_correct_choices_index_seq

\prg_new_conditional:Npnn \__examzh_choices_answer_visible:n #1 { TF }
  {
    \bool_if:NTF \l__examzh_choices_show_answer_bool
      {
        \seq_if_in:NnTF
          \l__examzh_choices_correct_choices_index_seq {#1}
          { \prg_return_true: }
          { \prg_return_false: }
      }
      { \prg_return_false: }
  }

\cs_new_protected:Npn \__examzh_choices_format_answer:nn #1#2
  {
    \__examzh_choices_answer_visible:nTF {#1}
      {
        \group_begin:
          \exp_args:NV \color \l__examzh_choices_answer_color_tl
          #2
        \group_end:
      }
      {#2}
  }

% 收集正确的选项，保存在 \l__examzh_choices_correct_choices_seq
\cs_new:Npn \__examzh_choices_collect_correct_choices:N #1
  % #1: \l__examzh_choices_seq
  {
    \seq_clear:N \l__examzh_choices_correct_choices_label_seq
    \seq_clear:N \l__examzh_choices_correct_choices_item_seq
    \seq_clear:N \l__examzh_choices_correct_choices_index_seq
    \seq_clear:N \l_tmpa_seq
    \seq_map_indexed_inline:Nn #1
      {
        % ##1: 选项序号
        % ##2: 选项内容
        % 如果分割后，第一个字符是 * 的，表明这是一个正确选项
        %（即用 \item* 来标记正确答案）
        \tl_if_head_eq_meaning:nNTF {##2} *
          {
            \seq_put_right:Nn
              \l__examzh_choices_correct_choices_index_seq {##1}
            \seq_put_right:Nn \l__examzh_choices_correct_choices_label_seq 
              { \__examzh_choices_correct_choices_label_transfrom:n {##1} }
            % 将去掉 * 号后的内容保存进 \l_tmpa_tl
            \tl_set:Nx \l_tmpa_tl { \tl_tail:n {##2} }
            % 去掉 * 和内容之间的空格
            \tl_trim_spaces:N \l_tmpa_tl
            \seq_put_right:NV \l__examzh_choices_correct_choices_item_seq 
              \l_tmpa_tl 
            \seq_put_right:NV \l_tmpa_seq \l_tmpa_tl
          }
          {
            \seq_put_right:Nn \l_tmpa_seq { ##2 }
          }
      }
    \seq_set_eq:NN #1 \l_tmpa_seq
  }

% 根据 label 的样式 \l__examzh_choices_label_tl 转化正确选项的样式
\cs_new:Npn \__examzh_choices_correct_choices_label_transfrom:n #1
  {
    \group_begin:
      \int_set:Nn \l__examzh_choices_index_int {#1}
      % 定义计数器转换函数（如 \Alph 等）
      \l__examzh_choices_counters_tl
      % 输出
      \l__examzh_choices_label_tl
    \group_end:
  }
% 输出正确的选项
\cs_new:Nn \__examzh_print_correctchoice:
  {
    \seq_if_empty:NF \l__examzh_choices_correct_choices_item_seq
      {
        \par
        参考答案：
        \seq_use:Nn \l__examzh_choices_correct_choices_label_seq {,~}
      }
  }


\dim_new:N \l__examzh_choices_item_width_dim
\dim_new:N \l__examzh_choices_item_min_height_dim

% 计算标签和选项内容的最大宽度，
% 分别保存到 \l__examzh_choices_label_width_dim 和 \l__examzh_choices_item_width_dim
% #1: \l__examzh_choices_seq
\cs_new:Npn \__examzh_choices_calc_max_width:N #1
  {
    % 下面这两个的想法是 xchoices 项目可以优化学习的地方
    % 因为 xchoices 是把变量先设置为第一项的参数，然后让后面的和前面的比
    % 这里相当于把“设置为第一项的参数”这一步，用默认的“端点量”来代替
    % 比如取最大的，就和 0 比，这样的话其实也会产生变量会变成第一项的参数的结果
    % 但是两者性质不同，此处处理让 第一项 「没有特殊性」
    % 后面的计算最小高度的也是如此
    \dim_zero:N \l__examzh_choices_item_width_dim
    \dim_set_eq:NN \l__examzh_choices_item_min_height_dim \c_max_dim
    \seq_map_indexed_inline:Nn #1
      {
        % -- 标签 --
        % 把标签整体放进 \l_tmpa_box
        \hbox_set:Nn \l_tmpa_box { \__examzh_choices_the_label:n {##1} }
        % 测量宽度
        \dim_set:Nn \l_tmpa_dim { \box_wd:N \l_tmpa_box }
        % 与当前最大值比较，最后效果是 \l__examzh_choices_label_width_dim 储存了所有标签中宽度最大的标签的宽度值
        \dim_compare:nNnT
          { \l_tmpa_dim } > { \l__examzh_choices_label_width_dim }
          { \dim_set_eq:NN \l__examzh_choices_label_width_dim \l_tmpa_dim }
        % -- 选项内容 --
        % 把内容放进 \l_tmpa_box 中
        \hbox_set:Nn \l_tmpa_box {##2}
        % 测量宽度
        \dim_set:Nn \l_tmpa_dim { \box_wd:N \l_tmpa_box }
        % 与当前最大值比较，最后效果是 \l__examzh_choices_item_width_dim 储存了所有选项内容中宽度最大的内容的宽度值
        \dim_compare:nNnT
          { \l_tmpa_dim } > { \l__examzh_choices_item_width_dim }
          {
            \dim_set_eq:NN \l__examzh_choices_item_width_dim
              \l_tmpa_dim
          }
        % -- 找到最小高度 --
        % 把内容高度储存到 \l_tmpb_dim
        \dim_set:Nn \l_tmpb_dim { \box_ht:N \l_tmpa_box }
        % 与当前最小值比较，最后效果是 \l__examzh_choices_item_min_height_dim 储存了所有内容中高度最小的内容的高度值
        \dim_compare:nNnT
          { \l_tmpb_dim } < { \l__examzh_choices_item_min_height_dim }
          { \dim_set_eq:NN \l__examzh_choices_item_min_height_dim \l_tmpb_dim }
        \box_clear:N \l_tmpa_box
      }
  }

% TODO 没看懂怎么实现的
\int_new:N \l__examzh_choices_index_int

% \Alph* 形式生成正确的标签
\cs_new:Npn \__examzh_choices_the_label:n #1
  {
    \group_begin:
      \int_set:Nn \l__examzh_choices_index_int 
        {
          \int_eval:n
            {
              \l__examzh_choices_item_index_int + #1 - 1
            }
        }
      \l__examzh_choices_counters_tl
      \l__examzh_choices_label_tl
    \group_end:
  }

% 超过这一高度阈值的选项视为插图模式
% 注意使用 tl
% TODO 为何要使用 tl 而不用 dim ？
\tl_new:N \l__examzh_choices_figure_mode_threshold_tl
\tl_set:Nn \l__examzh_choices_figure_mode_threshold_tl { 2 \baselineskip }

\cs_new:Npn \__examzh_choices_set_auto_label_pos:
  {
    \str_if_eq:VnT \l__examzh_choices_label_pos_tl { auto }
      {
        % 若最小高度超过阈值，推测其中包含插图，将标签位置改为左居中
        \dim_compare:nNnTF
          { \l__examzh_choices_item_min_height_dim } >
            { \l__examzh_choices_figure_mode_threshold_tl }
          { \tl_set:Nn \l__examzh_choices_label_pos_tl { left } }
          { \tl_set:Nn \l__examzh_choices_label_pos_tl { top-left } }
      }
  }


\int_new:N \l__examzh_tmp_int

% 计算选项的合适列数，存到 \l__examzh_choices_columns_int
\cs_new:Npn \__examzh_choices_calc_columns:
  {
    % 若标签不在底部，将 label-width 和 label-sep 加到 \l__examzh_choices_item_width_dim 里面
    \str_if_eq:VnF \l__examzh_choices_label_pos_tl { bottom }
      {
        \dim_add:Nn \l__examzh_choices_item_width_dim
          { \l__examzh_choices_label_width_dim + \l__examzh_choices_label_sep_dim }
      }
    % [总宽度 / 最大的选项宽度] = 列数 
    % 这个计算出来是作为「算出来的、可以排的最大列数」
    % 将要和下面的手动（或者默认的）最大列数进行比较，来确定最后排多少列
    \int_set:Nn \l__examzh_choices_columns_int
      {
        \int_div_truncate:nn
          { \l__examzh_choices_total_width_dim + \l__examzh_choices_column_sep_dim }
          { \l__examzh_choices_item_width_dim + \l__examzh_choices_column_sep_dim }
      }
    % 如果上面的计算算出来是 0 的话，就设置为 1
    \int_compare:nNnTF { \l__examzh_choices_columns_int } = {0}
      { \int_set:Nn \l__examzh_choices_columns_int {1} }
    % 从允许的最大列数开始，每次除以 2，直到行宽允许排下
    % 比如设置了最大列数是 4 ， 但是算出来可以排 5 
    % 那么就会将 [4 / 2] = 2 < 5 作为列数
    \int_set_eq:NN \l__examzh_tmp_int \l__examzh_choices_max_columns_int
    \int_while_do:nNnn
      { \l__examzh_tmp_int } > { \l__examzh_choices_columns_int }
      {
        \int_set:Nn \l__examzh_tmp_int
          { \int_div_truncate:nn { \l__examzh_tmp_int } {2} }
      }
    \int_set_eq:NN \l__examzh_choices_columns_int \l__examzh_tmp_int
  }


% 计算选项的最终宽度，保存到 \l__examzh_choices_item_width_dim
\cs_new:Npn \__examzh_choices_calc_item_width:
  {
    \dim_set:Nn \l__examzh_choices_item_width_dim
      {
        % TODO 不是很理解这里的算法
        ( \l__examzh_choices_total_width_dim
          - \l__examzh_choices_columns_int \l__examzh_choices_column_sep_dim
          + \l__examzh_choices_column_sep_dim
        ) / \l__examzh_choices_columns_int
      }
    % 若标签不在底部，将 label-width 和 label-sep 算进来
    % TODO 算进来？那怎么还是 sub？
    \str_if_eq:VnF \l__examzh_choices_label_pos_tl { bottom }
      {
        \dim_sub:Nn \l__examzh_choices_item_width_dim
          { \l__examzh_choices_label_width_dim + \l__examzh_choices_label_sep_dim }
      }
  }


\int_new:N \l__examzh_choices_current_col_int

% #1: \l__examzh_choices_seq
\cs_new:Npn \__examzh_print_choices:N #1
  {
    \int_zero:N \l__examzh_choices_current_col_int
    \seq_map_indexed_inline:Nn \l__examzh_choices_seq
      {
        \int_incr:N \l__examzh_choices_current_col_int
        % 当前列号重置为 1
        \int_compare:nNnT
          { \l__examzh_choices_current_col_int } > { \l__examzh_choices_columns_int }
          {
            % \par \noindent
            \\[ \l__examzh_choices_line_sep_skip ]
            % \newline
            % \skip_vertical:N \l__examzh_choices_line_sep_skip
            \int_set:Nn \l__examzh_choices_current_col_int {1}
          }
        % TODO 为什么 > 1 才加呢？ 这样的话第 1 列和第 2 列之间就没有这个间距？
        \int_compare:nNnT { \l__examzh_choices_current_col_int } > {1}
          {
            \skip_horizontal:N \l__examzh_choices_column_sep_dim
            % 增加一点弹性
            \skip_horizontal:n {0pt plus 1pt minus 1pt}
          }
        \__examzh_print_single_choice:nn {##1} {##2}
      }
    \par
  }


\coffin_new:N \l__examzh_choices_item_coffin
\coffin_new:N \l__examzh_choices_label_coffin
% \box_new:N \l__examzh_choices_item_box
% \box_new:N \l__examzh_choices_label_box
\cs_new:Npn \__examzh_print_single_choice:nn #1#2
  {
    % 选项标签
    \__examzh_choices_make_label_coffin:n {#1}
    % \__examzh_choices_make_label_box:n {#1}
    % 选项内容
    \__examzh_choices_make_item_coffin:nn {#1} {#2}
    % \__examzh_choices_make_item_box:n {#2}
    % 合并选项的标签和内容
    \str_case:Vn \l__examzh_choices_label_pos_tl
      {
        { top-left }
          {
            \coffin_join:NnnNnnnn
              \l__examzh_choices_label_coffin {r} {H}
              \l__examzh_choices_item_coffin  {l} {H}
              { \l__examzh_choices_label_sep_dim }
              { 0pt }
            % \hbox_set:Nn \l__examzh_choices_item_box
            %   {
            %     \box_use_drop:N \l__examzh_choices_label_box
            %     \kern \l__examzh_choices_label_sep_dim
            %     \box_use_drop:N \l__examzh_choices_item_box
            %   }
          }
        { left }
          {
            \coffin_join:NnnNnnnn
              \l__examzh_choices_label_coffin {r} {vc}
              \l__examzh_choices_item_coffin  {l} {vc}
              { \l__examzh_choices_label_sep_dim }
              { 0pt }
            % \hbox_set:Nn \l__examzh_choices_item_box
            %   {
            %     \box_move_down:nn
            %       {
            %         (
            %           \box_ht:N \l__examzh_choices_label_box -
            %           \box_dp:N \l__examzh_choices_label_box -
            %           \box_ht:N \l__examzh_choices_item_box +
            %           \box_dp:N \l__examzh_choices_item_box
            %         ) / 2
            %       }
            %       { \box_use_drop:N \l__examzh_choices_label_box }
            %     \kern \l__examzh_choices_label_sep_dim
            %     \box_use_drop:N \l__examzh_choices_item_box
            %   }
          }
        { bottom }
          {
            \coffin_join:NnnNnnnn
              \l__examzh_choices_label_coffin {hc} {t}
              \l__examzh_choices_item_coffin  {hc} {b}
              { 0pt }
              % { - \l__examzh_choices_label_sep_dim }
              { 0pt }
            % \hbox_set:Nn \l__examzh_choices_item_box
            %   {
            %     % \vbox_top:n
            %     %   {
            %     %     \box_use:N \l__examzh_choices_item_box
            %     %     \nointerlineskip
            %     %     % \kern \l__examzh_choices_label_sep_dim 
            %     %     \box_move_left:nn
            %     %       {
            %     %         (
            %     %           \box_wd:N \l__examzh_choices_label_box -
            %     %           \box_wd:N \l__examzh_choices_item_box
            %     %         ) / 2
            %     %       }
            %     %       { \box_use_drop:N \l__examzh_choices_label_box }
            %     %       \box_clear:N \l__examzh_choices_item_box
            %     %   }
            %     \hbox_set:Nn \l__examzh_choices_item_box
            %       {
            %         \box_use:N \l__examzh_choices_item_box
            %         \kern \dim_eval:n
            %           {
            %             ( - \box_wd:N \l__examzh_choices_label_box
            %               -  \box_wd:N \l__examzh_choices_item_box ) / 2 
            %           }
            %         \box_move_down:nn
            %           {
            %             \box_ht:N \l__examzh_choices_label_box +
            %             \box_dp:N \l__examzh_choices_item_box
            %             % + \l__examzh_choices_label_sep_dim 
            %           }
            %           { \box_use_drop:N \l__examzh_choices_label_box }
            %         \box_clear:N \l__examzh_choices_item_box
            %       }
            %   }
          }
      }
    % 输出合并后
    % \coffin_typeset:Nnnnn \l__examzh_choices_item_coffin {l} {H} {0pt} {0pt}
    \coffin_typeset:Nnnnn \l__examzh_choices_label_coffin {l} {H} {0pt} {0pt}
    \coffin_clear:N \l__examzh_choices_item_coffin
    \coffin_clear:N \l__examzh_choices_label_coffin
    % \box_use_drop:N \l__examzh_choices_item_box
  }

% 将标签内容存入 coffin
\cs_new:Npn \__examzh_choices_make_label_coffin:n #1
% 将标签内容存入 box
% \cs_new:Npn \__examzh_choices_make_label_box:n #1
  {
    \hcoffin_set:Nn \l__examzh_choices_label_coffin
    % \hbox_set:Nn \l__examzh_choices_label_box
      {
        \hbox_to_wd:nn { \l__examzh_choices_label_width_dim }
          {
            \__examzh_choices_format_answer:nn {#1}
              { \__examzh_choices_make_label:n {#1} }
            \strut
          }
      }
  }

\cs_new:Npn \__examzh_choices_make_label:n #1
  {
    \str_case:Vn \l__examzh_choices_label_align_tl
      {
        { left   } { \rlap { \__examzh_choices_the_label:n {#1} } \hss }
        { center } { \hss \clap { \__examzh_choices_the_label:n {#1} } \hss }
        { right  } { \hss \llap { \__examzh_choices_the_label:n {#1} } }
      }
  }

\bool_new:N \l__examzh_choices_figure_mode_bool

\cs_new_protected:Npn \__examzh_choices_set_item_line_spacing:
  {
    \skip_add:Nn \baselineskip { \l__examzh_choices_item_line_sep_skip }
    \skip_add:Nn \lineskip { \l__examzh_choices_item_line_sep_skip }
  }

% 将选项内容存入 coffin
\cs_new:Npn \__examzh_choices_make_item_coffin:nn #1#2
% 将选项内容存入 box
% \cs_new:Npn \__examzh_choices_make_item_box:n #1
  {
    \hcoffin_set:Nn \l__examzh_choices_item_coffin
    % \hbox_set:Nn \l__examzh_choices_item_box
      {
        % 优先尝试使用 hbox，这是因为在 \vbox_set 外部能保留原来的 \linewidth 和
        % \textwidth，方便用户在 \includegraphics 中使用
        \hbox_set:Nn \l_tmpa_box
          { \__examzh_choices_format_answer:nn {#1} {#2} }
        % 若盒子的自然高度大于 2 行，且深度为 0pt，设置为插图模式
        \bool_lazy_and:nnT
          {
            \dim_compare_p:nNn { \box_ht:N \l_tmpa_box } >
            { \l__examzh_choices_figure_mode_threshold_tl }
          }
          { \dim_compare_p:nNn { \box_dp:N \l_tmpa_box } < { 1pt } }
          { \bool_set_true:N \l__examzh_choices_figure_mode_bool }
        \vcoffin_set:Nnn \l_tmpa_coffin
          { \l__examzh_choices_item_width_dim }
        % \vbox_set:Nn \l_tmpa_box
          {
            \__examzh_choices_set_item_line_spacing:
            % \dim_set_eq:NN \parskip \c_zero_dim
            % \dim_set_eq:NN \parindent \listparindent
            \dim_set_eq:NN \hsize \l__examzh_choices_item_width_dim
            \dim_set_eq:NN \linewidth \hsize
            \dim_set_eq:NN \columnwidth \hsize
            \dim_set_eq:NN \parskip \c_zero_dim
            \dim_set_eq:NN \parindent \listparindent
            \dim_set:Nn \leftskip { 0pt }
            \dim_set:Nn \rightskip { 0pt }
            \noindent
            % \strut
            % 若标签在底部，将图片居中对齐。
            \str_if_eq:VnT \l__examzh_choices_label_pos_tl { bottom }
              { \centering }
            \dim_compare:nNnTF
              { \box_wd:N \l_tmpa_box } > { \l__examzh_choices_item_width_dim }
              { \__examzh_choices_format_answer:nn {#1} {#2} }
              { \box_use_drop:N \l_tmpa_box }
            % 使用 \strut 将行距撑开，防止跟下一行选项的间距过小
            \mode_if_horizontal:T { \strut }
          }
        \dim_set:Nn \l_tmpa_dim { \coffin_ht:N \l_tmpa_coffin }
        \bool_if:NT \l__examzh_choices_figure_mode_bool
        % \dim_set:Nn \l_tmpa_dim { \box_ht:N \l_tmpa_box }
        % \bool_if:NTF \l__examzh_choices_figure_mode_bool
        %   {
        %     \box_move_up:nn { \l_tmpa_dim - 0.7 \baselineskip } { \box_use_drop:N \l_tmpa_box }
        %   }
          {
            \coffin_set_horizontal_pole:Nnn \l_tmpa_coffin {T}
              { \l_tmpa_dim - 0.7 \baselineskip }
            % \vbox_top:n { \vbox_unpack_drop:N \l_tmpa_box }
          }
        \coffin_typeset:Nnnnn \l_tmpa_coffin {l} {T} {0pt} {0pt}
        \coffin_clear:N \l_tmpa_coffin
      }
  }


\AddChoicesCounter \circlednumber \__examzh_font_circled_number:n
\AddChoicesCounter \tikzcirclednumber \__examzh_tikz_circled_number:n


% \item* 只负责当前 choices 环境中的正确选项标记和显隐着色。
% 括号答案、答案收集与移动由统一答案模型另行处理。

\endinput