% Copyright 2026 Open-Guji (https://github.com/open-guji)
%
% Licensed under the Apache License, Version 2.0 (the "License");
% you may not use this file except in compliance with the License.
% You may obtain a copy of the License at
%
%     http://www.apache.org/licenses/LICENSE-2.0
%
% Unless required by applicable law or agreed to in writing, software
% distributed under the License is distributed on an "AS IS" BASIS,
% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
% See the License for the specific language governing permissions and
% limitations under the License.
% luatex-cn-guji-mulu.sty
% Catalog/Index (目录) support for traditional book typesetting
% This is a subpackage of luatex_cn
%
%
%   Or with raw commands (level = number of indent spaces, default 0):
%       \條目{卷一}           % level 0, no indent
%       \條目[1]{經部一}      % level 1, 1 space indent
%       \條目[2]{易類}        % level 2, 2 spaces indent
%
\RequirePackage{expl3}
\RequirePackage{xparse}
\ProvidesExplPackage {guji/luatex-cn-guji-mulu} {2026/02/18} {0.3.0} {Catalog/Index support for traditional books}

% Load the core column engine
\RequirePackage{core/luatex-cn-core-column}

% ============================================================================
% Internal Functions
% ============================================================================

% Output column with level-based indent
% #1: level (0, 1, 2, 3, ...) - represents actual number of full-width spaces
% #2: content
\cs_new:Nn \__luatexcn_mulu_output_column:nn
  {
    \int_case:nn { #1 }
      {
        { 0 } { \Column{ #2 } }
        { 1 } { \Column{ 　#2 } }
        { 2 } { \Column{ 　　#2 } }
        { 3 } { \Column{ 　　　#2 } }
        { 4 } { \Column{ 　　　　#2 } }
      }
  }

% ============================================================================
% User Commands
% ============================================================================

% \条目[level]{content} - Output a column entry with level-based indent
\NewDocumentCommand{\条目}{ O{0} +m }
  {
    \__luatexcn_mulu_output_column:nn { #1 } { #2 }
  }

% ============================================================================
% Environment (currently just a grouping wrapper)
% ============================================================================

\ExplSyntaxOff

% ============================================================================
% CJK Aliases (中文别名)
% ============================================================================
% English pinyin alias
\NewCommandCopy{\TiaoMu}{\条目}
% Traditional Chinese / 繁体
\NewCommandCopy{\條目}{\条目}

\endinput