% 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-decorate.sty
% Character decoration support for vertical typesetting
% This is a subpackage of luatex_cn
%
\RequirePackage{expl3}
\RequirePackage{xparse}
\ProvidesExplPackage {decorate/luatex-cn-decorate} {2026/02/18} {0.3.0} {Character Decoration Support}

% Decorate Command - Apply decoration to each character in content
% Syntax: \decorate[char=。, color=red, xshift=0pt, yshift=0pt]{content}
% Each character in {content} will have the decoration character applied

\tl_new:N \l__luatexcn_decorate_char_tl
\tl_new:N \l__luatexcn_decorate_color_tl
\tl_new:N \l__luatexcn_decorate_xshift_tl
\tl_new:N \l__luatexcn_decorate_yshift_tl
\tl_new:N \l__luatexcn_decorate_font_size_tl
\tl_new:N \l__luatexcn_decorate_scale_tl

\keys_define:nn { luatexcn / decorate }
  {
    char .tl_set:N = \l__luatexcn_decorate_char_tl,
    char .initial:n = 。,
    color .tl_set:N = \l__luatexcn_decorate_color_tl,
    color .initial:n = red,
    xshift .tl_set:N = \l__luatexcn_decorate_xshift_tl,
    xshift .initial:n = 0pt,
    yshift .tl_set:N = \l__luatexcn_decorate_yshift_tl,
    yshift .initial:n = 0pt,
    font-size .tl_set:N = \l__luatexcn_decorate_font_size_tl,
    font-size .initial:n = ,
    scale .tl_set:N = \l__luatexcn_decorate_scale_tl,
    scale .initial:n = 1.0,
  }

% Internal command to add decoration marker after current character
\cs_new:Npn \__luatexcn_decorate_one:n #1 {
  #1
  \lua_now:e {
    local~constants~=~require('core.luatex-cn-constants')
    constants.register_decorate(
      "\luaescapestring{\l__luatexcn_decorate_char_tl}",
      "\luaescapestring{\l__luatexcn_decorate_xshift_tl}",
      "\luaescapestring{\l__luatexcn_decorate_yshift_tl}",
      "\luaescapestring{\l__luatexcn_decorate_font_size_tl}",
      "\luaescapestring{\l__luatexcn_decorate_color_tl}",
      font.current(),
      "\luaescapestring{\l__luatexcn_decorate_scale_tl}"
    )
  }
  \box0\scan_stop:
}

\NewDocumentCommand{\decorate}{ O{} m }{%
  \group_begin:
    \keys_set:nn { luatexcn / decorate } { #1 }
    \tl_map_function:nN { #2 } \__luatexcn_decorate_one:n
  \group_end:
}

% ============================================================================
% CJK Key Aliases (中文键值别名)
% ============================================================================

% --- decorate namespace ---
\keys_define:nn { luatexcn / decorate }
  {
    字符 .tl_set:N = \l__luatexcn_decorate_char_tl,
    颜色 .tl_set:N = \l__luatexcn_decorate_color_tl,
    顏色 .tl_set:N = \l__luatexcn_decorate_color_tl,
    横偏 .tl_set:N = \l__luatexcn_decorate_xshift_tl,
    橫偏 .tl_set:N = \l__luatexcn_decorate_xshift_tl,
    横移 .tl_set:N = \l__luatexcn_decorate_xshift_tl,
    橫移 .tl_set:N = \l__luatexcn_decorate_xshift_tl,
    纵偏 .tl_set:N = \l__luatexcn_decorate_yshift_tl,
    縱偏 .tl_set:N = \l__luatexcn_decorate_yshift_tl,
    纵移 .tl_set:N = \l__luatexcn_decorate_yshift_tl,
    縱移 .tl_set:N = \l__luatexcn_decorate_yshift_tl,
    字号 .tl_set:N = \l__luatexcn_decorate_font_size_tl,
    字號 .tl_set:N = \l__luatexcn_decorate_font_size_tl,
    缩放 .tl_set:N = \l__luatexcn_decorate_scale_tl,
    縮放 .tl_set:N = \l__luatexcn_decorate_scale_tl,
  }

% ============================================================================
% EmphasisMark (着重号/圈点) - Convenience command for emphasis marking
% Applies a circle mark (。) to the right side of each character
% Syntax: \EmphasisMark[color=red]{content}
% ============================================================================
\tl_new:N \l__luatexcn_emphasis_color_tl

\keys_define:nn { luatexcn / emphasis }
  {
    color .tl_set:N = \l__luatexcn_emphasis_color_tl,
    color .initial:n = red,
  }

% --- emphasis namespace CJK aliases ---
\keys_define:nn { luatexcn / emphasis }
  {
    颜色 .tl_set:N = \l__luatexcn_emphasis_color_tl,
    顏色 .tl_set:N = \l__luatexcn_emphasis_color_tl,
  }

% ============================================================================
% CJK Aliases (中文别名)
% ============================================================================
% Simplified Chinese / 简体
\NewCommandCopy{\装饰}{\decorate}

\NewDocumentCommand{\EmphasisMark}{ O{} m }{%
  \group_begin:
    \keys_set:nn { luatexcn / emphasis } { #1 }
    \decorate[char=。, scale = 1.5, xshift=-0.7em, color=\l__luatexcn_emphasis_color_tl]{#2}
  \group_end:
}

\NewCommandCopy{\着重号}{\EmphasisMark}

% ============================================================================
% 改 (Fix/Correction) Command - Mark a character as corrected
% Used in classical Chinese text editing: 甲\改{乙} means "甲 is corrected to 乙"
% This overlays a 、(deletion mark) on the previous character and places the
% replacement character at bottom-right corner at half the font size
% Syntax: \改{replacement character}
\NewDocumentCommand{\fix}{ m }{%
  \group_begin:
    % First: overlay a 、 symbol to mark deletion (centered on the character)
    \lua_now:e {
      local~constants~=~require('core.luatex-cn-constants')
      constants.register_decorate(
        "、",
        "0em",
        "0em",
        nil,
        "black",
        nil,
        2
      )
    }%
    \box0\scan_stop:
    % Second: add the replacement character at bottom-right, half size
    \lua_now:e {
      local~constants~=~require('core.luatex-cn-constants')
      constants.register_decorate(
        "\luaescapestring{#1}",
        "-0.6em",
        "0.5em",
        nil,
        "black",
        nil,
        0.6
      )
    }%
    \box0\scan_stop:
  \group_end:
}

\NewCommandCopy{\改}{\fix}
% Traditional Chinese / 繁体
\NewCommandCopy{\裝飾}{\decorate}
\NewCommandCopy{\著重號}{\EmphasisMark}

% ============================================================================
% Underline / WavyUnderline - Now provided by luatex-cn-linemark.sty
% The old glyph-based implementation has been replaced with PDF line drawing.
% Commands \Underline, \WavyUnderline, \下划线, \波浪线 etc. are defined there.
% ============================================================================

\ExplSyntaxOff%
%
\endinput%