% Copyright 2026 Open-Guji (https://github.com/open-guji)
% ... (License header omitted for brevity)
% luatex-cn-guji-meipi.sty
% MeiPi (眉批) auto-positioned annotation support for vertical typesetting
% This is a subpackage of luatex_cn
%
% NOTE: This file must be loaded AFTER TextBox and PiZhu are defined
%

\RequirePackage{expl3}
\RequirePackage{xparse}
\ProvidesExplPackage {guji/luatex-cn-guji-meipi} {2026/02/26} {0.3.1} {MeiPi Auto-Positioned Annotation Support}

% Load the Lua module
\lua_now:n { require('guji.luatex-cn-guji-meipi') }

% MeiPi (眉批) - Auto-positioned floating annotation box
\tl_new:N \l__luatexcn_meipi_font_size_tl
\tl_new:N \l__luatexcn_meipi_color_tl
\tl_new:N \l__luatexcn_meipi_grid_width_tl
\tl_new:N \l__luatexcn_meipi_grid_height_tl
\tl_new:N \l__luatexcn_meipi_x_tl
\tl_new:N \l__luatexcn_meipi_y_tl
\tl_new:N \l__luatexcn_meipi_height_tl
\tl_new:N \l__luatexcn_meipi_spacing_tl
\tl_new:N \l__luatexcn_meipi_gap_tl

\keys_define:nn { luatexcn / meipi }
  {
    x .tl_set:N = \l__luatexcn_meipi_x_tl,
    x .initial:n = {},
    y .tl_set:N = \l__luatexcn_meipi_y_tl,
    y .initial:n = {},
    height .tl_set:N = \l__luatexcn_meipi_height_tl,
    height .initial:n = {7},
    font-size .tl_set:N = \l__luatexcn_meipi_font_size_tl,
    font-size .initial:n = {18pt},
    color .tl_set:N = \l__luatexcn_meipi_color_tl,
    color .initial:n = {1~0~0},
    grid-width .tl_set:N = \l__luatexcn_meipi_grid_width_tl,
    grid-width .initial:n = {20pt},
    grid-height .tl_set:N = \l__luatexcn_meipi_grid_height_tl,
    grid-height .initial:n = {19pt},
    spacing .tl_set:N = \l__luatexcn_meipi_spacing_tl,
    spacing .initial:n = {10pt},
    gap .tl_set:N = \l__luatexcn_meipi_gap_tl,
    gap .initial:n = {0pt},
  }

\NewDocumentCommand{\meipiSetup}{ m }
  {
    \keys_set:nn { luatexcn / meipi } { #1 }
    \lua_now:e {
      local~meipi~=~require('guji.luatex-cn-guji-meipi')
      meipi.setup({
        spacing~=~[=[\luaescapestring{\l__luatexcn_meipi_spacing_tl}]=],
        gap~=~[=[\luaescapestring{\l__luatexcn_meipi_gap_tl}]=]
      })
    }
  }

% Internal: Calculate annotation dimensions by typesetting content in a temp box
\dim_new:N \l__luatexcn_meipi_box_width_dim
\dim_new:N \l__luatexcn_meipi_box_height_dim
\box_new:N \l__luatexcn_meipi_temp_box
\tl_new:N \l__luatexcn_meipi_width_sp_tl
\tl_new:N \l__luatexcn_meipi_height_sp_tl

\NewDocumentCommand{\MeiPi}{ O{} +m }{%
  \group_begin:
    \keys_set:nn { luatexcn / meipi } { #1 }
    
    % Ensure grid dimensions are set to defaults if empty (defensive)
    \tl_if_empty:NT \l__luatexcn_meipi_grid_width_tl { \tl_set:Nn \l__luatexcn_meipi_grid_width_tl { 20pt } }
    \tl_if_empty:NT \l__luatexcn_meipi_grid_height_tl { \tl_set:Nn \l__luatexcn_meipi_grid_height_tl { 19pt } }

    % Setup Lua parameters for gap and spacing
    \lua_now:e {
      local~meipi~=~require('guji.luatex-cn-guji-meipi')
      meipi.setup({
        spacing~=~[=[\luaescapestring{\l__luatexcn_meipi_spacing_tl}]=],
        gap~=~[=[\luaescapestring{\l__luatexcn_meipi_gap_tl}]=]
      })
    }

    % Pre-calculate X position for center gap detection during TextBox layout
    % This ensures TextBox knows its floating position before layout happens
    \tl_if_empty:NTF \l__luatexcn_meipi_x_tl
      {
        % No user-specified x, estimate based on accumulated meipi positions
        \tl_set:Nx \l__luatexcn_meipi_x_tl {
          \lua_now:e { tex.sprint(require('guji.luatex-cn-guji-meipi').get_next_x_pt()) }
        }
      }
      { }

    % 1. Create TextBox with floating=false but pass x for center gap detection during layout
    % We use \use:x to expand variables before passing to TextBox
    % This ensures that \regex_match_... inside TextBox sees actual values (digits) not macro names
    \hbox_set:Nn \l__luatexcn_meipi_temp_box {
       \use:x {
         \exp_not:N \TextBox [
            height = \l__luatexcn_meipi_height_tl,
            font-size = \l__luatexcn_meipi_font_size_tl,
            font-color = \l__luatexcn_meipi_color_tl,
            grid-width = \l__luatexcn_meipi_grid_width_tl,
            grid-height = \l__luatexcn_meipi_grid_height_tl,
            floating = false,
            x = \l__luatexcn_meipi_x_tl
         ] { \exp_not:n { #2 } }
       }
    }

    % 2. Measure actual dimensions
    \dim_set:Nn \l__luatexcn_meipi_box_width_dim { \wd\l__luatexcn_meipi_temp_box }
    
    % Calculate height for Y positioning
    % Safe calculation: if contains 'pt' or units, use as is. Else use FP math.
    \str_if_in:NnTF \l__luatexcn_meipi_height_tl { p }
    {
         \dim_set:Nn \l__luatexcn_meipi_box_height_dim { \l__luatexcn_meipi_height_tl }
    }
    {
         \tl_if_empty:NTF \l__luatexcn_meipi_height_tl
         {
             % Fallback if height not specified: 5 lines of grid height
             \dim_set:Nn \l__luatexcn_meipi_box_height_dim { \fp_to_dim:n { 5 * \dim_to_fp:n { \l__luatexcn_meipi_grid_height_tl } } }
         }
         {
             % Use FP math to be absolutely safe (avoid dim expressions * operator issues)
             \dim_set:Nn \l__luatexcn_meipi_box_height_dim {
                \fp_to_dim:n {
                    \l__luatexcn_meipi_height_tl * \dim_to_fp:n { \l__luatexcn_meipi_grid_height_tl }
                }
             }
         }
    }

    % 3. Calculate coordinates based on what's provided
    % Prepare dimension values in sp for Lua
    \tl_set:Nx \l__luatexcn_meipi_width_sp_tl { \dim_to_decimal_in_sp:n { \l__luatexcn_meipi_box_width_dim } }
    \tl_set:Nx \l__luatexcn_meipi_height_sp_tl { \dim_to_decimal_in_sp:n { \l__luatexcn_meipi_box_height_dim } }

    \tl_if_empty:NTF \l__luatexcn_meipi_x_tl
      {
        % X not provided
        \tl_if_empty:NTF \l__luatexcn_meipi_y_tl
          {
            % Case 1: Neither X nor Y provided - calculate both
            \lua_now:e {
              require('guji.luatex-cn-guji-meipi').calculate_and_store(
                "\l__luatexcn_meipi_width_sp_tl",
                "\l__luatexcn_meipi_height_sp_tl"
              )
            }
            \tl_set:Nx \l__luatexcn_meipi_x_tl { \lua_now:e { tex.sprint(_G.meipi_x) } }
            \tl_set:Nx \l__luatexcn_meipi_y_tl { \lua_now:e { tex.sprint(_G.meipi_y) } }
          }
          {
            % Case 2: Only Y provided - calculate X (keep spacing from previous meipi)
            \lua_now:e {
              require('guji.luatex-cn-guji-meipi').calculate_x_and_store(
                "\l__luatexcn_meipi_width_sp_tl",
                "\l__luatexcn_meipi_height_sp_tl",
                "\l__luatexcn_meipi_y_tl"
              )
            }
            \tl_set:Nx \l__luatexcn_meipi_x_tl { \lua_now:e { tex.sprint(_G.meipi_x) } }
          }
      }
      {
        % X is provided
        \tl_if_empty:NTF \l__luatexcn_meipi_y_tl
          {
            % Case 3: Only X provided - calculate Y and register annotation
            \lua_now:e {
              require('guji.luatex-cn-guji-meipi').calculate_y_and_store(
                "\l__luatexcn_meipi_width_sp_tl",
                "\l__luatexcn_meipi_height_sp_tl",
                "\l__luatexcn_meipi_x_tl"
              )
            }
            \tl_set:Nx \l__luatexcn_meipi_y_tl { \lua_now:e { tex.sprint(_G.meipi_y) } }
          }
          {
            % Case 4: Both X and Y provided - register annotation for tracking
            \lua_now:e {
              require('guji.luatex-cn-guji-meipi').register_with_fixed_xy(
                "\l__luatexcn_meipi_width_sp_tl",
                "\l__luatexcn_meipi_height_sp_tl",
                "\l__luatexcn_meipi_x_tl",
                "\l__luatexcn_meipi_y_tl"
              )
            }
          }
      }

    % 4. Register the captured box as a floating box
    \lua_now:e {
        local~vertical_textbox~=~require('core.luatex-cn-core-textbox')
        local~box_num~=~\int_use:N \l__luatexcn_meipi_temp_box
        vertical_textbox.register_floating_box(box_num, {
            x~=~[=[\luaescapestring{\l__luatexcn_meipi_x_tl}]=],
            y~=~[=[\luaescapestring{\l__luatexcn_meipi_y_tl}]=]
        })
    }
    
  \group_end:
}

% Reset MeiPi registry at the start of each document
\AtBeginDocument{
  \lua_now:n { require('guji.luatex-cn-guji-meipi').reset() }
}

\ExplSyntaxOff%

% ============================================================================
% CJK Aliases (中文别名)
% ============================================================================
% Simplified Chinese / 简体
\NewCommandCopy{\眉批}{\MeiPi}
\NewCommandCopy{\眉批设置}{\meipiSetup}
% Traditional Chinese / 繁体
\NewCommandCopy{\眉批設置}{\meipiSetup}

% ============================================================
% Chinese key aliases / 中文 Key 别名
% ============================================================
\ExplSyntaxOn
\keys_define:nn { luatexcn / meipi }
  {
    % 简体
    横位 .tl_set:N = \l__luatexcn_meipi_x_tl,
    纵位 .tl_set:N = \l__luatexcn_meipi_y_tl,
    高度 .tl_set:N = \l__luatexcn_meipi_height_tl,
    字号 .tl_set:N = \l__luatexcn_meipi_font_size_tl,
    颜色 .tl_set:N = \l__luatexcn_meipi_color_tl,
    格宽 .tl_set:N = \l__luatexcn_meipi_grid_width_tl,
    格高 .tl_set:N = \l__luatexcn_meipi_grid_height_tl,
    间距 .tl_set:N = \l__luatexcn_meipi_spacing_tl,
    间隔 .tl_set:N = \l__luatexcn_meipi_gap_tl,
    % 繁体（与简体不同形的）
    橫位 .tl_set:N = \l__luatexcn_meipi_x_tl,
    縱位 .tl_set:N = \l__luatexcn_meipi_y_tl,
    字號 .tl_set:N = \l__luatexcn_meipi_font_size_tl,
    顏色 .tl_set:N = \l__luatexcn_meipi_color_tl,
    格寬 .tl_set:N = \l__luatexcn_meipi_grid_width_tl,
    間距 .tl_set:N = \l__luatexcn_meipi_spacing_tl,
    間隔 .tl_set:N = \l__luatexcn_meipi_gap_tl,
  }
\ExplSyntaxOff

\endinput%