% ----------------------------------------------------------------
% LaTeXbangla package - Enhanced LaTeX integration for Bangla 
% E-mail: adib.hasan8@gmail.com
% Released under the LaTeX Project Public License v1.3c or later
% See http://www.latex-project.org/lppl.txt
% ----------------------------------------------------------------
% This package simplifies the process of writing Bangla in LaTeX and
% addresses most of the common typesetting issues. Additional features
% include automatic transition between languages and many more. (See 
% examples) The user can just type in usual LaTeX syntax and expect 
% everything to work as it should.
% ------------------------------------------------------------------ 
% Copyright (C) 2016 by Adib Hasan adib.hasan8@gmail.com

% This work may be distributed and/or modified under the
% conditions of the LaTeX Project Public License (LPPL), either
% version 1.3c of this license or (at your option) any later
% version. The latest version of this license is in the file:

% http://www.latex-project.org/lppl.txt

% This work is "maintained" (as per LPPL maintenance status) by
% Adib Hasan

% This work consists of the files:  latexbangla.sty,
%                                   latexbangla.tex, and
%                                   latexbangla.pdf
%
% 
\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{latexbangla}[2016/10/31 v0.2 Enhanced LaTeX integration for Bangla]

\RequirePackage{polyglossia, fontspec, xkeyval, ifxetex}

% Because this package depends on ucharclasses which itself
% requires XeTeX's interchar classes
\RequireXeTeX

%Fully supported Bangla Fonts
%Other banglafonts *are* supported but there might be issues with whitespaces.
\def\@@Kalpurush{Kalpurush}
\def\@Kalpurush#1{
	\ifcase#1{Kalpurush}    %name
	\or{MatchLowercase}     %Scale
	\or{1.1}                %main WordSpace
	\or{1.5}                %tt WordSpace
	\else\fi
}
\def\@@SiyamRupali{SiyamRupali}
\def\@SiyamRupali#1{
	\ifcase#1{SiyamRupali}  %name
	\or{0.8}                %Scale
	\or{1.2}                %main WordSpace
	\or{1.8}                %tt WordSpace
	\else\fi
}
\def\@@SolaimanLipi{SolaimanLipi}
\def\@SolaimanLipi#1{
	\ifcase#1{SolaimanLipi} %name
	\or{0.9}                %Scale
	\or{1.5}                %main WordSpace
	\or{2.1}                %tt WordSpace
	\else\fi
}

\DeclareOptionX{banglamainfont}{%
	\if\relax\detokenize{#1}\relax
		\errmessage{Bangla main font not defined}	
	\else
		\def\bm@name{#1}
		\def\bm@@name{bmfont}
		\bm@init{\bm@name}
    \fi
}
\DeclareOptionX{banglattfont}{%
	\if\relax\detokenize{#1}\relax	
		\errmessage{Bangla tt font not defined}
	\else
		\def\btt@name{#1}
		\def\btt@@name{bttfont}
		\btt@init{\btt@name}
    \fi
}

\newif\if@none	
\newif\if@recom
\newif\if@full	
\@recomtrue
\DeclareOptionX{feature}{		
	\if\relax\detokenize{#1}\relax\fi
	\ifcase#1
		\@recomfalse		
		\@nonetrue
	\or\or\@fulltrue\fi
}

\newif\ifchange@num
\change@numtrue
\DeclareOptionX{changecounternumbering}{
	\if\relax\detokenize{#1}\relax\fi
	\ifcase#1\change@numfalse\fi
}

\def\bm@init#1{
	\ifx#1\@@Kalpurush
    	\def\bm@scale{\@Kalpurush{1}}
    	\def\bm@wordspace{\@Kalpurush{2}}
	\else\ifx#1\@@SiyamRupali
    	\def\bm@scale{\@SiyamRupali{1}}
    	\def\bm@wordspace{\@SiyamRupali{2}}
    \else\ifx#1\@@SolaimanLipi
    	\def\bm@scale{\@SolaimanLipi{1}}
    	\def\bm@wordspace{\@SolaimanLipi{2}}
	\else
	    \def\bm@scale{MatchLowercase}
    	\def\bm@wordspace{1}
    \fi\fi\fi
}
\def\btt@init#1{	
	\ifx#1\@@Kalpurush
    	\def\btt@scale{\@Kalpurush{1}}
    	\def\btt@wordspace{\@Kalpurush{3}}
	\else\ifx#1\@@SiyamRupali
    	\def\btt@scale{\@SiyamRupali{1}}
    	\def\btt@wordspace{\@SiyamRupali{3}}
    \else\ifx#1\@@SolaimanLipi
    	\def\btt@scale{\@SolaimanLipi{1}}
    	\def\btt@wordspace{\@SolaimanLipi{3}}
	\else
		\def\btt@scale{MatchLowercase}
    	\def\btt@wordspace{1.2}    
    \fi\fi\fi
}

\ProcessOptionsX\relax

%From polyglossia
\ifchange@num
	\setmainlanguage[changecounternumbering=true]{bengali}
\else
	\setmainlanguage{bengali}
\fi

\newfontfamily\bengalifont[%
	Script=Bengali,% 
	Scale=\bm@scale,%
	NFSSFamily=\bm@@name,%
	WordSpace=\bm@wordspace,%
	AutoFakeSlant,
	AutoFakeBold
	]{\bm@name}

\newfontfamily\bengalifonttt[%
	Script=Bengali,% 
	Scale=\btt@scale,%
	NFSSFamily=\btt@@name,
	WordSpace=\btt@wordspace,%
	AutoFakeSlant,
	AutoFakeBold
	]{\btt@name}

\newenvironment{latin}{\fontencoding{OT1}\ifx\f@family\btt@@name\fontfamily{lmtt}\else\fontfamily{lmr}\fi\selectfont}\relax

%Devanagari is required since Bangla fullstop dari ("0964) is in
%Devanagari block of Unicode
\RequirePackage[Latin, Bengali, Devanagari]{ucharclasses}
\setTransitionsForLatin{\begin{latin}}{\end{latin}}

%if feature=0 is provided no other modifications will be enabled
%However, from my personal experience, I find the following modifications to be useful.

%the default for feature option is 1, which enables the recommended modifications
\if@recom
	\RequirePackage{titlesec, amsthm, xpatch, amsfonts, amssymb, amsmath, enumerate, chngcntr, hyperref}
	%adding a dot after the number in titles
	\titlelabel{\thetitle.\enspace}
	
	%making the word "proof" in proof env. bold and adding a : after it.	
	\xpatchcmd{\proof}{\itshape}{\bfseries}{}{}
	\xpatchcmd{\proof}{\@addpunct{.}}{\@addpunct{:}}{}{}
		
	\counterwithin{equation}{section}

	\renewcommand\UrlFont{\fontencoding{OT1}\fontfamily{lmtt}\selectfont}

	%increases gap between lines	
	\linespread{1.1}
	
	%defining a \tobangla which converts numbers in any counter to bangla 	
	\def\@banglanumber#1{\expandafter\@@banglanumber\number#1\@nil}
	\def\@@banglanumber#1{\ifx#1\@nil
	\else\char\numexpr#1+"09E6\relax\expandafter\@@banglanumber\fi}
	\def\tobangla#1{\expandafter\@banglanumber\csname c@#1\endcsname}
	\def\numtobangla#1{\@@banglanumber#1\@nil}
	
	%Because polyglossia itself defines প্রমাণ as italic. I'm making it bold.	
	\addto\captionsbengali{\renewcommand\proofname{\bfseries প্রমাণ}}
	
	%a new solution environment	
	\newenvironment{solution}{\proof[\bfseries সমাধান]}{\endproof}
	
	\newtheoremstyle{custom}% name
	{3pt}% space above
	{3pt}% space below
	{\rm}% body font
	{}% indent amount
	{\bfseries}% theorem head font
	{:}% punctuation after theorem head
	{.5em}% space after theorem head
	{}% theorem head spec
	\theoremstyle{custom}
	\newtheorem{example}{\bfseries উদাহরণ}
	\newtheorem{problem}{\bfseries সমস্যা}
	\newtheorem{theorem}{\bfseries উপপাদ্য}[section]
	
	%converting all the useful counters not handled by polyglossia to bangla	
	\renewcommand{\theequation}{\thesection.\tobangla{equation}}
	\renewcommand{\thetheorem}{\thesection.\tobangla{theorem}}
	\renewcommand{\theexample}{\tobangla{example}}
	\renewcommand{\theproblem}{\tobangla{problem}}
	\renewcommand{\theenumi}{\tobangla{enumi}}
	\renewcommand{\theenumii}{\tobangla{enumii}}
	\renewcommand{\theenumiii}{\tobangla{enumiii}}
	\renewcommand{\thefootnote}{\tobangla{footnote}}
\fi

%feature=2 enabes further modifiations as follows
\if@full
	\RequirePackage{titlesec, amsthm, xpatch, amsfonts, amssymb, amsmath, enumerate, chngcntr}
	\theoremstyle{custom}
	\newtheorem{corollary}{\bfseries অনুসিদ্ধান্ত}[section]
	\newtheorem{property}{\bfseries বৈশিষ্ট্য}[section]
	\newtheorem*{remark}{\bfseries মন্তব্য}
	\newtheorem*{hint} {\bfseries হিন্ট}
	\renewcommand{\thecorollary}{\thesection.\tobangla{corollary}}
	\renewcommand{\theproperty}{\thesection.\tobangla{property}}
	\addto\captionsbengali{\renewcommand\abstractname{\bfseries সারসংক্ষেপ}}
	%\addto\captionsbengali{\renewcommand\referencename{\bfseries তথ্যসূত্রসমূহ}}
	\newenvironment{motive}{\proof[\bfseries মোটিভেশন]}{\phantom\qedhere\endproof}
	\def\equationautorefname~#1\null{(#1)\null}
\fi
\endinput