% Copyright 2015-... Maïeul Rouquette
% 
% Inspired by Paul Stanley http://tex.stackexchange.com/a/172777/7712
%
%
% This work may be distributed and/or modified under the
% conditions of the LaTeX Project Public License, either version 1.3
% of this license or (at your option) any later version.
% The latest version of this license is in
%   http://www.latex-project.org/lppl.txt
% and version 1.3 or later is part of all distributions of LaTeX
% version 2005/12/01 or later.
%
% This work has the LPPL maintenance status `maintained'.
% 
% The Current Maintainer of this work is Maïeul Rouquette
\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{biblatex-opcit-booktitle}[2015/07/02 v1.1.1 Manage op. cit. when using subentry]
\RequirePackage{xpatch}

\newbibmacro*{cite:seen:related}{%
 {\xifinlistcs{\thefield{crossref}}{blx@bsee@\the\c@refsection}%
   {}%
   {\listcsxadd{blx@bsee@\the\c@refsection}{\thefield{crossref}}}}}

\newcommand{\ifrelatedunseen}[2]{%
  \xifinlistcs{\thefield{crossref}}{blx@bsee@\the\c@refsection}%
   {#2}%
   {#1}}

\xpatchbibmacro{cite}%
  {\usebibmacro{cite:full}%
       \usebibmacro{cite:save}}%
  {\usebibmacro{cite:test:ifrelated}}%
  {}%
  {}%


\newbibmacro*{cite:test:ifrelated}%
      {\ifboolexpr {%
         test {\iffieldundef{crossref}}%
         or not (test {\ifentrytype{inbook}}%
               or test {\ifentrytype{incollection}}%
               or test {\ifentrytype{inproceedings}}%
               or test {\ifentrytype{bookinbook}})}%
       {\usebibmacro{cite:full}%
        \usebibmacro{cite:save}}%
       {\ifrelatedunseen%
        {\usebibmacro{cite:seen:related}%
         \usebibmacro{cite:full}%
         \usebibmacro{cite:save}}%
        {\usebibmacro{related:info}}}}
        
\newbibmacro*{related:info}{%
  % Here an hack to use the short form of the booktitle without recurring to a .dbx file in order to define new fields (because recurring to a .dbx file for such feature is complex for a little feature)
  \entrydata{\thefield{crossref}}{\savefield{shorttitle}{\shortbooktitle}}%
  \ifdef{\shortbooktitle}%
    {%
      \restorefield{booktitle}{\shortbooktitle}%
      \clearfield{booksubtitle}%
    }%
    {}%
  \usebibmacro{cite:full:citepages}%
  \usedriver%
    {\DeclareNameAlias{sortname}{default}}%
    {inbook:rel}%
}

\DeclareBibliographyDriver{inbook:rel}{%
  \usebibmacro{bibindex}%
  \usebibmacro{begentry}%
  \usebibmacro{author/translator+others}%
  \setunit{\labelnamepunct}\newblock
  \usebibmacro{title}%
  \newunit
  \printlist{language}%
  \newunit\newblock
  \usebibmacro{byauthor}%
  \newunit\newblock
  \usebibmacro{in:}%
  \usebibmacro{maintitle+booktitle}%
  \newunit\newblock
  \usebibmacro{byeditor+others}%
  \newunit%
  \iffieldundef{maintitle}%
    {\printfield{volume}%
     \printfield{part}}
    {}%
  \newunit%
  \bibstring[\mkibid]{opcit}%
  \newunit\newblock
  \usebibmacro{chapter+pages}%
  \newunit\newblock
  \setunit{\bibpagerefpunct}\newblock
  \usebibmacro{pageref}%
  \newunit\newblock
  \iftoggle{bbx:related}
    {\usebibmacro{related:init}%
     \usebibmacro{related}}
    {}%
  \usebibmacro{finentry}}

\endinput
