%% Last Modified: Fri Sep 07 22:02:45 2007.

\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{weiwER}
\typeout{Document Style `weiw_ER - Enhanced ER diagram support (ver 0.999)}

\RequirePackage[normalem]{ulem}

%% From http://www.tug.org/TeXnik/mainFAQ.cgi?file=misc/underline
\def\dotuline{\bgroup
  \ifdim\ULdepth=\maxdimen  % Set depth based on font, if not set already
   \settodepth\ULdepth{(j}\advance\ULdepth.4pt\fi
  \markoverwith{\begingroup
  \advance\ULdepth0.08ex
  \lower\ULdepth\hbox{\kern.15em .\kern.1em}%
  \endgroup}\ULon}

\def\dashuline{\bgroup
  \ifdim\ULdepth=\maxdimen  % Set depth based on font, if not set already
   \settodepth\ULdepth{(j}\advance\ULdepth.4pt\fi
  \markoverwith{\kern.15em
  \vtop{\kern\ULdepth \hrule width .3em}%
  \kern.15em}\ULon}


%% main
\RequirePackage{tikz}

% use libraries
\usetikzlibrary{er,shapes,snakes,calendar,matrix,backgrounds,folding,automata}


%% global declaration
\tikzstyle{every entity}=[fill=blue!20,draw=blue,thick]
\tikzstyle{every relationship}=[fill=orange!20,draw=orange,thick,aspect=2.0]
\tikzstyle{every attribute}=[fill=black!20,draw=black,font=\scriptsize]

\tikzstyle{weakentity}= [entity, double distance=2pt]
\tikzstyle{idrelationship}= [relationship, double distance=2pt]

% cannot add [sloped] to the style (ugly result for relationships that
% connects two entities on the same x-coordinate.
\tikzstyle{minmaxlabel}= [pos=0.5, auto, color=blue, font=\small]

\tikzstyle{erline}= [shorten <=1pt, shorten >=1pt] % to take care of shaped drawn with [double] style. 


%% macros
% attributes
\newcommand{\attrib}[4]{% #1: entity/relationship node, #2: angle, #3: text label, #4: pin distance (in mm)
  \draw[shorten <=1pt] (#1) -- +(#2:#4mm) node[attribute] {#3};
}

% composite attribute <-- therefore, must give an id, then other
% attributes can be easily added as if it is an entity
\newcommand{\cattrib}[5]{% #1: entity/relationship node, #2: angle, #3: text label, #4: pin distance (in mm)
  \draw[shorten <=1pt] (#1) -- +(#2:#4mm) node[attribute] (#5) {#3};
}

\newcommand{\pkattrib}[4]{% #1: entity/relationship node, #2: angle, #3: text label, #4: pin distance (in mm)
  \draw[shorten <=1pt] (#1) -- +(#2:#4mm) node[attribute] {\underline{#3}};
}

% derived attributes
\newcommand{\dvattrib}[4]{% #1: entity/relationship node, #2: angle, #3: text label, #4: pin distance (in mm)
  \draw[shorten <=1pt] (#1) -- +(#2:#4mm) node[attribute, dashed] {#3};
}

% multivalued attributes
\newcommand{\mvattrib}[4]{% #1: entity/relationship node, #2: angle, #3: text label, #4: pin distance (in mm)
  \draw[shorten <=1pt] (#1) -- +(#2:#4mm) node[attribute, double distance=2pt] {#3};
}

% partial key
\newcommand{\ptattrib}[4]{% #1: entity/relationship node, #2: angle, #3: text label, #4: pin distance (in mm)
  \draw[shorten <=1pt] (#1) -- +(#2:#4mm) node[attribute] {\dashuline{#3}};
}

\newcommand{\entity}[2]{% #1: entity node name, #2: text label
  \node[entity] (#1) {#2};
}


\newcommand{\weakentity}[2]{% #1: entity node name, #2: text label
  \node[weakentity] (#1) {#2};
}

\newcommand{\relationship}[2]{% #1: entity node name, #2: text label
  \node[relationship] (#1) {#2};
}

% identifying relationship
\newcommand{\idrelationship}[2]{% #1: entity node name, #2: text label
  \node[idrelationship] (#1) {#2};
}

% connect a relationship to 2 entities
\newcommand{\buildrelationship}[5]{% #1: relationship node name, #2: entity 1, #4: entity 2. #3 and #5 are min-max notations
  \draw[erline] (#2) -- (#1) node[minmaxlabel] {#3};
%  \draw[erline] (#1) -- (#4) node[minmaxlabel] {(#5)}; %% minmax lables on different sides
  \draw[erline] (#1) -- (#4) node[minmaxlabel] {#5};  %% minmax lables on the same side
}

\newcommand{\addrelationship}[3]{% #1: relationship node name, #2: entity 1, #3: min-max notations
  \draw[erline] (#2) -- (#1) node[minmaxlabel] {#3};  %% minmax lables on the same side
}














% %% Example Figures
% \begin{tikzpicture} %[ampersand replacement=\&] % to be used inside another environment
%   % matrix
%   \matrix[row sep=1cm, column sep=2cm] {
%     \entity{loan}{Loan}       & \idrelationship{has}{Has} & \weakentity{payment}{Payment} \\
%     \relationship{owns}{Owns} &                           &                               \\
%     \entity{branch}{Branch}   &                           & \relationship{test}{Test} \\
%   };
%   % relationships
%   \buildrelationship{has}{loan}{(0,1)}{payment}{(1,1)}
%   \buildrelationship{owns}{loan}{(1,1)}{branch}{(0,n)}
%   % have to simulate ternary relationship
%   \buildrelationship{test}{loan}{}{branch}{} % no need to specify minmax for ternary relationships
%   \addrelationship{test}{payment}{} % no need to specify minmax for ternary relationships
%   % attributes for entities
%   \pkattrib{loan}{180}{loanID}{20}
%   \attrib{loan}{140}{amount}{20}
%   \mvattrib{loan}{100}{multiVal}{20}
%   %
%   \dvattrib{payment}{0}{seq\_no}{20}
%   % attributes for relationships
%   \attrib{test}{0}{dummy}{20}
% \end{tikzpicture}