%D \module
%D   [     file=t-gantt,
%D      version=2012.08.19,
%D        title=\CONTEXT\ User Module,
%D     subtitle=Drawing Gantt charts,
%D       author={Adam Reviczky and Aditya Mahajan},
%D         date=\currentdate,
%D    copyright={Adam Reviczky and Aditya Mahajan},
%D      license=Public Domain]

%D Some macros for drawing Gantt charts using MetaPost.

\writestatus{loading}{ConTeXt User Module / metapost gantt chart}

\startmodule[gantt-s-mp]
\unprotect

\def\????gantt{@@@@gantt}

\definesystemvariable{gantt}

\startMPinclusions
  % temporary solution for a pattern substitute
  input hatching;
\stopMPinclusions

\newcount\ganttnum
\newcount\gantttitlenum
\newcount\ganttwidth

\newdimen\ganttlastx \ganttlastx = 0cm
\newdimen\nextganttlastx
\newdimen\titleunitlength \titleunitlength = 1cm
\newdimen\ganttunitlength \ganttunitlength = 1cm

\newdimen\gantttmpa
\newdimen\gantttmpb

% workaround for titleelement
\def\!!row{\numexpr\ganttnum-1\relax}

\unexpanded\def\setupgantt
        {\bgroup
         \dosingleempty
         \dosetupgantt}

\unexpanded\def\dosetupgantt[#1]%
        {\egroup
         \getparameters[\????gantt][#1]}

\setupgantt
        [factor=1,
         xunitlength=1cm,
         style=\tf,
         titlestyle=\tfx,
         drawledgerline=false]

\unexpanded\def\setupganttbar
        {\bgroup
         \dosingleempty
         \dosetupganttbar}

\unexpanded\def\dosetupganttbar[#1]%
        {\egroup
         \getparameters[\????gantt][#1]}

\setupganttbar
        [pattern=north east lines,
         color=black]

% The gantt environment draws the canvas of a gantt figure (realized as tikzpicture)
% The usage is \startgantt[...]{no of Tasks to plot}{no of time slots}
% The optional argument [...] can be filled in a key=value syntax, using one or more of the following keys:
%
% xunitlength - length of one time slot (default: 1cm)
% style - style of labels (default: \tf)
% titlestyle - style of title section (default: \tfx)
% drawledgerline  - Switch to enable/disable the drawing of horizontal ledger lines (default value: false)
\unexpanded\long\def\dostartgantt[#1]#2#3%
  {\getparameters[\????gantt][#1]%
   \gdef\gantt!factor{\@@@@ganttfactor}
   \gdef\gantt!ganttunitlength{\@@@@ganttxunitlength}
   \gdef\gantt!style{\getvalue{@@@@ganttstyle}}
   \gdef\gantt!titlestyle{\getvalue{@@@@gantttitlestyle}}
   \gdef\gantt!drawledgerline{\@@@@ganttdrawledgerline}

   \bgroup
   \newcount\ganttx \ganttx=0
   \newcount\ganttheight

   \def\ganttxstringtop{}
   \def\ganttxstringbottom{}

   \global\ganttwidth=#3
   \global\ganttnum=0

   \ganttheight=#2
   \advance\ganttheight by 1

   \startMPdrawing
     linecap := squared;
     linejoin := mitered;

     draw (0,0.5cm)--(0,1.4cm-\the\ganttheight*cm);
     draw (\the\ganttwidth*\gantt!ganttunitlength,0.5cm)--(\the\ganttwidth*\gantt!ganttunitlength,1.4cm-\the\ganttheight*cm);
     % draw x axis
     draw (0cm,-#2*cm+0.4cm)--(\the\ganttwidth*\gantt!ganttunitlength,-#2*cm+0.4cm);

     % draw grid
     for t=1 upto \the\ganttwidth:
       draw (\gantt!ganttunitlength*t,-0.5cm)--(\gantt!ganttunitlength*t,1.4cm-\the\ganttheight*cm) dashed withdots;
     endfor
   \stopMPdrawing
   \egroup
  }

\unexpanded\def\startgantt%
  {\dosingleempty\dostartgantt}

\unexpanded\def\stopgantt%
  {\startMPdrawing
     % debug
     % draw bbox currentpicture withcolor .625red;
     currentpicture := currentpicture scaled \gantt!factor;
   \stopMPdrawing
   \MPdrawingdonetrue\getMPdrawing
   \resetMPdrawing
   \doglobal\ganttnum=0
   }

% ganttitle is the environment for drawing the title section
\definestartstop[ganttitle][
  before={
    \ganttlastx = 0cm
    \doglobal\advance\ganttnum by 1
  },
  after={
    \ganttlastx = 0cm
  }
  ]

% \titleelement draws one element of the title
% usage: \titleelement{label}{length}
\unexpanded\long\def\dotitleelement#1#2%
  {\gantttmpa=\dimexpr\gantt!ganttunitlength*#2\relax
   \divide\gantttmpa by 2

   \startMPdrawing
     draw (\the\ganttlastx,0.5cm-\the\!!row*cm)--(\the\ganttlastx+#2*\gantt!ganttunitlength,0.5cm-\the\!!row*cm)--(\the\ganttlastx+#2*\gantt!ganttunitlength,0.5cm-0.6cm-\the\!!row*cm)--(\the\ganttlastx,0.5cm-0.6cm-\the\!!row*cm)--cycle;
     path diam; diam = (\the\ganttlastx,0.5cm-\the\!!row*cm)--(\the\ganttlastx+#2*\gantt!ganttunitlength,0.5cm-0.6cm-\the\!!row*cm);
     label (textext("\getvalue{gantt!titlestyle}{#1}"), center diam);
   \stopMPdrawing

   \ganttlastx=\dimexpr\ganttlastx+\gantt!ganttunitlength*#2\relax
  }

\unexpanded\def\titleelement%
  {\dotitleelement}

% \numtitle draws a numbered sequence of title elements
% usage: \numtitle{start number}{increment}{end number}{length of each title element}
\unexpanded\long\def\donumtitle#1#2#3#4%
  {\gantttitlenum=#1
   \dostepwiserecurse{#1}{#3}{#2}{
     \titleelement{\the\gantttitlenum}{#4}
     \advance\gantttitlenum by #2
   }
  }

\unexpanded\def\numtitle%
  {\donumtitle}

% \ganttbar draws a single, unconnected bar for representing a task
% usage: \ganttbar[pattern=<pattern>,color=<color>]{label}{start}{length}
% where the optional comma separated arguments are:
% pattern - not implemented with MetaPost yet! (FIXME)
% color - a color of the pattern (e.g. red, green blue gray, dark gray)
\unexpanded\long\def\doganttbar[#1]#2#3#4%
  {\bgroup
   \getparameters[\????gantt][#1]%
   \edef\gantt!pattern{\@@@@ganttpattern}
   \edef\gantt!color{\@@@@ganttcolor}

   \gantttmpa=\dimexpr\gantt!ganttunitlength*#3\relax
   \gantttmpb=\dimexpr\gantt!ganttunitlength*#4+\gantttmpa\relax

   \doif{\gantt!drawledgerline}{true}{
   \startMPdrawing
     draw (0,-\the\ganttnum*cm-0.2cm)--(\the\ganttwidth*\gantt!ganttunitlength,-\the\ganttnum*cm-0.2cm) dashed withdots;
   \stopMPdrawing
   }
   \startMPdrawing
     path diag; diag = (0,-\the\ganttnum*cm+0.1cm)--(0,-\the\ganttnum*cm+0.5cm);
     label.lft (textext("\getvalue{gantt!style}{#2}"), center diag);
     path f; f := (\the\gantttmpa,-\the\ganttnum*cm+0.1cm)--(\the\gantttmpb,-\the\ganttnum*cm+0.1cm)--(\the\gantttmpb,-\the\ganttnum*cm+0.5cm)--(\the\gantttmpa,-\the\ganttnum*cm+0.5cm)--cycle;

     hatchoptions(withcolor \gantt!color);
     draw f withcolor black;
     % workaround for transparent bug
     % hatchfill f withcolor transparent("normal",0,white) withcolor (45,1mm,-0.5bp);
     hatchfill f withcolor (45,1mm,-0.5bp);
   \stopMPdrawing

   \global\ganttlastx=\gantttmpb
   \egroup
   \doglobal\advance\ganttnum by 1
  }

\unexpanded\def\ganttbar
  {\dosingleempty\doganttbar}

% \ganttcon draws an arrow between to bars with specified coordinates
% usage: \ganttcon{startx}{starty}{endx}{endy}
\unexpanded\long\def\doganttcon#1#2#3#4%
  {\bgroup
   \startMPdrawing
     begingroup;
       interim linecap := squared;
       interim linejoin := rounded;

       drawarrow (#1*\gantt!ganttunitlength,-#2*cm+0.1cm+0.2cm)--(#1*\gantt!ganttunitlength+0.4*\gantt!ganttunitlength,-#2*cm+0.1*cm+0.2*cm)--(#1*\gantt!ganttunitlength+0.4*\gantt!ganttunitlength,-#2*cm-0.4*cm+0.2*cm)--(#1*\gantt!ganttunitlength-0.4*\gantt!ganttunitlength,-#2*cm-0.4*cm+0.2*cm)--(#1*\gantt!ganttunitlength-0.4*\gantt!ganttunitlength,-#4*cm+0.1*cm+0.2*cm)--(#3*\gantt!ganttunitlength,-#4*cm+0.1*cm+0.2*cm);
     endgroup;
   \stopMPdrawing
   \egroup
  }

\unexpanded\def\ganttcon
  {\doganttcon}

% \ganttbarcon draws a single bar *and* connects the bar with the previous bar for
% consecutive tasks
% usage: \ganttbarcon[pattern=<pattern>,color=<color>]{label}{start}{length}
% where the optional pattern argument are the same as for \ganttbar
\unexpanded\long\def\doganttbarcon[#1]#2#3#4%
  {\bgroup
   \getparameters[\????gantt][#1]%
   \edef\gantt!pattern{\@@@@ganttpattern}
   \edef\gantt!color{\@@@@ganttcolor}

   \nextganttlastx = \dimexpr\ganttlastx+\ganttunitlength*1\relax
   \ifdim\nextganttlastx>\dimexpr\gantt!ganttunitlength*#3\relax
     \startMPdrawing
     begingroup;
       interim linecap := squared;
       interim linejoin := rounded;

       drawarrow (\the\ganttlastx,-\the\ganttnum*cm+1.1*cm+0.2*cm)--(\the\ganttlastx+0.4*\gantt!ganttunitlength,-\the\ganttnum*cm+1.1*cm+0.2*cm)--(\the\ganttlastx+0.4*\gantt!ganttunitlength,-\the\ganttnum*cm+0.6*cm+0.2*cm)--(\the\ganttlastx-0.4*\gantt!ganttunitlength,-\the\ganttnum*cm+0.6*cm+0.2*cm)--(\the\ganttlastx-0.4*\gantt!ganttunitlength,-\the\ganttnum*cm+0.1*cm+0.2*cm)--(#3*\gantt!ganttunitlength,-\the\ganttnum*cm+0.1*cm+0.2*cm);
     endgroup;
     \stopMPdrawing
   \else
     \startMPdrawing
     begingroup;
       interim linecap := squared;
       interim linejoin := rounded;

       drawarrow (\the\ganttlastx,-\the\ganttnum*cm+1.1*cm+0.2*cm)--(\the\ganttlastx+0.4*\gantt!ganttunitlength,-\the\ganttnum*cm+1.1*cm+0.2*cm)--(\the\ganttlastx+0.4*\gantt!ganttunitlength,-\the\ganttnum*cm+0.1*cm+0.2*cm)--(#3*\gantt!ganttunitlength,-\the\ganttnum*cm+0.1*cm+0.2*cm);
     endgroup;
     \stopMPdrawing
   \fi

   \ganttbar[#1]{#2}{#3}{#4}
   \egroup
   \doglobal\advance\ganttnum by 1
  }

\unexpanded\def\ganttbarcon
  {\dosingleempty\doganttbarcon}

% \ganttgroup draws a bar to group tasks
% usage: \ganttgroup{label}{start}{length}
\unexpanded\long\def\doganttgroup#1#2#3%
  {\bgroup
   \gantttmpa=\dimexpr\gantt!ganttunitlength*#2\relax
   \gantttmpb=\dimexpr\gantt!ganttunitlength*#3+\gantttmpa\relax

   \doif{\gantt!drawledgerline}{true}{
     \startMPdrawing
       draw (0,-\the\ganttnum*cm-0.2cm)--(\the\ganttwidth*\gantt!ganttunitlength,-\the\ganttnum*cm-0.2cm) dashed withdots;
     \stopMPdrawing
   }
   \startMPdrawing
     pen diamond; diamond := makepen fulldiamond;
     path diag; diag = (0,-\the\ganttnum*cm+0.1cm)--(0,-\the\ganttnum*cm+0.5cm);
     label.lft (textext("\getvalue{gantt!style}{\bf #1}"), center diag);
     fill (\the\gantttmpa-0.14*cm,-\the\ganttnum*cm+0.2cm)--(\the\gantttmpb+0.14*cm,-\the\ganttnum*cm+0.2cm)--(\the\gantttmpb+0.14*cm,-\the\ganttnum*cm+0.4cm)--(\the\gantttmpa-0.14*cm,-\the\ganttnum*cm+0.4cm)--cycle withcolor black;
     fill fulldiamond scaled 0.3cm shifted (\the\gantttmpa+0.01cm,-\the\ganttnum*cm+0.2cm) withcolor black;
     fill fulldiamond scaled 0.3cm shifted (\the\gantttmpb-0.01cm,-\the\ganttnum*cm+0.2cm) withcolor black;
   \stopMPdrawing

   \global\ganttlastx=\gantttmpb
   \egroup
   \doglobal\advance\ganttnum by 1
  }

\unexpanded\def\ganttgroup
  {\doganttgroup}

% \ganttmilestone, draw a diamond to represent a milestone
% usage: \ganttgroup[color=<color>]{label}{start}
% color - a tikz color of the pattern (e.g. red, green blue gray, dark gray)
% for more information see the tikz documentation

% Declaring layers to abvoid superposition when you connect a \ganttmileston with a task
\unexpanded\long\def\doganttmilestone[#1]#2#3%
  {\bgroup
   \getparameters[\????gantt][#1]%
   \edef\gantt!color{\@@@@ganttcolor}

   \gantttmpa=\dimexpr\gantt!ganttunitlength*#3\relax
   \gantttmpb=\dimexpr\gantt!ganttunitlength*0+\gantttmpa\relax

   \doif{\gantt!drawledgerline}{true}{
     \startMPdrawing
       draw (0,-\the\ganttnum*cm-0.2cm)--(\the\ganttwidth*\gantt!ganttunitlength,-\the\ganttnum*cm-0.2cm) dashed withdots;
     \stopMPdrawing
   }
   \startMPdrawing
     pen diamond; diamond := makepen fulldiamond;
     path diag; diag = (0,-\the\ganttnum*cm+0.1cm)--(0,-\the\ganttnum*cm+0.5cm);
     label.lft (textext("\getvalue{gantt!style}{#2}"), center diag);
     fill fulldiamond scaled 0.3cm shifted (\the\gantttmpb,-\the\ganttnum*cm+0.3cm) withcolor \gantt!color;
   \stopMPdrawing

   \global\ganttlastx=\gantttmpb
   \egroup
   \doglobal\advance\ganttnum by 1
  }

\unexpanded\def\ganttmilestone
  {\dosingleempty\doganttmilestone}

% \ganttmilestonecon draws a single diamond *and* connects the diamond with the previous task
% usage: \ganttmilestonecon[color=<color>]{label}{start}{length}
% where the optional color argument are the same as for \ganttbar and \ganttmilestone
\unexpanded\long\def\doganttmilestonecon[#1]#2#3%
  {\bgroup
   \getparameters[\????gantt][#1]%
   \edef\gantt!color{\@@@@ganttcolor}

   \nextganttlastx = \dimexpr\ganttlastx+\ganttunitlength*1\relax
   \ifdim\nextganttlastx>\dimexpr\gantt!ganttunitlength*#3\relax
     \startMPdrawing
     begingroup;
       interim linecap := squared;
       interim linejoin := rounded;

       drawarrow (\the\ganttlastx,-\the\ganttnum*cm+1.1*cm+0.2*cm)--(\the\ganttlastx+0.4*\gantt!ganttunitlength,-\the\ganttnum*cm+1.1*cm+0.2*cm)--(\the\ganttlastx+0.4*\gantt!ganttunitlength,-\the\ganttnum*cm+0.6*cm+0.2*cm)--(\the\ganttlastx-0.4*\gantt!ganttunitlength-0.14*cm,-\the\ganttnum*cm+0.6*cm+0.2*cm)--(\the\ganttlastx-0.4*\gantt!ganttunitlength-0.14*cm,-\the\ganttnum*cm+0.1*cm+0.2*cm)--(#3*\gantt!ganttunitlength-0.14*cm,-\the\ganttnum*cm+0.1*cm+0.2*cm);
     endgroup;
     \stopMPdrawing
   \else
     \startMPdrawing
     begingroup;
       interim linecap := squared;
       interim linejoin := rounded;

       drawarrow (\the\ganttlastx,-\the\ganttnum*cm+1.1*cm+0.2*cm)--(\the\ganttlastx+0.4*\gantt!ganttunitlength,-\the\ganttnum*cm+1.1*cm+0.2*cm)--(\the\ganttlastx+0.4*\gantt!ganttunitlength,-\the\ganttnum*cm+0.1*cm+0.2*cm)--(#3*\gantt!ganttunitlength-0.14*cm,-\the\ganttnum*cm+0.1*cm+0.2*cm);
     endgroup;
     \stopMPdrawing
   \fi

   \ganttmilestone[#1]{#2}{#3}
   \egroup
   \doglobal\advance\ganttnum by 1
  }

\unexpanded\def\ganttmilestonecon
  {\dosingleempty\doganttmilestonecon}

\protect \stopmodule
