#!/usr/bin/perl -w
# $Id$
# -*- perl -*- vim:set ft=perl sw=4 sts=4:

# Usage: relational-schema out.png RELATION:_Primary_Key,.Foreign_Key,Etc
# To clarifiy, specifiy the relation name, followed by a colon, followed by
# the attributes seperated by commas.  Primary keys should be prefixed with
# an underscore, and foreign keys with a period.
# It is also possible to override or augment the functional dependencies by
# adding a second colon and additional specifications.  Since this was
# unnecessary for the assignment, it is not documented here.

use strict;
use Image::Imlib2;

use vars qw($font $maxwidth $pd $fh);
$font = "Verdana/11";
$maxwidth = 550;
$pd = 4; # Padding

my $out = shift or die "No output file specified.\n";
my @rows = @ARGV;
die "No rows.\n" unless (@rows);

my $image = new Image::Imlib2->new(1,1);
$image->add_font_path ("/usr/share/fonts/truetype/msttcorefonts");
$image->load_font($font);
($fh, $fh) = $image->get_text_size("(Ay)");
$image = new Image::Imlib2->new($maxwidth, ($#rows+1)*($fh*2+$pd*12+2));
$image->add_font_path ("/usr/share/fonts/truetype/msttcorefonts");
$image->load_font($font);
$image->set_color(255,255,255,255);
#$image->fill_rectangle(0,0,$maxwidth,($#rows+1)*($fh*2+$pd*12+2));

sub draw_boxed_text {
    my ($image, $text, $x, $y, $underline)=@_;
    $image->load_font($font);
    my ($w, $h) = $image->get_text_size($text);
    $image->set_color(255,255,255,255);
    $image->fill_rectangle($x,$y,$w+2*$pd+2,$fh+2*$pd+2);
    $image->set_color(0,0,0,255);
    $image->draw_rectangle($x,$y,$w+2*$pd+2,$fh+2*$pd+2);
    $image->draw_text($x+$pd,$y+$pd,$text);
    if(($underline||0)==1) { # Solid underline
	$image->draw_line($x+$pd,$y+$pd+$fh,$x+$w+$pd,$y+$pd+$fh);
    } elsif(($underline||0)==2) { # Dashed underline
	for(my $i=0;$i<$w;$i+=5) {
	    $image->draw_line($x+$pd+$i,$y+$pd+$fh,
		$x+$pd+($i+2>$w?$w$i+2),$y+$pd+$fh);
	}
    }
    return $w+2*$pd+1;
}

my $line=0;

foreach my $row (@rows) {
    my ($title,$element,@depends) = split (':',$row);
    my @elements = split (',',$element);
    my %elcenters = ();
    my (@in,@out);
    my ($toffset)=(2*$pd);
    while ($title =~ s/^>//) {
	$toffset += 16*$pd;
    }
    my ($offset) = ($toffset);
    foreach $element (@elements) {
	my $under=0;
	if ($element =~ s/^_//) {
	    $under=1;
	    push @out,($element);
	} elsif ($element =~ s/^\.//) {
	    $under=2;
	    push @in,($element);
	} else {
	    push @in,($element);
	    warn "Element $element in $title not marked as ".
	    "primary or foreign key.\n" if ($element=~/_ID$/);
	}
	my $o=draw_boxed_text($image,$element,$offset,$line+$fh+5*$pd,$under);
	$elcenters{$element}=($offset+$o/2);
	$offset+=$o;
    }
    my $updown=0;
    my $shifttitle=0;
    if((($#depends>=0 and $depends[0] eq 'auto') or $#depends=-1)
	    and $#in>=0 and $#out>=0) {
	$depends[0]=(join(",",@out)."/".join(",",@in));
    } elsif($#depends>=0 and $depends[0] eq 'auto') {
	shift @depends;
    }
    foreach my $depend (@depends) {
	unless ($depend) {
	    $updown++;
	    next;
	}
	$image->set_color(0,(32*($updown>>1))%128,(64*($updown>>1))%256,255);
	my ($out,$in) = split('/',$depend);
	my ($near, $far);
	my @out = split(',', $out);
	my @in  = split(',', $in );
	my @temp = sort { $elcenters{$a} <=> $elcenters{$b} } (@out, @in);
	if($updown%2==1) {
	    $shifttitle=1;
	    $near=$line+$fh+5*$pd-1;
	    $far=$line+$fh+1*$pd-1;
	} else {
	    $near=$line+2*$fh+7*$pd+2;
	    $far=$line+2*$fh+11*$pd+2;
	}
	$image->draw_line($elcenters{$temp[0]}+$pd*($updown>>1),
	    $far,$elcenters{$temp[$#temp]}+$pd*($updown>>1),$far);
	foreach $out (@out) {
	    $image->draw_line($elcenters{$out}+$pd*($updown>>1),
		$far,$elcenters{$out}+$pd*($updown>>1),$near);
	}
	foreach $in (@in) { # Draw arrowheads
	    my $arrow = Image::Imlib2::Polygon->new();
	    $arrow->add_point($elcenters{$in}+$pd*($updown>>1),$near);
	    $arrow->add_point($elcenters{$in}+$pd+$pd*($updown>>1),
		($near+$far)/2);
	    $arrow->add_point($elcenters{$in}-$pd+$pd*($updown>>1),
		($near+$far)/2);
	    $arrow->add_point($elcenters{$in},$near);
	    $arrow->fill();
	    $image->draw_line($elcenters{$in}+$pd*($updown>>1),
		$far,$elcenters{$in}+$pd*($updown>>1),$near);
	    $image->draw_polygon($arrow,1);
	}
	$updown++;
    }
    $image->set_color(0,0,0,255);
    $image->draw_text($toffset+$pd*2,$line+4*$pd-$shifttitle*(7*$pd/2),$title);
    $line+=2*$fh+12*$pd+2;
}


$image->save($out);