#!/usr/bin/perl

use strict;
use warnings;
use version;
use English qw( -no_match_vars );
use File::Basename;
use Getopt::Long;
use GraphViz;
use List::Util qw( max );
use Pod::Usage;
use Readonly;
use Scalar::Util qw( openhandle );
use Text::RecordParser;

Readonly our $VERSION => 1.01;

my $add_color    = 0;
my $fields       = '';
my $fs           = qq{\t};
my $is_directed  = 0;
my $layout       = 'circo';
my $out_file     = '';
my $out_format   = 'png';
my $rs           = qq{\n};
my $show_numbers = 0;

my ( $help, $man_page, $show_version );

GetOptions(
    'c|color'    => \$add_color,
    'd|directed' => \$is_directed,
    'format:s'   => \$out_format,
    'fs:s'       => \$fs,
    'f|fields:s' => \$fields,
    'help'       => \$help,
    'l|layout:s' => \$layout,
    'man'        => \$man_page,
    'n|numbers'  => \$show_numbers,
    'o|out:s'    => \$out_file,
    'rs:s'       => \$rs,
    'version'    => \$show_version,
) or pod2usage;

if ( $help || $man_page ) {
    pod2usage({
        -exitval => 0,
        -verbose => $man_page ? 2 : 1
    });
};

if ( $show_version ) {
    my $prog = basename( $PROGRAM_NAME );
    print "$prog $VERSION\n";
    exit 0;
}

if ( !@ARGV ) {
    pod2usage('No input files');
}
elsif ( @ARGV > 1 ) {
    pod2usage('Too many input files');
}

my %field_filter = map { $_, 1 } split( /\s*,\s*/, $fields );

my $file = shift @ARGV;
my $p    = Text::RecordParser->new(
    filename         => $file,
    field_separator  => $fs,
    record_separator => $rs,
    trim             => 1,
);

my $g = GraphViz->new( 
    directed      => $is_directed,
    layout        => $layout,
    bgcolor       => $add_color ? 'lightgoldenrodyellow' : 'white',
    no_overlap    => 1,
    node          => {
        style     => 'filled',
        fillcolor => 'white',
    }
);

my @cols = $p->field_list;
my %col_pos;
for my $i ( 1..$#cols ) { # skip first col
    my $col_name = $cols[ $i ];

    if ( %field_filter ) {
        next unless $field_filter{ $col_name };
    }

    $g->add_node( $col_name );

    $col_pos{ $i } = $col_name;
}

my $records = $p->fetchall_arrayref;
my @edges;
for my $data ( @$records ) {
    my $node_name = $data->[0];
    $g->add_node( $node_name );

    for my $i ( 1..$#cols ) {
        my $val = $data->[ $i ]  or next;
        my $col = $col_pos{ $i } or next;

        if ( %field_filter ) {
            next unless defined $field_filter{ $col };
        }

        if ( $val =~ /^\d+$/ && $val > 0 ) {
            push @edges, [ $cols[ $i ], $node_name, $val ];
        }
    }
}

my $max_val = max( map { $_->[-1] } @edges );
for my $edge ( @edges ) {
    my $val    = $edge->[-1];
    my $weight = ( $val / $max_val ) * .5;

    $g->add_edge( 
        $edge->[0], $edge->[1],
        $show_numbers ? ( label => $val ) : (),
        weight => $weight,
    );
}

my $method = join '', 'as_', lc $out_format;
if ( $out_file ) {
    open my $fh, '>', $out_file or die "Can't write '$out_file': $!\n";
    binmode $fh;
    print $fh $g->$method;
    close $fh;
    my $basename = basename( $out_file );
    print STDERR qq[Image created "$basename."\n];
}
else {
    print $g->$method;
}

__END__

# -------------------------------------------------------------------

=pod

=head1 NAME

tab2graph - turn tabular data into a graph

=head1 SYNOPSIS

  tab2graph [options] file.tab

Options:

  -c|--color           Add some color to the output (default is white)
  -d|--directed        Make graph directed (default is not)
  -l|--layout          GraphViz layout; choose from dot, neato, twopi,
                       circo (default), and fdp
  -f|--fields          Restrict to set of fields in first row
  -n|--numbers         Show the numbers (default is not)
  -o|--out             Name of output file (default is STDOUT)
  --format             Output format (default is PNG)
  --fs=x               Use "x" as the field separator (default is tab)
  --rs=x               Use "x" as the record separator (default is newline)

  --help               Show brief help and quit
  --man                Show full documentation

=head1 DESCRIPTION

Turns tabular data into a graph using GraphViz.  This may or may not 
be useful.

=head1 SEE ALSO

=over 4

=item * Text::RecordParser

=item * GraphViz

=back

=head1 AUTHOR

Ken Youens-Clark E<lt>kclark@cpan.orgE<gt>.

=head1 LICENSE AND COPYRIGHT

Copyright (C) 2009-10 Ken Youens-Clark.  All rights reserved.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2.

This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of 
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

=cut