#!/usr/bin/perl
use strict;
use warnings;

use Term::ANSIColor;
use List::Util qw( min );
use Getopt::Std;

getopts( 'c:x' );
my @color = split /,/, our $opt_c || 'bold red';

@ARGV or die <<"END_USAGE";
usage: @{[ colored( 'hl [ -c colour ] [ -x ] pattern [ file... ] [ < input ]', 'bold' ) ]}
       You can use capturing parens in your pattern. In that case,
       you can supply multiple attributes separated by commas,
       which will be used to individually colour the submatches.
       @{[ colored( '-x', 'bold' ) ]} will supress lines without matches.
END_USAGE

my $rx = shift;
$rx = qr/$rx/;

while ( <> ) {
	s{ $rx }{ colored_match() }gex or not( our $opt_x ) or next;
	print;
}

sub colored_match {
	my @START = @-;
	my @END = @+;
	my $last = min( $#color, $#START );

	if ( $last ) {
		push @START, $END[ 0 ];
		push @END, $END[ 0 ];
		$END[ 0 ] = $START[ 0 ];
		my $str;
		for my $i ( 0 .. $last ) {
			$str .= colored(
				substr( $_, $START[ $i ], $END[ $i ] - $START[ $i ] ),
				$color[ $i ],
			) unless $i == 0;
			$str .= colored(
				substr( $_, $END[ $i ], $START[ $i + 1 ] - $END[ $i ] ),
				$color[ 0 ],
			);
		}
		return $str;
	}
	else {
		return colored(
			substr( $_, $START[ 0 ], $END[ 0 ] - $START[ 0 ] ),
			$color[ 0 ],
		);
	}
}