#!/usr/bin/perl -w
# $Id$

#require 5.008;

use strict;
use Getopt::Mixed qw(nextOption);

my @lines = ();

my ($REL) = q$Revision: 1.4 $=~m/(\d+(?:\.\d+)+)/;
my $prefix = undef;
my $verbose = undef;
my $reverse = undef;
my $flag_choice = undef;
my $line = '';


# help(): print help text and exit
sub help {
	print "Usage: $0 [options]
  -h, --help           show this short help and exit
  -p, --prefix=PREFIX  prefix
  -r, --reverse        revert changes
  -v, --verbose        print superfluous info
  -V, --version        show version string and exit\n";
	exit;
}

# version(): print version info and exit
sub version {
	print "$0 r$REL, Jochen Striepe <ptxdist\@tolot.escape.de>\n";
	exit;
}

# esc(): escapes a scalar reference for use in perl regexp
sub esc { ${$_[0]} =~ s/([\[\]\(\)\*\.\-\^\$\@])/\\$1/g; }


# get command line params:
$0 =~ s!^.*/!!;
Getopt::Mixed::init('h p=s r v V help>h prefix>p reverse>r verbose>v version>V');
while (my ($opt, $val, $pretty) = nextOption()) {
	if	($opt eq 'h')		{ help(); }
	elsif ($opt eq 'p')		{ $prefix = $val; }
	elsif ($opt eq 'r')		{ $reverse = 1; }
	elsif ($opt eq 'v')		{ $verbose = 1; }
	elsif ($opt eq 'V')		{ version(); }
}
Getopt::Mixed::cleanup();

if (!defined $prefix) {
	print STDERR "Fatal: prefix not specified\n\n"; help; die;
}
if (defined $reverse) { esc(\$prefix); }


@lines = <STDIN>;

while (@lines) {
	$line = shift @lines;
	chomp($line);

	if (defined $reverse) {
		if ($line =~ s/^(\s*config\s+)$prefix/$1/e) {
			print STDERR "$prefix removed\n" if defined $verbose;
			$flag_choice = undef;
		}
		elsif ($line =~ /^\s*depends\s+(on\s)?\s*/) {
			while ($line =~ s/^(\s*depends\s+(on\s)?\s*(?:[0-9A-Z_]+\s+)*?)$prefix/$1/e) {
				print STDERR "$prefix removed\n" if defined $verbose;
			}
		}
		elsif ($line =~ s/^(\s*(?:default\s+\S+\s+)?if\s+)(.*)/$1/e) {
			while ($line =~ s/^(\s*(?:default\s+\S\s+)?if\s(?:[0-9A-Z_]+\s+)*?)$prefix/$1/e) {
				print STDERR "$prefix removed\n" if defined $verbose;
			}
		}
		elsif (defined $flag_choice) {
			if ($line =~ s/^(\s*default\s+)$prefix/$1/e) {
				print STDERR "$prefix removed\n" if defined $verbose;
			}
		}
	}
	elsif ($line =~ s/^(\s*config\s+)([0-9A-Z_]+)/$1.$prefix.$2/e) {
		print STDERR "$2 is now $prefix$2\n" if defined $verbose;
		$flag_choice = undef;
	}
	elsif ($line =~ s/^(\s*select\s+)([0-9A-Z_]+)/$1.$prefix.$2/e) {
		print STDERR "$2 is now $prefix$2\n" if defined $verbose;
		$flag_choice = undef;
	}
	elsif ($line =~ s/^(\s*depends\s+(on\s)?\s*)(.*)/$1/e) {
		my $foo = $3;
		while ($foo =~ s/^([^0-9A-Z_]*)([0-9A-Z_]+)(.*)/$3/e) {
			$line .= $1.$prefix.$2;
			print STDERR "$2 is now $prefix$2\n" if defined $verbose;
		}
		$line .= $foo;
	}
	elsif ($line =~ s/^(\s*(?:default\s+\S+\s+)?if\s+)(.*)/$1/e) {
		my $foo = $2;
		while ($foo =~ s/^([^0-9A-Z_]*)([0-9A-Z_]+)(.*)/$3/e) {
			$line .= $1.$prefix.$2;
			print STDERR "$2 is now $prefix$2\n" if defined $verbose;
		}
		$line .= $foo;
	}
	elsif (defined $flag_choice) {
		if ($line =~ s/^(\s*default\s+)([0-9A-Z_]+)/$1.$prefix.$2/e) {
			print STDERR "$2 is now $prefix$2\n" if defined $verbose;
		}
	}

	if ($line =~ /^choice/) {
		$flag_choice = 1;
	}

	print STDOUT "$line\n";
}

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# vim500:set tabstop=4
# eof