#!/usr/bin/perl -w

# gsr.pl
# Global Search and Replace
# Script to recursively search for a string and replace (or delete) it.
# Last Modified: October 2006

use strict;

die "Usage: perl gsr.pl [option] toplvldir searchstring replacestring\n
	\t-svn Check in files before modification\n
	\t-dirty Keep unmodified files as fileName.orig\n"
		unless $ARGV[1];

my $svn;
my $dirty;

# check for any options
while ($ARGV[0] =~ /^-/) {
	$svn = shift @ARGV if $ARGV[0] eq "-svn";
	$dirty = shift @ARGV if $ARGV[0] eq "-dirty";
}

my ($dir, $search, $replace) = @ARGV; # get the arguments
$replace = "" unless defined($replace); #if no replacement is given, define $replace so Perl will delete $search
print "I will search <$dir> for <$search> and replace it with <$replace>.\n\n";

chomp(my @files = `grep -ril $search $dir`); # let Grep do the dirty work, and remove new line characters

unless (@files) {
	print "$search doesn't appear in any files! Bye, now.\n";
	exit;
}

@files = sort @files; # put any hidden directories in the front
while ($files[0] =~ /.*\.svn.*/){ # get rid of any .svn dirs
	shift @files;
} 

print "<$search> appears in:\n";
if (@files) {
	foreach (@files) { print "\t$_\n"; }
	print "Shall I replace? (y/n): ";
}

chomp(my $continue = <STDIN>); # continue?

if ($continue =~ /^y/i) {
	system "svn ci -m \"GSR script checking in files before replace\" @files" if $svn; # check in the files if -svn
	sleep(5) if $svn; # wait for svn to work (yeah, I should probably do this another way)
	foreach (@files) {
		my $orig = "$_.orig";
		rename $_, "$orig"; # move file to file.orig
		open INPUT, "< $orig" or die "cannot open $_.orig for input: $!\n";
		open OUTPUT, "> $_" or die "cannot open $_ for output: $!\n";
		print "\tReplacing in $_\n";
		while (<INPUT>) { # do the replacement
			s/$search/$replace/g;
			print OUTPUT "$_";
		}
		close OUTPUT; # aren't I nice?
		close INPUT;
		unlink $orig unless $dirty; #delete the originals unless the user says no
	}
} else {
	print "Well, aren't you a waste of my time.\n";
}