#!/usr/bin/perl

use 5.010;
use strict;
use File::Slurp qw(edit_file_lines);
use Path::Class qw(file dir);

use constant SKIP       => 'SKIP';
use constant SIMULATION => 1;

sub process_file {
	my ($file, %param) = @_;
	
	# skip files that need skipping
	if ($param{skip}->($file) eq SKIP) {
		say { $param{log} } "Skipping $file";
		return 0;
	}
	
	if ($file->is_dir) {
		my $modified = 0;
		say { $param{log} } "Recursing into directory $file";
		foreach ($file->children) {
			$modified += process_file($_, %param);
		}
		say { $param{log} } "Finished with directory $file - modified $modified files inside";
		return $modified;
	}
		
	say { $param{log} } "Processing file $file";
	my $i = 0;
	my $modified = 0;
	edit_file_lines {
		$i++;
		foreach my $change (@{ $param{changes} }) {
			my ($match, $replace) = @$change;
			if (/$match/) {
				say { $param{log} } "Line $i matched $match - replacing with $replace";
				$modified = 1;
				s/$match/$replace/g unless SIMULATION;
			}
		}
	} $file;
	
	say { $param{log} } "Done with file $file";
	
	return $modified;
}

process_file(

	# starting point for crawl
	dir('somedir'),
	
	# list of changes to make
	changes => [
		[ qr{ChangeThis}i  => 'ToThis' ],
		[ qr{ChangeThat}i  => 'ToThat' ],
	],
	
	# sub which returns SKIP if a file (or directory) should be skipped
	skip => sub {
		my $file = shift;
		
		if ($file->is_dir and [$file->dir_list]->[-1] !~ /^[a-zA-Z0-9]/) {
			return SKIP;
		}
		
		return;
	},
	
	log => file('changling.log')->openw,
);