###############################################################################
# Kain Shin's First Perl Program
###############################################################################
#The purpose of this program is to identify all adjacent duplicate files
#and move them into another folder to be manually deleted by human hands

use strict;
use warnings;
use File::Find;
use File::Copy;
use File::Basename;

###############################################################################
#User tunables...

my $StartingDirectory = ".";
my $DestinationDirectory = "./0.DuplicateFilesToBeDeleted";

###############################################################################
#used in main program to detect of the files are EXACT copies of each other...
sub IsDuplicate
{
	#Parameters...
	my $FileNameA = $_[0];
	my $FileNameB = $_[1];
	#...Parameters
	
	my $FileSizeA = -s $FileNameA;
	my $FileSizeB = -s $FileNameB;
	my $SizesMatch = ( $FileSizeA == $FileSizeB );

	#Chop off the extension (last 4 chars)...
	$FileNameA = substr( $FileNameA, 0, length( $FileNameA )-4 );
	$FileNameB = substr( $FileNameB, 0, length( $FileNameB )-4 );

	#See if the names are related
	my $AFitsInB = ( -1 != index( $FileNameB, $FileNameA ) );
	my $BFitsInA = ( -1 != index( $FileNameA, $FileNameB ) );
	my $NamesRelated = $AFitsInB || $BFitsInA;

	return ( $SizesMatch && $NamesRelated );
}

###############################################################################
#used in main program to exile the file with the longer name into the DestinationDirectory...
sub MoveLongerFile
{
	#Parameters...
	my $FileNameA = $_[0];
	my $FileNameB = $_[1];
	#...Parameters

	my $NameLengthA = length( $FileNameA );
	my $NameLengthB = length( $FileNameB );
	my $ShortestName = $FileNameA;
	my $LongestName = $FileNameB;
	if ( $NameLengthA > $NameLengthB )
	{
		$ShortestName = $FileNameB;
		$LongestName = $FileNameA;
	}
	print "=== POTENTIAL DUPLICATE ===\n";
	print "KEPT:$ShortestName\n";
	print "MOVE:$LongestName\n";
	my $DestinationName = substr( $LongestName, 1 );
	$DestinationName = "$DestinationDirectory$DestinationName";
	mkdir $DestinationDirectory;
	my $MoveSuccess = move( $LongestName, $DestinationDirectory );
	if ( $MoveSuccess )
	{
		print "TO:$DestinationName\n";
	}
	else
	{
		print "FAILED:$DestinationName\n";
		print "$!\n";
	}
}

###############################################################################
#called from File::find...
my @gFilePaths;
my $gLastPath = 0;
sub AddFileToPath
{
	my $CurrentFileSize = -s $_;
	my $CurrentPath = $File::Find::dir;

	#Not a folder AND not the DestinationDirectory
	if ( ( $CurrentFileSize > 0 ) && ( $DestinationDirectory ne $CurrentPath ) )
	{
		#Give feedback on which path is being added
		if ( !$gLastPath || ( $gLastPath ne $CurrentPath ) )
		{
			print "Adding for Analysis:$CurrentPath\n";
			$gLastPath = $CurrentPath;
		}
	
		push( @gFilePaths, $File::Find::name );
	}
}

###############################################################################
#Main Program

#Fill gFilePaths with sorted path goodness...
find( \&AddFileToPath, $StartingDirectory );
@gFilePaths = sort @gFilePaths;

print "========================================================================\n";
print "Checking for duplicates...\n";
#Now, check for duplicates...
my $gLastFileName = 0;
my $bDuplicatesFound = 0;
foreach ( @gFilePaths )
{
	my $CurrentFileName = $_;

	if ( $gLastFileName && IsDuplicate( $gLastFileName, $CurrentFileName ) )
	{
		$bDuplicatesFound = 1;		
		MoveLongerFile( $gLastFileName, $CurrentFileName );
	}

	$gLastFileName = $CurrentFileName;
}

print "========================================================================\n";
if ( $bDuplicatesFound )
{
	print "One layer of duplicates have been moved to '$DestinationDirectory'\n";
	print "You may need to run this again because only adjacent files are tested against each other\n";
	print "Don't forget to delete your '$DestinationDirectory' folder to finalize the pruning of duplicates\n";
}
else
{
	print "Congratulations!  No duplicates were found\n";
	print "Make sure you do not have a rogue '$DestinationDirectory' folder lingering around\n";
}