#!/usr/bin/perl -w

use strict;
use warnings;
use Crypt::CBC;
use Fcntl ':flock';
use MIME::Base64;

my $encodedFileName = "BFSTest_encoded.csv";
my $decodedFileName = "BFSTest_decoded.csv";
my $decryptedFileName = "BFSTest_decrypted.csv";

my $cCipher = "Blowfish";
my $cKey = q{Abcdefghijklmnopqrstuvwxyz1234567890};
my $cIV = "randomiv";
my $cObject = Crypt::CBC->new({ key => $cKey, cipher => $cCipher });
croak( "Invalid cipher type for encryption" ) unless $cObject;

sub read_bytes {
	my ($fh, $to_read) = @_;
	my $buf = '';
	while ($to_read) {
		my $bytes_read = read($fh, $buf, $to_read, length($buf));
		die("$!\n") if !defined($bytes_read);
		die("Unexpected end of file\n") if !$bytes_read;
		$to_read -= $bytes_read;
	}
	return $buf;
}

sub decryptNETData {
	my ( $length, $buffer );

	print "Now DECRYPTING $decodedFileName for current client ... \n";
	open( my $fhREADFROM, "<", $decodedFileName ) || die("Cannot open encrypted file $decodedFileName");
	binmode $fhREADFROM;
	flock $fhREADFROM, LOCK_SH;
	open( finalFile, ">", $decryptedFileName ) || die("Cannot open file $decryptedFileName to write decrypted contents");
	binmode finalFile;
	flock finalFile, LOCK_EX;

	# Tried to slurp, decrypt and decode here, but that did not work either.
	my $decodedFile = do { local( $/ ) ; <$fhREADFROM> } ;
	utf8::decode( my $str = $cObject->decrypt( $decodedFile ) );
	print finalFile $str;

	#while (!eof($fhREADFROM)) {
	#	$length = unpack('N', read_bytes($fhREADFROM, 4));
	#	$buffer = read_bytes($fhREADFROM, $length);
	#	print finalFile $cObject->decrypt( $buffer );
	#}

	close $fhREADFROM;
	close finalFile;

	print "Decrypted $decodedFileName to $decryptedFileName. \n";
}

sub decodeData {
	open(my $fhENCODEDFILE, "<", $encodedFileName) || die("Cannot open file $encodedFileName");
	binmode $fhENCODEDFILE;
	flock $fhENCODEDFILE, LOCK_EX;

	open(my $fhDECODEDFILE, ">", $decodedFileName) || die("Cannot open file $decodedFileName");
	binmode $fhDECODEDFILE;
	flock $fhDECODEDFILE, LOCK_EX;

	my $utf8base64EncodedFile = do { local( $/ ) ; <$fhENCODEDFILE> } ;
	#utf8::decode( my $str = decode_base64($utf8base64EncodedFile) );
	print $fhDECODEDFILE decode_base64($utf8base64EncodedFile);

	close $fhENCODEDFILE;
	close $fhDECODEDFILE;

	print "Decoded $encodedFileName to $decodedFileName. \n";
}

decodeData();
decryptNETData();