#!/usr/bin/perl
use strict;
use IO::Handle;

# $Platon: encoder.pl,v 1.5 2002/04/10 13:11:26 jombik9 Exp $

#############################################################################
#                                                                           #
#  This script is intended do decrypt STDIN and write that to STDOUT.       #
#                                                                           #
#                                             =Nepto= <neptunko@pobox.sk>   #
#                                             Wolcano  <wolcano@pobox.sk>   #
# Method syntax :                                                           #
#                                                                           #
#   if (is_decodable_input) { <decode text> }                               #
#                                                                           #
# In output of <decode text> we switch the (START|END)_STR to indicate      #
# succesfull decoding...                                                    #
#                                                                           #
# Changes:                                                                  #
#                                                                           #
#	23-03-2001 creation (Neptun & Wol)                                      #
#	26-03-2001 changed ENCODE_1 start and end strings (Wol)                 #
#	27-03-2001 removed UPPER,LOWER encoding (Wol)                           #
#	29-03-2001 added auto_encode_1 detection and auto_use                   #
#                                                                       @heh#
#############################################################################

# System init.
select(STDERR); $| = 1;     # make unbuffered
select(STDOUT); $| = 1;     # make unbuffered

# constants/variables.
my $START_ENCODE_1_STR = '123';
my $END_ENCODE_1_STR = '321';

my $START_AUTO_ENCODE_1_STR = '%';
my $END_AUTO_ENCODE_1_STR = '%';
my $AUTO_ENCODE_1_PREFIX = '';

my $START_SWITCH_CASE_STR = 'aAbBcC';
my $END_SWITCH_CASE_STR = 'CcBbAa';

=pot
print '-' x 60, "\n";
print(STDERR "Encoder starts...\n");
print(STDERR "To use encode shortcuts, specify by: %<string>%\n");
print(STDERR "  then use \"<string> <string2>\" to encode <string2>\n");
printf(STDERR "To decode <string> use: %s <string> %s\n",
	$START_ENCODE_1_STR, $END_ENCODE_1_STR);
printf(STDERR "To switch case of <string> use: %s <string> %s\n",
	$START_SWITCH_CASE_STR, $END_SWITCH_CASE_STR);
print '-' x 60, "\n";
=cut

while (<STDIN>) {
#	chomp;

# detect autoencryption prefix flags and put the command into PREFIX
	if ($_ =~ /^($START_AUTO_ENCODE_1_STR)(.*)($END_AUTO_ENCODE_1_STR)(.*)$/) {
		$AUTO_ENCODE_1_PREFIX = $2;
# remove the PREFIX flags and continue
		$_ = $2 . $4 . "\n";
	}

# if INPUT starts with PREFIX we add the encode flags to the rest of the STR
	if (!($AUTO_ENCODE_1_PREFIX eq '') && ($_ =~ /^($AUTO_ENCODE_1_PREFIX)(.*)$/))
	{
		$_ = $AUTO_ENCODE_1_PREFIX . $START_ENCODE_1_STR . ' ' . $2 . ' ' . $END_ENCODE_1_STR . "\n";
	}

# ENCODE METHOD no. 1 (shift characters right according to position on keyboard)
	if ($_ =~ /^(.*)($START_ENCODE_1_STR)(.*)($END_ENCODE_1_STR)(.*)$/) {
		my $buf;

		$buf = $3;
		$buf =~ y/-abcdefghijklmnopqrstuvwxyz`,.;'[]ABCDEFGHIJKLMNOPQRSTUVWXYZ~<>:"{}123456789=0/=snvfrghjokl;,mp[wtdyibecuxz.`'a]qSNVFRGHJOKL:<MP{WTDYIBECUXZ>~"A}Q2345678901-/;

# otocime START a END .
		$_ = $1 . $4 . $buf . $2 . $5 . "\n";
	}


# DECODE METHOD no. 1
        elsif ($_ =~ /^(.*)($END_ENCODE_1_STR)(.*)($START_ENCODE_1_STR)(.*)$/) {
                my $buf;

                $buf = $3;
                $buf =~ y/-abcdefghijklmnopqrstuvwxyz`,.;'[]ABCDEFGHIJKLMNOPQRSTUVWXYZ~<>:"{}1234567890=/0'vxswdfguhjknbio]earycqzt`.m,l;p["VXSWDFGUHJKNBIO}EARYCQZT~>M<L:P{=123456789-/;

                $_ = $1 . $4 . $buf . $2 . $5 . "\n";
        }

# SWITCH_CASE encode
        if ($_ =~ /^(.*)($START_SWITCH_CASE_STR)(.*)($END_SWITCH_CASE_STR)(.*)$/) {
                my $buf;

                $buf = $3;
                $buf =~ y/abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ/ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz/;

                $_ = $1 . $4 . $buf . $2 . $5 . "\n";
        }

# SWITCH_CASE decode
        elsif ($_ =~ /^(.*)($END_SWITCH_CASE_STR)(.*)($START_SWITCH_CASE_STR)(.*)$/) {
                my $buf;

                $buf = $3;
                $buf =~ y/ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ/;

                $_ = $1 . $4 . $buf . $2 . $5 . "\n";
        }

	print STDOUT;
}

print "Exitting encoder.\n";