#!/usr/local/bin/perl -w

use strict;
use diagnostics;
use Tk;
use Tk::Dialog;

sub convert_main;
sub num2char;
sub char2num;
sub denary2string;
sub base2denary;
sub char2denary;

my $mw = MainWindow->new;
$mw->geometry("500x500");
$mw->minsize(qw(500 500));
$mw->maxsize(qw(500 500));
$mw->title("Mega-Converter");

my $top_frm = $mw->Frame->pack(-side => 'top', -fill => 'y', pady => 8
+);
my $mid_frm = $mw->Frame->pack(-side => 'top', -fill => 'x', pady => 8
+);
my $bottom_frm = $mw->Frame->pack(-side => 'top', -fill => 'x', pady =
+> 8);

my $left_frm = $mid_frm->Frame->pack(-side => 'left', 
    -fill => 'y', 
    -padx => 4, 
    -expand => 1, 
    -anchor => 'center');

my $mid_frm1 = $mid_frm->Frame->pack(-side => 'left', 
    -fill => 'y', 
    -padx => 4, 
    -expand => 1, 
    -anchor => 'center');

my $right_frm = $mid_frm->Frame->pack(-side => 'left', 
    -fill => 'y',
    -padx => 4,
    -expand => 1, 
    -anchor => 'center');

my $start_text = $top_frm->Text(-background => 'white',
    -height => 13)->pack;

my $convert_btn = $mid_frm1->Button(-text => 'Convert >>',
    -command => \&convert_main)
->pack(-side => 'top', pady => 2, padx => 2, -expand => 1, -anchor => 
+'center');

my $label2 = $left_frm->Label(-text => 'Convert From:',
    -padx => 4)
    ->pack(-side => 'top');

my $from_lb = $left_frm->Scrolled('Listbox',
    -exportselection => 0,
    -scrollbars => 'e',
    -selectmode => 'single',
    -background => 'white',
    -height => 5)->pack(-side => 'top');

$from_lb->insert('end', qw/Binary Octal Decimal Hex Char/);

my $label3 = $right_frm->Label(-text => 'Convert To:',
    -padx => 4)
    ->pack(-side => 'top');

my $to_lb = $right_frm->Scrolled('Listbox',
    -exportselection => 0,
    -scrollbars => 'e',
    -selectmode => 'single',
    -background => 'white',
    -height => 5)->pack(-side => 'top');

$to_lb->insert('end', qw/Binary Octal Decimal Hex Char/);

my $end_text = $bottom_frm->Text(-background => 'white',
    -height => 13)->pack;

my $dialog = $mw->Dialog;

MainLoop;

my ($start_string, $end_string, $base_from, $base_to);
my @start_values;

sub convert_main {

    my @base_values = (2, 8, 10, 16);
    my (@from_list, @to_list);
    my $err = 0;
    
    @from_list = $from_lb->curselection();
    @to_list = $to_lb->curselection();

    $base_from = $base_values[$from_list[0]];
    $base_to = $base_values[$to_list[0]];

    $start_string = $start_text->get('1.0', 'end');
    chomp($start_string);

    # Search for invalid entries
    # Binary
    if ($from_list[0] == 0 and !($start_string =~ m/^[0-1].+$/)) {
        $err = 1;
    }
    # Octal
    if ($from_list[0] == 1 and !($start_string =~ m/^[0-7].+$/)) {
        $err = 1;
    }
    # Denary (decimal)
    if ($from_list[0] == 2 and !($start_string =~ m/^[0-9].+$/)) {
        $err = 1;
    }

    # Hex
    if ($from_list[0] == 3 and !($start_string =~ m/^[0-9a-fA-F].+$/))
+ {
        $err = 1;
    }

    if ($err == 1) {
        $dialog->configure(-title => 'Invalid Entry', -text => 'Invali
+d value.');
        $dialog->Show;
        return;
    }
    
    if ($from_list[0] == 4) {
        @start_values = split(//, $start_string);
        char2num();
    }
    else {
        @start_values = split(/ /, $start_string);
        base2denary();
    }

    if ($to_list[0] == 4) {
        num2char();        
    }
    else {
        denary2string;
    }

    $start_string = '';
    $end_string = '';
    
}

sub num2char {
    my $value = '';

    $end_string = pack('C*', @start_values);

    $end_text->delete('1.0', 'end');
    $end_text->insert('1.0', $end_string);
}

sub char2num {
    my $value1 = '';
    my $value2 = '';
    my $index1 = 0;
    my @temp;
    my @temp2;

    foreach $value1 (@start_values) {
        @temp = split(//, $value1);
        foreach $value2 (@temp) {
            $temp2[$index1] = unpack('c*', $value2);
            $index1 += 1;
        }
    }

    @start_values = @temp2;
}

sub denary2string {
    my $value1 = 0;
    my $index1 = 0;
    my $index2 = 0;
    my $temp = '';

    my %character_map = (
        '10' => 'A',
        '11' => 'B',
        '12' => 'C',
        '13' => 'D',
        '14' => 'E',
        '15' => 'F',
    );

    foreach $value1 (@start_values) {
        while ($value1 >= $base_to**$index1) {
            $a = int(($value1/($base_to**$index1)) % $base_to);

            if (defined($character_map{$a})){
                $a = $character_map{$a};
            }

            $temp = $a.$temp;

            $index1 += 1;
        }
        
        if ($index2 > 0) {
            $end_string = $end_string.' '.$temp;
        }
        else {
            $end_string = $end_string.$temp;
        }

        $index1 = 0;
        $temp = '';
        $index2 += 1;
    }
    
    $end_text->delete('1.0', 'end');
    $end_text->insert('1.0', $end_string);
}

sub base2denary {
    my $value1 = 0;
    my $value2 = 0;
    my $final_num = 0;
    my $index = 0;
    my $index2 = 0;
    my @temp = ();

    foreach $value1 (@start_values) {
        @temp = split(//, $value1);
        @temp = reverse(@temp);
        foreach $value2 (@temp) {

            $value2 =~ s/(a|A)/10/;
            $value2 =~ s/(b|B)/11/;
            $value2 =~ s/(c|C)/12/;
            $value2 =~ s/(d|D)/13/;
            $value2 =~ s/(e|E)/14/;
            $value2 =~ s/(f|F)/15/;

            $final_num = $final_num + ($value2 * ($base_from**$index))
+;
            $index +=1;
        }
        $start_values[$index2] = $final_num;
        $index2 += 1;
        $final_num = 0;
        $index = 0;
    }
}