#!/usr/bin/perl

use DB_File;
use CGI;
use HTML::Template;

my $COINLIFETIME = 30;

my %coins_db;
my $cgi = CGI->new();
my $requestedcoinid = $cgi->param('coinid');
my $requestedaction = $cgi->param('action');
my $coinsindb=0;
my $flippedcoinsindb=0;

my $template;

sub printpage {
    $template->param(COINLIFETIME => $COINLIFETIME);
    $template->param(FLIPPEDCOINSINDB => $flippedcoinsindb);
    $template->param(COINSINDB => $coinsindb);
    $template->param(HTTP_HOST => $ENV{HTTP_HOST});
    print "Content-type: text/html\n\n", $template->output;
}

sub exitalert {
    $template = HTML::Template->new(filename => 'alert.html');
    $template->param(ALERTMSG => @_[0]);
    printpage();
    exit();
}

sub translateresult {
    if ( @_[0] == 0 ) {
	return "Heads";
    }
    else {
	return "Tails";
    }
}

if (-e "var/coins.db") {
    tie (%coins_db, DB_File, "var/coins.db") ||
        die ("Cannot open var/coins.db");
}
else {
    tie (%coins_db, DB_File, "var/coins.db", O_CREAT|O_RDWR, 0640) ||
        die ("Cannot create or open var/coins.db");
}

foreach my $key ( keys %coins_db )
{
    @value = split(/,/, $coins_db{$key});
    if ( time-$value[0] > $COINLIFETIME*(60*60*24) ) {
	delete $coins_db{$key};
    }

    $coinsindb++;
    if ( ($#value + 1) == 3 ) {
	$flippedcoinsindb++;
    }
}

if ( ! ($requestedcoinid =~ /\A[a-z0-9]*\z/) ) {
    exitalert("You sent me an invalid coin!");
}

if ( ! ($requestedaction =~ /\A[a-z]*\z/) ) {
    exitalert("You sent me an invalid action!");
}

if ( length($requestedcoinid) == 0 && $requestedaction eq "" ) {
    $template = HTML::Template->new(filename => 'create.html');
}
elsif ( length($requestedcoinid) == 0 && $requestedaction eq "create" ) {
    my @chars = ("a".."z", "0".."9");
    my $newcoinid;

    $newcoinid .= $chars[rand @chars] for 1..13;
    while ( exists $coins_db{$newcoinid} ) {
	$newcoinid = "";
	$newcoinid .= $chars[rand @chars] for 1..13;
    }

    $coins_db{$newcoinid} = time;

    $template = HTML::Template->new(filename => 'created.html');
    $template->param(NEWCOINID => $newcoinid);
}
elsif ( length($requestedcoinid) > 0 ) {
    if ( ! exists $coins_db{$requestedcoinid} ) {
	exitalert("The coinid $requestedcoinid does not exist!");
    }

    my @coininfo = split(/,/, $coins_db{$requestedcoinid});
    my $coininfosize = $#coininfo + 1;

    $template = HTML::Template->new(filename => 'usecoin.html');

    $template->param(REQUESTEDCOINID => $requestedcoinid);
    $template->param(COINCREATIONTIME => localtime($coininfo[0])."");

    if ( $coininfosize == 1 && $requestedaction eq "" ) {
	$template->param(STATUS_NOTYETFLIPPED => 1);
    }
    elsif ( $coininfosize == 1 && $requestedaction eq "flip" ) {
	$result = int(rand(2));
	$coins_db{$requestedcoinid} = $coins_db{$requestedcoinid} .
	    "," . time .
	    "," . $result;
	$template->param(STATUS_JUSTFLIPPED => 1);
	$template->param(COINRESULT => translateresult($result));
    }
    elsif ( $coininfosize == 3 ) {
	$template->param(STATUS_FLIPPED => 1);
	$template->param(COINFLIPPEDTIME => localtime($coininfo[1])."");
	$template->param(COINRESULT => translateresult($coininfo[2]));
    }
}

printpage();

untie(%coins_db);

exit;