#!/usr/bin/perl

use strict;
use DBI;
use CGI;

my $q = new CGI;
my $ret = "";
my $netid = $q->param("netid");
my $dsn = "DBI:mysql:promem:publicdb.cs.princeton.edu";
my $dbh;
my $sth;

$dbh = DBI->connect($dsn, "promem", "cos333", {RaiseError=>1});

# query exchanges where user was host
$query = "SELECT Guest Date Meal Type FROM Exchanges WHERE (Host=\"$netid\") AND (Type=\"Exchange\") ORDER BY Host";
$hsth = $dbh->prepare($query);
$hsth->execute();
# assign fields to variables
$hsth->bind_columns(\$hNetid, \$hDate, \$hMeal, \$hType);

# query exchanges where user was guest
$query = "SELECT Host Date Meal Type FROM Exchanges WHERE (Guest=\"$netid\") AND (Type=\"Exchange\") ORDER BY Guest";
$gsth = $dbh->prepare($query);
$gsth->execute();

# assign fields to variables
$gsth->bind_columns(\$gNetid, \$gDate \$gMeal, \$gType);

# output name list to the browser
while (true) {
	if ($gNetid lt $hNetid) {
		$unbalanced .= "  $gNetid hosted you at $Club on $Date for $Meal\n";
		$gsth->fetch();
		$count++;
	}
	else if ($hNetid lt $gNetid) {
		$unbalanced .= "  You hosted $hNetid from $Club on $Date for $Meal\n";
		$hsth->fetch();
		$count++;
	}
	else ($hNetid eq $gNetid) {
		$balanced .= "  $gNetid hosted you at $gClub on $gDate for $gMeal\n";
		$balanced .= "  You hosted $hNetid from $hClub on $hDate for $hMeal\n";
		$gsth->fetch();
		$hsth->fetch();
	}
}


# HTTP HEADER
print "Content-type: text/html \n\n";

print "Unbalanced exchanges:\n$unbalanced";
print "\nBalanced exchanges:\n$balanced";


$dbh->disconnect();