#!/usr/bin/perl
require "6837-cgilib.pl";

$file = "/pub/www/classes/6.837/F97/projects/signup.txt";

# Read in all the variables set by the form
&ReadParse(*input);

    # Print the header
print &PrintHeader;
print &HtmlTop ("6.837 Final Presentation Signup");
print "<hr><h3>Current time slots:</h3>";


open(FILE, "$file");
@lines = <FILE>;
close(FILE);

$groupinput = $input{'group'};
$timeinput = $input{'time'};
if ($groupinput eq "")
{
    $timeinput = "";
}
$count = 0;
$error = "";

for ($i = 0; $i <= $#lines; $i++)
{
    (@time[$i], @groupnum[$i]) = @lines[$i] =~ /^(.*) ! (.*)$/;
    if (@time[$i] eq $timeinput)
    {
	if (@groupnum[$i] eq "NOT TAKEN")
	{
	    @groupnum[$i] = $groupinput;
	}
	else
	{
	    $error = "Whoops! That time was already taken.";
	}
    }

    if (@groupnum[$i] eq "NOT TAKEN")
    {
	@freetime[$count] = @time[$i];
	$count += 1;
    }

}

print "<table><tr><td><b>Time</b><td><b>Group</b><td><td><b>Time</b><td><b>Group</b><td><td><b>Time</b><td><b>Group</b></tr>";
$half = $#lines / 3;
for ($i = 0; $i <= $half; $i++)
{
    print "<tr><td>@time[$i]</td><td>@groupnum[$i]</td><td><pre>        </pre></td>\n";
    print "<td>@time[$i + $half + 1]</td><td>@groupnum[$i + $half + 1]</td><td><pre>        </pre></td>\n";
    print "<td>@time[$i + (2 * $half) + 1]</td><td>@groupnum[$i + (2 * $half) + 1]</td></tr>\n";
}

print "</table><br>";

open(FILE, ">$file");
for ($i = 0; $i <= $#time; $i++)
{
    print FILE "@time[$i] ! @groupnum[$i]\n";
}
close(FILE);

print "<h3>Signup for a time slot</h3><form method=\"post\" action=\"http://graphics.lcs.mit.edu/cgi-bin/6837timeslot.pl\">";
print "<table><tr><td>Available slots:</td><td><select name=\"time\">";
for ($i = 0; $i <= $#freetime; $i++)
{
    print "<option>@freetime[$i]\n";
}
print "</select></td></tr>\n";
print <<EOF;

<tr><td>Group Number (2 digits only)</td><td><input type="text" name="group" size=2></td></tr>
<tr><td><input type="submit" value="Submit"></td><td></td></tr></table>
</form>
EOF


print &HtmlBot;