#!/usr/bin/perl -w

use strict;

use LWP::Simple;

header();

my @now = gmtime();
my $year = $now[5]+1900;

foreach my $y (2006 .. $year) {
    getyear($y);
}

footer();

sub getyear {
    my $year = shift;
    my $page = 
	get("http://doc.gold.ac.uk/mscac/cal/year.php?year_eventsDate=$year");
    while ($page =~ m{<td\ class="Calendar[^>]+>\s*<a[^>]+day\.php\?day=(\d+-\d+-\d+)"[^>]*>\d+</a>\s*<div[^>]*>\s*((?:<div\ class="CalendarEvent">.*?</div>\s*)+)}sgx
	   ) {
	my ($date, $stuff) = ($1, $2);
	#print $stuff . "\n";
	$date =~ s/\-//g;
	
	while ($stuff =~ /(\d\d:\d\d)\s+-\s+(\d\d:\d\d)\s+([^<]+)/sg) {
	    my ($start, $stop, $detail) = ($1, $2, $3);
	    
	    $start =~ s/://g;
	    $stop =~ s/://g;
	    $start =~ s/(\d\d\d\d).*/$1/;
	    $stop =~ s/(\d\d\d\d).*/$1/;

	    event($date, $start, $stop, $detail)
	}
    }
}


sub header {
    print "BEGIN:VCALENDAR
CALSCALE:GREGORIAN
METHOD:PUBLISH
X-WR-CALNAME:mscac
X-WR-TIMEZONE:Europe/London
BEGIN:VTIMEZONE
TZID:Europe/London
X-LIC-LOCATION:Europe/London
BEGIN:DAYLIGHT
TZOFFSETFROM:+0000
TZOFFSETTO:+0100
TZNAME:BST
DTSTART:19700329T010000
RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=-1SU
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:+0100
TZOFFSETTO:+0000
TZNAME:GMT
DTSTART:19701025T020000
RRULE:FREQ=YEARLY;BYMONTH=10;BYDAY=-1SU
END:STANDARD
END:VTIMEZONE
";
}

sub event {
    my ($date, $start, $stop, $detail) = @_;
    my $dtstart = "${date}T${start}";
    my $dtstop = "${date}T${stop}";
    my ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) =
			gmtime(time);
    my $now = sprintf("%04d%02d%02dT%02d%02d%02dZ",
		      $year + 1900,
		      $mon + 1,
		      $mday,
		      $hour,
		      $min,
		      $sec
		      );
    
    print "BEGIN:VEVENT
DTSTART;TZID=Europe/London:${dtstart}00
DTEND;TZID=Europe/London:${dtstop}00
DTSTAMP:$now
CREATED:$now
LAST-MODIFIED:$now
SEQUENCE:0
STATUS:CONFIRMED
SUMMARY:$detail
TRANSP:OPAQUE
END:VEVENT
";
}

sub footer {
    print "END:VCALENDAR\n\n";
}