#!/usr/bin/perl -w
# mkcalendar  - $Id$
# Copyright 2008 Perette Barella
# All Rights Reserved.
######################################################################

use Time::Local;
use Getopt::Std;

sub time_to_minute {
	my ($time) = @_;
	my ($hour, $minute) = split /:/, $time;
	return ($hour * 60) + $minute;
}

sub minute_to_time {
	my ($minute) = @_;
	my $hour = $minute / 60;
	$minute %= 60;
	if ($ampm_time) {
		my $printhour = $hour % 12;
		if ($printhour == 0) {
			 $printhour = 12;
		}
		return sprintf ("%d:%02d %sM", $printhour, $minute,
			$hour >= 12 ? "P" : "A");
	}
	return sprintf ("%02d:%02d", $hour, $minute);
}

sub get_real_dayname {
	my ($day) = @_;
	$day = "${day}day";
	($day eq "Tueday") && ($day="Tuesday");
	($day eq "Wedday") && ($day="Wednesday");
	($day eq "Thuday") && ($day="Thursday");
	($day eq "Satday") && ($day="Saturday");
	return $day;
    }

sub generate_format_timelist {
    for $day (split /,/, $weekdays) {
	print STDOUT "<LI>", get_real_dayname ($day), "\n\t<UL>";

	my $dayevents = $dailyevents {$day};
	if ($verbose) {
		print STDERR $day, " keys: ", join (",", keys %$dayevents), "\n";
	}
 	for $time (sort { $a <=> $b } keys %$dayevents) {
		$event = $dayevents->{$time};
		print STDOUT "\t<LI><SPAN CLASS=\"eventtime\">",
		    minute_to_time ($event->{starttime}),
		    "-",
		    minute_to_time ($event->{endtime}),
		    ": </SPAN> ",
		    $event->{description},
		    "\n";
 	}
	print STDOUT "\t</UL>\n";
    }
}


sub generate_format_eventlist {
    my @activities = split /,/, $event_order;
    my $multiple = ($#{activities} gt 0);
    for $activity (split /,/, $event_order) {
	if ($multiple) {
		print STDOUT "<LI>$activity\n\t<UL>";
	}
	for $day (split /,/, $weekdays) {
	    my $dayevents = $dailyevents {$day};
	    if ($verbose) {
	        print STDERR $day, " keys: ", join (",", keys %$dayevents), "\n";
	    }
	    for $time (sort { $a <=> $b } keys %$dayevents) {
		$event = $dayevents->{$time};
		if (index ($event->{description}, $activity) >= 0) {
		    print STDOUT "\t<LI>",
			get_real_dayname ($day),
			" ",
			minute_to_time ($event->{starttime}),
			"-",
			minute_to_time ($event->{endtime}),
			" ",
			$event->{description},
			"\n";
		}
	    }
	}
	if ($multiple) {
		print STDOUT "\t</UL>\n";
	}
    }
}

sub generate_table_format {
    $startminute = time_to_minute ($start);
    $endminute = time_to_minute ($end);

    # Add in "Empty" events representing when nothing is happening.
    for $day (split /,/, $weekdays) {
	# Make up a bogus "back" event to start with
	$lasttime = $startminute;
	$lastend = $startminute;
	$lastevent = { };
	$dailyevents {$day}{$endminute} = {
		description => "End calendar - to cause a last loop iteration"
	};

	my $dayevents = $dailyevents {$day};
	if ($verbose) {
		print STDERR $day, " keys: ", join (",", keys %$dayevents), "\n";
	}
 	for $time (sort { $a <=> $b } keys %$dayevents) {
		if ($debug) {
			print STDERR "Time=$time, lasttime=$lasttime, lastend=$lastend\n";
		}
		$event = $dayevents->{$time};
		# The last event in display gets the shorter
		# of its assigned time, or when this event starts.
		if ($lastend >= $time) {
			# Tell the last event to take up space to the
			# start of this event
			$lastevent->{rows} = ($time - $lasttime) / $interval;
		} else {
			# Adjust last end to an even interval
			$lastend = int (($lastend + $interval * 0.5) / $interval) * $interval;
			$lastevent->{rows} = int ($lastend - $lasttime) / $interval;
			# Create a fake event to fill in the intervening time.
			$dailyevents {$day}{$lastend} = {
				description => "",
				rows => ($time - $lastend) / $interval
			};
		}

		$lastevent = $event;
		$lasttime = $time;
		$lastend = $event->{endtime};
 	}
    }

    # Add headers for the day of the week
    print STDOUT "<TR><TH CLASS=\"timecolumn\">Time\n";
    for $day (split /,/, $weekdays) {
	$day = get_real_dayname ($day);
	print STDOUT "\t<TH>$day\n";
    }
    print STDOUT "</TR>";

    # Output the results!
    $time = $startminute;
    while ($time < $endminute) {
	if (($time - $startminute) % $timeinterval == 0) {
		print STDOUT "<TR><TH>",
			 minute_to_time ($time), "\n";
	} else {
		print STDOUT "<TR><TH>\n";
	}
	for $day (split /,/, $weekdays) {
		my $dayevents = $dailyevents {$day};
		if (exists $dayevents->{$time}) {
			$event = $dayevents->{$time};
			print STDOUT "\t<TD ROWSPAN=", $event->{rows}, ">\n";
			if (exists ($event->{starttime})) {
				print STDOUT "\t\t",
					minute_to_time ($event->{starttime}),
					"-",
					minute_to_time ($event->{endtime}),
					"<BR>",
					$event->{description}, "\n";
			}
		}
	}
	$time += $interval;
	print STDOUT "</TR>\n";
    }
}

$TABLE = 1;
$TIMELIST = 2;
$EVENTLIST = 3;

$publish = "";
$debug = 0;
$start = "0:00";
$end = "24:00";
$interval = 30;
$timeinterval = 60;
$verbose = 0;
$ampm_time = 0;
$weekdays = "Sun,Mon,Tue,Wed,Thu,Fri,Sat";
$output_format = $TABLE;
$event_order = "";

#----------------------------------------------------------------------
# Read the command line options.
#----------------------------------------------------------------------
if (!getopts ("btl:ad:o:s:e:i:t:f:Zv")) {
	usage ();
	exit 1
}

if (defined ($opt_b)) {
	$output_format = $TABLE;
}
if (defined ($opt_t)) {
	$output_format = $TIMELIST;
}
if (defined ($opt_l)) {
	$output_format = $EVENTLIST;
	$event_order = $opt_l;
}
if (defined ($opt_a)) {
	$ampm_time = 1;
}

if (defined ($opt_Z)) {
	$debug = 1;
}

if (defined ($opt_v)) {
	$verbose = 1;
}

if (defined ($opt_s)) {
	$start = $opt_s;
}

if (defined ($opt_e)) {
	$end = $opt_e;
}

if (defined ($opt_i)) {
	$interval = $opt_i;
}

if (defined ($opt_t)) {
	$timeinterval = $opt_t;
}

if (defined ($opt_d)) {
	$weekdays = $opt_d;
}

if (defined ($opt_f)) {
	$source = $opt_f;
} else {
	die "Source file not specified.";
}

if (defined ($opt_o)) {
	close (STDOUT);
	$dest = $opt_o;
	open STDOUT, "> $dest";
}

open (SOURCE, "< $source") || die "$source: Can't read";

print STDOUT	"m4_dnl Automated calendar system mkcalendar\n" .
		"m4_dnl Copyright 2008 Perette Barella.\n\n";

%dailyevents = (
	Sun => {},
	Mon => {},
	Tue => {},
	Wed => {},
	Thu => {},
	Fri => {},
	Sat => {}
);


my $day;
# Read the events from the file
while (<SOURCE>) {
	chomp;
	if (m/^\s*\#/ || m/^\s*$/) { next };

	my ($days, $times, @rest) = split /\s+/;
	$description = join(' ', @rest);

	my ($starttime, $endtime) = split /-/, $times;
	my $startminute = time_to_minute ($starttime);
	my $endminute = time_to_minute ($endtime);

	if ($verbose) {
		print STDERR "Days: $days\nTimes: $times ($startminute - $endminute)\nEvent: $description\n\n";
	}

	my $newevent = {
		starttime => $startminute,
		endtime => $endminute,
		description => $description
	};
	for $day (split /,/, $days) {
		# Don't allow multiple events on same day/time to clobber
		# each-other.
		$hash = $startminute * 100;
		while (exists ($dailyevents {$day}{$hash})) {
			$hash++;
		}
		$dailyevents {$day}{$hash} = $newevent;
	}
}


if ($output_format == $TABLE) {
    generate_table_format ();
} elsif ($output_format == $TIMELIST) {
    generate_format_timelist ();
} elsif ($output_format == $EVENTLIST) {
    generate_format_eventlist ();
}


close (DEST);
close (SOURCE);

exit (0);