#  $Id: daily.pl 0.05 2000/01/12 00:00:05 tom Exp $
#
#  daily.pl:  Processes Gcal resource file lines which are stored in the fixed
#               `DATE-PART HH1:MM1,HH2:MM2,%n,%t  FIXED-DATE-TEXT' format.
#               `HH1:MM1' is the time (HOUR:MINUTE) the fixed date takes place.
#               `HH2:MM2' is the time (HOUR:MINUTE) the fixed date is warned
#               in advance.  The valid range of HOUR is 00...23, and the
#               valid range of MINUTE is 00...59.  For example
#                 `0 08:15,00:30,%n,%t  Dentist'
#               creates a today's fixed date message of 30 minutes
#               starting at 07:45 until 08:15.
#
#  Any but default configuration could confuse this script.
#  It comes along with a UN*X script `daily' and a DOS batch `daily.bat'
#  which supports the correct usage.
#
#  It is *not* guaranteed that this script works for any other call than
#  the one given above but it could easily be modified and extended for
#  using other special modes of operation.
#
#  If you modify this script you have to rename the modified version.
#
#  If you make any improvements I would like to hear from you.
#  But I do not promise any support.
#
#  Copyright (c) 2000  Thomas Esken      <esken@uni-muenster.de>
#                      Im Hagenfeld 84
#                      D-48147 M"unster
#                      GERMANY
#
#  This software doesn't claim completeness, correctness or usability.
#  On principle I will not be liable for ANY damages or losses (implicit
#  or explicit), which result from using or handling my software.
#  If you use this software, you agree without any exception to this
#  agreement, which binds you LEGALLY !!
#
#  This program is free software; you can redistribute it and/or modify
#  it under the terms of the `GNU General Public License' as published by
#  the `Free Software Foundation'; either version 3, or (at your option)
#  any later version.
#
#  You should have received a copy of the `GNU General Public License'
#  along with this program; if not, write to the:
#
#
#
$[ = 1;			# set array base to 1

#
# Define the character Gcal uses to separate the file name
# and the line number of the fixed dates' origin.
#
$GCAL_SEP = '#';
#
# Define some constant values.
#
$HOURS_PER_DAY = 24;
$MINUTES_PER_HOUR = 60;
$MINUTES_PER_DAY = $HOURS_PER_DAY * $MINUTES_PER_HOUR;
#
# Define the default return value of this process, which is EXIT_FAILURE.
#
$EXIT_SUCCESS = 0;
$EXIT_FAILURE = 1;
#
$exit_status = $EXIT_FAILURE;

#
# Main block.
#
while (<>) {
    chop;	# strip record separator
    @Fld = split(/[ \n]/, $_, 9999);

    #
    # Skip all fields until the `HH1:MM1,HH2:MM2,%n,%t' timefield is detected.
    #
    $len_field = 0;
    $timefield = 1;
    if ($Fld[$timefield] =~ /[0-9]+\)/) {
	$len_field += (length($Fld[$timefield]) + 1);
	$timefield++;
    }
    while (substr($Fld[$timefield], 1, 1) !~ /[0-9]/ && $Fld[$timefield] ne '') {
	$len_field += (length($Fld[$timefield]) + 1);
	$timefield++;
    }
    if (substr($Fld[$timefield], 1, 1) =~ /[0-9]/) {
	$is_printed = 0;
	#
	# Compute the current time `minute of day'.
	#
	$actual = substr($Fld[$timefield], 25, 2) * $MINUTES_PER_HOUR + substr($Fld[$timefield], 28, 2);
	#
	# Compute the events time `minute of day'.
	#
	$event_hour = substr($Fld[$timefield], 1, 2);
	$event_minute = substr($Fld[$timefield], 4, 2);
	$event = $event_hour * $MINUTES_PER_HOUR + $event_minute;
	#
	# Compute the `number of minutes' the event must be displayed in advance.
	#
	$advance = substr($Fld[$timefield], 7, 2) * $MINUTES_PER_HOUR + substr($Fld[$timefield], 10, 2);
	#
	# Check whether the event is on tomorrow's day.
	#
	$tomorrows_event = 0;
	if ($event - $advance < 0) {
	    $tomorrows_event = 1;
	}
	#
	# Pre-check whether the event must be displayed.
	#
	if ($event - $advance <= $actual && ($event >= $actual || $tomorrows_event == 1)) {
	    #
	    # Store today's date text.
	    #
	    $the_date = substr($Fld[$timefield], 13, 11);
	    #
	    # Store currents time text.
	    #
	    $the_time = substr($Fld[$timefield], 25, 5);
	    #
	    # Detect the length of `timefield' field which is removed in output.
	    #
	    $len_field += length($Fld[$timefield]) + 1;
	    #
	    # Compute some constant values and assign some texts.
	    #
	    $date_text_1 = '';
	    $date_text_2 = '';
	    $minutes_active = $advance - ($event - $actual);
	    if ($tomorrows_event == 1) {
		#
		# Event was activated yesterday.
		#
		if ($minutes_active - $MINUTES_PER_DAY < 0) {
		    $date_text_2 = 'yesterday ';
		}
		else {
		    #
		    # Event will occur tomorrow.
		    #
		    $minutes_active -= $MINUTES_PER_DAY;
		    $date_text_1 = ' tomorrow';
		}
	    }
	    #
	    # Check again whether the event must be displayed.
	    #
	    if ($minutes_active <= $advance) {
		$is_printed = 1;
		#
		# Compute some more constant values.
		#
		$start_time = $event - $advance;
		if ($start_time < 0) {
		    $start_time += $MINUTES_PER_DAY;
		}
		#
		# And print the results in formatted manner.
		#
		if ($. > 1) {
		    printf "\n";
		}
		if ($timefield != 1) {
		    if ($Fld[1] =~ /^\(.+[#][0-9]+\)$/) {
			$file_name = '';
			$file_line = '';
			$mode = 0;
			$len = length($Fld[1]) - 1;
			for ($i = 2; $i <= $len; $i++) {
			    if (substr($Fld[1], $i, 1) eq $GCAL_SEP) {
				$mode++;
			    }
			    else {
				if ($mode == 0) {
				    $file_name = $file_name . substr($Fld[1], $i, 1);
				}
				else {
				    $file_line = $file_line . substr($Fld[1], $i, 1);
				}
			    }
			}
			$timefield--;
			printf "File: %s %d\n", $file_name, $file_line;
		    }
		}
		printf "Date: %s\nTime: %s\n", $the_date, $the_time;
		$remaining = $event - $actual;
		if ($remaining < 0) {
		    $remaining = $MINUTES_PER_DAY + ($event - $actual);
		}
		printf "Appointment  at: %02d:%02d%s (in %d minutes)\n", $event_hour,
		  $event_minute, $date_text_1, $remaining;
		printf "Activated since: %02d:%02d %s", $start_time / $MINUTES_PER_HOUR,
		  $start_time % $MINUTES_PER_HOUR, $date_text_2;
		if ($advance > 0) {
		    printf "(%d of %d minutes active)", $minutes_active, $advance;
		}
		printf "\nMessage text: ";
		if ($timefield != 1) {
		    for ($i = 1; $i < $timefield; $i++) {
			printf "%s ", $Fld[$i];
		    }
		}
		printf "%s\n", substr($_, $len_field + 1, 999999);
		#
		# Set the return value of this process to EXIT_SUCCESS.
		#
		$exit_status = $EXIT_SUCCESS;
	    }
	}
    }
    elsif ($is_printed == 1) {
	printf "              %s\n", $_;
    }
}

exit $exit_status;