use strict;
use warnings;

use Data::Dumper;

use Data::ICal;
use Data::ICal::DateTime;
use DateTime;
use DateTime::Event::Recurrence;

$| = 1;

# ----

my $data_file = "test.ics";    # "data.ics";  # .ics format input file

my $cal   = "";                # ICal object we use for the file
my $event = "";                # an ICal event

my $num_events = 0;            # Total events in the file

my $summary     = "";          # 'Interesting' attributes of an event
my $location    = "";
my $description = "";
my $rrule       = "";
my $sub_entries = "";

my $reqd_range_set  = "";      # Date range of interest
my $event_range_set = "";      # Date range for an event

my $event_it = "";             # Set iterator

my $rrule_exists = 0;          # Flag; some events have no repeats

my @events = ();               # list of event (structures)

my %HoA = ();                  # hash{date}->[ ev1, ev2, ... ]

# ---- Create a 'set' for the required date range
#      being 1-Sep-2018 through 31-Dec-2018

my $dta1 = DateTime->new(year => 2018, month => 9, day => 1);
my $dta2 = DateTime->new(year => 2018, month => 12, day => 31);
$reqd_range_set = DateTime::Set->from_datetimes( dates => [ $dta1, $dta2 ] );

printf("Required Date Range: %s through %s\n", $dta1->dmy(), $dta2->dmy());

# ---- Load and process events from file

$cal = Data::ICal->new(filename => $data_file);
@events = $cal->events();
$num_events = @events;
printf("Total Events: %d\n", $num_events);

# ----

my $event_ID = 0;
foreach $event (@events) {  # For each VEVENT...
   printf("%s\n", "-"x60);
   printf("      Event: %d\n", $event_ID);

# ----
   
   if ( defined($event->property('summary')) ) {       # Check: Summary ('Subject') defined?
      $summary = $event->property('summary')->[0]->value;
      
   } else {
      $summary = "[ MISSING ]";
      
   }

   if ( defined($event->property('description')) ) {   # Check: 'Description' defined?
      $description = $event->property('description')->[0]->value;
         
   } else {
      $description = "None";
      
   }
   
   if (defined($event->property('rrule'))) {           # Check: Recurrence Rules defined?
      $rrule_exists = 1;
      $rrule = $event->property('rrule')->[0]->value;
            
   } else {
      $rrule_exists = 0;
      $rrule = "None";
        
   }            
   
   if ( defined($event->property('location')) ) {      # Check: 'Location' defined?
      $location = $event->property('location')->[0]->value;
         
   } else {
      $location = "None";
      
   }
   
   if ( @{$event->entries} ) {                         # Check: Sub-entries defined?
      $sub_entries = "Exist";
      
   } else {
      $sub_entries = "None";
      
   }  

# ----

   printf("    Summary: %s\n", $summary);
   printf(" Start Date: %s\n", $event->start->dmy("-"));
   printf("   End Date: %s\n", $event->end->dmy("-"));
   printf("Description: %s\n", $description);
   printf("    Repeats: %s\n", $rrule);
   printf("Sub-Entries: %s\n", $sub_entries);
   printf("   Location: %s\n", $location);
   print "\n";
        
# ----

   unless ($rrule_exists) {                            # Just check THE DATE if there's no RRULE
      if ( $reqd_range_set->contains($event->start) ) {
#         printf("no RRULE: Event %d ..include: %s\n", $event_ID, $event->start->dmy("-"));
         push(@{$HoA{$event->start->ymd("-")}}, $event_ID);   # HoA{date}->[ ev1, ev2, ...]   
      }
      $event_ID++;      
      next;   
   }

# ---- If we're here, we'll process the RRULEs

   $event_range_set = $event->recurrence;              # Create a 'set' where the Recurrence Rules apply

   $event_it = $event_range_set->iterator(start => $dta1, end => $dta2);
   while ( my $dt = $event_it->next() ) {
#      printf("Using RRULE: Event %d: ..normal include: %s\n", $event_ID, $dt->dmy("-"));
      
      push(@{$HoA{$dt->ymd("-")}}, $event_ID);   # HoA{date}->[ ev1, ev2, ...]   

   }

   $event_ID++;
   
} # end: process another VEVENT
printf("\n");


# ---- We now have all the events mapped into structures

printf("OUTPUT %s\n\n", "-"x40);

foreach my $ky (sort keys %HoA) {
   my $buf = "";
   printf("%s: ", $ky);
   foreach (@{$HoA{$ky}}) {
      $buf .= $_ . ",";
   }
   chop($buf);
   printf("%s\n", $buf);

}

# ----

exit(0);