Google Calendar ICAL format - Events generator tool script

main.pl

#!/usr/bin/perl

# BEGIN:VCALENDAR
# VERSION:2.0
# PRODID:-//hacksw/handcal//NONSGML v1.0//EN
# BEGIN:VEVENT
# DTSTART:20190708T090000+0200
# DTEND:20190708T130000+0200
# SUMMARY:customerkik91
# END:VEVENT
# END:VCALENDAR

use 5.010;

use strict;
use warnings;

our $VERSION = 1.0;

use Data::Dumper;
use DateTime;
use Carp qw( croak );
use Readonly;

################################# VARIABLES ###################################
# Data
my $customer = 'mycustomer';
my $from     = '24/05/2019';
my $to       = '25/05/2019';

################################ PROGRAM ######################################
# Generate an ICAL
#
# - name of the event = $customer
# - event start date = $from
# - event end date = $to
#
# Two events will be generated for every date one from 9 AM to 1 PM and the
# othe from 2 PM to 6 PM
#

my $date_from = parse_date($from);
my $date_to   = parse_date($to);

my $dt1 = DateTime->new($date_from);
my $dt2 = DateTime->new($date_to);

say header() or croak;

my @results = @{ dates( $dt1, $dt2 ) };    # dereferencing!
for my $date (@results) {
    my $dt_start = $date->{'dt_start'};
    my $dt_end   = $date->{'dt_end'};

    my $event = qq|BEGIN:VEVENT\n|;
    $event = qq|${event}DTSTART:${dt_start}\n|;
    $event = qq|${event}DTEND:${dt_end}\n|;
    $event = qq|${event}SUMMARY:${customer}\n|;
    $event = qq|${event}END:VEVENT|;
    say $event or croak;
}

say footer() or croak;

sub header {
    my $header = qq|BEGIN:VCALENDAR\nVERSION:2.0|;
    $header = qq|$header\nPRODID:-//hacksw/handcal//NONSGML v1.0//EN|;
    return $header;
}

sub footer {
    my $footer = 'END:VCALENDAR';
    return $footer;
}

################################ MODULE #######################################
# Parse a date from standard time 31/12/2019 and returns a DateTime object
# or croaks
#
sub parse_date {
    my $str = shift;
    my %parsed_date;

    my $local_tz = DateTime::TimeZone->new( name => 'local' );

    if ( $str =~ qr/(\d{1,2})\/(\d{1,2})\/(\d{4})/mpsx ) {
        %parsed_date = ( day => $1, month => $2, year => $3 );
    }
    else {
        croak("Unable to parse date \"$str\"");
    }
    return \%parsed_date;
}

################################ MODULE #######################################
# Generate an array of dates from 'start' to 'end' formatted MM/DD/YYYY
#
sub dates {
    my $start  = shift;
    my $end    = shift;
    my @retval = ();
    Readonly::Array my @HOURS => ( { b => 9, e => 13 }, { b => 14, e => 18 } );

    my $duration = $end->delta_days($start);    # difference

    while ( $duration->in_units('days') > 0 ) {
        foreach my $hour (@HOURS) {
            $start->set_time_zone('local');

            $start->set_hour( $hour->{'b'} );
            my $dt_start = $start->strftime('%Y%m%dT%H%M%S%z');
            $start->set_hour( $hour->{'e'} );
            my $dt_end = $start->strftime('%Y%m%dT%H%M%S%z');

            my $el = {
                dt_start => $dt_start,
                dt_end   => $dt_end
            };

            push @retval, $el;

        }
        $duration = $end->subtract_datetime($start);
        $start->add( days => 1 );
    }
    return \@retval;
}