--- /dev/null
+package HTML::CalendarMonth::DateTool::DateTime;
+BEGIN {
+ $HTML::CalendarMonth::DateTool::DateTime::VERSION = '1.25';
+}
+
+# Interface to DateTime
+
+use strict;
+use warnings;
+use Carp;
+
+use base qw( HTML::CalendarMonth::DateTool );
+
+use DateTime;
+
+sub dow1st_and_lastday {
+ my($self, $month, $year) = @_;
+ $month ||= $self->month;
+ $year ||= $self->year;
+ my $lastday = $self->_last_dom_dt($year, $month);
+ my $dow1st = $self->dow(1);
+ ($dow1st, $lastday->day);
+}
+
+sub day_epoch {
+ my($self, $day, $month, $year) = @_;
+ $day || croak "day required.\n";
+ $month ||= $self->month;
+ $year ||= $self->year;
+ my $dt = $self->_new_dt($year, $month, $day);
+ $dt->epoch;
+}
+
+sub dow {
+ my($self, $day, $month, $year) = @_;
+ $day || croak "day required.\n";
+ $month ||= $self->month;
+ $year ||= $self->year;
+ my $dt = $self->_new_dt($year, $month, $day);
+ # convert from 1..7, starting with Mon, to 0..6, starting with Sun
+ $dt->dow % 7;
+}
+
+sub add_days {
+ my($self, $delta, $day, $month, $year) = @_;
+ defined $delta || croak "delta (in days) required.\n";
+ $day || croak "day required.\n";
+ $month ||= $self->month;
+ $year ||= $self->year;
+ my $dt = $self->_new_dt($year, $month, $day);
+ $dt->add(days => $delta);
+ ($dt->day, $dt->month, $dt->year);
+}
+
+sub week_of_year {
+ my($self, $day, $month, $year) = @_;
+ $day || croak "day required.\n";
+ $month ||= $self->month;
+ $year ||= $self->year;
+ my $dt = $self->_new_dt($year, $month, $day);
+ # returns ($year, $week)
+ $dt->week;
+}
+
+sub _new_dt {
+ my $self = shift;
+ my($year, $month, $day) = @_;
+ $year or croak "year and month required\n";
+ my %parms = (year => $year);
+ $parms{month} = $month if $month;
+ $parms{day} = $day if $day;
+ $parms{hour} = 0;
+ $parms{minute} = 0;
+ $parms{second} = 0;
+ DateTime->new(%parms);
+}
+
+sub _last_dom_dt {
+ my $self = shift;
+ my($year, $month) = @_;
+ $year && $month or croak "year and month required.\n";
+ DateTime->last_day_of_month(year => $year, month => $month);
+}
+
+1;