added utils.pm with get_rd_week

1 files changed, 56 insertions, 0 deletions

diff --git a/lib/RHRD/utils.pm b/lib/RHRD/utils.pm
new file mode 100755
index 0000000..3a49ebb
--- /dev/null
+++ b/lib/RHRD/utils.pm
@@ -0,0 +1,56 @@
+# rddb.pm
+#
+#  rhrdlibs
+#
+#  Copyright (C) 2015 Christian Pointner <equinox@helsinki.at>
+#
+#  This file is part of rhrdlibs.
+#
+#  rhrdlibs is free software: you can redistribute it and/or modify
+#  it under the terms of the GNU Affero General Public License as published by
+#  the Free Software Foundation, either version 3 of the License, or
+#  any later version.
+#
+#  rhrdlibs is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#  GNU Affero General Public License for more details.
+#
+#  You should have received a copy of the GNU Affero General Public License
+#  along with rhrdlibs. If not, see <http://www.gnu.org/licenses/>.
+#
+
+package RHRD::rddb;
+
+use strict;
+use DateTime;
+use DateTime::TimeZone;
+
+sub get_rd_week
+{
+  #
+  # This computes the current Rivendell Week based on the number
+  # of weeks since epoch.
+  #
+  # Explanation:
+  #  epoch was at 01.01.1970 which was a Thursday.
+  #  Monday in that week is (s-from-epoch + 3*24*60*60) seconds ago.
+  #  This needs to be adjusted by the timezone offset for Europe/Vienna
+  #  which is of course not constant (damn you daylight savings time)
+  #  Divide this by (7*24*60*60) and you get the number of
+  #  weeks since the Monday in the week of epoch adjusted for timezone offsets.
+  #  This week had week number 3 so add an offset of 2 and
+  #  get the modulo of 4. This rounded down gives you the current week
+  #  with 0 meaning Week 1. So add 1 to that number and you will get
+  #  the current RD week.
+  #
+  my $now = DateTime->now();
+  my $tz = DateTime::TimeZone->new(name => 'Europe/Vienna');
+  my $tz_offset = $tz->offset_for_datetime($now);
+  my $sEpoch = $now->epoch() + $tz_offset;
+  my $week = floor(((($sEpoch + 259200)/604800) + 2) % 4) + 1;
+
+  return $week;
+}
+
+return 1;