From 765bf0794a92522d13b75ced092ab0cfd8cdbf64 Mon Sep 17 00:00:00 2001
From: Daniel Friesel <derf@finalrewind.org>
Date: Thu, 6 Feb 2014 19:13:35 +0100
Subject: add lookahead option

---
 Changelog                    |  4 ++++
 bin/db-iris                  | 21 ++++++++++++++++++---
 lib/Travel/Status/DE/IRIS.pm | 17 +++++++++++++++--
 t/31-result-basics.t         | 20 +++++++++++++++++++-
 4 files changed, 56 insertions(+), 6 deletions(-)

diff --git a/Changelog b/Changelog
index 80a0c25..f7c5d33 100644
--- a/Changelog
+++ b/Changelog
@@ -1,3 +1,7 @@
+git HEAD
+
+    * IRIS / db-iris: Add lookahead option
+
 Travel::Status::DE::IRIS 0.02 - Mon Feb 03 2014
 
     * Fix warnings when encountering unplanned (fchg-only) trains without
diff --git a/bin/db-iris b/bin/db-iris
index 35ef783..75aec37 100755
--- a/bin/db-iris
+++ b/bin/db-iris
@@ -17,7 +17,7 @@ use List::MoreUtils qw(none);
 use Travel::Status::DE::IRIS;
 use Travel::Status::DE::IRIS::Stations;
 
-my ( $date, $time );
+my ( $date, $time, $lookahead );
 my $datetime = DateTime->now( time_zone => 'Europe/Berlin' );
 my $realtime = 0;
 my ( $filter_via, $track_via, $status_via );
@@ -34,6 +34,7 @@ GetOptions(
 	'c|class=s@'    => \@grep_class,
 	'd|date=s'      => \$date,
 	'h|help'        => sub { show_help(0) },
+	'l|lookahead=i' => \$lookahead,
 	'o|output=s@'   => \@edata_pre,
 	'p|platform=s@' => \@grep_platform,
 	'r|realtime'    => \$realtime,
@@ -93,10 +94,14 @@ for my $efield (@edata_pre) {
 }
 
 my $status = Travel::Status::DE::IRIS->new(
-	datetime => $datetime,
-	station  => $station,
+	datetime  => $datetime,
+	lookahead => $lookahead,
+	station   => $station,
 );
 if ($track_via) {
+
+	# lookahead should not be used here - the via stop is reached an unknown
+	# amount of time later
 	$status_via = Travel::Status::DE::IRIS->new(
 		datetime => $datetime,
 		station  => $track_via,
@@ -378,6 +383,16 @@ Request results for I<date> in dd.mm. oder dd.mm.YYYY format. Note that only
 slight (a few hours max) deviations from the current time are supported by the
 IRIS backend, larger ones will not return data.
 
+=item B<-l>, B<--lookahead> I<int>
+
+Return only those results which are less than I<int> minutes in the future.
+Defaults to 240 (4 hours).
+
+Note that this is only an upper limit, not a guarantee to get every train
+with a departure in less than I<int> minutes. This guarantee holds only for
+I<int> below 120. However, any non-negative number is accepted for this
+option.
+
 =item B<-o>, B<--output> I<outputtypes>
 
 For each result, output I<outputtypes> in addition to the normal time, delay,
diff --git a/lib/Travel/Status/DE/IRIS.pm b/lib/Travel/Status/DE/IRIS.pm
index 2d4d068..03aa89c 100644
--- a/lib/Travel/Status/DE/IRIS.pm
+++ b/lib/Travel/Status/DE/IRIS.pm
@@ -30,7 +30,8 @@ sub new {
 		  // DateTime->now( time_zone => 'Europe/Berlin' ),
 		iris_base => $opt{iris_base}
 		  // 'http://iris.noncd.db.de/iris-tts/timetable',
-		station    => $opt{station},
+		lookahead => $opt{lookahead} // ( 4 * 60 ),
+		station => $opt{station},
 		user_agent => $ua,
 	};
 
@@ -68,7 +69,7 @@ sub new {
 		my $d
 		  = ( $_->departure // $_->arrival )
 		  ->subtract_datetime( $self->{datetime} );
-		not $d->is_negative and $d->in_units('hours') < 4
+		not $d->is_negative and $d->in_units('minutes') < $self->{lookahead}
 	} @{ $self->{results} };
 
 	@{ $self->{results} }
@@ -303,6 +304,18 @@ current date and time.
 
 IRIS base url, defaults to C<< http://iris.noncd.db.de/iris-tts/timetable >>.
 
+=item B<lookahead> => I<int>
+
+Compute only those results which are less than I<int> minutes in the future.
+Default: 240 (4 hours).
+
+Note that the DeutscheBahn IRIS backend only provides schedules up to four
+to five hours into the future, and this module only requests data for up to
+three hours. So in most cases, setting this to a value above 180 minutes will
+have no effect. However, as the IRIS occasionally contains unscheduled
+departures or qos messages known far in advance (e.g. 12 hours from now), any
+non-negative integer is accepted.
+
 =item B<station> => I<stationcode>
 
 Mandatory: Which station to return departures for. Note that this is not a
diff --git a/t/31-result-basics.t b/t/31-result-basics.t
index 9a76e91..7f9423b 100644
--- a/t/31-result-basics.t
+++ b/t/31-result-basics.t
@@ -5,7 +5,7 @@ use 5.014;
 use utf8;
 
 use DateTime;
-use Test::More tests => 435;
+use Test::More tests => 436;
 use Test::Fatal;
 
 use Travel::Status::DE::IRIS;
@@ -87,3 +87,21 @@ $status = Travel::Status::DE::IRIS->new(
 @results = $status->results;
 
 is(@results, 0, 'no data available -> empty result list');
+
+$status = Travel::Status::DE::IRIS->new(
+	iris_base => 'file:t/in',
+	lookahead => 0,
+	station   => 'EE',
+	datetime  => DateTime->new(
+		year      => 2014,
+		month     => 1,
+		day       => 3,
+		hour      => 20,
+		minute    => 1,
+		time_zone => 'Europe/Berlin'
+	)
+);
+
+@results = $status->results;
+
+is(@results, 0, 'lookahead 0 -> no results');
-- 
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