From 7789f8202f60f69ce015b1bc34eb0c076d7545b5 Mon Sep 17 00:00:00 2001
From: Daniel Friesel <derf@finalrewind.org>
Date: Sun, 24 May 2020 18:38:08 +0200
Subject: animate train position in map

---
 lib/DBInfoscreen/Controller/Map.pm | 475 +++++++++++++++++++++++++------------
 1 file changed, 328 insertions(+), 147 deletions(-)

(limited to 'lib/DBInfoscreen/Controller/Map.pm')

diff --git a/lib/DBInfoscreen/Controller/Map.pm b/lib/DBInfoscreen/Controller/Map.pm
index d618e8c..7013b63 100644
--- a/lib/DBInfoscreen/Controller/Map.pm
+++ b/lib/DBInfoscreen/Controller/Map.pm
@@ -10,8 +10,17 @@ use Geo::Distance;
 
 my $dbf_version = qx{git describe --dirty} || 'experimental';
 
+my $strp = DateTime::Format::Strptime->new(
+	pattern   => '%Y-%m-%dT%H:%M:%S.000%z',
+	time_zone => 'Europe/Berlin',
+);
+
 chomp $dbf_version;
 
+# Input: (HAFAS TripID, line number)
+# Output: Promise returning a
+# https://github.com/public-transport/hafas-client/blob/4/docs/trip.md instance
+# on success
 sub get_hafas_polyline_p {
 	my ( $self, $trip_id, $line ) = @_;
 
@@ -63,7 +72,19 @@ sub get_hafas_polyline_p {
 	return $promise;
 }
 
-sub estimate_train_position {
+# Input:
+#   now: DateTime
+#   from: current/previous stop
+#         {dep => DateTime, name => str, lat => float, lon => float}
+#   to: next stop
+#       {arr => DateTime, name => str, lat => float, lon => float}
+#   features: https://github.com/public-transport/hafas-client/blob/4/docs/trip.md features array
+# Output: list of estimated train positions in [lat, lon] format.
+# - current position
+# - position 2 seconds from now
+# - position 4 seconds from now
+# - ...
+sub estimate_train_positions {
 	my (%opt) = @_;
 
 	my $now = $opt{now};
@@ -74,8 +95,13 @@ sub estimate_train_position {
 	my $to_name   = $opt{to}{name};
 	my $features  = $opt{features};
 
-	my $route_part_completion_ratio
-	  = ( $now->epoch - $from_dt->epoch ) / ( $to_dt->epoch - $from_dt->epoch );
+	my @train_positions;
+
+	my $time_complete = $now->epoch - $from_dt->epoch;
+	my $time_total    = $to_dt->epoch - $from_dt->epoch;
+
+	my @completion_ratios
+	  = map { ( $time_complete + ( $_ * 2 ) ) / $time_total } ( 0 .. 45 );
 
 	my $geo = Geo::Distance->new;
 	my ( $from_index, $to_index );
@@ -109,32 +135,214 @@ sub estimate_train_position {
 				);
 			}
 		}
-		my $marker_distance = $total_distance * $route_part_completion_ratio;
+		my @marker_distances = map { $total_distance * $_ } @completion_ratios;
 		$total_distance = 0;
 		for my $j ( $from_index + 1 .. $to_index ) {
 			my $prev = $features->[ $j - 1 ]{geometry}{coordinates};
 			my $this = $features->[$j]{geometry}{coordinates};
 			if ( $prev and $this ) {
+				my $prev_distance = $total_distance;
 				$total_distance += $geo->distance(
 					'kilometer', $prev->[0], $prev->[1],
 					$this->[0],  $this->[1]
 				);
-			}
-			if ( $total_distance > $marker_distance ) {
+				for my $i ( @train_positions .. $#marker_distances ) {
+					my $marker_distance = $marker_distances[$i];
+					if ( $total_distance > $marker_distance ) {
+
+						# completion ratio for the line between (prev, this)
+						my $sub_ratio = 1;
+						if ( $total_distance != $prev_distance ) {
+							$sub_ratio = ( $marker_distance - $prev_distance )
+							  / ( $total_distance - $prev_distance );
+						}
 
-				# return (lat, lon)
-				return ( $this->[1], $this->[0] );
+						my $lat = $prev->[1]
+						  + ( $this->[1] - $prev->[1] ) * $sub_ratio;
+						my $lon = $prev->[0]
+						  + ( $this->[0] - $prev->[0] ) * $sub_ratio;
+
+						push( @train_positions, [ $lat, $lon ] );
+					}
+				}
+				if ( @train_positions == @completion_ratios ) {
+					return @train_positions;
+				}
 			}
 		}
+		if (@train_positions) {
+			return @train_positions;
+		}
 	}
 	else {
-		my $lat = $opt{from}{lat}
-		  + ( $opt{to}{lat} - $opt{from}{lat} ) * $route_part_completion_ratio;
-		my $lon = $opt{from}{lon}
-		  + ( $opt{to}{lon} - $opt{from}{lon} ) * $route_part_completion_ratio;
-		return ( $lat, $lon );
+		for my $ratio (@completion_ratios) {
+			my $lat
+			  = $opt{from}{lat} + ( $opt{to}{lat} - $opt{from}{lat} ) * $ratio;
+			my $lon
+			  = $opt{from}{lon} + ( $opt{to}{lon} - $opt{from}{lon} ) * $ratio;
+			push( @train_positions, [ $lat, $lon ] );
+		}
+		return @train_positions;
+	}
+	return [ $opt{to}{lat}, $opt{to}{lon} ];
+}
+
+# Input:
+#   now: DateTime
+#   route: hash
+#     lat: float
+#     lon: float
+#     name: str
+#     arr: DateTime
+#     dep: DateTime
+#   features: ref to transport.rest features list
+#  Output:
+#    next_stop: {type, station}
+#    positions: [current position [lat, lon], 2s from now, 4s from now, ...]
+sub estimate_train_positions2 {
+	my (%opt) = @_;
+	my $now   = $opt{now};
+	my @route = @{ $opt{route} // [] };
+
+	my @train_positions;
+	my $next_stop;
+
+	for my $i ( 1 .. $#route ) {
+		if (    $route[$i]{arr}
+			and $route[ $i - 1 ]{dep}
+			and $now > $route[ $i - 1 ]{dep}
+			and $now < $route[$i]{arr} )
+		{
+
+			# (current position, future positons...) in 2 second steps
+			@train_positions = estimate_train_positions(
+				from     => $route[ $i - 1 ],
+				to       => $route[$i],
+				now      => $now,
+				features => $opt{features},
+			);
+
+			$next_stop = {
+				type    => 'next',
+				station => $route[$i],
+			};
+			last;
+		}
+		if ( $route[ $i - 1 ]{dep} and $now <= $route[ $i - 1 ]{dep} ) {
+			@train_positions
+			  = ( [ $route[ $i - 1 ]{lat}, $route[ $i - 1 ]{lon} ] );
+			$next_stop = {
+				type    => 'present',
+				station => $route[ $i - 1 ],
+			};
+			last;
+		}
 	}
-	return ( $opt{to}{lat}, $opt{to}{lon} );
+
+	if ( not $next_stop ) {
+		@train_positions = ( [ $route[-1]{lat}, $route[-1]{lon} ] );
+		$next_stop       = {
+			type    => 'present',
+			station => $route[-1]
+		};
+	}
+
+	my $position_now = shift @train_positions;
+
+	return {
+		next_stop    => $next_stop,
+		position_now => $position_now,
+		positions    => \@train_positions,
+	};
+}
+
+sub route_to_ajax {
+	my (@stopovers) = @_;
+
+	my @route_entries;
+
+	for my $stop (@stopovers) {
+		my @stop_entries = ( $stop->{stop}{name} );
+		my $platform;
+
+		if ( $stop->{arrival}
+			and my $arr = $strp->parse_datetime( $stop->{arrival} ) )
+		{
+			my $delay = ( $stop->{arrivalDelay} // 0 ) / 60;
+			$platform = $stop->{arrivalPlatform};
+
+			push( @stop_entries, $arr->epoch, $delay );
+		}
+		else {
+			push( @stop_entries, q{}, q{} );
+		}
+
+		if ( $stop->{departure}
+			and my $dep = $strp->parse_datetime( $stop->{departure} ) )
+		{
+			my $delay = ( $stop->{departureDelay} // 0 ) / 60;
+			$platform //= $stop->{departurePlatform} // q{};
+
+			push( @stop_entries, $dep->epoch, $delay, $platform );
+		}
+		else {
+			push( @stop_entries, q{}, q{}, q{} );
+		}
+
+		push( @route_entries, join( ';', @stop_entries ) );
+	}
+
+	return join( '|', @route_entries );
+}
+
+# Input: List of transport.rest stopovers
+# Output: List of preprocessed stops. Each is a hash with the following keys:
+#   lat: float
+#   lon: float
+#   name: str
+#   arr: DateTime
+#   dep: DateTime
+#   arr_delay: int
+#   dep_delay: int
+#   platform: str
+sub stopovers_to_route {
+	my (@stopovers) = @_;
+	my @route;
+
+	for my $stop (@stopovers) {
+		my @stop_lines = ( $stop->{stop}{name} );
+		my ( $platform, $arr, $dep, $arr_delay, $dep_delay );
+
+		if (    $stop->{arrival}
+			and $arr = $strp->parse_datetime( $stop->{arrival} ) )
+		{
+			$arr_delay = ( $stop->{arrivalDelay} // 0 ) / 60;
+			$platform //= $stop->{arrivalPlatform};
+		}
+
+		if (    $stop->{departure}
+			and $dep = $strp->parse_datetime( $stop->{departure} ) )
+		{
+			$dep_delay = ( $stop->{departureDelay} // 0 ) / 60;
+			$platform //= $stop->{departurePlatform};
+		}
+
+		push(
+			@route,
+			{
+				lat       => $stop->{stop}{location}{latitude},
+				lon       => $stop->{stop}{location}{longitude},
+				name      => $stop->{stop}{name},
+				arr       => $arr,
+				dep       => $dep,
+				arr_delay => $arr_delay,
+				dep_delay => $dep_delay,
+				platform  => $platform,
+			}
+		);
+
+	}
+	return @route;
 }
 
 sub route {
@@ -154,17 +362,13 @@ sub route {
 			my @polyline = @{ $pl->{polyline} };
 			my @line_pairs;
 			my @station_coordinates;
-			my @route;
 
 			my @markers;
 			my $next_stop;
 
-			my $now  = DateTime->now( time_zone => 'Europe/Berlin' );
-			my $strp = DateTime::Format::Strptime->new(
-				pattern   => '%Y-%m-%dT%H:%M:%S.000%z',
-				time_zone => 'Europe/Berlin',
-			);
+			my $now = DateTime->now( time_zone => 'Europe/Berlin' );
 
+			# @line_pairs are used to draw the train's journey on the map
 			for my $i ( 1 .. $#polyline ) {
 				push(
 					@line_pairs,
@@ -175,164 +379,85 @@ sub route {
 				);
 			}
 
-			for my $stop ( @{ $pl->{raw}{stopovers} // [] } ) {
-				my @stop_lines = ( $stop->{stop}{name} );
-				my ( $platform, $arr, $dep, $arr_delay, $dep_delay );
+			my @route = stopovers_to_route( @{ $pl->{raw}{stopovers} // [] } );
+
+			# Prepare from/to markers and name/time/delay overlays for stations
+			for my $stop (@route) {
+				my @stop_lines = ( $stop->{name} );
 
-				if ( $from_name and $stop->{stop}{name} eq $from_name ) {
+				if ( $from_name and $stop->{name} eq $from_name ) {
 					push(
 						@markers,
 						{
-							lon   => $stop->{stop}{location}{longitude},
-							lat   => $stop->{stop}{location}{latitude},
-							title => $stop->{stop}{name},
+							lon   => $stop->{lon},
+							lat   => $stop->{lat},
+							title => $stop->{name},
 							icon  => 'goldIcon',
 						}
 					);
 				}
-				if ( $to_name and $stop->{stop}{name} eq $to_name ) {
+				if ( $to_name and $stop->{name} eq $to_name ) {
 					push(
 						@markers,
 						{
-							lon   => $stop->{stop}{location}{longitude},
-							lat   => $stop->{stop}{location}{latitude},
-							title => $stop->{stop}{name},
+							lon   => $stop->{lon},
+							lat   => $stop->{lat},
+							title => $stop->{name},
 							icon  => 'greenIcon',
 						}
 					);
 				}
 
-				if (    $stop->{arrival}
-					and $arr = $strp->parse_datetime( $stop->{arrival} ) )
-				{
-					$arr_delay = ( $stop->{arrivalDelay} // 0 ) / 60;
-					$platform //= $stop->{arrivalPlatform};
-					my $arr_line = $arr->strftime('Ankunft: %H:%M');
-					if ($arr_delay) {
-						$arr_line .= sprintf( ' (%+d)', $arr_delay );
+				if ( $stop->{platform} ) {
+					push( @stop_lines, 'Gleis ' . $stop->{platform} );
+				}
+				if ( $stop->{arr} ) {
+					my $arr_line = $stop->{arr}->strftime('Ankunft: %H:%M');
+					if ( $stop->{arr_delay} ) {
+						$arr_line .= sprintf( ' (%+d)', $stop->{arr_delay} );
 					}
 					push( @stop_lines, $arr_line );
 				}
-
-				if (    $stop->{departure}
-					and $dep = $strp->parse_datetime( $stop->{departure} ) )
-				{
-					$dep_delay = ( $stop->{departureDelay} // 0 ) / 60;
-					$platform //= $stop->{departurePlatform};
-					my $dep_line = $dep->strftime('Abfahrt: %H:%M');
-					if ($dep_delay) {
-						$dep_line .= sprintf( ' (%+d)', $dep_delay );
+				if ( $stop->{dep} ) {
+					my $dep_line = $stop->{dep}->strftime('Abfahrt: %H:%M');
+					if ( $stop->{dep_delay} ) {
+						$dep_line .= sprintf( ' (%+d)', $stop->{dep_delay} );
 					}
 					push( @stop_lines, $dep_line );
 				}
 
-				if ($platform) {
-					splice( @stop_lines, 1, 0, "Gleis $platform" );
-				}
-
-				push(
-					@station_coordinates,
-					[
-						[
-							$stop->{stop}{location}{latitude},
-							$stop->{stop}{location}{longitude}
-						],
-						[@stop_lines],
-					]
-				);
-				push(
-					@route,
-					{
-						lat       => $stop->{stop}{location}{latitude},
-						lon       => $stop->{stop}{location}{longitude},
-						name      => $stop->{stop}{name},
-						arr       => $arr,
-						dep       => $dep,
-						arr_delay => $arr_delay,
-						dep_delay => $dep_delay,
-						platform  => $platform,
-					}
-				);
-
+				push( @station_coordinates,
+					[ [ $stop->{lat}, $stop->{lon} ], [@stop_lines], ] );
 			}
 
-			for my $i ( 1 .. $#route ) {
-				if (    $route[$i]{arr}
-					and $route[ $i - 1 ]{dep}
-					and $now > $route[ $i - 1 ]{dep}
-					and $now < $route[$i]{arr} )
-				{
-
-					my $title = $pl->{name};
-					if ( $route[$i]{arr_delay} ) {
-						$title .= sprintf( ' (%+d)', $route[$i]{arr_delay} );
-					}
-
-					my ( $train_lat, $train_lon ) = estimate_train_position(
-						from     => $route[ $i - 1 ],
-						to       => $route[$i],
-						now      => $now,
-						features => $pl->{raw}{polyline}{features},
-					);
-
-					push(
-						@markers,
-						{
-							lat   => $train_lat,
-							lon   => $train_lon,
-							title => $title
-						}
-					);
+			my $train_pos = estimate_train_positions2(
+				now      => $now,
+				route    => \@route,
+				features => $pl->{raw}{polyline}{features},
+			);
 
-					$next_stop = {
-						type    => 'next',
-						station => $route[$i],
-					};
-					last;
-				}
-				if ( $route[ $i - 1 ]{dep} and $now <= $route[ $i - 1 ]{dep} ) {
-					my $title = $pl->{name};
-					if ( $route[$i]{arr_delay} ) {
-						$title .= sprintf( ' (%+d)', $route[$i]{arr_delay} );
-					}
-					push(
-						@markers,
-						{
-							lat   => $route[ $i - 1 ]{lat},
-							lon   => $route[ $i - 1 ]{lon},
-							title => $title
-						}
-					);
-					$next_stop = {
-						type    => 'present',
-						station => $route[ $i - 1 ],
-					};
-					last;
+			push(
+				@markers,
+				{
+					lat   => $train_pos->{position_now}[0],
+					lon   => $train_pos->{position_now}[1],
+					title => $pl->{name}
 				}
-			}
-			if ( not @markers ) {
-				push(
-					@markers,
-					{
-						lat   => $route[-1]{lat},
-						lon   => $route[-1]{lon},
-						title => $route[-1]{name} . ' - Endstation',
-					}
-				);
-				$next_stop = {
-					type    => 'present',
-					station => $route[-1]
-				};
-			}
+			);
+			$next_stop = $train_pos->{next_stop};
 
 			$self->render(
 				'route_map',
-				title     => $pl->{name},
-				hide_opts => 1,
-				with_map  => 1,
-				origin    => {
+				title      => $pl->{name},
+				hide_opts  => 1,
+				with_map   => 1,
+				ajax_req   => "${trip_id}/${line_no}",
+				ajax_route => route_to_ajax( @{ $pl->{raw}{stopovers} // [] } ),
+				ajax_polyline => join( '|',
+					map { join( ';', @{$_} ) } @{ $train_pos->{positions} } ),
+				origin => {
 					name => $pl->{raw}{origin}{name},
-					ts   => $pl->{raw}{dep_line}
+					ts   => $pl->{raw}{departure}
 					? scalar $strp->parse_datetime( $pl->{raw}{departure} )
 					: undef,
 				},
@@ -374,4 +499,60 @@ sub route {
 	)->wait;
 }
 
+sub ajax_route {
+	my ($self)  = @_;
+	my $trip_id = $self->stash('tripid');
+	my $line_no = $self->stash('lineno');
+
+	delete $self->stash->{layout};
+
+	$self->render_later;
+
+	$self->get_hafas_polyline_p( $trip_id, $line_no )->then(
+		sub {
+			my ($pl) = @_;
+
+			my $now = DateTime->now( time_zone => 'Europe/Berlin' );
+
+			my @route = stopovers_to_route( @{ $pl->{raw}{stopovers} // [] } );
+
+			my $train_pos = estimate_train_positions2(
+				now      => $now,
+				route    => \@route,
+				features => $pl->{raw}{polyline}{features},
+			);
+
+			my @polyline = @{ $pl->{polyline} };
+			$self->render(
+				'_map_infobox',
+				ajax_req   => "${trip_id}/${line_no}",
+				ajax_route => route_to_ajax( @{ $pl->{raw}{stopovers} // [] } ),
+				ajax_polyline => join( '|',
+					map { join( ';', @{$_} ) } @{ $train_pos->{positions} } ),
+				origin => {
+					name => $pl->{raw}{origin}{name},
+					ts   => $pl->{raw}{departure}
+					? scalar $strp->parse_datetime( $pl->{raw}{departure} )
+					: undef,
+				},
+				destination => {
+					name => $pl->{raw}{destination}{name},
+					ts   => $pl->{raw}{arrival}
+					? scalar $strp->parse_datetime( $pl->{raw}{arrival} )
+					: undef,
+				},
+				next_stop => $train_pos->{next_stop},
+			);
+		}
+	)->catch(
+		sub {
+			my ($err) = @_;
+			$self->render(
+				'_error',
+				error => $err,
+			);
+		}
+	)->wait;
+}
+
 1;
-- 
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