history map: skip duplicates earlier

use DateTime::Format::Strptime;

use List::Util qw(uniq);

use List::UtilsBy qw(uniq_by);

use List::MoreUtils qw(first_index);

use Travel::Status::DE::IRIS::Stations;

sub homepage {

	  grep { exists $location->{$_} } @stations;

	my @station_pairs;

	my %seen;

	for my $journey (@journeys) {

		my @route      = map { $_->[0] } @{ $journey->{route} };

		my $from_index = first_index { $_ eq $journey->{from_name} } @route;

		my $to_index   = first_index { $_ eq $journey->{to_name} } @route;

		if ( $from_index == -1 or $to_index == -1 ) {

			next;

		}

		@route = @route[ $from_index .. $to_index ];

		my $key = join( '|', @route );

		if ( $seen{$key} ) {

			next;

		}

		$seen{$key} = 1;

		# direction does not matter at the moment

		$seen{ join( '|', reverse @route ) } = 1;

		my $prev_station = shift @route;

		my $within       = 0;

		for my $station (@route) {

			if ( $prev_station eq $journey->{from_name} ) {

				$within = 1;

			}

			if ($within) {

			push( @station_pairs, [ $prev_station, $station ] );

			}

			$prev_station = $station;

			if ( $station eq $journey->{to_name} ) {

				$within = 0;

			}

		}

	}