1 files changed, 29 insertions, 0 deletions
diff --git a/share/csv2json b/share/csv2json
index 1cfd3ee..9e6340c 100755
--- a/share/csv2json
+++ b/share/csv2json
@@ -48,5 +48,34 @@ for my $line (@csv_lines) {
 
 @stations = sort { $a->{name} cmp $b->{name} } @stations;
 
+my $have_duplicates = 0;
+my @names           = map { $_->{name} } @stations;
+my @ds100           = map { $_->{ds100} } @stations;
+my @uic_ids         = map { $_->{uic} } @stations;
+
+for my $i ( 1 .. $#names ) {
+	if ( $names[ $i - 1 ] eq $names[$i] ) {
+		say "Duplicate station name: $names[$i]";
+		$have_duplicates = 1;
+	}
+}
+for my $i ( 1 .. $#ds100 ) {
+	if ( $ds100[ $i - 1 ] eq $ds100[$i] ) {
+		say "Duplicate DS100 code: $ds100[$i]";
+		$have_duplicates = 1;
+	}
+}
+for my $i ( 1 .. $#uic_ids ) {
+	if ( $uic_ids[ $i - 1 ] == $uic_ids[$i] ) {
+		say "Duplicate UIC ID: $uic_ids[$i]";
+		$have_duplicates = 1;
+	}
+}
+
+if ($have_duplicates) {
+	say "Data has NOT been converted to stations.json";
+	say "Please remove duplicates and run $0 again";
+}
+
 my $json_out = JSON->new->utf8->canonical->pretty->encode( [@stations] );
 write_file( 'stations.json', $json_out );