Add previousLegs into GTFS GraphQL API

application/src/main/java/org/opentripplanner/apis/gtfs/datafetchers/LegImpl.java

@@ -28,6 +28,7 @@
 import org.opentripplanner.routing.alertpatch.TransitAlert;
 import org.opentripplanner.routing.alternativelegs.AlternativeLegs;
 import org.opentripplanner.routing.alternativelegs.AlternativeLegsFilter;
+import org.opentripplanner.routing.alternativelegs.NavigationDirection;
 import org.opentripplanner.transit.model.network.Route;
 import org.opentripplanner.transit.model.organization.Agency;
 import org.opentripplanner.transit.model.timetable.Trip;
@@ -275,8 +276,17 @@ private Leg getSource(DataFetchingEnvironment environment) {
     return environment.getSource();
   }
 
+  @Override
+  public DataFetcher<Iterable<Leg>> previousLegs() {
+    return alternativeLegs(NavigationDirection.PREVIOUS);
+  }
+
   @Override
   public DataFetcher<Iterable<Leg>> nextLegs() {
+    return alternativeLegs(NavigationDirection.NEXT);
+  }
+
+  private DataFetcher<Iterable<Leg>> alternativeLegs(NavigationDirection direction) {
     return environment -> {
       if (environment.getSource() instanceof ScheduledTransitLeg originalLeg) {
         var args = new GraphQLTypes.GraphQLLegNextLegsArgs(environment.getArguments());
@@ -311,7 +321,7 @@ public DataFetcher<Iterable<Leg>> nextLegs() {
             environment.getSource(),
             numberOfLegs,
             environment.<GraphQLRequestContext>getContext().transitService(),
-            false,
+            direction,
             AlternativeLegsFilter.NO_FILTER,
             limitToExactOriginStop,
             limitToExactDestinationStop

application/src/main/java/org/opentripplanner/apis/gtfs/generated/GraphQLDataFetchers.java

@@ -503,6 +503,8 @@ public interface GraphQLLeg {
 
     public DataFetcher<String> pickupType();
 
+    public DataFetcher<Iterable<Leg>> previousLegs();
+
     public DataFetcher<Boolean> realTime();
 
     public DataFetcher<GraphQLRealtimeState> realtimeState();

application/src/main/java/org/opentripplanner/apis/gtfs/generated/GraphQLTypes.java

@@ -1318,6 +1318,69 @@ public void setGraphQLOriginModesWithParentStation(
     }
   }
 
+  public static class GraphQLLegPreviousLegsArgs {
+
+    private List<GraphQLTransitMode> destinationModesWithParentStation;
+    private Integer numberOfLegs;
+    private List<GraphQLTransitMode> originModesWithParentStation;
+
+    public GraphQLLegPreviousLegsArgs(Map<String, Object> args) {
+      if (args != null) {
+        if (args.get("destinationModesWithParentStation") != null) {
+          this.destinationModesWithParentStation =
+            ((List<Object>) args.get("destinationModesWithParentStation")).stream()
+              .map(item ->
+                item instanceof GraphQLTransitMode
+                  ? item
+                  : GraphQLTransitMode.valueOf((String) item)
+              )
+              .map(GraphQLTransitMode.class::cast)
+              .collect(Collectors.toList());
+        }
+        this.numberOfLegs = (Integer) args.get("numberOfLegs");
+        if (args.get("originModesWithParentStation") != null) {
+          this.originModesWithParentStation =
+            ((List<Object>) args.get("originModesWithParentStation")).stream()
+              .map(item ->
+                item instanceof GraphQLTransitMode
+                  ? item
+                  : GraphQLTransitMode.valueOf((String) item)
+              )
+              .map(GraphQLTransitMode.class::cast)
+              .collect(Collectors.toList());
+        }
+      }
+    }
+
+    public List<GraphQLTransitMode> getGraphQLDestinationModesWithParentStation() {
+      return this.destinationModesWithParentStation;
+    }
+
+    public Integer getGraphQLNumberOfLegs() {
+      return this.numberOfLegs;
+    }
+
+    public List<GraphQLTransitMode> getGraphQLOriginModesWithParentStation() {
+      return this.originModesWithParentStation;
+    }
+
+    public void setGraphQLDestinationModesWithParentStation(
+      List<GraphQLTransitMode> destinationModesWithParentStation
+    ) {
+      this.destinationModesWithParentStation = destinationModesWithParentStation;
+    }
+
+    public void setGraphQLNumberOfLegs(Integer numberOfLegs) {
+      this.numberOfLegs = numberOfLegs;
+    }
+
+    public void setGraphQLOriginModesWithParentStation(
+      List<GraphQLTransitMode> originModesWithParentStation
+    ) {
+      this.originModesWithParentStation = originModesWithParentStation;
+    }
+  }
+
   public static class GraphQLLocalDateRangeInput {
 
     private java.time.LocalDate end;

application/src/main/java/org/opentripplanner/apis/transmodel/model/plan/LegType.java

@@ -33,6 +33,7 @@
 import org.opentripplanner.model.plan.TransitLeg;
 import org.opentripplanner.model.plan.legreference.LegReferenceSerializer;
 import org.opentripplanner.routing.alternativelegs.AlternativeLegs;
+import org.opentripplanner.routing.alternativelegs.NavigationDirection;
 
 public class LegType {
 
@@ -485,7 +486,7 @@ public static GraphQLObjectType create(
               leg,
               env.getArgument("previous"),
               GqlUtil.getTransitService(env),
-              true,
+              NavigationDirection.PREVIOUS,
               env.getArgument("filter")
             );
           })
@@ -525,7 +526,7 @@ public static GraphQLObjectType create(
               leg,
               env.getArgument("next"),
               GqlUtil.getTransitService(env),
-              false,
+              NavigationDirection.NEXT,
               env.getArgument("filter")
             );
           })

application/src/main/java/org/opentripplanner/routing/alternativelegs/AlternativeLegs.java

@@ -45,18 +45,10 @@ public static List<ScheduledTransitLeg> getAlternativeLegs(
     Leg leg,
     Integer numberLegs,
     TransitService transitService,
-    boolean searchBackward,
+    NavigationDirection direction,
     AlternativeLegsFilter filter
   ) {
-    return getAlternativeLegs(
-      leg,
-      numberLegs,
-      transitService,
-      searchBackward,
-      filter,
-      false,
-      false
-    );
+    return getAlternativeLegs(leg, numberLegs, transitService, direction, filter, false, false);
   }
 
   /**
@@ -66,9 +58,8 @@ public static List<ScheduledTransitLeg> getAlternativeLegs(
    * @param numberLegs           The number of alternative legs requested. If fewer legs are found,
    *                             only the found legs are returned.
    * @param transitService       The transit service used for the search
-   * @param includeDepartBefore  Boolean indicating whether the alternative legs should depart
-   *                             earlier or later than the original leg True if earlier, false if
-   *                             later.
+   * @param direction            Indicating whether the alternative legs should depart before or
+   *                             after than the original.
    * @param filter               AlternativeLegsFilter indicating which properties of the original
    *                             leg should not change in the alternative legs
    * @param exactOriginStop      Boolean indicating whether the exact departure stop of the original
@@ -82,7 +73,7 @@ public static List<ScheduledTransitLeg> getAlternativeLegs(
     Leg leg,
     Integer numberLegs,
     TransitService transitService,
-    boolean includeDepartBefore,
+    NavigationDirection direction,
     AlternativeLegsFilter filter,
     boolean exactOriginStop,
     boolean exactDestinationStop
@@ -105,7 +96,7 @@ public static List<ScheduledTransitLeg> getAlternativeLegs(
       ScheduledTransitLeg::getStartTime
     );
 
-    if (includeDepartBefore) {
+    if (direction == NavigationDirection.PREVIOUS) {
       legComparator = legComparator.reversed();
     }
 
@@ -119,13 +110,7 @@ public static List<ScheduledTransitLeg> getAlternativeLegs(
       .distinct()
       .flatMap(tripPattern -> withBoardingAlightingPositions(origins, destinations, tripPattern))
       .flatMap(t ->
-        generateLegs(
-          transitService,
-          t,
-          leg.getStartTime(),
-          leg.getServiceDate(),
-          includeDepartBefore
-        )
+        generateLegs(transitService, t, leg.getStartTime(), leg.getServiceDate(), direction)
       )
       .filter(Predicate.not(leg::isPartiallySameTransitLeg))
       .sorted(legComparator)
@@ -142,7 +127,7 @@ private static Stream<ScheduledTransitLeg> generateLegs(
     TripPatternBetweenStops tripPatternBetweenStops,
     ZonedDateTime departureTime,
     LocalDate originalDate,
-    boolean includeDepartBefore
+    NavigationDirection direction
   ) {
     TripPattern pattern = tripPatternBetweenStops.tripPattern;
     int boardingPosition = tripPatternBetweenStops.positions.boardingPosition;
@@ -155,7 +140,7 @@ private static Stream<ScheduledTransitLeg> generateLegs(
       tts.getServiceDayMidnight() + tts.getRealtimeDeparture()
     );
 
-    if (includeDepartBefore) {
+    if (direction == NavigationDirection.PREVIOUS) {
       comparator = comparator.reversed();
     }
 
@@ -185,7 +170,7 @@ private static Stream<ScheduledTransitLeg> generateLegs(
           continue;
         }
 
-        boolean departureTimeInRange = includeDepartBefore
+        boolean departureTimeInRange = direction == NavigationDirection.PREVIOUS
           ? tripTimes.getDepartureTime(boardingPosition) <= secondsSinceMidnight
           : tripTimes.getDepartureTime(boardingPosition) >= secondsSinceMidnight;
 

application/src/main/java/org/opentripplanner/routing/alternativelegs/NavigationDirection.java

@@ -0,0 +1,16 @@
+package org.opentripplanner.routing.alternativelegs;
+
+/**
+ * This enum describes how the user navigates on a list of items.
+ */
+public enum NavigationDirection {
+  /**
+   * Get the next set of items.
+   */
+  NEXT,
+
+  /**
+   * Get the previous set of items.
+   */
+  PREVIOUS,
+}

application/src/main/resources/org/opentripplanner/apis/gtfs/schema.graphqls

@@ -722,6 +722,24 @@ type Leg {
   pickupBookingInfo: BookingInfo
   "This is used to indicate if boarding this leg is possible only with special arrangements."
   pickupType: PickupDropoffType
+  "Previous legs with same origin and destination stops or stations"
+  previousLegs(
+    """
+    Transportation modes for which all stops in the parent station are used as possible destination stops
+    for the previous legs. For modes not listed, only the exact destination stop of the leg is considered.
+    """
+    destinationModesWithParentStation: [TransitMode!],
+    """
+    The number of alternative legs searched. If fewer than the requested number are found,
+    then only the found legs are returned.
+    """
+    numberOfLegs: Int!,
+    """
+    Transportation modes for which all stops in the parent station are used as possible origin stops
+    for the previous legs. For modes not listed, only the exact origin stop of the leg is considered.
+    """
+    originModesWithParentStation: [TransitMode!]
+  ): [Leg!]
   "Whether there is real-time data about this Leg"
   realTime: Boolean
   "State of real-time data"

application/src/test/java/org/opentripplanner/routing/stoptimes/AlternativeLegsTest.java

@@ -12,6 +12,7 @@
 import org.opentripplanner.model.plan.legreference.ScheduledTransitLegReference;
 import org.opentripplanner.routing.alternativelegs.AlternativeLegs;
 import org.opentripplanner.routing.alternativelegs.AlternativeLegsFilter;
+import org.opentripplanner.routing.alternativelegs.NavigationDirection;
 import org.opentripplanner.transit.model.framework.FeedScopedId;
 import org.opentripplanner.transit.service.DefaultTransitService;
 
@@ -51,7 +52,7 @@ void testPreviousLegs() {
       originalLeg,
       3,
       transitService,
-      true,
+      NavigationDirection.PREVIOUS,
       AlternativeLegsFilter.NO_FILTER
     );
 
@@ -85,7 +86,7 @@ void testNextLegs() {
       originalLeg,
       3,
       transitService,
-      false,
+      NavigationDirection.NEXT,
       AlternativeLegsFilter.NO_FILTER
     );
 
@@ -119,7 +120,7 @@ void testCircularRoutes() {
       originalLeg,
       2,
       transitService,
-      false,
+      NavigationDirection.NEXT,
       AlternativeLegsFilter.NO_FILTER
     );
 
@@ -147,7 +148,7 @@ void testComplexCircularRoutes() {
       originalLeg,
       2,
       transitService,
-      false,
+      NavigationDirection.NEXT,
       AlternativeLegsFilter.NO_FILTER
     );
     var legs = toString(alternativeLegs);