more

cmd/planner/planner.go

@@ -13,7 +13,6 @@ import (
 // TripPlanner handles preprocessed transit data for efficient routing
 type TripPlanner struct {
 	*reader.TripData
-	graph map[string][]Edge
 }
 
 const (
@@ -22,6 +21,8 @@ const (
 	maxWaitBetweenTrips = 1 * time.Hour
 	//trajectoryAngleTolerance = 220.0
 	maxTravelDuration = 12 * time.Hour
+	maxInitialWait    = 90 * time.Minute
+	searchWindow      = 4 * time.Hour
 )
 
 // NewTripPlanner creates a new trip planner instance
@@ -115,18 +116,51 @@ func tripStopIndex(trip *types.Trip, st *types.StopTime) int {
 
 // FindRoutes finds the best routes (up to num) between two stops starting at the given time
 func (tp *TripPlanner) FindRoute(from, to string, when time.Time) ([]*Route, error) {
-
 	fromStop := tp.GetStop(from)
 	toStop := tp.GetStop(to)
-
 	if fromStop == nil || toStop == nil {
 		return nil, fmt.Errorf("invalid from or to stop")
 	}
+
+	exclude := make(map[string]struct{})
+	results := make([]*Route, 0, 3)
+	timeCursor := when
+	const maxAttempts = 5
+	var lastErr error
+
+	for attempts := 0; attempts < maxAttempts && len(results) < 3; attempts++ {
+		limit := 3 - len(results)
+		routes, err := tp.searchRoutesAStar(fromStop, toStop, timeCursor, exclude, limit)
+		if err == nil {
+			results = append(results, routes...)
+		} else {
+			lastErr = err
+		}
+		timeCursor = timeCursor.Add(10 * time.Minute)
+	}
+
+	if len(results) == 0 {
+		if lastErr != nil {
+			return nil, lastErr
+		}
+		return nil, fmt.Errorf("no route found")
+	}
+
+	return results, nil
+}
+
+func (tp *TripPlanner) searchRoutesAStar(fromStop, toStop *types.Stop, when time.Time, exclude map[string]struct{}, limit int) ([]*Route, error) {
+	if limit <= 0 {
+		return nil, nil
+	}
 	open := priorityQueue{}
 	heap.Init(&open)
 	bestCost := make(map[string]float64)
 	startSeconds := types.AsSecondsAfterMidnight(when)
+	startSecondsFloat := float64(startSeconds)
 	initCount := 0
+	initialWaitLimit := maxInitialWait.Seconds()
+	searchWindowLimit := searchWindow.Seconds()
 
 	for tripWithDeparture := range fromStop.GetTripsAfter(when) {
 		trip := tripWithDeparture.Trip
@@ -138,10 +172,17 @@ func (tp *TripPlanner) FindRoute(from, to string, when time.Time) ([]*Route, err
 		if idx < 0 {
 			continue
 		}
-		wait := float64(startStopTime.DepartureTime - startSeconds)
+		departureDelta := float64(startStopTime.DepartureTime) - startSecondsFloat
+		if searchWindow > 0 && departureDelta > searchWindowLimit {
+			continue
+		}
+		wait := departureDelta
 		if wait < 0 {
 			wait = 0
 		}
+		if maxInitialWait > 0 && wait > initialWaitLimit {
+			continue
+		}
 		node := &searchNode{
 			stopTime:  startStopTime,
 			index:     idx,
@@ -155,23 +196,41 @@ func (tp *TripPlanner) FindRoute(from, to string, when time.Time) ([]*Route, err
 	}
 
 	if initCount == 0 {
-		return nil, fmt.Errorf("no departures from %s after %s", from, when.Format(time.RFC3339))
+		return nil, fmt.Errorf("no departures from %s after %s", fromStop.StopName, when.Format(time.RFC3339))
 	}
 
-	routes := make([]*Route, 0, 3)
+	routes := make([]*Route, 0, limit)
 
-	for open.Len() > 0 && len(routes) < 3 {
+	for open.Len() > 0 && len(routes) < limit {
 		current := heap.Pop(&open).(*pqItem).node
 		if current.stopTime.StopId == toStop.StopId {
 			route := buildRouteFromNode(current)
 			if route != nil {
+				signature := routeSignature(route)
+				if signature == "" {
+					continue
+				}
+				if _, seen := exclude[signature]; seen {
+					continue
+				}
+				exclude[signature] = struct{}{}
 				routes = append(routes, route)
+				if len(routes) >= limit {
+					break
+				}
 			}
 			continue
 		}
 		if current.g > maxTravelDuration.Seconds() {
 			continue
 		}
+		if searchWindow > 0 {
+			currentDelta := float64(current.stopTime.DepartureTime) - startSecondsFloat
+			if currentDelta > searchWindowLimit {
+				continue
+			}
+		}
+
 		tpp := tp.Trips[current.stopTime.TripId]
 		if tpp != nil {
 			for i := current.index + 1; i < len(tpp.Stops); i++ {
@@ -187,6 +246,12 @@ func (tp *TripPlanner) FindRoute(from, to string, when time.Time) ([]*Route, err
 				if newCost > maxTravelDuration.Seconds() {
 					continue
 				}
+				if searchWindow > 0 {
+					nextDepartureDelta := float64(next.DepartureTime) - startSecondsFloat
+					if nextDepartureDelta > searchWindowLimit {
+						continue
+					}
+				}
 				key := nodeKey(next)
 				if prev, ok := bestCost[key]; ok && newCost >= prev {
 					continue
@@ -225,6 +290,12 @@ func (tp *TripPlanner) FindRoute(from, to string, when time.Time) ([]*Route, err
 			if newCost > maxTravelDuration.Seconds() {
 				continue
 			}
+			if searchWindow > 0 {
+				transferDepartureDelta := float64(transferStopTime.DepartureTime) - startSecondsFloat
+				if transferDepartureDelta > searchWindowLimit {
+					continue
+				}
+			}
 			idx := tripStopIndex(otherTrip, transferStopTime)
 			if idx < 0 {
 				continue
@@ -281,6 +352,18 @@ func buildRouteFromNode(goal *searchNode) *Route {
 	return &Route{Legs: legs}
 }
 
+func routeSignature(route *Route) string {
+	if route == nil {
+		return ""
+	}
+	if len(route.Legs) == 0 {
+		return ""
+	}
+	start := int(route.StartTime())
+	duration := route.Duration()
+	return fmt.Sprintf("%d:%d", start, duration)
+}
+
 func NewLeg(fromStop, toStop *types.StopTime) Leg {
 	trip, ok := toStop.Stop.Trips[toStop.TripId]
 	if !ok {