/**
* Converts a list of street edges to a list of turn-by-turn directions.
*
* @param edges : A list of street edges
* @return
*/
private List<WalkStep> getWalkSteps(List<State> states) {
List<WalkStep> steps = new ArrayList<WalkStep>();
WalkStep step = null;
double lastAngle = 0, distance = 0; // distance used for appending elevation profiles
int roundaboutExit = 0; // track whether we are in a roundabout, and if so the exit number
String roundaboutPreviousStreet = null;
for (State currState : states) {
State backState = currState.getBackState();
Edge edge = currState.getBackEdge();
EdgeNarrative edgeNarrative = currState.getBackEdgeNarrative();
boolean createdNewStep = false;
if (edge instanceof FreeEdge) {
continue;
}
if (!edgeNarrative.getMode().isOnStreetNonTransit()) {
continue; // ignore STLs and the like
}
Geometry geom = edgeNarrative.getGeometry();
if (geom == null) {
continue;
}
// generate a step for getting off an elevator (all
// elevator narrative generation occurs when alighting). We don't need to know what came
// before or will come after
if (edge instanceof ElevatorAlightEdge) {
// don't care what came before or comes after
step = createWalkStep(currState);
// tell the user where to get off the elevator using the exit notation, so the
// i18n interface will say 'Elevator to <exit>'
// what happens is that the webapp sees name == null and ignores that, and it sees
// exit != null and uses to <exit>
// the floor name is the AlightEdge name
// reset to avoid confusion with 'Elevator on floor 1 to floor 1'
step.streetName = ((ElevatorAlightEdge) edge).getName();
step.relativeDirection = RelativeDirection.ELEVATOR;
steps.add(step);
continue;
}
String streetName = edgeNarrative.getName();
int idx = streetName.indexOf('(');
String streetNameNoParens;
if (idx > 0) streetNameNoParens = streetName.substring(0, idx - 1);
else streetNameNoParens = streetName;
if (step == null) {
// first step
step = createWalkStep(currState);
createdNewStep = true;
steps.add(step);
double thisAngle = DirectionUtils.getFirstAngle(geom);
step.setAbsoluteDirection(thisAngle);
// new step, set distance to length of first edge
distance = edgeNarrative.getDistance();
} else if ((step.streetName != null && !step.streetNameNoParens().equals(streetNameNoParens))
&& (!step.bogusName || !edgeNarrative.hasBogusName())) {
/* street name has changed */
if (roundaboutExit > 0) {
// if we were just on a roundabout,
// make note of which exit was taken in the existing step
step.exit = Integer.toString(roundaboutExit); // ordinal numbers from
if (streetNameNoParens.equals(roundaboutPreviousStreet)) {
step.stayOn = true;
}
// localization
roundaboutExit = 0;
}
/* start a new step */
step = createWalkStep(currState);
createdNewStep = true;
steps.add(step);
if (edgeNarrative.isRoundabout()) {
// indicate that we are now on a roundabout
// and use one-based exit numbering
roundaboutExit = 1;
roundaboutPreviousStreet = backState.getBackEdgeNarrative().getName();
idx = roundaboutPreviousStreet.indexOf('(');
if (idx > 0) roundaboutPreviousStreet = roundaboutPreviousStreet.substring(0, idx - 1);
}
double thisAngle = DirectionUtils.getFirstAngle(geom);
step.setDirections(lastAngle, thisAngle, edgeNarrative.isRoundabout());
// new step, set distance to length of first edge
distance = edgeNarrative.getDistance();
} else {
/* street name has not changed */
double thisAngle = DirectionUtils.getFirstAngle(geom);
RelativeDirection direction =
WalkStep.getRelativeDirection(lastAngle, thisAngle, edgeNarrative.isRoundabout());
boolean optionsBefore = backState.multipleOptionsBefore();
if (edgeNarrative.isRoundabout()) {
// we are on a roundabout, and have already traversed at least one edge of it.
if (optionsBefore) {
// increment exit count if we passed one.
roundaboutExit += 1;
}
}
if (edgeNarrative.isRoundabout() || direction == RelativeDirection.CONTINUE) {
// we are continuing almost straight, or continuing along a roundabout.
// just append elevation info onto the existing step.
} else {
// we are not on a roundabout, and not continuing straight through.
// figure out if there were other plausible turn options at the last
// intersection
// to see if we should generate a "left to continue" instruction.
boolean shouldGenerateContinue = false;
if (edge instanceof PlainStreetEdge) {
// the next edges will be TinyTurnEdges or PlainStreetEdges, we hope
double angleDiff = getAbsoluteAngleDiff(thisAngle, lastAngle);
for (Edge alternative : backState.getVertex().getOutgoingStreetEdges()) {
if (alternative instanceof TinyTurnEdge) {
// a tiny turn edge has no geometry, but the next
// edge will be a TurnEdge or PSE and will have direction
alternative = alternative.getToVertex().getOutgoingStreetEdges().get(0);
}
if (alternative.getName().equals(streetName)) {
// alternatives that have the same name
// are usually caused by street splits
continue;
}
double altAngle = DirectionUtils.getFirstAngle(alternative.getGeometry());
double altAngleDiff = getAbsoluteAngleDiff(altAngle, lastAngle);
if (angleDiff > Math.PI / 4 || altAngleDiff - angleDiff < Math.PI / 16) {
shouldGenerateContinue = true;
break;
}
}
} else if (edge instanceof TinyTurnEdge) {
// do nothing as this will be handled in other cases
} else {
double angleDiff = getAbsoluteAngleDiff(lastAngle, thisAngle);
// in the case of a turn edge, we actually have to go back two steps to see
// where
// else we might be, as once we are on the streetvertex leading into this
// edge,
// we are stuck
State twoStatesBack = backState.getBackState();
Vertex backVertex = twoStatesBack.getVertex();
for (Edge alternative : backVertex.getOutgoingStreetEdges()) {
List<Edge> alternatives = alternative.getToVertex().getOutgoingStreetEdges();
if (alternatives.size() == 0) {
continue; // this is not an alternative
}
alternative = alternatives.get(0);
if (alternative.getName().equals(streetName)) {
// alternatives that have the same name
// are usually caused by street splits
continue;
}
double altAngle = DirectionUtils.getFirstAngle(alternative.getGeometry());
double altAngleDiff = getAbsoluteAngleDiff(altAngle, lastAngle);
if (angleDiff > Math.PI / 4 || altAngleDiff - angleDiff < Math.PI / 16) {
shouldGenerateContinue = true;
break;
}
}
}
if (shouldGenerateContinue) {
// turn to stay on same-named street
step = createWalkStep(currState);
createdNewStep = true;
steps.add(step);
step.setDirections(lastAngle, thisAngle, false);
step.stayOn = true;
// new step, set distance to length of first edge
distance = edgeNarrative.getDistance();
}
}
}
if (createdNewStep) {
// check last three steps for zag
int last = steps.size() - 1;
if (last >= 2) {
WalkStep threeBack = steps.get(last - 2);
WalkStep twoBack = steps.get(last - 1);
WalkStep lastStep = steps.get(last);
if (twoBack.distance < MAX_ZAG_DISTANCE
&& lastStep.streetNameNoParens().equals(threeBack.streetNameNoParens())) {
// total hack to remove zags.
steps.remove(last);
steps.remove(last - 1);
step = threeBack;
step.distance += twoBack.distance;
if (twoBack.elevation != null) {
if (step.elevation == null) {
step.elevation = twoBack.elevation;
} else {
for (P2<Double> d : twoBack.elevation) {
step.elevation.add(new P2<Double>(d.getFirst() + step.distance, d.getSecond()));
}
}
}
}
}
} else {
if (step.elevation != null) {
List<P2<Double>> s = encodeElevationProfile(edge, distance);
if (step.elevation != null && step.elevation.size() > 0) {
step.elevation.addAll(s);
} else {
step.elevation = s;
}
}
distance += edgeNarrative.getDistance();
}
// increment the total length for this step
step.distance += edgeNarrative.getDistance();
step.addAlerts(edgeNarrative.getNotes());
lastAngle = DirectionUtils.getLastAngle(geom);
}
return steps;
}
