core: stdcm: move "max delay" logic to edge

Signed-off-by: Eloi Charpentier <[email protected]>

Author: eckter

core/src/main/kotlin/fr/sncf/osrd/stdcm/graph/STDCMEdge.kt

@@ -92,7 +92,7 @@ data class STDCMEdge(
                     stopDuration,
                     graph.delayManager.getMaxAdditionalStopDuration(
                         infraExplorerWithNewEnvelope,
-                        timeData.earliestReachableTime + totalTime
+                        getEdgeEndTime(),
                     )
                 ),
                 endSpeed,
@@ -172,4 +172,23 @@ data class STDCMEdge(
     fun fromTravelledOffset(travelledPathOffset: Offset<TravelledPath>): Offset<BlockPath> {
         return infraExplorer.getIncrementalPath().fromTravelledPath(travelledPathOffset)
     }
+
+    /** Return the time at which the train quits this edge and moves on to the next. */
+    private fun getEdgeEndTime(): Double {
+        return timeData.earliestReachableTime + totalTime
+    }
+
+    /**
+     * Return how much delay we can add on this edge. We need to be given the time added on the next
+     * edges (both departure delaying and allowances), as they carry over previous edges.
+     */
+    fun getMaxAddedDelay(addedAllowanceOnNextEdges: Double): Double {
+        val maxAddedDelay = timeData.timeOfNextConflictAtLocation - getEdgeEndTime()
+        return maxAddedDelay - addedAllowanceOnNextEdges
+    }
+
+    /** Return all delay added to this edge, engineering + departure delay */
+    fun getTotalAddedDelayOnEdge(): Double {
+        return timeData.delayAddedToLastDeparture + (engineeringAllowance?.extraDuration ?: 0.0)
+    }
 }

core/src/main/kotlin/fr/sncf/osrd/stdcm/graph/STDCMGraph.kt

@@ -162,6 +162,8 @@ class STDCMGraph(
         while (true) {
             val edge = node.previousEdge ?: return maxTime
 
+            // TODO: this is wrong, we should use `edge.getMaxAddedDelay` instead.
+            // But doing so can lead to infinite loops, especially in the unit test "infraWithLoop".
             val latestTimeWithMaxShift =
                 edge.timeData.earliestReachableTime +
                     edge.totalTime +

core/src/main/kotlin/fr/sncf/osrd/stdcm/graph/engineering_allowance/SimulationSegment.kt

@@ -67,9 +67,7 @@ fun generatePreviousSimulationSegments(
         if (currentEdge.endAtStop) break
 
         val envelope = currentEdge.originalEnvelope
-        val edgeEndTime = currentEdge.timeData.earliestReachableTime + currentEdge.totalTime
-        val maxAddedDelay =
-            currentEdge.timeData.timeOfNextConflictAtLocation - edgeEndTime - alreadyAddedDelay
+        val maxAddedDelay = currentEdge.getMaxAddedDelay(alreadyAddedDelay)
         if (maxAddedDelay <= 0.0) break
 
         val backwardsPointPairs =
@@ -103,8 +101,7 @@ fun generatePreviousSimulationSegments(
                 )
             )
         }
-        currentEdge.engineeringAllowance?.let { alreadyAddedDelay += it.extraDuration }
-        alreadyAddedDelay += currentEdge.timeData.delayAddedToLastDeparture
+        alreadyAddedDelay += currentEdge.getTotalAddedDelayOnEdge()
         currentEdge = currentEdge.previousNode.previousEdge
     }
 }