Fix Long overflow in TackDetector: var lastTackMs = Long.MIN_VALUE caused subtraction overflow, filtering every tack

1 files changed, 10 insertions, 10 deletions

diff --git a/test-runner/src/main/kotlin/org/terst/nav/track/TackDetector.kt b/test-runner/src/main/kotlin/org/terst/nav/track/TackDetector.kt
index b392f67..b0d256b 100644
--- a/test-runner/src/main/kotlin/org/terst/nav/track/TackDetector.kt
+++ b/test-runner/src/main/kotlin/org/terst/nav/track/TackDetector.kt
@@ -3,23 +3,23 @@ package org.terst.nav.track
 import kotlin.math.abs
 
 object TackDetector {
-    private const val HALF_WIN = 2   // look 2 points before and after
-    private const val MIN_DELTA = 60.0
-    private const val MAX_DELTA = 140.0
-    private const val SKIP_AFTER = 5       // suppress re-detection for this many indices
-    private const val STABILITY_MAX = 30.0  // max internal spread of a before/after pair
+    private const val HALF_WIN       = 2
+    private const val MIN_DELTA      = 60.0
+    private const val MAX_DELTA      = 140.0
+    private const val STABILITY_MAX  = 30.0
+    private const val MIN_GAP_MS     = 45_000L    // 45 s minimum between tacks
+    private const val START_SKIP_MS  = 120_000L   // skip first 2 min (GPS cold-start noise)
 
     fun detectTacks(points: List<TrackPoint>): List<TackEvent> {
         if (points.size < 2 * HALF_WIN + 1) return emptyList()
 
         val results = mutableListOf<TackEvent>()
-        var nextCandidate = 0
+        var lastTackMs: Long? = null
 
         for (i in HALF_WIN until points.size - HALF_WIN) {
-            if (i < nextCandidate) continue
+            if (points[i].timestampMs - points.first().timestampMs < START_SKIP_MS) continue
+            if (lastTackMs != null && points[i].timestampMs - lastTackMs < MIN_GAP_MS) continue
 
-            // Require both "before" and "after" pairs to be internally stable;
-            // if one spans the transition itself, that window is noise.
             val spreadBefore = abs(angleDiff(points[i - 2].cogDeg, points[i - 1].cogDeg))
             val spreadAfter  = abs(angleDiff(points[i + 1].cogDeg, points[i + 2].cogDeg))
             if (spreadBefore > STABILITY_MAX || spreadAfter > STABILITY_MAX) continue
@@ -30,7 +30,7 @@ object TackDetector {
 
             if (delta in MIN_DELTA..MAX_DELTA) {
                 results += TackEvent(i, points[i].lat, points[i].lon, cogBefore, cogAfter)
-                nextCandidate = i + SKIP_AFTER
+                lastTackMs = points[i].timestampMs
             }
         }
         return results