From 96fb8971eb844d1d6f6617b70020eac3172b9385 Mon Sep 17 00:00:00 2001
From: Mathieu Moran <mathieumoran1@gmail.com>
Date: Tue, 11 Aug 2026 02:27:17 -0400
Subject: [PATCH] fix(phase26): server trip detection mirrors Pi motion-aware
 logic (BUG-04)

---
 server/modules/db.py | 126 ++++++++++++++++++++++++++++++-------------
 1 file changed, 88 insertions(+), 38 deletions(-)

diff --git a/server/modules/db.py b/server/modules/db.py
index e2a45c8..34e41e6 100644
--- a/server/modules/db.py
+++ b/server/modules/db.py
@@ -280,7 +280,19 @@ _TRIP_GAP_S = 300  # 5 minutes
 
 
 def compute_trips_for_device(device_id):
-    """Recompute trip boundaries from tracking_points and upsert into trips table."""
+    """Recompute trip boundaries from tracking_points and upsert into trips table.
+
+    Mirrors the Pi's motion-aware trip-detection logic (modules/app_trip.py):
+    OBD wheel speed > 1 km/h is the primary motion signal. GPS displacement
+    >= 8 m per step (3 consecutive) is the fallback. A 5-minute gap between
+    motion events starts a new trip. This prevents parked idle rows from
+    merging two separate drives into one.
+    """
+    INACTIVITY_SECONDS = 5 * 60
+    GPS_MOTION_METERS = 8
+    MIN_GPS_MOTION_SAMPLES = 3
+    MAX_GPS_SAMPLE_GAP_SECONDS = 30
+
     with get_cursor() as cur:
         cur.execute(
             """
@@ -293,59 +305,97 @@ def compute_trips_for_device(device_id):
         )
         rows = cur.fetchall()
 
-    if not rows:
+    if len(rows) < 2:
         return 0
 
     import math
 
-    def haversine(lat1, lon1, lat2, lon2):
+    def haversine_km(lat1, lon1, lat2, lon2):
         R = 6371.0
         dlat = math.radians(lat2 - lat1)
         dlon = math.radians(lon2 - lon1)
-        a = math.sin(dlat/2)**2 + math.cos(math.radians(lat1)) * math.cos(math.radians(lat2)) * math.sin(dlon/2)**2
+        a = (math.sin(dlat / 2) ** 2
+             + math.cos(math.radians(lat1)) * math.cos(math.radians(lat2))
+             * math.sin(dlon / 2) ** 2)
         return R * 2 * math.atan2(math.sqrt(a), math.sqrt(1 - a))
 
-    # Split into segments by gap
-    segments = []
-    current = [rows[0]]
-    for prev, curr in zip(rows, rows[1:]):
-        gap = (curr[0] - prev[0]).total_seconds()
-        if gap > _TRIP_GAP_S:
-            segments.append(current)
-            current = [curr]
-        else:
-            current.append(curr)
-    segments.append(current)
+    # Detect motion events per step
+    obd_motion = []   # indices where OBD speed > 1 km/h
+    gps_motion = []   # indices where GPS displacement >= 8 m
 
-    # Build trip records
+    for i in range(1, len(rows)):
+        prev = rows[i - 1]
+        curr = rows[i]
+        gap = (curr[0] - prev[0]).total_seconds()
+        speed = curr[3] or 0
+        has_obd = speed > 1
+        has_gps = False
+        if 0 < gap <= MAX_GPS_SAMPLE_GAP_SECONDS:
+            d = haversine_km(prev[1], prev[2], curr[1], curr[2])
+            if d * 1000 >= GPS_MOTION_METERS:
+                has_gps = True
+        if has_obd:
+            obd_motion.append(i)
+        if has_gps:
+            gps_motion.append(i)
+
+    # Qualify GPS motion: need 3+ consecutive within 30s gap
+    qualified_gps = set()
+    seq = []
+    for idx in gps_motion:
+        if not seq or (rows[idx][0] - rows[seq[-1]][0]).total_seconds() > MAX_GPS_SAMPLE_GAP_SECONDS:
+            seq = [idx]
+        else:
+            seq.append(idx)
+        if len(seq) >= MIN_GPS_MOTION_SAMPLES:
+            qualified_gps.update(seq)
+
+    # All motion indices, sorted
+    motion_indices = sorted(set(obd_motion) | qualified_gps)
+    if not motion_indices:
+        return 0
+
+    # Group motion indices into trip boundaries by inactivity gap
+    groups = []
+    for idx in motion_indices:
+        if not groups or (rows[idx][0] - rows[groups[-1][-1]][0]).total_seconds() > INACTIVITY_SECONDS:
+            groups.append([idx])
+        else:
+            groups[-1].append(idx)
+
+    # Build trip records from each group
     trips = []
-    for seg in segments:
-        if len(seg) < 2:
+    for group in groups:
+        start_idx = max(0, group[0] - 1)
+        end_idx = group[-1]
+        seg_rows = rows[start_idx:end_idx + 1]
+
+        distance = 0
+        speeds = []
+        for i in range(1, len(seg_rows)):
+            d = haversine_km(seg_rows[i - 1][1], seg_rows[i - 1][2],
+                             seg_rows[i][1], seg_rows[i][2])
+            distance += d
+            s = seg_rows[i][3]
+            if s is not None and s > 0:
+                speeds.append(s)
+
+        duration_s = int((seg_rows[-1][0] - seg_rows[0][0]).total_seconds())
+        if duration_s < 30 or distance < 0.05:
             continue
-        start_time = seg[0][0]
-        end_time = seg[-1][0]
-        duration_s = int((end_time - start_time).total_seconds())
-        if duration_s < 30:
-            continue
-        dist = sum(
-            haversine(seg[i][1], seg[i][2], seg[i+1][1], seg[i+1][2])
-            for i in range(len(seg) - 1)
-        )
-        if dist < 0.05:  # skip <50m blips
-            continue
-        speeds = [r[3] for r in seg if r[3] is not None]
+
         trips.append({
-            "start_time": start_time,
-            "end_time": end_time,
-            "distance_km": round(dist, 3),
+            "start_time": seg_rows[0][0],
+            "end_time": seg_rows[-1][0],
+            "distance_km": round(distance, 3),
             "duration_s": duration_s,
             "avg_speed_kmh": round(sum(speeds) / len(speeds), 1) if speeds else None,
             "max_speed_kmh": round(max(speeds), 1) if speeds else None,
-            "start_lat": seg[0][1],
-            "start_lon": seg[0][2],
-            "end_lat": seg[-1][1],
-            "end_lon": seg[-1][2],
-            "point_count": len(seg),
+            "start_lat": seg_rows[0][1],
+            "start_lon": seg_rows[0][2],
+            "end_lat": seg_rows[-1][1],
+            "end_lon": seg_rows[-1][2],
+            "point_count": len(seg_rows),
         })
 
     with get_cursor(commit=True) as cur: