feat: show step count per activity session

app/src/main/java/com/podometer/data/db/SensorWindow.kt

@@ -5,7 +5,7 @@ import androidx.room.Entity
 import androidx.room.PrimaryKey
 
 /**
- * Room entity storing a single 5-second classifier window of raw sensor data.
+ * Room entity storing a single 30-second classifier window of raw sensor data.
  *
  * These windows are recorded continuously by [com.podometer.service.StepTrackingService]
  * and retained for 7 days. They enable retroactive recomputation of activity sessions

app/src/main/java/com/podometer/domain/model/ActivitySession.kt

@@ -16,13 +16,15 @@ package com.podometer.domain.model
  *                              this session. Used for override/reclassification.
  * @property isManualOverride   True when the opening transition was manually
  *                              overridden by the user.
+ * @property stepCount          Total steps detected during this session.
  */
 data class ActivitySession(
     val activity: ActivityState,
     val startTime: Long,
     val endTime: Long?,
     val startTransitionId: Int,
     val isManualOverride: Boolean,
+    val stepCount: Int = 0,
 )
 
 /**

app/src/main/java/com/podometer/domain/usecase/RecomputeActivitySessionsUseCase.kt

@@ -21,7 +21,7 @@ import javax.inject.Singleton
  * activity sessions for a given date.
  *
  * This enables retroactive recomputation when classifier parameters change —
- * the raw 5-second windows are retained for 7 days and can be replayed at any
+ * the raw 30-second windows are retained for 7 days and can be replayed at any
  * time to generate updated session data.
  */
 interface RecomputeActivitySessionsUseCase {
@@ -94,7 +94,26 @@ class RecomputeActivitySessionsUseCaseImpl @Inject constructor(
                 }
             }
 
-            return buildActivitySessions(transitions, nowMillis)
+            val sessions = buildActivitySessions(transitions, nowMillis)
+            return attachStepCounts(sessions, windows)
+        }
+
+        /**
+         * Sums [SensorWindow.stepCount] for each session's time range and returns
+         * sessions with [ActivitySession.stepCount] populated.
+         */
+        private fun attachStepCounts(
+            sessions: List<ActivitySession>,
+            windows: List<SensorWindow>,
+        ): List<ActivitySession> {
+            if (sessions.isEmpty() || windows.isEmpty()) return sessions
+            return sessions.map { session ->
+                val endTime = session.endTime ?: Long.MAX_VALUE
+                val steps = windows
+                    .filter { it.timestamp in session.startTime until endTime }
+                    .sumOf { it.stepCount }
+                session.copy(stepCount = steps)
+            }
         }
     }
 }

app/src/main/java/com/podometer/ui/dashboard/ActivityLog.kt

@@ -284,9 +284,19 @@ private fun ActivityLogItem(
             text = durationText,
             style = MaterialTheme.typography.bodySmall,
             color = MaterialTheme.colorScheme.onSurfaceVariant,
-            modifier = Modifier.weight(1f),
         )
 
+        if (session.stepCount > 0) {
+            Spacer(modifier = Modifier.width(8.dp))
+            Text(
+                text = stringResource(R.string.activity_session_steps, session.stepCount),
+                style = MaterialTheme.typography.bodySmall,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+            )
+        }
+
+        Spacer(modifier = Modifier.weight(1f))
+
         if (session.isManualOverride) {
             Spacer(modifier = Modifier.width(8.dp))
             AssistChip(
@@ -408,6 +418,7 @@ private fun PreviewActivityLogMultiple() {
             endTime = 10L * hour + 30L * 60_000L,
             startTransitionId = 1,
             isManualOverride = false,
+            stepCount = 1247,
         ),
         ActivitySession(
             activity = ActivityState.CYCLING,
@@ -422,6 +433,7 @@ private fun PreviewActivityLogMultiple() {
             endTime = null,
             startTransitionId = 3,
             isManualOverride = false,
+            stepCount = 312,
         ),
     )
     PodometerTheme {

app/src/main/res/values/strings.xml

@@ -70,6 +70,7 @@
 
     <!-- ActivityLog labels -->
     <string name="activity_session_ongoing">ongoing</string>
+    <string name="activity_session_steps">%1$d steps</string>
     <string name="cd_activity_session_item">%1$s session, %2$s, %3$s</string>
     <string name="cd_activity_override_options">Override options for session at %1$s</string>
 

app/src/test/java/com/podometer/domain/usecase/RecomputeActivitySessionsUseCaseTest.kt

@@ -50,6 +50,27 @@ class RecomputeActivitySessionsUseCaseTest {
         assertEquals(ActivityState.WALKING, sessions[0].activity)
     }
 
+    @Test
+    fun `replayWindows attaches step counts to walking sessions`() {
+        val windows = (0 until 40).map { i ->
+            SensorWindow(
+                id = i.toLong(),
+                timestamp = 1_000_000L + i * 5_000L,
+                magnitudeVariance = 1.0,
+                stepFrequencyHz = 1.8,
+                stepCount = 9,
+            )
+        }
+
+        val sessions = RecomputeActivitySessionsUseCaseImpl.replayWindows(
+            windows = windows,
+            nowMillis = nowMillis,
+        )
+
+        assertTrue("Expected at least one session", sessions.isNotEmpty())
+        assertTrue("Walking session should have steps > 0", sessions[0].stepCount > 0)
+    }
+
     @Test
     fun `replayWindows detects cycling session from sustained cycling windows`() {
         // First, we need some STILL state, then transition to cycling.