Fitness Age: "N more nights" countdown while it's building (iOS + Android)

Packages/StrandAnalytics/Sources/StrandAnalytics/FitnessAgeEngine.swift

@@ -198,6 +198,12 @@ extension FitnessAgeEngine {
     /// Coverage at/above which an input reads as fully satisfied (a "confident" week).
     public static let goodCoverageDays = 6
 
+    /// Nights of resting-HR still needed before the headline can compute AT ALL — the countdown the
+    /// not-ready card shows ("N more nights of wear…"). 0 once `minCoverageDays` is met. Assumes continued
+    /// nightly wear (a skipped night just doesn't advance the count). Shared with the Android engine so both
+    /// platforms show the same number.
+    public static func nightsUntilReady(rhrDays: Int) -> Int { max(0, minCoverageDays - rhrDays) }
+
     private static func coverageStatus(_ days: Int, floor: Int) -> FitnessReadinessStatus {
         if days >= goodCoverageDays { return .satisfied }
         if days >= floor || days > 0 { return .partial }

Packages/StrandAnalytics/Tests/StrandAnalyticsTests/FitnessAgeEngineTests.swift

@@ -156,4 +156,17 @@ final class FitnessAgeEngineTests: XCTestCase {
                                                  hasHeightWeight: false, hasWaist: false)
         XCTAssertEqual(r.confidence, .ready)
     }
+
+    // The not-ready countdown: nights of RHR still needed to reach the floor (minCoverageDays = 4).
+    func testNightsUntilReadyCountsDownToTheFloor() {
+        XCTAssertEqual(FitnessAgeEngine.nightsUntilReady(rhrDays: 0), 4)
+        XCTAssertEqual(FitnessAgeEngine.nightsUntilReady(rhrDays: 1), 3)
+        XCTAssertEqual(FitnessAgeEngine.nightsUntilReady(rhrDays: 3), 1)
+    }
+
+    // At/above the floor it's 0 (never negative), so the card flips to "ready" with no leftover countdown.
+    func testNightsUntilReadyZeroAtOrAboveFloor() {
+        XCTAssertEqual(FitnessAgeEngine.nightsUntilReady(rhrDays: 4), 0)
+        XCTAssertEqual(FitnessAgeEngine.nightsUntilReady(rhrDays: 7), 0)
+    }
 }

Strand/Screens/HealthView.swift

@@ -688,6 +688,23 @@ private struct FitnessAgeSection: View {
             hasWaist: profile.waistCm > 0)
     }
 
+    /// The not-ready card's lead: a concrete countdown of nights-of-wear still needed (from the shared
+    /// `nightsUntilReady`), noting the profile basics only when they're actually missing. Copy is kept
+    /// WORD-FOR-WORD identical to the Android `fitnessReadyLead` so the two platforms match.
+    private func fitnessReadyLead() -> String {
+        let rhrDays = repo.days.suffix(7).compactMap { $0.restingHr }.count
+        let remaining = FitnessAgeEngine.nightsUntilReady(rhrDays: rhrDays)
+        let needsBasics = profile.age <= 0 || profile.sex.isEmpty
+        switch (remaining, needsBasics) {
+        case (0, false): return String(localized: "A few more days and we can show your Fitness Age.")
+        case (0, true):  return String(localized: "Add your age and sex below and we can show your Fitness Age.")
+        case (1, false): return String(localized: "1 more night of wear and we can show your Fitness Age.")
+        case (1, true):  return String(localized: "1 more night of wear, plus your age and sex below, and we can show your Fitness Age.")
+        case (let n, false): return String(localized: "\(n) more nights of wear and we can show your Fitness Age.")
+        case (let n, true):  return String(localized: "\(n) more nights of wear, plus your age and sex below, and we can show your Fitness Age.")
+        }
+    }
+
     var body: some View {
         VStack(alignment: .leading, spacing: NoopMetrics.gap) {
             SectionHeader("Fitness Age", overline: "Weekly",
@@ -720,12 +737,11 @@ private struct FitnessAgeSection: View {
                     .transition(.opacity)
             }
         } else if loaded {
-            // No value yet: lead with the checklist so the user sees exactly what's still needed.
+            // No value yet: lead with a concrete countdown ("N more nights of wear…") so the user knows
+            // how far off it is, then the checklist shows exactly what's still needed.
             ReadinessChecklistCard(
                 readiness: readiness,
-                lead: readiness.canCompute
-                    ? "A few more days and we can show your Fitness Age."
-                    : "A few more days of wear, plus the basics below, and we can show your Fitness Age.",
+                lead: fitnessReadyLead(),
                 onFix: { fitnessSheet = .settings })
         } else {
             // Brief read of the weekly value; honest placeholder rather than an empty gap.

android/app/src/main/java/com/noop/analytics/FitnessAgeEngine.kt

@@ -122,6 +122,11 @@ object FitnessAgeEngine {
     const val minCoverageDays = 4
     const val goodCoverageDays = 6
 
+    /** Nights of resting-HR still needed before the headline can compute AT ALL — the countdown the
+     *  not-ready card shows ("N more nights of wear…"). 0 once [minCoverageDays] is met. Assumes continued
+     *  nightly wear. Shared with the iOS engine so both platforms show the same number. */
+    fun nightsUntilReady(rhrDays: Int): Int = maxOf(0, minCoverageDays - rhrDays)
+
     private fun coverageStatus(days: Int, floor: Int): FitnessReadinessStatus = when {
         days >= goodCoverageDays -> FitnessReadinessStatus.SATISFIED
         days >= floor || days > 0 -> FitnessReadinessStatus.PARTIAL

android/app/src/main/java/com/noop/ui/HealthScreen.kt

@@ -598,10 +598,10 @@ private fun FitnessAgeSection(vm: AppViewModel, days: List<DailyMetric>, profile
     // age; activity (a scored strain day) is an enrichment signal; height/weight/waist sit under the
     // VO₂max role. Age/sex come from the profile. Approximate by design — the weekly value is the
     // authority; this just explains the gaps.
+    // rhrDays drives BOTH the readiness verdict AND the not-ready countdown lead, so hoist it out.
+    val rhrDays = remember(days) { days.takeLast(7).count { it.restingHr != null } }
     val readiness = remember(days, profile.age, profile.sex, profile.waistCm) {
-        val last7 = days.takeLast(7)
-        val rhrDays = last7.count { it.restingHr != null }
-        val activityDays = last7.count { it.strain != null }
+        val activityDays = days.takeLast(7).count { it.strain != null }
         FitnessAgeEngine.assessReadiness(
             hasAge = profile.age > 0,
             hasSex = profile.sex.isNotBlank(),
@@ -629,8 +629,9 @@ private fun FitnessAgeSection(vm: AppViewModel, days: List<DailyMetric>, profile
                 FitnessReadinessCard(readiness = readiness, headed = false)
             }
         } else {
-            // No weekly value yet — surface the checklist directly so the user knows what's pending.
-            FitnessReadinessCard(readiness = readiness, headed = true)
+            // No weekly value yet — lead with a concrete countdown, then the checklist.
+            FitnessReadinessCard(readiness = readiness, headed = true,
+                lead = fitnessReadyLead(rhrDays, profile.age > 0, profile.sex.isNotBlank()))
         }
     }
 }
@@ -897,11 +898,27 @@ private fun FitnessAgeHero(
     }
 }
 
+/** The not-ready card's lead: a concrete countdown of nights-of-wear still needed (from the shared
+ *  [FitnessAgeEngine.nightsUntilReady]), noting the profile basics only when actually missing. Copy is kept
+ *  WORD-FOR-WORD identical to the iOS `fitnessReadyLead` (HealthView) so the two platforms match. */
+private fun fitnessReadyLead(rhrDays: Int, hasAge: Boolean, hasSex: Boolean): String {
+    val remaining = FitnessAgeEngine.nightsUntilReady(rhrDays)
+    val needsBasics = !hasAge || !hasSex
+    return when {
+        remaining == 0 && !needsBasics -> "A few more days and we can show your Fitness Age."
+        remaining == 0 && needsBasics  -> "Add your age and sex below and we can show your Fitness Age."
+        remaining == 1 && !needsBasics -> "1 more night of wear and we can show your Fitness Age."
+        remaining == 1 && needsBasics  -> "1 more night of wear, plus your age and sex below, and we can show your Fitness Age."
+        !needsBasics -> "$remaining more nights of wear and we can show your Fitness Age."
+        else         -> "$remaining more nights of wear, plus your age and sex below, and we can show your Fitness Age."
+    }
+}
+
 /** The readiness checklist card: each input as a ✓ / ⚠ / ○ glyph + its detail, grouped by role into
- *  "Drives your Fitness Age" and "Unlocks your VO₂max". When [headed] (no value yet) it leads with a
- *  "a few more days" heading and floats the required-missing items to the top of their group. */
+ *  "Drives your Fitness Age" and "Unlocks your VO₂max". When [headed] (no value yet) it leads with the
+ *  [lead] countdown and floats the required-missing items to the top of their group. */
 @Composable
-private fun FitnessReadinessCard(readiness: FitnessAgeReadiness, headed: Boolean) {
+private fun FitnessReadinessCard(readiness: FitnessAgeReadiness, headed: Boolean, lead: String = "") {
     val drivesAge = readiness.items
         .filter { it.role == FitnessReadinessRole.DRIVES_AGE }
         .sortedBy { if (headed) readinessSortKey(it) else 0 }
@@ -914,7 +931,7 @@ private fun FitnessReadinessCard(readiness: FitnessAgeReadiness, headed: Boolean
             if (headed) {
                 Column(verticalArrangement = Arrangement.spacedBy(Metrics.space4)) {
                     Text(
-                        "A few more days and we can show your Fitness Age",
+                        lead.ifBlank { "A few more days and we can show your Fitness Age." },
                         style = NoopType.headline,
                         color = Palette.textPrimary,
                     )