Read a past night against its own sleep need, not today's

lib/compute/derivation_engine.dart

@@ -7312,7 +7312,7 @@ class DerivationEngine {
       // one layer up on the output.
       final builtForDay = LocalDb.localDayLabelNow();
       final builtAtEpoch = DateTime.now().millisecondsSinceEpoch ~/ 1000;
-      final (bundleJson, dropped) = await _runIsolateCancellable(
+      final (bundleJson, dropped, needMin) = await _runIsolateCancellable(
         () {
           final bundle =
               buildCrossDayBundle(
@@ -7331,7 +7331,9 @@ class DerivationEngine {
           final paths = <String>[];
           final safe = sanitizeForJson(bundle, paths) as Map<String, dynamic>;
           if (paths.isNotEmpty) safe['encode_dropped_fields'] = paths;
-          return (jsonEncode(safe), paths);
+          // Read here, not by re-decoding bundleJson on the main isolate (the
+          // hang the comment above is about).
+          return (jsonEncode(safe), paths, crossDayNeedMin(safe));
         },
         _crossDayTimeout,
         label: 'crossday',
@@ -7342,7 +7344,15 @@ class DerivationEngine {
         _log('crossday: zone changed during the build; not stored');
         return false;
       }
-      if (!await LocalDb.putReviewedBaseline('crossday', bundleJson, reviewRevision)) {
+      // `series`: the need this build computed, kept per day: the artifact
+      // only ever holds the latest one, so without this every past night was
+      // read against TODAY's need (#619). Same transaction as the artifact,
+      // so the day's row always matches the artifact that day last served; a
+      // later build the same day replaces both. null when the need abstained,
+      // so a past day reads "—", never a stale value. No backfill: an earlier
+      // day's need was never stored anywhere.
+      if (!await LocalDb.putReviewedBaseline('crossday', bundleJson, reviewRevision,
+          series: (date: builtForDay, key: 'sleep_need_min', value: needMin))) {
         _log('crossday: newer activity review; leaving its refresh queued');
         return false;
       }
@@ -7403,6 +7413,16 @@ class DerivationEngine {
     return out;
   }
 
+  /// The learned sleep need in a crossday bundle, in whole minutes, or null
+  /// when `sleep_coach.need` abstained or is missing — the same field and
+  /// rounding `LocalRepositoryImpl._sleepNeedMin` reads.
+  static double? crossDayNeedMin(Map<String, dynamic> bundle) =>
+      switch (bundle['sleep_coach']) {
+        {'need': {'value': {'need_sec': final num s}}} =>
+          (s / 60).roundToDouble(),
+        _ => null,
+      };
+
   /// The phone zone a `crossday_input` artifact was built in. Its records are
   /// zone-RELATIVE (`clock_shift_sec` is "this night's clock minus the zone the
   /// record was built in"), so an artifact built before a flight, served after

lib/data/db.dart

@@ -13341,13 +13341,22 @@ class LocalDb {
   }
 
   /// A calculation started before a review must never publish over it.
-  static Future<bool> putReviewedBaseline(String key, String payloadJson, int expectedRevision) async {
+  /// [series], when given, is one `metric_series` row derived from this same
+  /// payload, written in the same transaction so the two can never disagree
+  /// (derivation runs in more than one isolate, so two builds can interleave).
+  static Future<bool> putReviewedBaseline(String key, String payloadJson, int expectedRevision,
+      {({String date, String key, double? value})? series}) async {
     return (await instance).transaction((tx) async {
       final rows = await tx.query('activity_review_meta', columns: ['revision']);
       final revision = rows.isEmpty ? 0 : rows.single['revision'] as int;
       if (revision != expectedRevision) return false;
       await tx.insert('baselines', {'key': key, 'payload_json': payloadJson,
         'updated_at': DateTime.now().millisecondsSinceEpoch}, conflictAlgorithm: ConflictAlgorithm.replace);
+      if (series != null) {
+        await tx.insert('metric_series',
+            {'date': series.date, 'key': series.key, 'value': series.value},
+            conflictAlgorithm: ConflictAlgorithm.replace);
+      }
       return true;
     });
   }

lib/data/local_repository_impl.dart

@@ -1096,7 +1096,12 @@ class LocalRepositoryImpl extends LocalRepository {
       return v == null ? null : (v / 60).round();
     }
 
-    final needMin = _sleepNeedMin(await _crossDay());
+    // Today: the live estimate. A past night: the need computed on that day
+    // (written per day by the crossday pass), absent if none was — never
+    // today's estimate, which postdates the night (#619).
+    final needMin = _isTodayLabel(date)
+        ? _sleepNeedMin(await _crossDay())
+        : (await LocalDb.metricValueOn(date, 'sleep_need_min'))?.round();
     final sleepConf = _sub(b, 'sleep.accounting')?['confidence'] as num?;
     // Sleep periods (main + naps) for the periods screen. The main period is
     // enriched HERE with the hypnogram + stage minutes: derivation builds the
@@ -1166,9 +1171,9 @@ class LocalRepositoryImpl extends LocalRepository {
       // field getDayHeart already read; no new computation.
       'spo2': b['spo2'],
       // Sleep need, and the debt against it — both only when the need was
-      // actually learned (`sleep_coach.need`, see [_sleepNeedMin]; it is the
-      // current personal estimate, and the artifact behind it is refused once
-      // it is more than a week old). There is no 8 h default: it made the gauge
+      // actually learned (`sleep_coach.need`, see [_sleepNeedMin]; today's is
+      // the current personal estimate, a past night's the one stored for that
+      // day — see `needMin` above). There is no 8 h default: it made the gauge
       // "always read", which is the point, since what it read was a population
       // figure presented as this user's own. Absent keys leave the gauge in its
       // honest empty state.

test/sleep_need_per_night_test.dart

@@ -0,0 +1,178 @@
+// #619: a past night is read against the sleep need the app had computed ON
+// that day, not against today's estimate. The crossday artifact only ever holds
+// the latest need, so `_runCrossDay` also files it per day under
+// `metric_series` `sleep_need_min`; `getDaySleepV2` reads that row for any day
+// but today, and reads nothing (no need, no debt) when there is none.
+
+import 'dart:convert';
+
+import 'package:flutter_test/flutter_test.dart';
+import 'package:path/path.dart' as p;
+import 'package:sqflite_common_ffi/sqflite_ffi.dart';
+
+import 'package:openstrap_edge/compute/derivation_engine.dart';
+import 'package:openstrap_edge/data/day_label.dart';
+import 'package:openstrap_edge/data/db.dart';
+import 'package:openstrap_edge/data/local_repository_impl.dart';
+
+void main() {
+  group('crossDayNeedMin', () {
+    test('reads sleep_coach.need in whole minutes', () {
+      expect(
+        DerivationEngine.crossDayNeedMin({
+          'sleep_coach': {
+            'need': {
+              'value': {'need_sec': 462 * 60 + 29},
+              'confidence': 0.7,
+            },
+          },
+        }),
+        462.0,
+      );
+    });
+
+    test('is null when the need abstained or the block is missing', () {
+      expect(DerivationEngine.crossDayNeedMin({}), isNull);
+      expect(
+        DerivationEngine.crossDayNeedMin({
+          'sleep_coach': {
+            'need': {'value': null, 'reason': 'need_nights'},
+          },
+        }),
+        isNull,
+      );
+      expect(
+        DerivationEngine.crossDayNeedMin({'sleep_coach': 'garbage'}),
+        isNull,
+      );
+    });
+  });
+
+  group('getDaySleepV2 sleep need per night', () {
+    late LocalRepositoryImpl repo;
+    late String today;
+    late String pastDay;
+
+    String label(DateTime d) => dayLabelOf(d);
+
+    String bundle(String day) => jsonEncode({
+          'date': day,
+          'sleep': {
+            'accounting': {
+              'value': {'tst_sec': 420 * 60, 'efficiency_pct': 90.0},
+            },
+          },
+        });
+
+    setUpAll(() async {
+      sqfliteFfiInit();
+      databaseFactory = databaseFactoryFfi;
+      LocalDb.dbName = 'openstrap_sleep_need_per_night_test.db';
+      await databaseFactory.deleteDatabase(
+        p.join(await databaseFactory.getDatabasesPath(), LocalDb.dbName),
+      );
+      repo = LocalRepositoryImpl(getProfileMap: () => const {});
+    });
+
+    tearDownAll(() async {
+      await LocalDb.close();
+      await databaseFactory.deleteDatabase(
+        p.join(await databaseFactory.getDatabasesPath(), LocalDb.dbName),
+      );
+    });
+
+    setUp(() async {
+      // Per test, not once: a run that crosses local midnight would otherwise
+      // read a fixture "today" as a past day.
+      today = todayLabel();
+      final t = DateTime.parse(today);
+      pastDay = label(DateTime(t.year, t.month, t.day - 3));
+      final db = await LocalDb.instance;
+      await db.delete('day_result');
+      await db.delete('baselines');
+      await db.delete('metric_series');
+      for (final day in [pastDay, today]) {
+        await LocalDb.putDayResult(
+          dayId: day,
+          algoVersion: kAlgoVersion,
+          payloadJson: bundle(day),
+          windowJson: '{}',
+        );
+      }
+      // Today's crossday artifact says 480 min.
+      await LocalDb.putBaseline(
+        'crossday',
+        jsonEncode({
+          'algo_version': kAlgoVersion,
+          'built_for_day': today,
+          'sleep_coach': {
+            'need': {
+              'value': {'need_sec': 480 * 60},
+              'confidence': 0.7,
+              'tier': 'ESTIMATE',
+            },
+          },
+        }),
+      );
+    });
+
+    test('a past night uses the need stored for that day, not today\'s',
+        () async {
+      await LocalDb.putMetricSeriesValue(pastDay, 'sleep_need_min', 450);
+
+      final night = await repo.getDaySleepV2(pastDay);
+      expect(night['need_min'], 450);
+      expect(night['debt_min'], 30); // 450 need - 420 asleep
+    });
+
+    test('a past night with no stored need has no need and no debt', () async {
+      final night = await repo.getDaySleepV2(pastDay);
+      expect(night['has_sleep'], isNot(false));
+      expect(night.containsKey('need_min'), isFalse);
+      expect(night.containsKey('debt_min'), isFalse);
+    });
+
+    test('a need that abstained later the same day clears the stored one',
+        () async {
+      await LocalDb.putMetricSeriesValue(pastDay, 'sleep_need_min', 450);
+      await LocalDb.putMetricSeriesValue(pastDay, 'sleep_need_min', null);
+
+      final rows = await (await LocalDb.instance).query('metric_series',
+          where: 'date = ? AND key = ?',
+          whereArgs: [pastDay, 'sleep_need_min']);
+      expect(rows, hasLength(1));
+      expect((await repo.getDaySleepV2(pastDay)).containsKey('need_min'),
+          isFalse);
+    });
+
+    test('the crossday write stores the artifact and its day\'s need together, '
+        'or neither', () async {
+      Future<double?> stored() => LocalDb.metricValueOn(today, 'sleep_need_min');
+      final revision = await LocalDb.activityReviewRevision();
+
+      expect(
+          await LocalDb.putReviewedBaseline('crossday', '{"v":1}', revision,
+              series: (date: today, key: 'sleep_need_min', value: 455.0)),
+          isTrue);
+      expect(await stored(), 455.0);
+      expect((await LocalDb.baseline('crossday'))?['payload_json'], '{"v":1}');
+
+      // A stale build (a newer activity review landed) writes nothing.
+      expect(
+          await LocalDb.putReviewedBaseline('crossday', '{"v":2}', revision + 1,
+              series: (date: today, key: 'sleep_need_min', value: 400.0)),
+          isFalse);
+      expect(await stored(), 455.0);
+      expect((await LocalDb.baseline('crossday'))?['payload_json'], '{"v":1}');
+    });
+
+    test('today still reads the live crossday need', () async {
+      // A stored row for today must not override the live estimate.
+      await LocalDb.putMetricSeriesValue(today, 'sleep_need_min', 450);
+
+      final night = await repo.getDaySleepV2(today);
+      expect(night['need_min'], 480);
+      expect(night['debt_min'], 60);
+    });
+  });
+}