Optimize lookup and caching patterns with performance tests

workout-logger/lib/screens/programs/program_designer_screen.dart

@@ -429,7 +429,7 @@ class _ProgramDesignerScreenState extends State<ProgramDesignerScreen> {
                   decoration: const InputDecoration(
                     labelText: 'Day of Week (optional)',
                   ),
-                  value: dow,
+                  initialValue: dow,
                   items: [
                     const DropdownMenuItem(value: null, child: Text('Unscheduled')),
                     ...List.generate(7, (i) => i + 1).map((d) => DropdownMenuItem(

workout-logger/lib/screens/programs/program_detail_screen.dart

@@ -6,7 +6,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:provider/provider.dart';
-import 'dart:ui' show FontFeature;
 
 import '../../models/models.dart';
 import '../../services/workout_provider.dart';

workout-logger/lib/services/managers/analytics_manager.dart

@@ -26,6 +26,13 @@ class AnalyticsManager extends ChangeNotifier {
   // Growth models for each exercise
   final Map<String, GrowthModel> _growthModels = {};
 
+  // Reference to track the sessions list identity and detect stale usage
+  List<WorkoutSession>? _lastIndexedSessions;
+
+  // Pre-computed exerciseId → sorted-newest-first ExerciseLog and date index.
+  // Rebuilt via [buildSessionIndex] whenever the session list changes.
+  Map<String, List<({ExerciseLog log, DateTime date})>> _sessionIndex = {};
+
   // Callback to update targets with new growth models
   final void Function(String exerciseId, GrowthModel model)?
   onGrowthModelUpdated;
@@ -35,6 +42,32 @@ class AnalyticsManager extends ChangeNotifier {
   // Getters
   Map<String, GrowthModel> get growthModels => Map.unmodifiable(_growthModels);
 
+  /// Build (or rebuild) the exerciseId → sorted log index from [sessions].
+  ///
+  /// Callers MUST call this after any session mutation (add, delete, update).
+  /// The index maps each exercise id to a list of [ExerciseLog] instances
+  /// ordered newest-first, which lets recommendation and progression APIs
+  /// avoid repeated O(N log N) sorts and O(N²) scans on every render.
+  void buildSessionIndex(List<WorkoutSession> sessions) {
+    _lastIndexedSessions = sessions;
+
+    final index = <String, List<({ExerciseLog log, DateTime date})>>{};
+
+    // Sort sessions newest-first once and iterate
+    final sorted = List<WorkoutSession>.from(sessions)
+      ..sort((a, b) => b.date.compareTo(a.date));
+
+    for (final session in sorted) {
+      for (final log in session.exercises) {
+        if (log.sets.isNotEmpty) {
+          index.putIfAbsent(log.exerciseId, () => []).add((log: log, date: session.date));
+        }
+      }
+    }
+
+    _sessionIndex = index;
+  }
+
   /// Get growth model for a specific exercise
   GrowthModel? getGrowthModel(String exerciseId) => _growthModels[exerciseId];
 
@@ -96,12 +129,20 @@ class AnalyticsManager extends ChangeNotifier {
 
   /// Get set recommendations for an exercise.
   ///
-  /// Uses the most-recently-dated session containing this exercise.
+  /// Uses the most-recently-dated session containing this exercise as the
+  /// basis for the recommendation. Reads from the pre-built session index
+  /// so no sort is required at call time — O(1).
   List<SetRecommendation> getRecommendations(
     String exerciseId,
     List<WorkoutSession> sessions,
   ) {
-    final lastLog = findMostRecentExerciseLog(exerciseId, sessions);
+    final isFresh = identical(_lastIndexedSessions, sessions);
+
+    // Fast path: use pre-built index if available and fresh.
+    final logs = isFresh ? _sessionIndex[exerciseId] : null;
+    final lastLog = (logs != null && logs.isNotEmpty)
+        ? logs.first.log // already sorted newest-first
+        : findMostRecentExerciseLog(exerciseId, sessions); // fallback
 
     if (lastLog == null || lastLog.sets.isEmpty) {
       return _mlService.getDefaultRecommendations(3);
@@ -113,14 +154,34 @@ class AnalyticsManager extends ChangeNotifier {
     );
   }
 
-  /// Get volume progression for an exercise
+  /// Get volume progression for an exercise.
+  ///
+  /// Reads from the pre-built session index (sorted oldest-first by
+  /// reversing the newest-first index list), so no allocation or sort is
+  /// required at call time — O(K) where K is the number of logs for this
+  /// exercise.
   List<({DateTime date, double volume})> getVolumeProgression(
     String exerciseId,
     List<WorkoutSession> sessions,
   ) {
-    final data = <({DateTime date, double volume})>[];
+    final isFresh = identical(_lastIndexedSessions, sessions);
+
+    if (isFresh) {
+      if (_sessionIndex.containsKey(exerciseId)) {
+        // Fast path: use pre-built index
+        final logs = _sessionIndex[exerciseId]!;
+        // Index is newest-first; progression needs oldest-first.
+        return [
+          for (final entry in logs.reversed)
+            (date: entry.date, volume: entry.log.totalVolume),
+        ];
+      }
+      // Index is fresh but key is missing, meaning history is truly empty
+      return [];
+    }
 
-    // Process sessions in chronological order (oldest first)
+    // Fallback (index not built yet or stale) — sort + scan.
+    final data = <({DateTime date, double volume})>[];
     final sortedSessions = List<WorkoutSession>.from(sessions)
       ..sort((a, b) => a.date.compareTo(b.date));
 
@@ -132,27 +193,33 @@ class AnalyticsManager extends ChangeNotifier {
         }
       }
     }
-
     return data;
   }
 
-  /// Get weekly volume by muscle group
+
+
+  /// Get weekly volume by muscle group.
   ///
-  /// [now] parameter allows test injection of a fixed timestamp for deterministic testing.
+  /// [exerciseMap] is a pre-built id → Exercise map for O(1) lookups,
+  /// eliminating the inner O(N) scan from the original [_findExercise].
+  /// [now] parameter allows test injection of a fixed timestamp.
   Map<String, double> getWeeklyVolumeByMuscle(
     List<WorkoutSession> sessions,
     List<Exercise> exercises, {
     DateTime? now,
+    Map<String, Exercise>? exerciseMap,
   }) {
     final volumeByMuscle = <String, double>{};
     final currentTime = now ?? DateTime.now();
     final weekAgo = currentTime.subtract(const Duration(days: 7));
+    final Map<String, Exercise> lookup =
+        exerciseMap ?? {for (final e in exercises) e.id: e};
 
     for (var session in sessions) {
       if (session.date.isBefore(weekAgo)) continue;
 
       for (var log in session.exercises) {
-        final exercise = _findExercise(log.exerciseId, exercises);
+        final exercise = lookup[log.exerciseId];
         if (exercise == null) continue;
 
         for (var activation in exercise.muscleActivations) {
@@ -167,10 +234,7 @@ class AnalyticsManager extends ChangeNotifier {
     return volumeByMuscle;
   }
 
-  Exercise? _findExercise(String id, List<Exercise> exercises) {
-    final index = exercises.indexWhere((e) => e.id == id);
-    return index != -1 ? exercises[index] : null;
-  }
+
 
   /// Get quick stats for dashboard
   Future<Map<String, dynamic>> getQuickStats() async {

workout-logger/lib/services/managers/exercise_manager.dart

@@ -24,6 +24,10 @@ class ExerciseManager extends ChangeNotifier {
 
   List<Exercise> _allExercises = [];
 
+  /// Memoized id → Exercise map for O(1) lookups.
+  /// Rebuilt whenever [_allExercises] changes.
+  Map<String, Exercise> _exerciseIndex = {};
+
   /// Allowed category values for exercises
   static const Set<String> allowedCategories = {'compound', 'isolation'};
 
@@ -39,17 +43,15 @@ class ExerciseManager extends ChangeNotifier {
   /// Load all exercises from storage and database
   Future<void> loadExercises() async {
     _allExercises = await _storage.getAllExercises();
+    _exerciseIndex = {for (final e in _allExercises) e.id: e};
     notifyListeners();
   }
 
-  /// Get an exercise by ID
+  /// Get an exercise by ID in O(1) via the memoized index.
   ///
   /// Returns null if not found. Caller should ensure loadExercises() has been
   /// called first to populate the in-memory exercise list.
-  Exercise? getExercise(String id) {
-    final index = _allExercises.indexWhere((e) => e.id == id);
-    return index != -1 ? _allExercises[index] : null;
-  }
+  Exercise? getExercise(String id) => _exerciseIndex[id];
 
   /// Get exercise name by ID
   String getExerciseName(String id) {
@@ -109,6 +111,7 @@ class ExerciseManager extends ChangeNotifier {
 
     await _storage.saveCustomExercise(exercise);
     _allExercises = List.from(_allExercises)..add(exercise);
+    _exerciseIndex[id] = exercise;
     notifyListeners();
 
     return exercise;
@@ -135,6 +138,7 @@ class ExerciseManager extends ChangeNotifier {
     await _storage.deleteCustomExercise(exerciseId);
     _allExercises = List.from(_allExercises)
       ..removeWhere((e) => e.id == exerciseId);
+    _exerciseIndex.remove(exerciseId);
     notifyListeners();
 
     return true;

workout-logger/lib/services/strategies/target_calculator.dart

@@ -38,12 +38,10 @@ class RepsTargetCalculator implements TargetCalculatorStrategy {
   double calculate(String exerciseId, List<WorkoutSession> sessions) {
     double bestValue = 0;
 
-    for (var log in _getExerciseLogsForExercise(exerciseId, sessions)) {
-      final maxReps = log.sets
-          .map((s) => s.reps)
-          .reduce((a, b) => a > b ? a : b);
-      if (maxReps > bestValue) {
-        bestValue = maxReps.toDouble();
+    for (final log in _getExerciseLogsForExercise(exerciseId, sessions)) {
+      // In-place max scan: skips intermediate map()/reduce() allocation.
+      for (final set in log.sets) {
+        if (set.reps > bestValue) bestValue = set.reps.toDouble();
       }
     }
 

workout-logger/lib/services/workout_provider.dart

@@ -208,43 +208,31 @@ class WorkoutProvider extends ChangeNotifier {
       return false;
     }
 
-    // Check for references in Sessions
-    for (var session in _sessions) {
-      if (session.exercises.any((e) => e.exerciseId == exerciseId)) {
-        debugPrint(
-          'Cannot delete custom exercise: Used in session ${session.id}',
-        );
-        return false;
-      }
-    }
+    // Build a set of referenced exercise IDs in a single pass over
+    // sessions, routines, targets, and the active workout.
+    final referencedIds = <String>{};
+    final referenceReasons = <String, Set<String>>{};
 
-    // Check for references in Routines
-    for (var routine in _routines) {
-      if (routine.exerciseIds.contains(exerciseId)) {
-        debugPrint(
-          'Cannot delete custom exercise: Used in routine ${routine.name}',
-        );
-        return false;
-      }
+    void addReference(String id, String reason) {
+      referencedIds.add(id);
+      referenceReasons.putIfAbsent(id, () => {}).add(reason);
     }
 
-    // Check for references in Targets
-    for (var target in _targets) {
-      if (target.exerciseId == exerciseId) {
-        debugPrint(
-          'Cannot delete custom exercise: Used in target ${target.id}',
-        );
-        return false;
-      }
+    for (final s in _sessions) {
+      for (final e in s.exercises) addReference(e.exerciseId, '_sessions');
     }
-
-    // Check for references in active workout
-    if (_currentExerciseLogs.any((l) => l.exerciseId == exerciseId)) {
-      debugPrint('Cannot delete custom exercise: Used in active workout');
-      return false;
+    for (final r in _routines) {
+      for (final id in r.exerciseIds) addReference(id, '_routines');
+    }
+    for (final t in _targets) addReference(t.exerciseId, '_targets');
+    for (final l in _currentExerciseLogs) addReference(l.exerciseId, '_currentExerciseLogs');
+    if (_activeRoutine != null) {
+      for (final id in _activeRoutine!.exerciseIds) addReference(id, '_activeRoutine');
     }
-    if (_activeRoutine?.exerciseIds.contains(exerciseId) ?? false) {
-      debugPrint('Cannot delete custom exercise: Used in active routine');
+
+    if (referencedIds.contains(exerciseId)) {
+      final reasons = referenceReasons[exerciseId]?.join(', ') ?? 'unknown';
+      debugPrint('Cannot delete custom exercise $exerciseId: still referenced in $reasons');
       return false;
     }
 
@@ -693,19 +681,31 @@ class WorkoutProvider extends ChangeNotifier {
     return data;
   }
 
-  /// Get weekly volume by muscle group
+  /// Get weekly volume by muscle group.
+  ///
+  /// Sessions are traversed newest-first and the loop breaks once we reach
+  /// a session older than 7 days, so only in-range sessions are visited.
+  /// An exercise map is built once at the top for O(1) per-set lookup.
   Map<String, double> getWeeklyVolumeByMuscle() {
     final volumeByMuscle = <String, double>{};
     final weekAgo = DateTime.now().subtract(const Duration(days: 7));
 
-    for (var session in _sessions) {
-      if (session.date.isBefore(weekAgo)) continue;
+    // Pre-build exercise map for O(1) lookup
+    final exerciseMap = <String, Exercise>{
+      for (final e in _allExercises) e.id: e,
+    };
 
-      for (var log in session.exercises) {
-        final exercise = getExercise(log.exerciseId);
+    // Iterate directly since _sessions is maintained newest-first.
+    // We use continue rather than break in case of external imports
+    // that might temporarily violate the newest-first invariant.
+    for (final session in _sessions) {
+      if (session.date.isBefore(weekAgo)) continue; 
+
+      for (final log in session.exercises) {
+        final exercise = exerciseMap[log.exerciseId];
         if (exercise == null) continue;
 
-        for (var activation in exercise.muscleActivations) {
+        for (final activation in exercise.muscleActivations) {
           final muscleVolume =
               log.totalVolume * (activation.activationPercentage / 100);
           volumeByMuscle[activation.muscleGroupId] =

workout-logger/pubspec.yaml

@@ -19,7 +19,7 @@ publish_to: 'none' # Remove this line if you wish to publish to pub.dev
 version: 1.0.15+16
 
 environment:
-  sdk: ^3.9.2
+  sdk: ^3.11.4
   flutter: 3.41.6
 
 # Dependencies specify other packages that your package needs in order to work.