feat: Implement Gemini AI service for AI coach functionality

workout-logger/lib/main.dart

@@ -9,7 +9,8 @@ import 'package:provider/provider.dart';
 
 import 'services/storage_service.dart';
 import 'services/ml_service.dart';
-import 'services/gemini_service.dart';
+import 'services/ai/gemini_ai_service.dart';
+import 'services/ai/coach_tool_service.dart';
 import 'services/health_connect_service.dart';
 import 'services/interfaces/storage_service_interface.dart';
 import 'services/interfaces/ml_service_interface.dart';
@@ -21,6 +22,7 @@ import 'services/managers/program_manager.dart';
 import 'services/managers/history_manager.dart';
 import 'services/managers/health_sync_manager.dart';
 import 'services/managers/pr_manager.dart';
+import 'services/managers/conversation_manager.dart';
 import 'theme/app_theme.dart';
 import 'screens/home_screen.dart';
 import 'screens/onboarding_screen.dart';
@@ -62,7 +64,10 @@ class WorkoutLoggerApp extends StatelessWidget {
  static final HistoryManager _historyManager =
  HistoryManager(_storageService, healthSyncManager: _healthSyncManager);
  static final PRManager _prManager = PRManager(_storageService);
- static final GeminiService _geminiService = GeminiService();
+ static final GeminiAiService _geminiService =
+ GeminiAiService(storage: _storageService);
+ static final ConversationManager _conversationManager =
+ ConversationManager(_storageService);
 
  const WorkoutLoggerApp({super.key});
 
@@ -89,7 +94,15 @@ class WorkoutLoggerApp extends StatelessWidget {
  // Provided as ChangeNotifier so HistoryScreen rebuilds on sync badge changes.
  ChangeNotifierProvider<HistoryManager>.value(value: _historyManager),
  ChangeNotifierProvider<PRManager>.value(value: _prManager),
- ChangeNotifierProvider<GeminiService>.value(value: _geminiService),
+ // GeminiAiService is the single AI backend instance. It's a ChangeNotifier
+ // (settings UI watches isConfigured/model), so it's provided as such.
+ // Consumers that should depend on the abstraction (the coach ViewModel,
+ // program generator) receive it typed as IAiService at construction —
+ // the future firebase_ai swap point — without a separate provider.
+ ChangeNotifierProvider<GeminiAiService>.value(value: _geminiService),
+ ChangeNotifierProvider<ConversationManager>.value(
+ value: _conversationManager,
+ ),
  // WorkoutProvider receives dependencies via constructor injection
  ChangeNotifierProvider(
  create: (_) => WorkoutProvider(
@@ -99,6 +112,13 @@ class WorkoutLoggerApp extends StatelessWidget {
  programManager: _programManager,
  ),
  ),
+ // CoachToolService backs AI tool calls; reads from WorkoutProvider + PRManager.
+ Provider<CoachToolService>(
+ create: (ctx) => CoachToolService(
+ ctx.read<WorkoutProvider>(),
+ ctx.read<PRManager>(),
+ ),
+ ),
  ],
  child: MaterialApp(
  title: 'Workout Logger',
@@ -135,12 +155,17 @@ class _AppInitializerState extends State<AppInitializer> {
  final historyManager = context.read<HistoryManager>();
  final prManager = context.read<PRManager>();
  final api = context.read<ApiService>();
- final gemini = context.read<GeminiService>();
+ final gemini = context.read<GeminiAiService>();
 
  try {
  await provider.init();
  await settings.init();
  gemini.init(settings.geminiApiKey, model: settings.geminiModel);
+ try {
+ await gemini.loadUsage();
+ } catch (e, st) {
+ debugPrint('gemini.loadUsage failed: $e\n$st');
+ }
  await historyManager.loadSessions();
  await prManager.load();
  await prManager.backfillFromSessions(historyManager.sessions);

workout-logger/lib/models/models.dart

@@ -812,3 +812,101 @@ class TrainingProgram {
  createdAt == _sentinel ? this.createdAt : createdAt as DateTime,
  );
 }
+
+// ==================== AI Coach Chat ====================
+
+/// A single message in an AI coach conversation.
+class ChatMessage {
+ final String id;
+ final String role; // 'user' | 'model'
+ final String text;
+ final DateTime timestamp;
+
+ ChatMessage({
+ String? id,
+ required this.role,
+ required this.text,
+ DateTime? timestamp,
+ }) : id = id ?? _uuid.v4(),
+ timestamp = timestamp ?? DateTime.now();
+
+ Map<String, dynamic> toJson() => {
+ 'id': id,
+ 'role': role,
+ 'text': text,
+ 'timestamp': timestamp.toIso8601String(),
+ };
+
+ factory ChatMessage.fromJson(Map<String, dynamic> json) => ChatMessage(
+ id: json['id'] as String?,
+ role: json['role'] as String,
+ text: json['text'] as String,
+ timestamp: DateTime.parse(json['timestamp'] as String),
+ );
+
+ ChatMessage copyWith({
+ Object? role = _sentinel,
+ Object? text = _sentinel,
+ Object? timestamp = _sentinel,
+ }) => ChatMessage(
+ id: id,
+ role: role == _sentinel ? this.role : role as String,
+ text: text == _sentinel ? this.text : text as String,
+ timestamp: timestamp == _sentinel ? this.timestamp : timestamp as DateTime,
+ );
+}
+
+/// A persisted AI coach conversation: an ordered list of [ChatMessage]s.
+class Conversation {
+ final String id;
+ final String title;
+ final DateTime createdAt;
+ final DateTime updatedAt;
+ final List<ChatMessage> messages;
+
+ Conversation({
+ String? id,
+ required this.title,
+ DateTime? createdAt,
+ DateTime? updatedAt,
+ List<ChatMessage>? messages,
+ }) : id = id ?? _uuid.v4(),
+ createdAt = createdAt ?? DateTime.now(),
+ updatedAt = updatedAt ?? createdAt ?? DateTime.now(),
+ messages = messages ?? const [];
+
+ Map<String, dynamic> toJson() => {
+ 'id': id,
+ 'title': title,
+ 'createdAt': createdAt.toIso8601String(),
+ 'updatedAt': updatedAt.toIso8601String(),
+ 'messages': messages.map((m) => m.toJson()).toList(),
+ };
+
+ factory Conversation.fromJson(Map<String, dynamic> json) => Conversation(
+ id: json['id'] as String?,
+ title: json['title'] as String,
+ createdAt: DateTime.parse(json['createdAt'] as String),
+ updatedAt: json['updatedAt'] != null
+ ? DateTime.parse(json['updatedAt'] as String)
+ : DateTime.parse(json['createdAt'] as String),
+ messages: (json['messages'] as List)
+ .map((m) => ChatMessage.fromJson(m as Map<String, dynamic>))
+ .toList(),
+ );
+
+ Conversation copyWith({
+ Object? title = _sentinel,
+ Object? createdAt = _sentinel,
+ Object? updatedAt = _sentinel,
+ Object? messages = _sentinel,
+ }) => Conversation(
+ id: id,
+ title: title == _sentinel ? this.title : title as String,
+ createdAt: createdAt == _sentinel ? this.createdAt : createdAt as DateTime,
+ updatedAt: updatedAt == _sentinel ? this.updatedAt : updatedAt as DateTime,
+ messages: messages == _sentinel
+ ? this.messages
+ : messages as List<ChatMessage>,
+ );
+}