Initial commit

lib/providers/chat_provider.dart

@@ -0,0 +1,151 @@
+import 'package:flutter/material.dart';
+import 'package:drift/drift.dart';
+import 'package:trainhub_flutter/database/database.dart';
+
+class ChatProvider extends ChangeNotifier {
+  final AppDatabase database;
+
+  List<ChatSession> _sessions = [];
+  List<ChatMessage> _currentMessages = [];
+  ChatSession? _activeSession;
+
+  List<ChatSession> get sessions => _sessions;
+  List<ChatMessage> get currentMessages => _currentMessages;
+  ChatSession? get activeSession => _activeSession;
+
+  bool _isTyping = false;
+  bool get isTyping => _isTyping;
+
+  ChatProvider(this.database) {
+    _loadSessions();
+  }
+
+  Future<void> _loadSessions() async {
+    _sessions =
+        await (database.select(database.chatSessions)..orderBy([
+              (t) => OrderingTerm(
+                expression: t.createdAt,
+                mode: OrderingMode.desc,
+              ),
+            ]))
+            .get();
+    notifyListeners();
+  }
+
+  Future<void> createSession() async {
+    final id = DateTime.now().toIso8601String();
+    final session = ChatSessionsCompanion.insert(
+      id: id,
+      title: const Value('New Chat'),
+      createdAt: DateTime.now().toIso8601String(),
+      updatedAt: DateTime.now().toIso8601String(),
+    );
+    await database.into(database.chatSessions).insert(session);
+    await _loadSessions();
+    await loadSession(id);
+  }
+
+  Future<void> deleteSession(String id) async {
+    await (database.delete(
+      database.chatSessions,
+    )..where((t) => t.id.equals(id))).go();
+    if (_activeSession?.id == id) {
+      _activeSession = null;
+      _currentMessages = [];
+    }
+    await _loadSessions();
+  }
+
+  Future<void> loadSession(String id) async {
+    final session = await (database.select(
+      database.chatSessions,
+    )..where((t) => t.id.equals(id))).getSingleOrNull();
+    if (session != null) {
+      _activeSession = session;
+      await _loadMessages(id);
+    }
+  }
+
+  Future<void> _loadMessages(String sessionId) async {
+    _currentMessages =
+        await (database.select(database.chatMessages)
+              ..where((t) => t.sessionId.equals(sessionId))
+              ..orderBy([
+                (t) => OrderingTerm(
+                  expression: t.createdAt,
+                  mode: OrderingMode.asc,
+                ),
+              ]))
+            .get();
+    notifyListeners();
+  }
+
+  Future<void> sendMessage(String content) async {
+    if (_activeSession == null) {
+      await createSession();
+    }
+    final sessionId = _activeSession!.id;
+
+    // User Message
+    final userMsgId = DateTime.now().toIso8601String();
+    await database
+        .into(database.chatMessages)
+        .insert(
+          ChatMessagesCompanion.insert(
+            id: userMsgId,
+            sessionId: sessionId,
+            role: 'user',
+            content: content,
+            createdAt: DateTime.now().toIso8601String(),
+          ),
+        );
+    await _loadMessages(sessionId);
+
+    // AI Response (Mock)
+    _isTyping = true;
+    notifyListeners();
+
+    await Future.delayed(const Duration(seconds: 1)); // Simulate latency
+
+    final aiMsgId = DateTime.now().toIso8601String();
+    final response = _getMockResponse(content);
+
+    await database
+        .into(database.chatMessages)
+        .insert(
+          ChatMessagesCompanion.insert(
+            id: aiMsgId,
+            sessionId: sessionId,
+            role: 'assistant',
+            content: response,
+            createdAt: DateTime.now().toIso8601String(),
+          ),
+        );
+
+    // Update session title if it's the first message
+    if (_currentMessages.length <= 2) {
+      final newTitle = content.length > 30
+          ? '${content.substring(0, 30)}...'
+          : content;
+      await (database.update(database.chatSessions)
+            ..where((t) => t.id.equals(sessionId)))
+          .write(ChatSessionsCompanion(title: Value(newTitle)));
+      await _loadSessions();
+    }
+
+    _isTyping = false;
+    await _loadMessages(sessionId);
+  }
+
+  String _getMockResponse(String input) {
+    input = input.toLowerCase();
+    if (input.contains('plan') || input.contains('program')) {
+      return "I can help you design a training plan! What are your goals? Strength, hypertrophy, or endurance?";
+    } else if (input.contains('squat') || input.contains('bench')) {
+      return "Compound movements are great. Remember to maintain proper form. For squats, keep your chest up and knees tracking over toes.";
+    } else if (input.contains('nutrition') || input.contains('eat')) {
+      return "Nutrition is key. Aim for 1.6-2.2g of protein per kg of bodyweight if you're training hard.";
+    }
+    return "I'm your AI training assistant. How can I help you today?";
+  }
+}