Implement saveConversation() method in AIService

lib/ai_agent/ai_service.dart

@@ -1,5 +1,7 @@
 import 'dart:convert';
 import 'package:http/http.dart' as http;
+import 'package:cloud_firestore/cloud_firestore.dart';
+import 'package:flutter/foundation.dart';
 import 'package:connect/config/app_config.dart';
 import 'package:connect/services/points_service.dart';
 
@@ -154,18 +156,33 @@ Always be encouraging and help users get the most out of Connect!
 
   /// Saves conversation history to Firestore for analytics and improvement.
   /// 
-  /// This method can be implemented to store user interactions with Dino,
+  /// Stores user interactions with Dino to the 'ai_conversations' collection,
   /// which helps analyze user needs and improve AI responses over time.
   /// 
   /// [userId] The ID of the user having the conversation
   /// [userMessage] The message sent by the user
   /// [aiResponse] The response generated by the AI
   /// 
-  /// Example implementation would save to a 'conversations' collection
-  /// in Firestore with timestamp and user context.
+  /// Saves to the 'ai_conversations' collection in Firestore with timestamp.
   static Future<void> saveConversation(String userId, String userMessage, String aiResponse) async {
-    // You can implement this to save conversations for analytics
-    // This helps improve the AI responses over time
+    // Validate input parameters
+    if (userId.isEmpty || userMessage.trim().isEmpty || aiResponse.trim().isEmpty) {
+      debugPrint('Cannot save conversation: Invalid parameters provided');
+      return;
+    }
+
+    try {
+      await FirebaseFirestore.instance
+          .collection('ai_conversations')
+          .add({
+            'userId': userId,
+            'userMessage': userMessage,
+            'aiResponse': aiResponse,
+            'timestamp': FieldValue.serverTimestamp(),
+          });
+    } catch (e) {
+      debugPrint('Failed to save conversation to Firestore: $e');
+    }
   }
 
   /// Gets a list of suggested questions users can ask Dino.