ADD : Timestamp to display messages in order

Sources/dafl_project_flutter/lib/model/message.dart

@@ -4,11 +4,13 @@ class Message {
   String idSender;
   String idReceiver;
   String content;
+  String timestamp;
 
 
   Message({required this.idSender,
     required this.idReceiver,
-    required this.content
+    required this.content,
+    required this.timestamp
   });
 
 
@@ -17,6 +19,7 @@ class Message {
       'idSender': idSender,
       'idReceiver': idReceiver,
       'content': content,
+      'timestamp' : timestamp
     };
   }
 
@@ -26,6 +29,7 @@ class Message {
       idSender: data['idSender'],
       idReceiver: data['idReceiver'],
       content: data['content'],
+        timestamp: data['timestamp']
     );
   }
 }

Sources/dafl_project_flutter/lib/services/messaging/message_database_service.dart

@@ -54,6 +54,7 @@ class MessageDatabaseService{
         .collection('messages')
         .doc(chatId)
         .collection(chatId)
+        .orderBy('timestamp', descending: true)
         .snapshots().map(_getAllMessages);
   }
 }

Sources/dafl_project_flutter/lib/views/pages/main/p_conversation.dart

@@ -24,7 +24,7 @@ class _ConversationPageState extends State<ConversationPage> {
   final messageTextField = TextEditingController();
 
   void sendMessage(String content, String idSender, String idReceiver) {
-    Message messageToSend = Message(idSender: idSender, idReceiver: idReceiver, content: content);
+    Message messageToSend = Message(idSender: idSender, idReceiver: idReceiver, content: content, timestamp: DateTime.now().toString());
 
     MyApp.controller.sendMessage(messageToSend, idSender, idReceiver);