From ebd6c1803296a28ae8030b11ace219d0898abf25 Mon Sep 17 00:00:00 2001
From: Yohann D'ANELLO <ynerant@crans.org>
Date: Mon, 21 Dec 2020 16:04:16 +0100
Subject: [PATCH] Ignore duplicate messages

Signed-off-by: Yohann D'ANELLO <ynerant@crans.org>
---
 squinnondation/hazel.py    | 34 +++++++++++++++++++++++++++++++++-
 squinnondation/messages.py |  5 ++++-
 2 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/squinnondation/hazel.py b/squinnondation/hazel.py
index f72f31a..b01428d 100644
--- a/squinnondation/hazel.py
+++ b/squinnondation/hazel.py
@@ -1,6 +1,6 @@
 # Copyright (C) 2020 by eichhornchen, ÿnérant
 # SPDX-License-Identifier: GPL-3.0-or-later
-
+from datetime import datetime
 from typing import Any, Tuple
 from ipaddress import IPv6Address
 from threading import Thread
@@ -49,6 +49,7 @@ class Squirrel(Hazelnut):
         self.last_line = -1
 
         self.history = []
+        self.received_messages = dict()
         self.history_pad = curses.newpad(curses.LINES - 2, curses.COLS)
         self.input_pad = curses.newpad(1, curses.COLS)
         self.emoji_pad = curses.newpad(18, 12)
@@ -252,6 +253,19 @@ class Squirrel(Hazelnut):
         if self.last_line == len(self.history) - 2:
             self.last_line += 1
 
+    def receive_message_from(self, msg: str, sender_id: int, nonce: int) -> bool:
+        """
+        This method is called by a DataTLV, sent by a real person.
+        This add the message in the history if not already done.
+        Returns True iff the message was not already received previously.
+        """
+        if (sender_id, nonce) in self.received_messages:
+            return False
+
+        self.add_message(msg)
+        self.received_messages[(sender_id, nonce)] = Message(msg, sender_id, nonce)
+        return True
+
     def add_system_message(self, msg: str) -> None:
         """
         Add a new system log message.
@@ -457,3 +471,21 @@ class Worm(Thread):
                     tlv.handle(self.squirrel, hazelnut)
                 self.squirrel.refresh_history()
                 self.squirrel.refresh_input()
+
+
+class Message:
+    """
+    This class symbolises the data sent by a real client, excluding system messages.
+    This is useful to check unicity or to save and load messages.
+    """
+    content: str
+    # TODO: Replace the id by the good (potential) hazel
+    sender_id: int
+    nonce: int
+    created_at: datetime
+
+    def __init__(self, content: str, sender_id: int, nonce: int, created_at: datetime = None):
+        self.content = content
+        self.sender_id = sender_id
+        self.nonce = nonce
+        self.created_at = created_at or datetime.now()
diff --git a/squinnondation/messages.py b/squinnondation/messages.py
index 8e49f85..7080e74 100644
--- a/squinnondation/messages.py
+++ b/squinnondation/messages.py
@@ -208,7 +208,10 @@ class DataTLV(TLV):
         TODO: Check that the tuple (sender_id, nonce) is unique to avoid duplicates.
         """
         msg = self.data.decode('UTF-8')
-        squirrel.add_message(msg)
+        if not squirrel.receive_message_from(msg, self.sender_id, self.nonce):
+            # The message was already received
+            return
+
         nickname_match = re.match("(.*): (.*)", msg)
         if nickname_match is None:
             squirrel.send_packet(sender, Packet.construct(WarningTLV.construct(