From 47d61623b4bbc43df58b5aa1835de0f4c48c2ed2 Mon Sep 17 00:00:00 2001
From: Fabian Sauter <sauter.fabian@mailbox.org>
Date: Sun, 1 Mar 2020 18:26:34 +0100
Subject: [PATCH] Fixed a cause for duplicate MUC messages #46

When messages do not have an id attribute, but instead only an MAM archive node with an id attribute UWPX would handle them as new unique messages.
---
 XMPP_API/Classes/Consts.cs                    |  2 ++
 .../Network/XML/Messages/MessageMessage.cs    | 26 ++++++++++++++++++-
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/XMPP_API/Classes/Consts.cs b/XMPP_API/Classes/Consts.cs
index ac67fa5b3..7167e3f4d 100644
--- a/XMPP_API/Classes/Consts.cs
+++ b/XMPP_API/Classes/Consts.cs
@@ -85,5 +85,7 @@ public static class Consts
         public const string XML_XEP_0336_NAMESPACE = "urn:xmpp:xdata:dynamic";
         // XEP-IoT:
         public const string XML_XEP_IOT_NAMESPACE = "urn:xmpp:uwpx:iot";
+        // XEP-0313 (Message Archive Management)
+        public const string XML_XEP_0313_NAMESPACE = "urn:xmpp:mam:tmp";
     }
 }
diff --git a/XMPP_API/Classes/Network/XML/Messages/MessageMessage.cs b/XMPP_API/Classes/Network/XML/Messages/MessageMessage.cs
index 928f4dce3..83a56185d 100644
--- a/XMPP_API/Classes/Network/XML/Messages/MessageMessage.cs
+++ b/XMPP_API/Classes/Network/XML/Messages/MessageMessage.cs
@@ -53,7 +53,7 @@ public MessageMessage(XmlNode node, string type) : this(node, CarbonCopyType.NON
             chatMessageId = null;
         }
 
-        public MessageMessage(XmlNode node, CarbonCopyType ccType) : base(node.Attributes["from"]?.Value, node.Attributes["to"]?.Value, (node.Attributes["id"]?.Value) ?? getRandomId())
+        public MessageMessage(XmlNode node, CarbonCopyType ccType) : base(node.Attributes["from"]?.Value, node.Attributes["to"]?.Value, loadMessageId(node))
         {
             CC_TYPE = ccType;
             if (!node.HasChildNodes)
@@ -130,6 +130,30 @@ public DateTime getDelay()
             return delay;
         }
 
+        protected static string loadMessageId(XmlNode node)
+        {
+            // Check for the default message ID attribute:
+            string id = node.Attributes["id"]?.Value;
+            if (!(id is null))
+            {
+                return id;
+            }
+
+            // Check for a MAM-ID in the archived node:
+            XmlNode archivedNode = XMLUtils.getChildNode(node, "archived", Consts.XML_XMLNS, Consts.XML_XEP_0313_NAMESPACE);
+            if (!(archivedNode is null))
+            {
+                id = archivedNode.Attributes["id"]?.Value;
+                if (!(id is null))
+                {
+                    return id;
+                }
+            }
+
+            // Fall back to a new message ID:
+            return getRandomId();
+        }
+
         #endregion
         //--------------------------------------------------------Misc Methods:---------------------------------------------------------------\\
         #region --Misc Methods (Public)--