diff --git a/back/saveLogic.js b/back/saveLogic.js
new file mode 100644
index 0000000..81ca271
--- /dev/null
+++ b/back/saveLogic.js
@@ -0,0 +1,42 @@
+if (message.isReply()) {
+    // todo transfer
+    if (message.replyToThread()) {
+        if (message.hasSameMember(parent)) {
+            addToThread();
+        } else {
+            createThread();
+        }
+    } else {
+        if (message.isInGroup()) {
+            if (message.hasSameMember(parent)) {
+                addToGroup();
+            } else {
+                createThread();
+            }
+        } else {
+            if (message.isFromChannelOwner()) {
+                addToChannel(); // todo not sure (with references)
+            } else {
+                createThread();
+            }
+        }
+    }
+} else {
+    if (message.isFromUser()) {
+        if (message.isDm()) {
+            if (firstMessage()) {
+                createDM();
+            } else {
+                addToDm();
+            }
+        } else {
+            createRoom();
+        }
+    } else {
+        if (firstMessage()) {
+            createRoom();
+        } else {
+            addToRoom();
+        }
+    }
+}
\ No newline at end of file