From 018f4a751ac4bff9113874666a92b4c5d8679af3 Mon Sep 17 00:00:00 2001
From: Alex Auvolat <alex@adnab.me>
Date: Sun, 1 Mar 2020 13:27:29 +0100
Subject: [PATCH] Read backlog; handle messages in the correct order

---
 connector/external/external.go | 17 +++++++++++++++-
 external/messenger.py          | 36 +++++++++++++++++++++++++++++++++-
 2 files changed, 51 insertions(+), 2 deletions(-)

diff --git a/connector/external/external.go b/connector/external/external.go
index 741802c..9a4137d 100644
--- a/connector/external/external.go
+++ b/connector/external/external.go
@@ -86,6 +86,7 @@ type External struct {
 	generation int
 	proc       *exec.Cmd
 
+	handlerChan      chan *extMessageWithData
 	counter          uint64
 	inflightRequests map[uint64]chan *extMessageWithData
 	lock             sync.Mutex
@@ -110,6 +111,9 @@ func (ext *External) Configure(c Configuration) error {
 
 	ext.generation += 1
 
+	ext.handlerChan = make(chan *extMessageWithData)
+	go ext.handlerLoop(ext.generation)
+
 	err = ext.setupProc()
 	if err != nil {
 		return err
@@ -254,7 +258,17 @@ func (ext *External) recvLoop() {
 				}
 			}()
 		} else {
-			go ext.handleCmd(&msg)
+			ext.handlerChan <- &msg
+		}
+	}
+}
+
+func (ext *External) handlerLoop(generation int) {
+	for ext.handlerChan != nil && ext.generation == generation {
+		select {
+		case msg := <-ext.handlerChan:
+			ext.handleCmd(msg)
+		case <-time.After(10 * time.Second):
 		}
 	}
 }
@@ -311,6 +325,7 @@ func (ext *External) Close() {
 	ext.recv = nil
 	ext.send = nil
 	ext.sendJson = nil
+	ext.handlerChan = nil
 
 	go func() {
 		time.Sleep(10 * time.Second)
diff --git a/external/messenger.py b/external/messenger.py
index 6ec6e9c..792a356 100755
--- a/external/messenger.py
+++ b/external/messenger.py
@@ -141,7 +141,25 @@ class InitialSyncThread(threading.Thread):
             })
 
     def backlog_room(self, thread):
-        pass # TODO
+        prev_last_seen = self.bridge.cache_get("last_seen_%s"%thread.uid)
+        if prev_last_seen == "":
+            messages = self.client.fetchThreadMessages(thread.uid, limit=100)
+        else:
+            messages = []
+            found = False
+            while not Found:
+                before = None
+                if len(messages) > 0:
+                    before = messages[-1].timestamp
+                page = self.client.fetchThreadMessages(thread.uid, before=before, limit=20)
+                for m in page:
+                    if m.uid == prev_last_seen:
+                        found = True
+                        break
+                    else:
+                        messages.append(m)
+        for m in reversed(messages):
+            self.bridge.handleMessage(thread, m)
 
 
 
@@ -150,11 +168,13 @@ class InitialSyncThread(threading.Thread):
 class MessengerBridge:
     def __init__(self):
         self.rev_uid = {}
+        self.uid_map = {}
 
     def getUserId(self, user):
         if user.url is not None and not "?" in user.url:
             user_id = user.url.split("/")[-1]
             self.rev_uid[user_id] = user.uid
+            self.uid_map[user.uid] = user_id
             return user_id
         else:
             return user.uid
@@ -274,6 +294,20 @@ class MessengerBridge:
         del self.cache_gets[num]
         return rep
 
+    def handleMessage(self, thread, m):
+        author = m.author
+        if author in self.uid_map:
+            author = self.uid_map[m.author]
+
+            event = {
+                    "type": EVENT_MESSAGE,
+                    "author": author,
+                    "text": m.text,
+                }
+            if thread.type == ThreadType.GROUP:
+                event["room"] = thread.uid
+            self.write({"_type": EVENT, "data": event})
+
 
 if __name__ == "__main__":
     bridge = MessengerBridge()