From 9722a1ce6f6400ca976cd1a6161830ed148ece68 Mon Sep 17 00:00:00 2001
From: Tulir Asokan <tulir@maunium.net>
Date: Sat, 27 Jan 2018 17:27:44 +0200
Subject: [PATCH] Implement Matrix->Telegram redactions

---
 README.md                  | 2 +-
 mautrix_telegram/db.py     | 2 +-
 mautrix_telegram/matrix.py | 8 ++++++++
 mautrix_telegram/portal.py | 8 ++++++++
 4 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 4368d23f..8fe9c980 100644
--- a/README.md
+++ b/README.md
@@ -64,7 +64,7 @@ does not do this automatically.
   * [ ] Locations (not implemented in Riot)
   * [x] Images
   * [x] Files
-  * [ ] Message redactions
+  * [x] Message redactions
   * [ ] Presence (currently always shown as online on Telegram)
   * [ ] Typing notifications (may not be possible)
   * [ ] Pinning messages
diff --git a/mautrix_telegram/db.py b/mautrix_telegram/db.py
index 60ef1369..71f04d9e 100644
--- a/mautrix_telegram/db.py
+++ b/mautrix_telegram/db.py
@@ -41,7 +41,7 @@ class Message(Base):
     tgid = Column(Integer, primary_key=True)
     user = Column(Integer, ForeignKey("user.tgid"), primary_key=True)
 
-    __table_args__ = (UniqueConstraint('mxid', 'mx_room', name='_mx_id_room'), )
+    __table_args__ = (UniqueConstraint('mxid', 'mx_room', 'user', name='_mx_id_room'), )
 
 
 class User(Base):
diff --git a/mautrix_telegram/matrix.py b/mautrix_telegram/matrix.py
index 93c1e5bd..430273ad 100644
--- a/mautrix_telegram/matrix.py
+++ b/mautrix_telegram/matrix.py
@@ -87,6 +87,12 @@ class MatrixHandler:
             self.commands.handle(room, sender, command, args, is_management,
                                  is_portal=portal is not None)
 
+    def handle_redaction(self, room, sender, event_id):
+        portal = Portal.get_by_mxid(room)
+        sender = User.get_by_mxid(sender)
+        if portal:
+            portal.handle_matrix_deletion(sender, event_id)
+
     def filter_matrix_event(self, event):
         return event["sender"] == self.az.bot_mxid or self.is_puppet(event["sender"])
 
@@ -106,3 +112,5 @@ class MatrixHandler:
                 pass
         elif type == "m.room.message":
             self.handle_message(evt["room_id"], evt["sender"], content, evt["event_id"])
+        elif type == "m.room.redaction":
+            self.handle_redaction(evt["room_id"], evt["sender"], evt["redacts"])
diff --git a/mautrix_telegram/portal.py b/mautrix_telegram/portal.py
index 5eb7abf7..0216dcf3 100644
--- a/mautrix_telegram/portal.py
+++ b/mautrix_telegram/portal.py
@@ -229,6 +229,14 @@ class Portal:
             DBMessage(tgid=response.id, mx_room=self.mxid, mxid=event_id, user=sender.tgid))
         self.db.commit()
 
+    def handle_matrix_deletion(self, deleter, event_id):
+        message = DBMessage.query.filter(DBMessage.mxid == event_id and
+                                         DBMessage.user == deleter.tgid and
+                                         DBMessage.mx_room == self.mxid).one_or_none()
+        if not message:
+            return
+        deleter.client.delete_messages(self.peer, [message.tgid])
+
     # endregion
     # region Telegram event handling