Send Threaded Messages

This MR deals with only sending threaded messages. Showing threads will turn up in a follow up. This allows you to start a new thread by clicking reply in thread to a normal message. 

You can also do a threaded reply to a threaded message in the main timeline at the moment because those messages aren't shown in a separate thread timeline yet but will be in future.

autotests/data/test-eventhandler-sync.json

@@ -0,0 +1,381 @@
+{
+  "account_data": {
+    "events": [
+      {
+        "content": {
+          "tags": {
+            "u.work": {
+              "order": 0.9
+            }
+          }
+        },
+        "type": "m.tag"
+      },
+      {
+        "content": {
+          "custom_config_key": "custom_config_value"
+        },
+        "type": "org.example.custom.room.config"
+      }
+    ]
+  },
+  "ephemeral": {
+    "events": [
+      {
+        "content": {
+          "user_ids": [
+            "@alice:matrix.org",
+            "@bob:example.com"
+          ]
+        },
+        "room_id": "!jEsUZKDJdhlrceRyVU:example.org",
+        "type": "m.typing"
+      },
+      {
+        "content": {
+          "$153456789:example.org": {
+            "m.read": {
+              "@alice:matrix.org": {
+                "ts": 1436451550453
+              }
+            }
+          }
+        },
+        "type": "m.receipt"
+      },
+      {
+        "content": {
+          "$1532735824654:example.org": {
+            "m.read": {
+              "@bob:example.com": {
+                "ts": 1436451550453
+              }
+            }
+          }
+        },
+        "type": "m.receipt"
+      },
+      {
+        "content": {
+          "$1532735824654:example.org": {
+            "m.read": {
+              "@tim:example.com": {
+                "ts": 1436451550454
+              }
+            }
+          }
+        },
+        "type": "m.receipt"
+      },
+      {
+        "content": {
+          "$1532735824654:example.org": {
+            "m.read": {
+              "@jeff:example.com": {
+                "ts": 1436451550455
+              }
+            }
+          }
+        },
+        "type": "m.receipt"
+      },
+      {
+        "content": {
+          "$1532735824654:example.org": {
+            "m.read": {
+              "@tina:example.com": {
+                "ts": 1436451550456
+              }
+            }
+          }
+        },
+        "type": "m.receipt"
+      },
+      {
+        "content": {
+          "$1532735824654:example.org": {
+            "m.read": {
+              "@sally:example.com": {
+                "ts": 1436451550457
+              }
+            }
+          }
+        },
+        "type": "m.receipt"
+      },
+      {
+        "content": {
+          "$1532735824654:example.org": {
+            "m.read": {
+              "@fred:example.com": {
+                "ts": 1436451550458
+              }
+            }
+          }
+        },
+        "type": "m.receipt"
+      }
+    ]
+  },
+  "state": {
+    "events": [
+      {
+        "content": {
+          "avatar_url": "mxc://example.org/SEsfnsuifSDFSSEF",
+          "displayname": "Alice Margatroid",
+          "membership": "join",
+          "reason": "Looking for support"
+        },
+        "event_id": "$143273582443PhrSn:example.org",
+        "origin_server_ts": 1432735824653,
+        "room_id": "!jEsUZKDJdhlrceRyVU:example.org",
+        "sender": "@example:example.org",
+        "state_key": "@alice:example.org",
+        "type": "m.room.member",
+        "unsigned": {
+          "age": 1234
+        }
+      }
+    ]
+  },
+  "summary": {
+    "m.heroes": [
+      "@alice:example.com",
+      "@bob:example.com"
+    ],
+    "m.invited_member_count": 0,
+    "m.joined_member_count": 2
+  },
+  "timeline": {
+    "events": [
+      {
+        "content": {
+          "body": "This is an example\ntext message",
+          "format": "org.matrix.custom.html",
+          "formatted_body": "<b>This is an example<br>text message</b>",
+          "msgtype": "m.text"
+        },
+        "event_id": "$153456789:example.org",
+        "origin_server_ts": 1432735824654,
+        "room_id": "!jEsUZKDJdhlrceRyVU:example.org",
+        "sender": "@example:example.org",
+        "type": "m.room.message",
+        "unsigned": {
+          "age": 1232
+        }
+      },
+      {
+        "content": {
+          "avatar_url": "mxc://kde.org/123456",
+          "displayname": "after",
+          "membership": "join"
+        },
+        "origin_server_ts": 1690651134736,
+        "sender": "@example:example.org",
+        "state_key": "@example:example.org",
+        "type": "m.room.member",
+        "unsigned": {
+          "replaces_state": "$1234567890:example.org",
+          "prev_content": {
+            "avatar_url": "mxc://kde.org/12345",
+            "displayname": "before",
+            "membership": "join"
+          },
+          "prev_sender": "@example:example.orgg",
+          "age": 1234
+        },
+        "event_id": "$143273583553PhrSn:example.org",
+        "room_id": "!jEsUZKDJdhlrceRyVU:example.org"
+      },
+      {
+        "content": {
+          "body": "This is a highlight @bob:kde.org and this is a link https://kde.org",
+          "format": "org.matrix.custom.html",
+          "msgtype": "m.text"
+        },
+        "event_id": "$1532735824654:example.org",
+        "origin_server_ts": 1532735824654,
+        "room_id": "!jEsUZKDJdhlrceRyVU:example.org",
+        "sender": "@example:example.org",
+        "type": "m.room.message",
+        "unsigned": {
+          "age": 1233
+        }
+      },
+      {
+        "content": {
+            "m.relates_to": {
+            "event_id": "$153456789:example.org",
+            "key": "👍",
+            "rel_type": "m.annotation"
+            }
+        },
+        "origin_server_ts": 1690322545182,
+        "room_id": "!jEsUZKDJdhlrceRyVU:example.org",
+        "sender": "@alice:matrix.org",
+        "type": "m.reaction",
+        "unsigned": {
+            "age": 390159120
+        },
+        "event_id": "$163456789:example.org",
+        "age": 390159120
+      },
+      {
+        "age": 4926305285,
+        "content": {
+            "body": "video caption",
+            "filename": "video.mp4",
+            "info": {
+                "duration": 10,
+                "h": 1080,
+                "mimetype": "video/mp4",
+                "size": 62650636,
+                "w": 1920,
+                "thumbnail_info": {
+                    "h": 450,
+                    "mimetype": "image/jpeg",
+                    "size": 382249,
+                    "w": 800
+                },
+                "thumbnail_url": "mxc://kde.org/2234567"
+            },
+            "msgtype": "m.video",
+            "url": "mxc://kde.org/1234567"
+        },
+        "event_id": "$263456789:example.org",
+        "origin_server_ts": 1685793783330,
+        "room_id": "!jEsUZKDJdhlrceRyVU:example.org",
+        "sender": "@example:example.org",
+        "type": "m.room.message",
+        "unsigned": {
+            "age": 4926305285
+        },
+        "user_id": "@example:example.org"
+      },
+      {
+        "content": {
+            "body": "> <@example:example.org> This is an example\ntext message\n\nreply",
+            "format": "org.matrix.custom.html",
+            "formatted_body": "<mx-reply><blockquote><a href=\"https://matrix.to/#/!jEsUZKDJdhlrceRyVU:example.org/$153456789:example.org?via=kde.org&via=matrix.org\">In reply to</a> <a href=\"https://matrix.to/#/@example:example.org\">@example:example.org</a><br><b>This is an example<br>text message</b></blockquote></mx-reply>reply",
+            "m.relates_to": {
+                "m.in_reply_to": {
+                    "event_id": "$153456789:example.org"
+                }
+            },
+            "msgtype": "m.text"
+        },
+        "origin_server_ts": 1690725965572,
+        "sender": "@alice:matrix.org",
+        "type": "m.room.message",
+        "unsigned": {
+            "age": 98
+        },
+        "event_id": "$154456789:example.org",
+        "room_id": "!jEsUZKDJdhlrceRyVU:example.org"
+      },
+      {
+        "content": {
+            "body": "> <@example:example.org> video caption\n\nreply",
+            "m.relates_to": {
+                "m.in_reply_to": {
+                    "event_id": "$263456789:example.org"
+                }
+            },
+            "msgtype": "m.text"
+        },
+        "origin_server_ts": 1690725965573,
+        "sender": "@alice:matrix.org",
+        "type": "m.room.message",
+        "unsigned": {
+            "age": 98
+        },
+        "event_id": "$154456799:example.org",
+        "room_id": "!jEsUZKDJdhlrceRyVU:example.org"
+      },
+      {
+        "age": 96845207,
+        "content": {
+            "body": "Lat: 51.7035, Lon: -1.14394",
+            "geo_uri": "geo:51.7035,-1.14394",
+            "msgtype": "m.location",
+            "org.matrix.msc1767.text": "Lat: 51.7035, Lon: -1.14394",
+            "org.matrix.msc3488.asset": {
+                "type": "m.pin"
+            },
+            "org.matrix.msc3488.location": {
+                "uri": "geo:51.7035,-1.14394"
+            }
+        },
+        "event_id": "$1544567999:example.org",
+        "origin_server_ts": 1690821582876,
+        "room_id": "!jEsUZKDJdhlrceRyVU:example.org",
+        "sender": "@example:example.org",
+        "type": "m.room.message",
+        "unsigned": {
+            "age": 96845207
+        }
+      },
+      {
+        "content": {
+          "body": "Thread root",
+          "format": "org.matrix.custom.html",
+          "msgtype": "m.text"
+        },
+        "event_id": "$threadroot:example.org",
+        "origin_server_ts": 1690821582879,
+        "room_id": "!jEsUZKDJdhlrceRyVU:example.org",
+        "sender": "@example:example.org",
+        "type": "m.room.message",
+        "unsigned": {
+          "age": 1232
+        }
+      },
+      {
+        "content": {
+          "body": "Thread message 1",
+          "msgtype": "m.text",
+          "m.relates_to": {
+                "rel_type": "m.thread",
+                "event_id": "$threadroot:example.org",
+                "m.in_reply_to": {
+                    "event_id": "$threadroot:example.org"
+                },
+                "is_falling_back": true
+            }
+        },
+        "event_id": "$threadmessage1:example.org",
+        "origin_server_ts": 1690821582890,
+        "room_id": "!jEsUZKDJdhlrceRyVU:example.org",
+        "sender": "@example:example.org",
+        "type": "m.room.message",
+        "unsigned": {
+          "age": 1238
+        }
+      },
+      {
+        "content": {
+          "body": "Thread message 2",
+          "msgtype": "m.text",
+          "m.relates_to": {
+                "rel_type": "m.thread",
+                "event_id": "$threadroot:example.org",
+                "m.in_reply_to": {
+                    "event_id": "$threadmessage1:example.org"
+                },
+                "is_falling_back": true
+            }
+        },
+        "event_id": "$threadmessage2:example.org",
+        "origin_server_ts": 1690821582890,
+        "room_id": "!jEsUZKDJdhlrceRyVU:example.org",
+        "sender": "@example:example.org",
+        "type": "m.room.message",
+        "unsigned": {
+          "age": 1238
+        }
+      }
+    ],
+    "limited": true,
+    "prev_batch": "t34-23535_0_0"
+  }
+}

autotests/eventhandlertest.cpp

@@ -64,6 +64,7 @@ private Q_SLOTS:
     void replyAuthor();
     void replyBody();
     void replyMediaInfo();
+    void thread();
     void location();
     void readMarkers();
 };
@@ -73,329 +74,11 @@ void EventHandlerTest::initTestCase()
     connection = Connection::makeMockConnection(QStringLiteral("@bob:kde.org"));
     room = new TestRoom(connection, QStringLiteral("#myroom:kde.org"), JoinState::Join);
 
-    const auto json = QJsonDocument::fromJson(R"EVENT({
+    QFile testEventHandlerSyncFile;
-  "account_data": {
+    testEventHandlerSyncFile.setFileName(QLatin1String(DATA_DIR) + u'/' + QLatin1String("test-eventhandler-sync.json"));
-    "events": [
+    testEventHandlerSyncFile.open(QIODevice::ReadOnly);
-      {
+    const auto testEventHandlerSyncJson = QJsonDocument::fromJson(testEventHandlerSyncFile.readAll());
-        "content": {
+    SyncRoomData roomData(QStringLiteral("@bob:kde.org"), JoinState::Join, testEventHandlerSyncJson.object());
-          "tags": {
-            "u.work": {
-              "order": 0.9
-            }
-          }
-        },
-        "type": "m.tag"
-      },
-      {
-        "content": {
-          "custom_config_key": "custom_config_value"
-        },
-        "type": "org.example.custom.room.config"
-      }
-    ]
-  },
-  "ephemeral": {
-    "events": [
-      {
-        "content": {
-          "user_ids": [
-            "@alice:matrix.org",
-            "@bob:example.com"
-          ]
-        },
-        "room_id": "!jEsUZKDJdhlrceRyVU:example.org",
-        "type": "m.typing"
-      },
-      {
-        "content": {
-          "$153456789:example.org": {
-            "m.read": {
-              "@alice:matrix.org": {
-                "ts": 1436451550453
-              }
-            }
-          }
-        },
-        "type": "m.receipt"
-      },
-      {
-        "content": {
-          "$1532735824654:example.org": {
-            "m.read": {
-              "@bob:example.com": {
-                "ts": 1436451550453
-              }
-            }
-          }
-        },
-        "type": "m.receipt"
-      },
-      {
-        "content": {
-          "$1532735824654:example.org": {
-            "m.read": {
-              "@tim:example.com": {
-                "ts": 1436451550454
-              }
-            }
-          }
-        },
-        "type": "m.receipt"
-      },
-      {
-        "content": {
-          "$1532735824654:example.org": {
-            "m.read": {
-              "@jeff:example.com": {
-                "ts": 1436451550455
-              }
-            }
-          }
-        },
-        "type": "m.receipt"
-      },
-      {
-        "content": {
-          "$1532735824654:example.org": {
-            "m.read": {
-              "@tina:example.com": {
-                "ts": 1436451550456
-              }
-            }
-          }
-        },
-        "type": "m.receipt"
-      },
-      {
-        "content": {
-          "$1532735824654:example.org": {
-            "m.read": {
-              "@sally:example.com": {
-                "ts": 1436451550457
-              }
-            }
-          }
-        },
-        "type": "m.receipt"
-      },
-      {
-        "content": {
-          "$1532735824654:example.org": {
-            "m.read": {
-              "@fred:example.com": {
-                "ts": 1436451550458
-              }
-            }
-          }
-        },
-        "type": "m.receipt"
-      }
-    ]
-  },
-  "state": {
-    "events": [
-      {
-        "content": {
-          "avatar_url": "mxc://example.org/SEsfnsuifSDFSSEF",
-          "displayname": "Alice Margatroid",
-          "membership": "join",
-          "reason": "Looking for support"
-        },
-        "event_id": "$143273582443PhrSn:example.org",
-        "origin_server_ts": 1432735824653,
-        "room_id": "!jEsUZKDJdhlrceRyVU:example.org",
-        "sender": "@example:example.org",
-        "state_key": "@alice:example.org",
-        "type": "m.room.member",
-        "unsigned": {
-          "age": 1234
-        }
-      }
-    ]
-  },
-  "summary": {
-    "m.heroes": [
-      "@alice:example.com",
-      "@bob:example.com"
-    ],
-    "m.invited_member_count": 0,
-    "m.joined_member_count": 2
-  },
-  "timeline": {
-    "events": [
-      {
-        "content": {
-          "body": "This is an example\ntext message",
-          "format": "org.matrix.custom.html",
-          "formatted_body": "<b>This is an example<br>text message</b>",
-          "msgtype": "m.text"
-        },
-        "event_id": "$153456789:example.org",
-        "origin_server_ts": 1432735824654,
-        "room_id": "!jEsUZKDJdhlrceRyVU:example.org",
-        "sender": "@example:example.org",
-        "type": "m.room.message",
-        "unsigned": {
-          "age": 1232
-        }
-      },
-      {
-        "content": {
-          "avatar_url": "mxc://kde.org/123456",
-          "displayname": "after",
-          "membership": "join"
-        },
-        "origin_server_ts": 1690651134736,
-        "sender": "@example:example.org",
-        "state_key": "@example:example.org",
-        "type": "m.room.member",
-        "unsigned": {
-          "replaces_state": "$1234567890:example.org",
-          "prev_content": {
-            "avatar_url": "mxc://kde.org/12345",
-            "displayname": "before",
-            "membership": "join"
-          },
-          "prev_sender": "@example:example.orgg",
-          "age": 1234
-        },
-        "event_id": "$143273583553PhrSn:example.org",
-        "room_id": "!jEsUZKDJdhlrceRyVU:example.org"
-      },
-      {
-        "content": {
-          "body": "This is a highlight @bob:kde.org and this is a link https://kde.org",
-          "format": "org.matrix.custom.html",
-          "msgtype": "m.text"
-        },
-        "event_id": "$1532735824654:example.org",
-        "origin_server_ts": 1532735824654,
-        "room_id": "!jEsUZKDJdhlrceRyVU:example.org",
-        "sender": "@example:example.org",
-        "type": "m.room.message",
-        "unsigned": {
-          "age": 1233
-        }
-      },
-      {
-        "content": {
-            "m.relates_to": {
-            "event_id": "$153456789:example.org",
-            "key": "👍",
-            "rel_type": "m.annotation"
-            }
-        },
-        "origin_server_ts": 1690322545182,
-        "room_id": "!jEsUZKDJdhlrceRyVU:example.org",
-        "sender": "@alice:matrix.org",
-        "type": "m.reaction",
-        "unsigned": {
-            "age": 390159120
-        },
-        "event_id": "$163456789:example.org",
-        "age": 390159120
-      },
-      {
-        "age": 4926305285,
-        "content": {
-            "body": "video caption",
-            "filename": "video.mp4",
-            "info": {
-                "duration": 10,
-                "h": 1080,
-                "mimetype": "video/mp4",
-                "size": 62650636,
-                "w": 1920,
-                "thumbnail_info": {
-                    "h": 450,
-                    "mimetype": "image/jpeg",
-                    "size": 382249,
-                    "w": 800
-                },
-                "thumbnail_url": "mxc://kde.org/2234567"
-            },
-            "msgtype": "m.video",
-            "url": "mxc://kde.org/1234567"
-        },
-        "event_id": "$263456789:example.org",
-        "origin_server_ts": 1685793783330,
-        "room_id": "!jEsUZKDJdhlrceRyVU:example.org",
-        "sender": "@example:example.org",
-        "type": "m.room.message",
-        "unsigned": {
-            "age": 4926305285
-        },
-        "user_id": "@example:example.org"
-      },
-      {
-        "content": {
-            "body": "> <@example:example.org> This is an example\ntext message\n\nreply",
-            "format": "org.matrix.custom.html",
-            "formatted_body": "<mx-reply><blockquote><a href=\"https://matrix.to/#/!jEsUZKDJdhlrceRyVU:example.org/$153456789:example.org?via=kde.org&via=matrix.org\">In reply to</a> <a href=\"https://matrix.to/#/@example:example.org\">@example:example.org</a><br><b>This is an example<br>text message</b></blockquote></mx-reply>reply",
-            "m.relates_to": {
-                "m.in_reply_to": {
-                    "event_id": "$153456789:example.org"
-                }
-            },
-            "msgtype": "m.text"
-        },
-        "origin_server_ts": 1690725965572,
-        "sender": "@alice:matrix.org",
-        "type": "m.room.message",
-        "unsigned": {
-            "age": 98
-        },
-        "event_id": "$154456789:example.org",
-        "room_id": "!jEsUZKDJdhlrceRyVU:example.org"
-      },
-      {
-        "content": {
-            "body": "> <@example:example.org> video caption\n\nreply",
-            "m.relates_to": {
-                "m.in_reply_to": {
-                    "event_id": "$263456789:example.org"
-                }
-            },
-            "msgtype": "m.text"
-        },
-        "origin_server_ts": 1690725965573,
-        "sender": "@alice:matrix.org",
-        "type": "m.room.message",
-        "unsigned": {
-            "age": 98
-        },
-        "event_id": "$154456799:example.org",
-        "room_id": "!jEsUZKDJdhlrceRyVU:example.org"
-      },
-      {
-        "age": 96845207,
-        "content": {
-            "body": "Lat: 51.7035, Lon: -1.14394",
-            "geo_uri": "geo:51.7035,-1.14394",
-            "msgtype": "m.location",
-            "org.matrix.msc1767.text": "Lat: 51.7035, Lon: -1.14394",
-            "org.matrix.msc3488.asset": {
-                "type": "m.pin"
-            },
-            "org.matrix.msc3488.location": {
-                "uri": "geo:51.7035,-1.14394"
-            }
-        },
-        "event_id": "$1544567999:example.org",
-        "origin_server_ts": 1690821582876,
-        "room_id": "!jEsUZKDJdhlrceRyVU:example.org",
-        "sender": "@example:example.org",
-        "type": "m.room.message",
-        "unsigned": {
-            "age": 96845207
-        }
-      }
-    ],
-    "limited": true,
-    "prev_batch": "t34-23535_0_0"
-  }
-})EVENT");
-    SyncRoomData roomData(QStringLiteral("@bob:kde.org"), JoinState::Join, json.object());
     room->update(std::move(roomData));
 
     eventHandler.setRoom(room);
@@ -686,6 +369,29 @@ void EventHandlerTest::replyMediaInfo()
     QCOMPARE(thumbnailInfo["height"_ls], 450);
 }
 
+void EventHandlerTest::thread()
+{
+    auto event = room->messageEvents().at(0).get();
+    eventHandler.setEvent(event);
+
+    QCOMPARE(eventHandler.isThreaded(), false);
+    QCOMPARE(eventHandler.threadRoot(), QString());
+
+    event = room->messageEvents().at(9).get();
+    eventHandler.setEvent(event);
+
+    QCOMPARE(eventHandler.isThreaded(), true);
+    QCOMPARE(eventHandler.threadRoot(), QStringLiteral("$threadroot:example.org"));
+    QCOMPARE(eventHandler.getReplyId(), QStringLiteral("$threadroot:example.org"));
+
+    event = room->messageEvents().at(10).get();
+    eventHandler.setEvent(event);
+
+    QCOMPARE(eventHandler.isThreaded(), true);
+    QCOMPARE(eventHandler.threadRoot(), QStringLiteral("$threadroot:example.org"));
+    QCOMPARE(eventHandler.getReplyId(), QStringLiteral("$threadmessage1:example.org"));
+}
+
 void EventHandlerTest::location()
 {
     auto event = room->messageEvents().at(7).get();

src/actionshandler.cpp

@@ -149,7 +149,7 @@ void ActionsHandler::handleMessage(const QString &text, QString handledText, Cha
         return;
     }
 
-    m_room->postMessage(text, handledText, messageType, chatBarCache->replyId(), chatBarCache->editId());
+    m_room->postMessage(text, handledText, messageType, chatBarCache->replyId(), chatBarCache->editId(), chatBarCache->threadId());
 }
 
 void ActionsHandler::checkEffects(const QString &text)

src/chatbarcache.cpp

@@ -51,6 +51,7 @@ void ChatBarCache::setReplyId(const QString &replyId)
     }
     m_attachmentPath = QString();
     Q_EMIT relationIdChanged();
+    Q_EMIT attachmentPathChanged();
 }
 
 bool ChatBarCache::isEditing() const
@@ -79,6 +80,7 @@ void ChatBarCache::setEditId(const QString &editId)
     }
     m_attachmentPath = QString();
     Q_EMIT relationIdChanged();
+    Q_EMIT attachmentPathChanged();
 }
 
 QVariantMap ChatBarCache::relationUser() const
@@ -121,6 +123,25 @@ QString ChatBarCache::relationMessage() const
     return {};
 }
 
+bool ChatBarCache::isThreaded() const
+{
+    return !m_threadId.isEmpty();
+}
+
+QString ChatBarCache::threadId() const
+{
+    return m_threadId;
+}
+
+void ChatBarCache::setThreadId(const QString &threadId)
+{
+    if (m_threadId == threadId) {
+        return;
+    }
+    m_threadId = threadId;
+    Q_EMIT threadIdChanged();
+}
+
 QString ChatBarCache::attachmentPath() const
 {
     return m_attachmentPath;
@@ -135,6 +156,7 @@ void ChatBarCache::setAttachmentPath(const QString &attachmentPath)
     m_relationType = None;
     m_relationId = QString();
     Q_EMIT attachmentPathChanged();
+    Q_EMIT relationIdChanged();
 }
 
 QList<Mention> *ChatBarCache::mentions()

src/chatbarcache.h

@@ -113,6 +113,16 @@ class ChatBarCache : public QObject
      */
     Q_PROPERTY(QString relationMessage READ relationMessage NOTIFY relationIdChanged)
 
+    /**
+     * @brief Whether the chat bar is replying in a thread.
+     */
+    Q_PROPERTY(bool isThreaded READ isThreaded NOTIFY threadIdChanged)
+
+    /**
+     * @brief The Matrix message ID of thread root event, if any.
+     */
+    Q_PROPERTY(QString threadId READ threadId WRITE setThreadId NOTIFY threadIdChanged)
+
     /**
      * @brief The local path for a file to send, if any.
      *
@@ -152,6 +162,10 @@ public:
 
     QString relationMessage() const;
 
+    bool isThreaded() const;
+    QString threadId() const;
+    void setThreadId(const QString &threadId);
+
     QString attachmentPath() const;
     void setAttachmentPath(const QString &attachmentPath);
 
@@ -173,12 +187,14 @@ public:
 Q_SIGNALS:
     void textChanged();
     void relationIdChanged();
+    void threadIdChanged();
     void attachmentPathChanged();
 
 private:
     QString m_text = QString();
     QString m_relationId = QString();
     RelationType m_relationType = RelationType::None;
+    QString m_threadId = QString();
     QString m_attachmentPath = QString();
     QList<Mention> m_mentions;
     QString m_savedText;

src/eventhandler.cpp

@@ -901,6 +901,28 @@ QVariantMap EventHandler::getReplyMediaInfo() const
     return getMediaInfoForEvent(replyPtr);
 }
 
+bool EventHandler::isThreaded() const
+{
+    return (m_event->contentPart<QJsonObject>("m.relates_to"_ls).contains("rel_type"_ls)
+            && m_event->contentPart<QJsonObject>("m.relates_to"_ls)["rel_type"_ls].toString() == "m.thread"_ls)
+        || (!m_event->unsignedPart<QJsonObject>("m.relations"_ls).isEmpty() && m_event->unsignedPart<QJsonObject>("m.relations"_ls).contains("m.thread"_ls));
+}
+
+QString EventHandler::threadRoot() const
+{
+    // Get the thread root ID from m.relates_to if it exists.
+    if (m_event->contentPart<QJsonObject>("m.relates_to"_ls).contains("rel_type"_ls)
+        && m_event->contentPart<QJsonObject>("m.relates_to"_ls)["rel_type"_ls].toString() == "m.thread"_ls) {
+        return m_event->contentPart<QJsonObject>("m.relates_to"_ls)["event_id"_ls].toString();
+    }
+    // For thread root events they have an m.relations in the unsigned part with a m.thread object.
+    // If so return the event ID as it is the root.
+    if (!m_event->unsignedPart<QJsonObject>("m.relations"_ls).isEmpty() && m_event->unsignedPart<QJsonObject>("m.relations"_ls).contains("m.thread"_ls)) {
+        return getId();
+    }
+    return {};
+}
+
 float EventHandler::getLatitude() const
 {
     const auto geoUri = m_event->contentJson()["geo_uri"_ls].toString();

src/eventhandler.h

@@ -326,6 +326,20 @@ public:
      */
     QVariantMap getReplyMediaInfo() const;
 
+    /**
+     * @brief Whether the message is part of a thread.
+     *
+     * i.e. There is a rel_type of m.thread.
+     */
+    bool isThreaded() const;
+
+    /**
+     * @brief Return the Matrix ID of the thread's root message.
+     *
+     * Empty if this not part of a thread.
+     */
+    QString threadRoot() const;
+
     /**
      * @brief Return the latitude for the event.
      *

src/models/messageeventmodel.cpp

@@ -47,6 +47,8 @@ QHash<int, QByteArray> MessageEventModel::roleNames() const
     roles[ReplyDelegateTypeRole] = "replyDelegateType";
     roles[ReplyDisplayRole] = "replyDisplay";
     roles[ReplyMediaInfoRole] = "replyMediaInfo";
+    roles[IsThreadedRole] = "isThreaded";
+    roles[ThreadRootRole] = "threadRoot";
     roles[ShowAuthorRole] = "showAuthor";
     roles[ShowSectionRole] = "showSection";
     roles[ReadMarkersRole] = "readMarkers";
@@ -586,6 +588,14 @@ QVariant MessageEventModel::data(const QModelIndex &idx, int role) const
         return eventHandler.getReplyMediaInfo();
     }
 
+    if (role == IsThreadedRole) {
+        return eventHandler.isThreaded();
+    }
+
+    if (role == ThreadRootRole) {
+        return eventHandler.threadRoot();
+    }
+
     if (role == ShowAuthorRole) {
         for (auto r = row + 1; r < rowCount(); ++r) {
             auto i = index(r);

src/models/messageeventmodel.h

@@ -63,6 +63,9 @@ public:
         ReplyDisplayRole, /**< The body of the message that was replied to. */
         ReplyMediaInfoRole, /**< The media info of the message that was replied to. */
 
+        IsThreadedRole,
+        ThreadRootRole,
+
         ShowAuthorRole, /**< Whether the author's name should be shown. */
         ShowSectionRole, /**< Whether the section header should be shown. */
 

src/neochatroom.cpp

@@ -526,20 +526,63 @@ QString msgTypeToString(MessageEventType msgType)
     }
 }
 
-void NeoChatRoom::postMessage(const QString &rawText, const QString &text, MessageEventType type, const QString &replyEventId, const QString &relateToEventId)
+void NeoChatRoom::postMessage(const QString &rawText,
+                              const QString &text,
+                              MessageEventType type,
+                              const QString &replyEventId,
+                              const QString &relateToEventId,
+                              const QString &threadRootId)
 {
-    postHtmlMessage(rawText, text, type, replyEventId, relateToEventId);
+    postHtmlMessage(rawText, text, type, replyEventId, relateToEventId, threadRootId);
 }
 
-void NeoChatRoom::postHtmlMessage(const QString &text, const QString &html, MessageEventType type, const QString &replyEventId, const QString &relateToEventId)
+void NeoChatRoom::postHtmlMessage(const QString &text,
+                                  const QString &html,
+                                  MessageEventType type,
+                                  const QString &replyEventId,
+                                  const QString &relateToEventId,
+                                  const QString &threadRootId)
 {
     bool isReply = !replyEventId.isEmpty();
     bool isEdit = !relateToEventId.isEmpty();
+    bool isThread = !threadRootId.isEmpty();
     const auto replyIt = findInTimeline(replyEventId);
     if (replyIt == historyEdge()) {
         isReply = false;
     }
 
+    if (isThread) {
+        EventHandler eventHandler;
+        eventHandler.setRoom(this);
+        eventHandler.setEvent(&**replyIt);
+
+        const bool isFallingBack = !eventHandler.isThreaded();
+
+        // clang-format off
+        QJsonObject json{
+          {"msgtype"_ls, msgTypeToString(type)},
+          {"body"_ls, text},
+          {"format"_ls, "org.matrix.custom.html"_ls},
+          {"m.relates_to"_ls,
+            QJsonObject {
+              {"rel_type"_ls, "m.thread"_ls},
+              {"event_id"_ls, threadRootId},
+              {"is_falling_back"_ls, isFallingBack},
+              {"m.in_reply_to"_ls,
+                QJsonObject {
+                  {"event_id"_ls, replyEventId}
+                }
+              }
+            }
+          },
+          {"formatted_body"_ls, html}
+        };
+        // clang-format on
+
+        postJson("m.room.message"_ls, json);
+        return;
+    }
+
     if (isEdit) {
         QJsonObject json{
             {"type"_ls, "m.room.message"_ls},

src/neochatroom.h

@@ -884,7 +884,8 @@ public Q_SLOTS:
                      const QString &cleanedText,
                      Quotient::MessageEventType type = Quotient::MessageEventType::Text,
                      const QString &replyEventId = QString(),
-                     const QString &relateToEventId = QString());
+                     const QString &relateToEventId = QString(),
+                     const QString &threadRootId = QString());
 
     /**
      * @brief Send an html message to the room.
@@ -899,7 +900,8 @@ public Q_SLOTS:
                          const QString &html,
                          Quotient::MessageEventType type = Quotient::MessageEventType::Text,
                          const QString &replyEventId = QString(),
-                         const QString &relateToEventId = QString());
+                         const QString &relateToEventId = QString(),
+                         const QString &threadRootId = QString());
 
     /**
      * @brief Set the room avatar.

src/qml/HoverActions.qml

@@ -105,6 +105,16 @@ QQC2.Control {
                         root.currentRoom.editCache.editId = "";
                         root.focusChatBar();
                     }
+                },
+                Kirigami.Action {
+                    text: i18n("Reply in Thread")
+                    icon.name: "dialog-messages"
+                    onTriggered: {
+                        root.currentRoom.mainCache.replyId = root.delegate.eventId;
+                        root.currentRoom.mainCache.threadId = root.delegate.isThreaded ? root.delegate.threadRoot : root.delegate.eventId;
+                        root.currentRoom.editCache.editId = "";
+                        root.focusChatBar();
+                    }
                 }
             ]
 

src/qml/MessageDelegate.qml

@@ -187,6 +187,10 @@ TimelineDelegate {
      */
     required property var replyMediaInfo
 
+    required property bool isThreaded
+
+    required property string threadRoot
+
     /**
      * @brief Whether this message is replying to another.
      */