ask to join when room id is unknown

src/domain/session/RoomViewModelObservable.js

@@ -65,6 +65,8 @@ export class RoomViewModelObservable extends ObservableValue {
             return this._sessionViewModel._createRoomViewModel(this.id);
         } else if (status.archived) {
             return await this._sessionViewModel._createArchivedRoomViewModel(this.id);
+        } else {
+            return this._sessionViewModel._createUnknownRoomViewModel(this.id);
         }
         return null;
     }

src/domain/session/SessionViewModel.js

@@ -17,6 +17,7 @@ limitations under the License.
 
 import {LeftPanelViewModel} from "./leftpanel/LeftPanelViewModel.js";
 import {RoomViewModel} from "./room/RoomViewModel.js";
+import {UnknownRoomViewModel} from "./room/UnknownRoomViewModel.js";
 import {InviteViewModel} from "./room/InviteViewModel.js";
 import {LightboxViewModel} from "./room/LightboxViewModel.js";
 import {SessionStatusViewModel} from "./SessionStatusViewModel.js";
@@ -162,6 +163,13 @@ export class SessionViewModel extends ViewModel {
         return null;
     }
 
+    _createUnknownRoomViewModel(roomIdOrAlias) {
+        return new UnknownRoomViewModel(this.childOptions({
+            roomIdOrAlias,
+            session: this._sessionContainer.session,
+        }));
+    }
+
     async _createArchivedRoomViewModel(roomId) {
         const room = await this._sessionContainer.session.loadArchivedRoom(roomId);
         if (room) {

src/domain/session/room/UnknownRoomViewModel.js

@@ -0,0 +1,59 @@
+/*
+Copyright 2020 Bruno Windels <bruno@windels.cloud>
+Copyright 2020 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import {ViewModel} from "../../ViewModel.js";
+
+export class UnknownRoomViewModel extends ViewModel {
+    constructor(options) {
+        super(options);
+        const {roomIdOrAlias, session} = options;
+        this._session = session;
+        this._roomIdOrAlias = roomIdOrAlias;
+        this._error = null;
+        this._busy = false;
+    }
+
+    get error() {
+        return this._error?.message;
+    }
+
+    get description() {
+        return this.i18n`You are currently not in ${this._roomIdOrAlias}. Want to join it?`;
+    }
+
+    async join() {
+        this._busy = true;
+        this.emitChange("busy");
+        try {
+            const roomId = await this._session.joinRoom(this._roomIdOrAlias);
+            // navigate to roomId if we were at the alias
+            this.navigation.push("room", roomId);
+        } catch (err) {
+            this._error = err;
+            this._busy = false;
+            this.emitChange("error");
+        }
+    }
+
+    get busy() {
+        return this._busy;
+    }
+
+    get kind() {
+        return "unknown";
+    }
+}

src/platform/web/ui/session/SessionView.js

@@ -17,6 +17,7 @@ limitations under the License.
 
 import {LeftPanelView} from "./leftpanel/LeftPanelView.js";
 import {RoomView} from "./room/RoomView.js";
+import {UnknownRoomView} from "./room/UnknownRoomView.js";
 import {InviteView} from "./room/InviteView.js";
 import {LightboxView} from "./room/LightboxView.js";
 import {TemplateView} from "../general/TemplateView.js";
@@ -43,8 +44,10 @@ export class SessionView extends TemplateView {
                 } else if (vm.currentRoomViewModel) {
                     if (vm.currentRoomViewModel.kind === "invite") {
                         return new InviteView(vm.currentRoomViewModel);
-                    } else {
+                    } else if (vm.currentRoomViewModel.kind === "room") {
                         return new RoomView(vm.currentRoomViewModel);
+                    } else {
+                        return new UnknownRoomView(vm.currentRoomViewModel);
                     }
                 } else {
                     return new StaticView(t => t.div({className: "room-placeholder"}, t.h2(vm.i18n`Choose a room on the left side.`)));

src/platform/web/ui/session/room/UnknownRoomView.js

@@ -0,0 +1,38 @@
+/*
+Copyright 2020 Bruno Windels <bruno@windels.cloud>
+Copyright 2020 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import {TemplateView} from "../../general/TemplateView.js";
+import {Popup} from "../../general/Popup.js";
+import {Menu} from "../../general/Menu.js";
+import {TimelineList} from "./TimelineList.js";
+import {TimelineLoadingView} from "./TimelineLoadingView.js";
+import {MessageComposer} from "./MessageComposer.js";
+import {RoomArchivedView} from "./RoomArchivedView.js";
+import {AvatarView} from "../../avatar.js";
+
+export class UnknownRoomView extends TemplateView {
+    render(t, vm) {
+        return t.main({className: "UnknownRoomView middle"}, [
+            t.h2(vm.description),
+            t.div(t.button({
+                className: "button-action primary",
+                onClick: () => vm.join(),
+                disabled: vm => vm.busy,
+            }, vm.i18n`Join room`))
+        ]);
+    }
+}